context.cxx

#include <cgv/base/group.h>
#include "context.h"
#include <cgv/media/image/image_writer.h>
#include <cgv/math/ftransform.h>
#include <cgv/base/traverser.h>
#include <cgv/render/drawable.h>
#include <cgv/render/shader_program.h>
 
using namespace cgv::base;
using namespace cgv::media::image;
 
#define SAFE_STACK_POP(STACK, WHERE) \
if(STACK.size() == 1) error("context::" WHERE "() ... attempt to completely empty stack avoided."); \
else STACK.pop();
 
namespace cgv {
    namespace render {
 
        
const int nr_backgrounds = 5;
float background_colors[] = {
    0,0,0,0,
    1.0f, 0.4f, 0.5f,0,
    0.4f, 1, 0.7f,0,
    0.5f, 0.5f, 1,0,
    1,1,1,0,
};
 
 
context_config::context_config()
{
    depth_buffer = true;
    double_buffer = true;
    alpha_buffer = true;
    stencil_bits = -1;
    accumulation_bits = -1;
    depth_bits = -1;
    forward_compatible = false;
    stencil_buffer = false;
    accumulation_buffer = false;
    multi_sample_buffer = false;
    stereo_buffer = false;
 
#ifdef _DEBUG
    debug = true;
#else
    debug = false;
#endif
    core_profile = true;
    accumulation_bits = 0;
    version_major = -1;
    version_minor = -1;
    nr_multi_samples = -1;
}
 
bool context::recreate_context()
{
    return false;
}
 
bool context_config::self_reflect(cgv::reflect::reflection_handler& srh)
{
    return
        srh.reflect_member("version_major", version_major) &&
        srh.reflect_member("version_minor", version_minor) &&
        srh.reflect_member("core_profile", core_profile) &&
        srh.reflect_member("debug", debug) &&
        srh.reflect_member("double_buffer", context_config::double_buffer) &&
        srh.reflect_member("alpha_buffer", alpha_buffer) &&
        srh.reflect_member("stencil_buffer", stencil_buffer) &&
        srh.reflect_member("depth_buffer", depth_buffer) &&
        srh.reflect_member("depth_bits", depth_bits) &&
        srh.reflect_member("stencil_bits", stencil_bits) &&
        srh.reflect_member("accumulation_buffer", accumulation_buffer) &&
        srh.reflect_member("accumulation_bits", accumulation_bits) &&
        srh.reflect_member("multi_sample_buffer", multi_sample_buffer) &&
        srh.reflect_member("nr_multi_samples", nr_multi_samples) &&
        srh.reflect_member("stereo_buffer", stereo_buffer);
}
 
render_config::render_config()
{
    fullscreen_monitor = -1;
    window_width = 640;
    window_height = 480;
    abort_on_error = false;;
    dialog_on_error = true;
    show_error_on_console = true;
}
 
std::string render_config::get_type_name() const
{
    return "render_config";
}
 
bool render_config::self_reflect(cgv::reflect::reflection_handler& srh)
{
    return
        context_config::self_reflect(srh) &&
        srh.reflect_member("fullscreen_monitor", fullscreen_monitor) &&
        srh.reflect_member("window_width", window_width) &&
        srh.reflect_member("window_height", window_height) &&
        srh.reflect_member("abort_on_error", abort_on_error) &&
        srh.reflect_member("dialog_on_error", dialog_on_error) &&
        srh.reflect_member("show_error_on_console", show_error_on_console);
}
 
render_config_ptr get_render_config()
{
    static render_config_ptr rcp = new render_config();
    return rcp;
}
 
context::context()
{
    *static_cast<context_config*>(this) = *get_render_config();
 
    gpu_vendor = GPU_VENDOR_UNKNOWN;
 
    current_background = 0;
    bg_color_stack.push(vec4(0.0f));
    bg_depth_stack.push(1.0f);
    bg_stencil_stack.push(0);
    bg_accum_color_stack.push(vec4(0.0f));
 
    DepthTestState depth_test_state;
    depth_test_state.enabled = false;
    depth_test_state.test_func = CF_LESS;
    depth_test_state_stack.push(depth_test_state);
 
    cull_state_stack.push(CM_OFF);
 
    BlendState blend_state;
    blend_state.enabled = false;
    blend_state.src_color = BF_ONE;
    blend_state.src_alpha = BF_ONE;
    blend_state.dst_color = BF_ZERO;
    blend_state.dst_alpha = BF_ZERO;
    blend_state_stack.push(blend_state);
 
    BufferMask buffer_mask;
    buffer_mask.depth_flag = true;
    buffer_mask.red_flag = true;
    buffer_mask.green_flag = true;
    buffer_mask.blue_flag = true;
    buffer_mask.alpha_flag = true;
    buffer_mask_stack.push(buffer_mask);
 
    static frame_buffer_base fbb;
    frame_buffer_stack.push(&fbb);
    modelview_matrix_stack.push(cgv::math::identity4<double>());
    projection_matrix_stack.push(cgv::math::identity4<double>());
    window_transformation_stack.push(std::vector<window_transformation>());
    window_transformation wt;
    wt.viewport = ivec4(0, 0, 640, 480);
    wt.depth_range = dvec2(0, 1);
    window_transformation_stack.top().push_back(wt);
 
    x_offset = 10;
    y_offset = 20;
    tab_size = 5;
    cursor_x = x_offset;
    cursor_y = y_offset;
    nr_identations = 0;
    at_line_begin = true;
    enable_vsync = true;
    current_color = rgba(1, 1, 1, 1);
    sRGB_framebuffer = false;
    gamma3 = vec3(2.2f);
 
    default_render_flags = RenderPassFlags(RPF_DEFAULT);
    
    current_font_size = 14;
    
    phong_shading = true;
 
    do_screen_shot = false;
    light_source_handle = 1;
 
    use_shader_file_cache = true;
    auto_set_view_in_current_shader_program = true;
    auto_set_gamma_in_current_shader_program = true;
    auto_set_lights_in_current_shader_program = true;
    auto_set_material_in_current_shader_program = true;
    support_compatibility_mode = true;
    draw_in_compatibility_mode = false;
    debug_render_passes = false;
 
    default_light_source[0].set_local_to_eye(true);
    default_light_source[0].set_position(vec3(-0.4f, 0.3f, 0.8f));
    default_light_source[0].set_emission(rgb(0.74f));
    default_light_source[0].set_ambient_scale(0.07f);
    default_light_source[1].set_local_to_eye(true);
    default_light_source[1].set_position(vec3(0.0f, 1.0f, 0.0f));
    default_light_source[1].set_emission(rgb(0.74f));
    default_light_source[1].set_ambient_scale(0.07f);
    default_light_source_handles[0] = 0;
    default_light_source_handles[1] = 0;
 
    current_material_ptr = 0;
    current_material_is_textured = false;
}
 
void context::error(const std::string& message, const render_component* rc) const
{
    if (rc)
        rc->last_error = message;
    if (get_render_config()->show_error_on_console)
        std::cerr << message << std::endl;
    if (get_render_config()->abort_on_error)
        abort();
}
 
GPUVendorID context::get_gpu_vendor_id() const
{
    return gpu_vendor;
}
 
const device_capabilities& context::get_device_capabilities() const {
    return gpu_capabilities;
}
 
context::~context()
{
}
 
void context::init_render_pass()
{
}
 
void context::draw_textual_info()
{
}
 
void context::perform_screen_shot()
{
}
 
void context::destruct_render_objects()
{
 
}
 
void context::finish_render_pass()
{
}
 
 
void context::configure_new_child(base_ptr child)
{
    if (is_created()) {
        make_current();
 
        // use last traverser constructor argument to ensure that set_context and init are also called on hidden drawables
 
        single_method_action<cgv::render::drawable,void,cgv::render::context*> sma(this, &drawable::set_context);
        traverser(sma, "nc", cgv::base::TS_DEPTH_FIRST, false, true).traverse(child);
 
        single_method_action<cgv::render::drawable,bool,cgv::render::context&> sma1(*this, &drawable::init);
        if (!traverser(sma1, "nc", cgv::base::TS_DEPTH_FIRST, false, true).traverse(child)) 
            error(child->get_type_name()+"::init(context&) failed");
 
        post_redraw();
    }
}
 
void context::push_bg_color() {
    bg_color_stack.push(get_bg_color());
}
 
void context::pop_bg_color() {
    SAFE_STACK_POP(bg_color_stack, "pop_bg_color");
    set_bg_color(get_bg_color());
}
 
void context::set_bg_color(vec4 rgba) {
    bg_color_stack.top() = rgba;
}
 
void context::set_bg_color(float r, float g, float b, float a)
{
    set_bg_color(vec4(r, g, b, a));
}
 
vec4 context::get_bg_color() const {
    return bg_color_stack.top();
}
 
void context::put_bg_color(float* rgba) const {
    auto& c = bg_color_stack.top();
    rgba[0] = c[0];
    rgba[1] = c[1];
    rgba[2] = c[2];
    rgba[3] = c[3];
}
 
void context::set_bg_alpha(float a)
{
    bg_color_stack.top()[3] = a;
}
 
float context::get_bg_alpha() const {
    return bg_color_stack.top()[3];
}
 
void context::set_bg_clr_idx(unsigned int idx) {
    current_background = idx;
    if(idx == -1)
        current_background = nr_backgrounds - 1;
    else if(current_background >= nr_backgrounds)
        current_background = 0;
    set_bg_color(background_colors[4 * current_background], background_colors[4 * current_background + 1], background_colors[4 * current_background + 2], background_colors[4 * current_background + 3]);
}
 
unsigned int context::get_bg_clr_idx() const {
    return current_background;
}
 
void context::push_bg_depth() {
    bg_depth_stack.push(get_bg_depth());
}
 
void context::pop_bg_depth() {
    SAFE_STACK_POP(bg_depth_stack, "pop_bg_depth");
    set_bg_depth(get_bg_depth());
}
 
void context::set_bg_depth(float d) {
    bg_depth_stack.top() = d;
}
 
float context::get_bg_depth() const {
    return bg_depth_stack.top();
}
 
void context::push_bg_stencil() {
    bg_stencil_stack.push(get_bg_stencil());
}
 
void context::pop_bg_stencil() {
    SAFE_STACK_POP(bg_stencil_stack, "pop_bg_stencil");
    set_bg_stencil(get_bg_stencil());
}
 
void context::set_bg_stencil(int s) {
    bg_stencil_stack.top() = s;
}
 
int context::get_bg_stencil() const {
    return bg_stencil_stack.top();
}
 
void context::push_bg_accum_color() {
    bg_accum_color_stack.push(get_bg_accum_color());
}
 
void context::pop_bg_accum_color() {
    SAFE_STACK_POP(bg_accum_color_stack, "pop_bg_accum_color");
    set_bg_accum_color(get_bg_accum_color());
}
 
void context::set_bg_accum_color(vec4 rgba) {
    bg_accum_color_stack.top() = rgba;
}
 
void context::set_bg_accum_color(float r, float g, float b, float a) {
    set_bg_accum_color(vec4(r, g, b, a));
}
 
vec4 context::get_bg_accum_color() const {
    return bg_accum_color_stack.top();
}
 
void context::put_bg_accum_color(float* rgba) const {
    auto& c = bg_accum_color_stack.top();
    rgba[0] = c[0];
    rgba[1] = c[1];
    rgba[2] = c[2];
    rgba[3] = c[3];
}
 
void context::set_bg_accum_alpha(float a) {
    bg_accum_color_stack.top()[3] = a;
}
 
float context::get_bg_accum_alpha() const {
    return bg_accum_color_stack.top()[3];
}
 
void context::enable_phong_shading()
{
    phong_shading = true;
    error("context::enable_phong_shading() deprecated");
}
 
void context::disable_phong_shading()
{
    phong_shading = false;
    error("context::disable_phong_shading() deprecated");
}
 
void context::enable_material(const cgv::media::illum::phong_material& mat, MaterialSide ms, float alpha)
{
    error("context::enable_material(phong_material) deprecated");
 
}
void context::disable_material(const cgv::media::illum::phong_material& mat)
{
    error("context::disable_material(phong_material) deprecated");
}
void context::enable_material(const textured_material& mat, MaterialSide ms, float alpha)
{
    error("context::enable_material(textured_material) deprecated");
}
 
void context::enable_sRGB_framebuffer(bool do_enable)
{
    sRGB_framebuffer = do_enable;
}
 
shader_program_base* context::get_current_program() const
{
    if (shader_program_stack.empty()) {
        //error("context::get_current_program() called in core profile without current shader program");
        return 0;
    }
    shader_program_base& prog = *shader_program_stack.top();
    return &prog;
}
 
void context::enable_shader_file_cache()
{
    use_shader_file_cache = true;
}
 
void context::disable_shader_file_cache()
{
    use_shader_file_cache = false;
}
 
bool context::is_shader_file_cache_enabled() const
{
    return use_shader_file_cache;
}
 
size_t context::get_nr_light_sources() const 
{
    return light_sources.size(); 
}
 
vec3 context::get_light_eye_position(const cgv::media::illum::light_source& light, bool place_now) const
{
    vec3 Le = light.get_position();
    if (place_now && !light.is_local_to_eye()) {
        dvec4 hL(Le, light.get_type() == cgv::media::illum::LT_DIRECTIONAL ? 0.0f : 1.0f);
        hL = get_modelview_matrix()*hL;
        Le = (const dvec3&)hL;
        if (light.get_type() != cgv::media::illum::LT_DIRECTIONAL)
            Le /= float(hL(3));
    }
    return Le;
}
 
vec3 context::get_light_eye_spot_direction(const cgv::media::illum::light_source& light, bool place_now) const
{
    vec3 sd = light.get_spot_direction();
    if (place_now && !light.is_local_to_eye()) {
        dvec4 hSd(sd, 0.0f);
        hSd = get_modelview_matrix()*hSd;
        sd = (const dvec3&)hSd;
    }
    float norm = sd.length();
    if (norm > 1e-8f)
        sd /= norm;
    return sd;
}
 
void* context::add_light_source(const cgv::media::illum::light_source& light, bool enabled, bool place_now)
{
    // construct new light source handle
    ++light_source_handle;
    void* handle = reinterpret_cast<void*>(light_source_handle);
    // determine light source position
    vec3 Le = get_light_eye_position(light, place_now);
    vec3 sd = get_light_eye_spot_direction(light, place_now);
    //
    int idx = -1;
    if (enabled) {
        idx = int(enabled_light_source_handles.size());
        enabled_light_source_handles.push_back(handle);
    }
    // store new light source in map
    light_sources[handle] = std::pair<cgv::media::illum::light_source, light_source_status>(
        light, { enabled, Le, sd, idx });
    // set light sources in shader code if necessary
    if (enabled)
        on_lights_changed();
    // return handle of new light source
    return handle;
}
bool context::remove_light_source(void* handle)
{
    // find handle in map
    auto iter = light_sources.find(handle);
    if (iter == light_sources.end())
        return false;
    // check if light source was enabled
    if (iter->second.second.enabled) {
        // then remove from list of enabled light sources
        enabled_light_source_handles.erase(enabled_light_source_handles.begin() + iter->second.second.light_source_index);
        // and correct indices of moved light sources
        for (int i = iter->second.second.light_source_index; i < (int)enabled_light_source_handles.size(); ++i)
            light_sources[enabled_light_source_handles[i]].second.light_source_index = i;
        on_lights_changed();
    }
    // remove from map
    light_sources.erase(iter);
    return true;
}
const cgv::media::illum::light_source& context::get_light_source(void* handle) const
{
    const auto iter = light_sources.find(handle);
    return iter->second.first;
}
 
const context::light_source_status& context::get_light_source_status(void* handle) const
{
    const auto iter = light_sources.find(handle);
    return iter->second.second;
}
 
 
void context::set_light_source(void* handle, const cgv::media::illum::light_source& light, bool place_now)
{
    auto iter = light_sources.find(handle);
    iter->second.first = light;
    if (place_now)
        place_light_source(handle);
    else {
        if (iter->second.second.enabled)
            on_lights_changed();
    }
}
 
void context::set_current_view(shader_program& prog, bool modelview_deps, bool projection_deps) const
{
    if (modelview_deps) {
        cgv::math::fmat<float, 4, 4> V(modelview_matrix_stack.top());
        prog.set_uniform(*this, "modelview_matrix", V);
        prog.set_uniform(*this, "inverse_modelview_matrix", inv(V));
        cgv::math::fmat<float, 3, 3> NM;
        NM(0, 0) = V(0, 0);
        NM(0, 1) = V(0, 1);
        NM(0, 2) = V(0, 2);
        NM(1, 0) = V(1, 0);
        NM(1, 1) = V(1, 1);
        NM(1, 2) = V(1, 2);
        NM(2, 0) = V(2, 0);
        NM(2, 1) = V(2, 1);
        NM(2, 2) = V(2, 2);
        NM.transpose();
        prog.set_uniform(*this, "inverse_normal_matrix", NM);
        NM = inv(NM);
        prog.set_uniform(*this, "normal_matrix", NM);
    }
    if (projection_deps) {
        cgv::math::fmat<float, 4, 4> P(projection_matrix_stack.top());
        prog.set_uniform(*this, "projection_matrix", P);
        prog.set_uniform(*this, "inverse_projection_matrix", inv(P));
    }
}
 
void context::set_current_material(shader_program& prog) const
{
    if (!current_material_ptr)
        return;
 
    prog.set_material_uniform(*this, "material", *current_material_ptr);
    if (current_material_is_textured) {
 
    }
}
 
void context::set_current_lights(shader_program& prog) const
{
    size_t nr_lights = get_nr_enabled_light_sources();
    for (size_t i = 0; i < nr_lights; ++i) {
        std::string prefix = std::string("light_sources[") + cgv::utils::to_string(i) + "]";
        void* light_source_handle = get_enabled_light_source_handle(i);
        const auto iter = light_sources.find(light_source_handle);
        if (prog.set_light_uniform(*this, prefix, iter->second.first)) {
            prog.set_uniform(*this, prefix + ".position", iter->second.second.eye_position);
            prog.set_uniform(*this, prefix + ".spot_direction", iter->second.second.eye_spot_direction);
        }
    }
    prog.set_uniform(*this, "nr_light_sources", (int)nr_lights);
}
 
void context::on_lights_changed()
{
    if (!auto_set_lights_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
 
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_use_lights())
        return;
 
    set_current_lights(prog);
}
 
void context::place_light_source(void* handle)
{
    auto iter = light_sources.find(handle);
    // determine light source position
    iter->second.second.eye_position = get_light_eye_position(iter->second.first, true);
    iter->second.second.eye_spot_direction = get_light_eye_spot_direction(iter->second.first, true);
    if (iter->second.second.enabled)
        on_lights_changed();
}
 
unsigned context::get_max_nr_enabled_light_sources() const
{
    return 8;
}
 
size_t context::get_nr_enabled_light_sources() const
{
    return enabled_light_source_handles.size();
}
 
void* context::get_enabled_light_source_handle(size_t i) const
{
    return enabled_light_source_handles[i];
}
bool context::is_light_source_enabled(void* handle)
{
    auto iter = light_sources.find(handle);
    if (iter == light_sources.end())
        return false;
    return iter->second.second.enabled;
}
 
bool context::enable_light_source(void* handle)
{
    auto iter = light_sources.find(handle);
    if (iter == light_sources.end())
        return false;
    if (iter->second.second.enabled)
        return true;
    iter->second.second.enabled = true;
    iter->second.second.light_source_index = int(enabled_light_source_handles.size());
    enabled_light_source_handles.push_back(handle);
    on_lights_changed();
    return true;
}
 
bool context::disable_light_source(void* handle)
{
    auto iter = light_sources.find(handle);
    if (iter == light_sources.end())
        return false;
    if (!iter->second.second.enabled)
        return true;
    iter->second.second.enabled = false;
    enabled_light_source_handles.erase(enabled_light_source_handles.begin()+iter->second.second.light_source_index);
    for (int i= iter->second.second.light_source_index; i < (int)enabled_light_source_handles.size(); ++i)
        light_sources[enabled_light_source_handles[i]].second.light_source_index = i;
    iter->second.second.light_source_index = -1;
    on_lights_changed();
    return true;
 
}
const cgv::media::illum::light_source& context::get_default_light_source(size_t i) const
{
    return default_light_source[i];
}
 
void context::set_default_light_source(size_t i, const cgv::media::illum::light_source& ls)
{
    default_light_source[i] = ls;
}
 
std::string get_render_pass_name(RenderPass rp)
{
    const char* render_pass_names[] = {
    "RP_NONE",
    "RP_MAIN",                 
    "RP_STEREO",               
    "RP_SHADOW_MAP",           
    "RP_SHADOW_VOLUME",        
    "RP_OPAQUE_SURFACES",      
    "RP_TRANSPARENT_SURFACES", 
    "RP_PICK",                 
    "RP_USER_DEFINED"
    };
    return render_pass_names[rp];
};
 
unsigned context::get_render_pass_recursion_depth() const
{
    return (unsigned)render_pass_stack.size();
}
 
RenderPass context::get_render_pass() const
{
    if (render_pass_stack.empty())
        return RP_NONE;
    return render_pass_stack.top().pass;
}
RenderPassFlags context::get_render_pass_flags() const
{
    if (render_pass_stack.empty())
        return RPF_NONE;
    return render_pass_stack.top().flags;
}
 
RenderPassFlags context::get_default_render_pass_flags() const
{
    return default_render_flags;
}
void context::set_default_render_pass_flags(RenderPassFlags rpf)
{
    default_render_flags = rpf;
    if (!in_render_process())
        post_redraw();
}
 
void* context::get_render_pass_user_data() const
{
    return render_pass_stack.top().user_data;
}
 
void context::set_debug_render_passes(bool _debug)
{
    debug_render_passes = _debug;
}
 
void context::render_pass_debug_output(const render_info& ri, const std::string& info)
{
    if (!debug_render_passes)
        return;
    std::cout 
        << std::string(2 * (render_pass_stack.size()-1), ' ')
        << get_render_pass_name(ri.pass) << " <"
        << ri.user_data;
    if (ri.pass_index != -1)
        std::cout << ":" << ri.pass_index;
    std::cout << "> " << info << std::endl;
}
 
void context::render_pass(RenderPass rp, RenderPassFlags rpf, void* user_data, int rp_idx)
{
    // ensure that default light sources are created
    if (default_light_source_handles[0] == 0) {
        for (unsigned i=0; i<nr_default_light_sources; ++i)
            default_light_source_handles[i] = add_light_source(default_light_source[i], false, false);
    }
    render_info ri;
    ri.pass  = rp;
    ri.flags = rpf;
    ri.user_data = user_data;
    ri.pass_index = rp_idx;
    render_pass_stack.push(ri);
    render_pass_debug_output(ri, "init");
    init_render_pass();
    if (get_render_pass_flags()&RPF_SET_LIGHTS) {
        for (unsigned i = 0; i < nr_default_light_sources; ++i)
            place_light_source(default_light_source_handles[i]);
    }
 
    group* grp = dynamic_cast<group*>(this);
    if (grp && (rpf&RPF_DRAWABLES_DRAW)) {
        render_pass_debug_output(ri, "draw+finish_draw");
        matched_method_action<drawable,void,void,context&>
            mma(*this, &drawable::draw, &drawable::finish_draw, true, true);
        traverser(mma).traverse(group_ptr(grp));
    }
    if (rpf & RPF_DRAW_TEXTUAL_INFO) {
        render_pass_debug_output(ri, "textual_info");
        draw_textual_info();
    }
    if (grp && (rpf&RPF_DRAWABLES_FINISH_FRAME)) {
        render_pass_debug_output(ri, "finish_frame");
        single_method_action<drawable,void,context&>
            sma(*this, &drawable::finish_frame, true, true);
        traverser(sma).traverse(group_ptr(grp));
    }
    if (grp && (rpf&RPF_DRAWABLES_AFTER_FINISH)) {
        render_pass_debug_output(ri, "after_finish");
        single_method_action<drawable,void,context&>
            sma(*this, &drawable::after_finish, true, true);
        traverser(sma).traverse(group_ptr(grp));
    }
    if ((rpf&RPF_HANDLE_SCREEN_SHOT) && do_screen_shot) {
        render_pass_debug_output(ri, "screenshot");
        perform_screen_shot();
        do_screen_shot = false;
    }
    render_pass_debug_output(ri, "finish render pass");
    finish_render_pass();
    render_pass_stack.pop();
}
 
void context::process_text(const std::string& text)
{
    push_pixel_coords();
    unsigned int i, j = 0;
    for (i = 0; i<text.size(); ++i) {
        int n = i-j;
        switch (text[i]) {
        case '\a' :
            draw_text(text.substr(j,n));
            ++nr_identations;
            if (at_line_begin)
                cursor_x += (int)(tab_size*current_font_size);
            j = i+1;
            break;
        case '\b' :
            draw_text(text.substr(j,n));
            if (nr_identations > 0) {
                --nr_identations;
                if (at_line_begin)
                    cursor_x -= (int)(tab_size*current_font_size);
            }
            j = i+1;
            break;
        case '\t' :
            draw_text(text.substr(j,n));
            cursor_x = (((cursor_x-x_offset)/(int)(tab_size*current_font_size))+1)*(int)(tab_size*current_font_size)+x_offset;
            at_line_begin = false;
            j = i+1;
            break;
        case '\n' :
            draw_text(text.substr(j,n));
            cursor_x = x_offset+(int)(nr_identations*tab_size*current_font_size);
            cursor_y -= (int)(1.2f*current_font_size);
            at_line_begin = true;
            j = i+1;
            break;
        default:
            at_line_begin = false;
        }
    }   
    draw_text(text.substr(j,i-j));
    pop_pixel_coords();
}
 
void context::draw_text(const std::string& text)
{
    if (current_font_face.empty())
        return;
    float x = (float)cursor_x;
    float y = (float)cursor_y;
    current_font_face->draw_text(x, y, text);
    cursor_x = int(x + 0.5f);
    cursor_y = int(y + 0.5f);
}
 
 
std::ostream& context::output_stream()
{
    return out_stream;
}
 
void context::enable_font_face(media::font::font_face_ptr font_face, float font_size)
{
    if (!(font_face == current_font_face) || font_size != current_font_size) {
        font_face->enable(this, font_size);
        current_font_face = font_face;
        current_font_size = font_size;
    }
}
 
float context::get_current_font_size() const
{
    return current_font_size;
}
 
cgv::media::font::font_face_ptr context::get_current_font_face() const
{
    return current_font_face;
}
 
 
bool context::write_frame_buffer_to_image(const std::string& file_name, cgv::data::ComponentFormat cf,
                                                        FrameBufferType buffer_type, unsigned int x, unsigned int y, int w, int h,
                                                        float depth_offset, float depth_scale)
{
    cgv::data::data_view dv;
    if (cf == cgv::data::CF_D) {
        if (read_frame_buffer(dv, x, y, buffer_type, cgv::type::info::TI_FLT32, cf, w, h)) {
            cgv::data::data_format df("uint8[L]");
            df.set_width(dv.get_format()->get_width());
            df.set_height(dv.get_format()->get_height());
            cgv::data::data_view dv1(&df);
            size_t n = df.get_width()*df.get_height();
            const float* src = dv.get_ptr<float>();
            unsigned char* dst = dv1.get_ptr<unsigned char>();
            for (size_t i=0; i<n; ++i, ++dst, ++src)
                *dst = (unsigned char)((*src - depth_offset)*depth_scale*255);
            image_writer w(file_name);
            if (w.write_image(dv1)) {
                return true;
            }
        }
    }
    else if (read_frame_buffer(dv, x, y, buffer_type, cgv::type::info::TI_UINT8, cf, w, h)) {
        if (cf == cgv::data::CF_S) {
            const_cast<cgv::data::data_format*>(dv.get_format())->set_component_names("L");
            size_t n = dv.get_format()->get_width()*dv.get_format()->get_height();
            unsigned char* dst = dv.get_ptr<unsigned char>();
            unsigned char s = (int)depth_scale;
            for (size_t i=0; i<n; ++i, ++dst)
                *dst *= s;
        }
        image_writer w(file_name);
        if (w.write_image(dv)) {
            return true;
        }
    }
    return false;
}
 
std::string to_string(TextureWrap wrap)
{
    const char* wrap_str[] = {
        "repeat", "clamp", "clamp_to_edge", "clamp_to_border", "mirror_clamp",
        "mirror_clamp_to_edge", "mirror_clamp_to_border"
    };
    return wrap_str[wrap];
}
 
 
std::string to_string(TextureType tt)
{
    const char* tt_str[] = {
        "undefined", "Texture1D", "Texture2D", "Texture3D", "CubeTexture"
    };
    return tt_str[tt];
}
 
std::string to_string(TextureCubeSides tcs)
{
    const char* tcs_str[] = {
        "x+", "x-", "y+", "y-", "z+", "z-"
    };
    return tcs_str[tcs];
}
 
std::string to_string(PrimitiveType pt)
{
    const char* pt_str[] = {
        "undef", "points", "lines", "lines_adjacency", "line_strip", "line_strip_adjacency", "line_loop", 
        "triangles", "triangles_adjacency", "triangle_strip", "triangle_strip_adjacency", "triangle_fan", 
        "quads", "quad_strip", "polygon", "patches"
    };
    return pt_str[pt];
}
 
 
std::string to_string(TextureFilter filter_type)
{
    const char* filter_str[] = {
        "nearest", 
        "linear", 
        "nearest_mipmap_nearest", 
        "linear_mipmap_nearest", 
        "nearest_mipmap_linear",
        "linear_mipmap_linear",
        "anisotrop"
    };
    return filter_str[filter_type];
}
 
// declare some colors by name
float black[4]     = { 0, 0, 0, 1 };
float white[4]     = { 1, 1, 1, 1 };
float gray[4]      = { 0.25f, 0.25f, 0.25f, 1 };
float green[4]     = { 0, 1, 0, 1 };
float brown[4]     = { 0.3f, 0.1f, 0, 1 };
float dark_red[4]  = { 0.4f, 0, 0, 1 };
float cyan[4]      = { 0, 1, 1, 1 };
float yellow[4]    = { 1, 1, 0, 1 };
float red[4]       = { 1, 0, 0, 1 };
float blue[4]      = { 0, 0, 1, 1 };
 
void compute_face_normals(const float* vertices, float* normals, const int* vertex_indices, int* normal_indices, int nr_faces, int face_degree)
{
    for (int i = 0; i < nr_faces; ++i) {
        vec3& normal = reinterpret_cast<vec3&>(normals[3 * i]);
        normal.zeros();
        vec3 reference_pnt = *reinterpret_cast<const vec3*>(vertices + 3 * vertex_indices[face_degree*i + face_degree - 1]);
        vec3 last_difference;
        last_difference.zeros();
        for (int j = 0; j < face_degree; ++j) {
            vec3 new_difference = *reinterpret_cast<const vec3*>(vertices + 3 * vertex_indices[face_degree*i + j]) - reference_pnt;
            normal += cross(last_difference, new_difference);
            last_difference = new_difference;
        }
        normal.normalize();
        for (int j = 0; j<face_degree; ++j)
            normal_indices[face_degree*i+j] = i;
    }
}
 
void context::tesselate_unit_cube(bool flip_normals, bool edges)
{
    static float V[8*3] = {
        -1,-1,+1,
        +1,-1,+1,
        -1,+1,+1,
        +1,+1,+1,
        -1,-1,-1,
        +1,-1,-1,
        -1,+1,-1,
        +1,+1,-1
    };
    static float N[6*3] = {
        -1,0,0, +1,0,0, 
        0,-1,0, 0,+1,0,
        0,0,-1, 0,0,+1
    };
    static const float ot = float(1.0 / 3);
    static const float tt = float(2.0 / 3);
    static float T[14*2] = {
         0,ot , 0,tt ,
         0.25f,0 , 0.25f,ot ,
         0.25f,tt , 0.25f,1 ,
         0.5f,0 , 0.5f,ot ,
         0.5f,tt , 0.5f,1 ,
         0.75f,ot , 0.75f,tt ,
         1,ot , 1,tt 
    };
    static int F[6*4] = {
        0,2,6,4,
        1,5,7,3,
        0,4,5,1,
        2,3,7,6,
        4,6,7,5,
        0,1,3,2 
    };
    static int FN[6*4] = {
        0,0,0,0, 1,1,1,1,
        2,2,2,2, 3,3,3,3,
        4,4,4,4, 5,5,5,5
    };
    static int FT[6*4] = {
        3,4,1,0 ,7,10,11,8 ,
        3,2,6,7 ,4,8,9,5 ,
        12,13,11,10 ,3,7,8,4 
    };
    if (edges)
        draw_edges_of_faces(V, N, T, F, FN, FT, 6, 4, flip_normals);
    else
        draw_faces(V,N,T,F,FN,FT,6,4, flip_normals);
}
 
void context::tesselate_box(const cgv::media::axis_aligned_box<double, 3>& B, bool flip_normals, bool edges) const
{
    static float N[6 * 3] = {
        -1, 0, 0, +1, 0, 0,
        0, -1, 0, 0, +1, 0,
        0, 0, -1, 0, 0, +1
    };
    static int F[6 * 4] = {
        0, 2, 6, 4,
        1, 5, 7, 3,
        0, 4, 5, 1,
        2, 3, 7, 6,
        4, 6, 7, 5,
        0, 1, 3, 2
    };
    static int FN[6 * 4] = {
        0, 0, 0, 0, 1, 1, 1, 1,
        2, 2, 2, 2, 3, 3, 3, 3,
        4, 4, 4, 4, 5, 5, 5, 5
    };
    float V[8 * 3];
 
    for (unsigned i = 0; i < 8; ++i) {
        V[3 * i]     = float((i & 1) == 0 ? B.get_min_pnt()(0) : B.get_max_pnt()(0));
        V[3 * i + 1] = float((i & 2) == 0 ? B.get_min_pnt()(1) : B.get_max_pnt()(1));
        V[3 * i + 2] = float((i & 4) != 0 ? B.get_min_pnt()(2) : B.get_max_pnt()(2));
    }
    if (edges)
        draw_edges_of_faces(V, N, 0, F, FN, 0, 6, 4, flip_normals);
    else
        draw_faces(V, N, 0, F, FN, 0, 6, 4, flip_normals);
}
 
void context::tesselate_unit_prism(bool flip_normals, bool edges)
{
    static const float V[6*3] = {
        -1, -1, -1,
         1, -1, -1,
         0, -1,  1,
        -1,  1, -1,
         1,  1, -1,
         0,  1,  1
    };
    static float a = 1.0f/sqrt(5.0f);
    static float b = 2*a;
    static const float N[5*3] = {
         0,-1, 0,
         0, 1, 0,
         0, 0,-1,
        -b, 0, a, 
         b, 0, a
    };
    static const int FT[2*3] = { 0,1,2, 5,4,3 };
    static const int FQ[8] = { 4,1, 3,0, 5,2, 4,1};
    static const int FTN[2*3] = { 0,0,0, 1,1,1 };
    static const int FQN[8] = { 2,2, 2,2, 3,3, 4,4, };
 
    if (edges) {
        draw_edges_of_faces(V, N, 0, FT, FTN, 0, 2, 3, flip_normals);
        draw_edges_of_strip_or_fan(V, N, 0, FQ, FQN, 0, 3, 4, flip_normals);
    }
    else {
        draw_faces(V, N, 0, FT, FTN, 0, 2, 3, flip_normals);
        draw_strip_or_fan(V, N, 0, FQ, FQN, 0, 3, 4, flip_normals);
    }
}
 
void context::tesselate_unit_disk(int resolution, bool flip_normals, bool edges)
{
    std::vector<float> V; V.reserve(3*(resolution+1));
    std::vector<float> N; N.reserve(3*(resolution+1));
    std::vector<float> T; T.reserve(2*(resolution+1));
 
    std::vector<int> F; F.resize(resolution+1);
    int i;
    for (i = 0; i <= resolution; ++i)
        F[i] = i;
 
    float step = float(2*M_PI/resolution);
    float phi   = 0;
    for (i = 0; i <= resolution; ++i, phi += step) {
        float cp = cos(phi);
        float sp = sin(phi);
        N.push_back(0);
        N.push_back(0);
        N.push_back(1);
        T.push_back((float)i/resolution);
        T.push_back(1);
        V.push_back(cp);
        V.push_back(sp);
        V.push_back(0);
    }
    if (edges)
        draw_edges_of_faces(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], 1, resolution + 1, flip_normals);
    else
        draw_faces(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], 1, resolution + 1, flip_normals);
}
 
void context::tesselate_unit_cone(int resolution, bool flip_normals, bool edges)
{
    std::vector<float> V; V.reserve(6*(resolution+1));
    std::vector<float> N; N.reserve(6*(resolution+1));
    std::vector<float> T; T.reserve(4*(resolution+1));
 
    std::vector<int> F; F.resize(2*resolution+2);
    int i;
    for (i = 0; i <= 2*resolution+1; ++i)
        F[i] = i;
 
    static float a = 1.0f/sqrt(5.0f);
    static float b = 2*a;
    float step = float(2*M_PI/resolution);
    float phi   = 0;
    float u = 0;
    float duv = float(1.0/resolution);
    for (int i = 0; i <= resolution; ++i, u += duv, phi += step) {
        float cp = cos(phi); 
        float sp = sin(phi);
        N.push_back(b*cp);
        N.push_back(b*sp);
        N.push_back(a);
        T.push_back(u);
        T.push_back(1);
        V.push_back(0);
        V.push_back(0);
        V.push_back(1);
        N.push_back(b*cp);
        N.push_back(b*sp);
        N.push_back(a);
        T.push_back(u);
        T.push_back(0);
        V.push_back(cp);
        V.push_back(sp);
        V.push_back(-1);
    }
    if (edges)
        draw_edges_of_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
    else
        draw_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
}
 
void context::tesselate_unit_cylinder(int resolution, bool flip_normals, bool edges)
{
    std::vector<float> V; V.reserve(6*(resolution+1));
    std::vector<float> N; N.reserve(6*(resolution+1));
    std::vector<float> T; T.reserve(4*(resolution+1));
 
    std::vector<int> F; F.resize(2*(resolution+1));
    int i;
    for (i = 0; i <= 2*resolution+1; ++i)
        F[i] = i;
 
    float step = float(2*M_PI/resolution);
    float phi   = 0;
    float u = 0;
    float duv = float(1.0/resolution);
    for (int i = 0; i <= resolution; ++i, u += duv, phi += step) {
        float cp = cos(phi);
        float sp = sin(phi);
        N.push_back(cp);
        N.push_back(sp);
        N.push_back(0);
        T.push_back(u);
        T.push_back(1);
        V.push_back(cp);
        V.push_back(sp);
        V.push_back(1);
        N.push_back(cp);
        N.push_back(sp);
        N.push_back(0);
        T.push_back(u);
        T.push_back(0);
        V.push_back(cp);
        V.push_back(sp);
        V.push_back(-1);
    }
    if (edges)
        draw_edges_of_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
    else
        draw_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
}
 
void context::tesselate_unit_torus(float minor_radius, int resolution, bool flip_normals, bool edges)
{
    std::vector<float> V; V.resize(6*(resolution+1));
    std::vector<float> N; N.resize(6*(resolution+1));
    std::vector<float> T; T.resize(4*(resolution+1));
    std::vector<int> F; F.resize(2*(resolution+1));
    int i;
    for (int i = 0; i <= resolution; ++i) {
        F[2*i] = 2*i;
        F[2*i+1] = 2*i+1;
    }
    float step  = float(2*M_PI/resolution);
    float phi   = 0;
    float cp1   = 1, sp1 = 0;
    float u = 0;
    float duv = float(1.0/resolution);
    for (i = 0; i < resolution; ++i, u += duv) {
        float cp0 = cp1, sp0 = sp1;
        phi += step;
        cp1 = cos(phi); 
        sp1 = sin(phi);
        float theta = 0;
        float v = 0;
        int kv=0, kn=0, kt=0;
        for (int j = 0; j <= resolution; ++j, theta += step, v += duv) {
            float ct = cos(theta), st = sin(theta);
            N[kn++] = ct*cp0;
            N[kn++] = ct*sp0;
            N[kn++] = st;
            T[kt++] = u;
            T[kt++] = v;
            V[kv++] = cp0+minor_radius*cp0*ct;
            V[kv++] = sp0+minor_radius*sp0*ct;
            V[kv++] = minor_radius*st;
            N[kn++] = ct*cp1;
            N[kn++] = ct*sp1;
            N[kn++] = st;
            T[kt++] = u+duv;
            T[kt++] = v;
            V[kv++] = cp1+minor_radius*cp1*ct;
            V[kv++] = sp1+minor_radius*sp1*ct;
            V[kv++] = minor_radius*st;
        }
        if (edges)
            draw_edges_of_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
        else
            draw_strip_or_fan(&V[0],&N[0],&T[0],&F[0],&F[0],&F[0],resolution,4,false, flip_normals);
    }
}
void context::tesselate_unit_sphere(int resolution, bool flip_normals, bool edges)
{
    std::vector<float> V; V.resize(6*(resolution+1));
    std::vector<float> N; N.resize(6*(resolution+1));
    std::vector<float> T; T.resize(4*(resolution+1));
    std::vector<int> F; F.resize(2*(resolution+1));
    int i;
    for (int i = 0; i <= resolution; ++i) {
        F[2*i] = 2*i;
        F[2*i+1] = 2*i+1;
    }
    float step = float(M_PI/resolution);
    float phi   = 0;
    float cp1   = 1, sp1 = 0;
    float u = 0;
    float duv = float(1.0/resolution);
    for (i = 0; i < resolution; ++i, u += duv) {
        float cp0 = cp1, sp0 = sp1;
        phi += 2*step;
        cp1 = cos(phi); 
        sp1 = sin(phi);
        float theta = float(-0.5*M_PI);
        float v = 0;
        int kv=0, kn=0, kt=0;
        for (int j = 0; j <= resolution; ++j, theta += step, v += duv) {
            float ct = cos(theta), st = sin(theta);
            N[kn++] = ct*cp0;
            N[kn++] = ct*sp0;
            N[kn++] = st;
            T[kt++] = u;
            T[kt++] = v;
            V[kv++] = ct*cp0;
            V[kv++] = ct*sp0;
            V[kv++] = st;
            N[kn++] = ct*cp1;
            N[kn++] = ct*sp1;
            N[kn++] = st;
            T[kt++] = u+duv;
            T[kt++] = v;
            V[kv++] = ct*cp1;
            V[kv++] = ct*sp1;
            V[kv++] = st;
        }
        if (edges)
            draw_edges_of_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
        else
            draw_strip_or_fan(&V[0], &N[0], &T[0], &F[0], &F[0], &F[0], resolution, 4, false, flip_normals);
    }
 
}
void context::tesselate_unit_tetrahedron(bool flip_normals, bool edges)
{
    static const float a = float(1.0/(2*sqrt(3.0)));
    static const float b = float(1.0/(3*sqrt(3.0/2)));
    static const float V[4*3] = {
         -0.5, -a, -b,
          0.5, -a, -b,
            0,2*a, -b,
            0,  0,2*b
    };
    static const int F[4*3] = {
        0,2,1,3,2,0,3,0,1,3,1,2
    };
    static int FN[4*3];
    static float N[4*3];
    static bool computed = false;
    if (!computed) {
        compute_face_normals(V, N, F, FN, 4, 3);
        computed = true;
    }
    if (edges)
        draw_edges_of_faces(V, N, 0, F, FN, 0, 4, 3, flip_normals);
    else
        draw_faces(V, N, 0, F, FN, 0, 4, 3, flip_normals);
}
 
 
void context::tesselate_unit_square(bool flip_normals, bool edges)
{
    static float N[1*3] = {
        0,0,+1
    };
    static float V[4*3] = {
        -1,-1,0, +1,-1,0,
        +1,+1,0, -1,+1,0
    };
    static float T[4*2] = {
        0,0, 1,0,
        1,1, 0,1
    };
    static int FN[1*4] = {
        0,0,0,0
    };
    static int F[1*4] = {
        0,1,2,3
    };
    if (edges)
        draw_edges_of_faces(V, N, T, F, FN, F, 1, 4, flip_normals);
    else
        draw_faces(V, N, T, F, FN, F, 1, 4, flip_normals);
}
 
 
void context::tesselate_unit_octahedron(bool flip_normals, bool edges)
{
    static float N[8*3] = {
        -1,-1,+1, +1,-1,+1, -1,+1,+1, +1,+1,+1,
        -1,-1,-1, +1,-1,-1, -1,+1,-1, +1,+1,-1
    };
    static float V[6*3] = {
        -1,0,0, +1,0,0,
        0,-1,0, 0,+1,0,
        0,0,-1, 0,0,+1
    };
    static int FN[8*3] = {
        0,0,0,
        1,1,1,
        2,2,2,
        3,3,3,
        4,4,4,
        5,5,5,
        6,6,6,
        7,7,7
    };
    static int F[8*3] = {
        0,2,5,
        1,5,2,
        5,3,0,
        3,5,1,
        4,2,0,
        4,1,2,
        3,4,0,
        1,4,3
    };
    if (edges)
        draw_edges_of_faces(V, N, 0, F, FN, 0, 8, 3, flip_normals);
    else
        draw_faces(V, N, 0, F, FN, 0, 8, 3, flip_normals);
}
 
void tesselate_unit_dodecahedron_or_icosahedron(context& c, bool dual, bool flip_normals, bool edges)
{
    static const float h = 0.4472135956f;
    static const float r = 0.8944271912f;
    static const float s = float(M_PI/2.5);
    static const float o = float(M_PI/5);
    static const float V[13*3] = {
        0,0,-1,
        r*sin(1*s),r*cos(1*s),-h,
        r*sin(2*s),r*cos(2*s),-h,
        r*sin(3*s),r*cos(3*s),-h,
        r*sin(4*s),r*cos(4*s),-h,
        r*sin(5*s),r*cos(5*s),-h,
        r*sin(1*s+o),r*cos(1*s+o),h,
        r*sin(2*s+o),r*cos(2*s+o),h,
        r*sin(3*s+o),r*cos(3*s+o),h,
        r*sin(4*s+o),r*cos(4*s+o),h,
        r*sin(5*s+o),r*cos(5*s+o),h,
        0,0,1,
        0,0,0
    };
    static int F[20*3] = {
        0,1,2, 0,2,3, 0,3,4, 0,4,5, 0,5,1,
        6,2,1, 2,6,7, 7,3,2, 3,7,8, 8,4,3, 4,8,9, 9,5,4, 5,9,10, 10,1,5, 6,1,10,
        11,6,10, 11,10,9, 11,9,8, 11,8,7, 11,7,6
    };
    static int DF[12*5] = {
        0,1,2,3,4,
        5,6,7,1,0,
        7,8,9,2,1,
        9,10,11,3,2,
        11,12,13,4,3,
        13,14,5,0,4,
        16,15,14,13,12,
        17,16,12,11,10,
        18,17,10,9,8,
        19,18,8,7,6,
        15,19,6,5,14,
        15,16,17,18,19
    };
    static float N[20*3];
    static int FN[20*3];
    static int DFN[12*5] = {
        0,0,0,0,0,
        2,2,2,2,2,
        3,3,3,3,3,
        4,4,4,4,4,
        5,5,5,5,5,
        1,1,1,1,1,
        10,10,10,10,10,
        9,9,9,9,9,
        8,8,8,8,8,
        7,7,7,7,7,
        6,6,6,6,6,
        11,11,11,11,11
    };
 
    static bool computed = false;
    if (!computed) {
        compute_face_normals(V, N, F, FN, 20, 3);
        computed = true;
    }
    if (!dual) {
        if (edges)
            c.draw_edges_of_faces(V, N, 0, F, FN, 0, 20, 3, flip_normals);
        else
            c.draw_faces(V, N, 0, F, FN, 0, 20, 3, flip_normals);
    }
    else {
        if (edges)
            c.draw_edges_of_faces(N, V, 0, DF, DFN, 0, 12, 5, flip_normals);
        else
            c.draw_faces(N, V, 0, DF, DFN, 0, 12, 5, flip_normals);
    }
}
 
void context::tesselate_unit_dodecahedron(bool flip_normals, bool edges)
{
    tesselate_unit_dodecahedron_or_icosahedron(*this, true, flip_normals, edges);
}
void context::tesselate_unit_icosahedron(bool flip_normals, bool edges)
{
    tesselate_unit_dodecahedron_or_icosahedron(*this, false, flip_normals, edges);
}
 
void context::set_gamma(float _gamma)
{
    set_gamma3(vec3(_gamma));
}
void context::set_current_gamma(shader_program& prog) const
{
    int gi = prog.get_uniform_location(*this, "gamma");
    if (gi != -1)
        prog.set_uniform(*this, gi, get_gamma());
    int gi3 = prog.get_uniform_location(*this, "gamma3");
    if (gi3 != -1)
        prog.set_uniform(*this, gi3, get_gamma3());
}
 
void context::set_gamma3(const vec3& _gamma3)
{
    gamma3 = _gamma3;
    if (!auto_set_gamma_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
 
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (prog.does_use_gamma())
        set_current_gamma(prog);
}
 
const cgv::media::illum::surface_material* context::get_current_material() const
{
    return current_material_ptr;
}
 
const rgba& context::get_color() const
{
    return current_color;
}
 
void context::set_color(const rgba& clr)
{
    current_color = clr;
    if (shader_program_stack.empty())
        return;
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_context_set_color())
        return;
    int clr_loc = prog.get_color_index();
    if (clr_loc == -1)
        return;
    prog.set_attribute(*this, clr_loc, clr);
}
 
void context::set_material(const cgv::media::illum::surface_material& material)
{
    current_material_ptr = &material;
    current_material_is_textured = false;
 
    if (!auto_set_material_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
 
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_use_material())
        return;
 
    prog.set_material_uniform(*this, "material", material);
}
 
void context::set_textured_material(const textured_material& material)
{
    current_material_ptr = &material;
    current_material_is_textured = true;
 
    if (!auto_set_material_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
 
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_use_material())
        return;
 
    prog.set_textured_material_uniform(*this, "material", material);
}
 
void context::push_depth_test_state() {
    depth_test_state_stack.push(get_depth_test_state());
}
 
void context::pop_depth_test_state() {
    SAFE_STACK_POP(depth_test_state_stack, "pop_depth_test_state");
    set_depth_test_state(get_depth_test_state());
}
 
context::DepthTestState context::get_depth_test_state() const {
    return depth_test_state_stack.top();
}
 
void context::set_depth_test_state(DepthTestState state) {
    depth_test_state_stack.top() = state;
}
 
void context::set_depth_func(CompareFunction func) {
    depth_test_state_stack.top().test_func = func;
}
 
 
void context::enable_depth_test() {
    depth_test_state_stack.top().enabled = true;
}
 
void context::disable_depth_test() {
    depth_test_state_stack.top().enabled = false;
}
 
void context::push_cull_state() {
    cull_state_stack.push(get_cull_state());
}
 
void context::pop_cull_state() {
    SAFE_STACK_POP(cull_state_stack, "pop_cull_state");
    set_cull_state(get_cull_state());
}
 
CullingMode context::get_cull_state() const {
    return cull_state_stack.top();
}
 
void context::set_cull_state(CullingMode culling_mode) {
    cull_state_stack.push(culling_mode);
}
 
void context::push_blend_state() {
    blend_state_stack.push(get_blend_state());
}
 
void context::pop_blend_state() {
    SAFE_STACK_POP(blend_state_stack, "pop_blend_state");
    set_blend_state(get_blend_state());
}
 
context::BlendState context::get_blend_state() const {
    return blend_state_stack.top();
}
 
void context::set_blend_state(BlendState state) {
    blend_state_stack.top() = state;
}
 
void context::set_blend_func(BlendFunction src_factor, BlendFunction dst_factor) {
    BlendState& state = blend_state_stack.top();
    state.src_color = src_factor;
    state.dst_color = dst_factor;
    state.src_alpha = src_factor;
    state.dst_alpha = dst_factor;
}
 
void context::set_blend_func_separate(BlendFunction src_color_factor, BlendFunction dst_color_factor, BlendFunction src_alpha_factor, BlendFunction dst_alpha_factor) {
    BlendState& state = blend_state_stack.top();
    state.src_color = src_color_factor;
    state.dst_color = dst_color_factor;
    state.src_alpha = src_alpha_factor;
    state.dst_alpha = dst_alpha_factor;
}
 
void context::set_blend_func_front_to_back() {
    set_blend_func(BF_ONE_MINUS_DST_ALPHA, BF_ONE);
}
void context::set_blend_func_back_to_front() {
    set_blend_func(BF_SRC_ALPHA, BF_ONE_MINUS_SRC_ALPHA);
}
 
void context::enable_blending() {
    blend_state_stack.top().enabled = true;
}
 
void context::disable_blending() {
    blend_state_stack.top().enabled = false;
}
 
void context::push_buffer_mask() {
    buffer_mask_stack.push(get_buffer_mask());
}
 
void context::pop_buffer_mask() {
    SAFE_STACK_POP(buffer_mask_stack, "pop_buffer_mask");
    set_buffer_mask(get_buffer_mask());
}
 
context::BufferMask context::get_buffer_mask() const {
    return buffer_mask_stack.top();
}
 
void context::set_buffer_mask(BufferMask mask) {
    buffer_mask_stack.top() = mask;
}
 
bool context::get_depth_mask() const {
    return buffer_mask_stack.top().depth_flag;
}
 
void context::set_depth_mask(bool flag) {
    buffer_mask_stack.top().depth_flag = flag;
}
 
bvec4 context::get_color_mask() const {
    auto& mask = buffer_mask_stack.top();
    return bvec4(mask.red_flag, mask.green_flag, mask.blue_flag, mask.alpha_flag);
}
 
void context::set_color_mask(bvec4 flags) {
    auto& mask = buffer_mask_stack.top();
    mask.red_flag = flags[0];
    mask.green_flag = flags[1];
    mask.blue_flag = flags[2];
    mask.alpha_flag = flags[3];
}
 
void context::push_modelview_matrix()
{
    modelview_matrix_stack.push(get_modelview_matrix());
}
 
void context::mul_modelview_matrix(const dmat4& V)
{
    set_modelview_matrix(get_modelview_matrix()*V);
}
 
void context::pop_modelview_matrix()
{
    SAFE_STACK_POP(modelview_matrix_stack, "pop_modelview_matrix");
    set_modelview_matrix(modelview_matrix_stack.top());
}
void context::push_projection_matrix() 
{
    projection_matrix_stack.push(get_projection_matrix());
}
void context::pop_projection_matrix()
{
    SAFE_STACK_POP(projection_matrix_stack, "pop_projection_matrix");
    set_projection_matrix(projection_matrix_stack.top());
}
void context::mul_projection_matrix(const dmat4& P)
{
    set_projection_matrix(get_projection_matrix()*P);
}
 
void context::set_modelview_matrix(const dmat4& V)
{
    // set new modelview matrix on matrix stack
    modelview_matrix_stack.top() = V;
 
    // update in current shader
    if (!auto_set_view_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_use_view())
        return;
    set_current_view(prog, true, false);
}
 
void context::set_projection_matrix(const dmat4& P)
{
    // set new projection matrix on matrix stack
    projection_matrix_stack.top() = P;
 
    // update in current shader
    if (!auto_set_view_in_current_shader_program)
        return;
 
    if (shader_program_stack.empty())
        return;
    cgv::render::shader_program& prog = *static_cast<cgv::render::shader_program*>(shader_program_stack.top());
    if (!prog.does_use_view())
        return;
    set_current_view(prog, false, true);
}
 
void context::push_window_transformation_array()
{
    window_transformation_stack.push(window_transformation_stack.top());
}
void context::pop_window_transformation_array()
{
    SAFE_STACK_POP(window_transformation_stack, "pop_window_transformation_array");
}
 
bool context::ensure_window_transformation_index(int& array_index)
{
    if (array_index == -1) {
        window_transformation_stack.top().resize(1);
        array_index = 0;
        return true;
    }
    else {
        if (array_index >= (int)window_transformation_stack.top().size()) {
            if (array_index > (int)get_max_window_transformation_array_size()) {
                std::string message("context::ensure_window_transformation_index() ... attempt to resize window transformation array larger than maximum allowed size of ");
                message += cgv::utils::to_string(get_max_window_transformation_array_size());
                error(message);
                return false;
            }
            window_transformation_stack.top().resize(array_index + 1);
        }
    }
    return true;
}
 
void context::set_viewport(const ivec4& viewport, int array_index)
{
    if (!ensure_window_transformation_index(array_index))
        return;
    window_transformation_stack.top().at(array_index).viewport = viewport;
}
 
void context::set_depth_range(const dvec2& depth_range, int array_index)
{
    if (!ensure_window_transformation_index(array_index))
        return;
    window_transformation_stack.top().at(array_index).depth_range = depth_range;
}
 
const std::vector<window_transformation>& context::get_window_transformation_array() const
{
    return window_transformation_stack.top();
}
 
dmat4 context::get_window_matrix(unsigned array_index) const
{
    if (array_index >= window_transformation_stack.top().size()) {
        std::string message("context::get_window_matrix() ... attempt to query window matrix with array index ");
        message += cgv::utils::to_string(array_index);
        message += " out of range [0,";
        message += cgv::utils::to_string(window_transformation_stack.top().size());
        message += "[";
        error(message);
        return cgv::math::identity4<double>();
    }
    const window_transformation& wt = window_transformation_stack.top()[array_index];
    dmat4 M = cgv::math::identity4<double>();
    M(0, 0) = 0.5*wt.viewport[2];
    M(0, 3) = M(0, 0) + wt.viewport[0];
    M(1, 1) = 0.5*wt.viewport[3];
    M(1, 3) = M(1, 1) + wt.viewport[1];
    M(2, 2) = 0.5*(wt.depth_range[1] - wt.depth_range[0]);
    M(2, 3) = M(2, 2) + wt.depth_range[0];
    return M;
}
dmat4 context::get_modelview_projection_window_matrix(unsigned array_index) const
{
    return get_window_matrix(array_index)*get_projection_matrix()*get_modelview_matrix();
}
 
vec3 context::get_model_point(const dvec3& p_window, const dmat4& modelview_projection_window_matrix) 
{
    dmatn A(4, 4, &modelview_projection_window_matrix(0, 0));
    dvecn x;
    dvecn b(p_window(0), p_window(1), p_window(2), 1.0);
    svd_solve(A, b, x);
    return vec3(float(x(0) / x(3)), float(x(1) / x(3)), float(x(2) / x(3)));
}
 
void context::set_cursor(int x, int y)
{
    output_stream().flush();
    cursor_x = x;
    cursor_y = y;
    x_offset = x;
    y_offset = y;
    nr_identations = 0;
    at_line_begin = true;
}
 
void context::put_cursor_coords(const vecn& p, int& x, int& y) const
{
    dvec4 p4(0, 0, 0, 1);
    for (unsigned int c = 0; c < p.size(); ++c)
        p4(c) = p(c);
 
    p4 = get_modelview_projection_window_matrix() * p4;
 
    x = (int)(p4(0) / p4(3));
    y = (int)(p4(1) / p4(3));
}
 
void context::set_cursor(const vecn& pos, 
        const std::string& text, TextAlignment ta,
        int x_offset, int y_offset)
{
    int x,y;
    put_cursor_coords(pos, x, y);
    if (!text.empty() && get_current_font_face()) {
        float h = get_current_font_size();
        float w = get_current_font_face()->measure_text_width(text, h);
        switch (ta&3) {
        case 0 : x -= (int)(floor(w)*0.5f);break;
        case 2 : x -= (int)floor(w);break;
        default: break;
        }
        switch (ta&12) {
        case 0 : y -= (int)(floor(h)*0.3f);break;
        case 4 : y -= (int)(floor(h)*0.6f); break;
        default: break;
        }
    }
    x += x_offset;
    y += y_offset;
    set_cursor(x,y);
}
 
void context::get_cursor(int& x, int& y) const
{
    x = cursor_x;
    y = cursor_y;
}
 
dmat4 context::get_modelview_projection_device_matrix() const
{
    return get_window_matrix()*get_projection_matrix()*get_modelview_matrix();
}
 
void context::tesselate_arrow(double length, double aspect, double rel_tip_radius, double tip_aspect, int res, bool edges)
{
    std::cout << "tesselate_arrow not implemented in cgv::render::context" << std::endl;
}
 
void context::tesselate_arrow(const cgv::math::fvec<double, 3>& start, const cgv::math::fvec<double, 3>& end, double aspect, double rel_tip_radius, double tip_aspect, int res, bool edges)
{
    std::cout << "tesselate_arrow not implemented in cgv::render::context" << std::endl;
}
 
void context::draw_light_source(const cgv::media::illum::light_source& l, float intensity_scale, float light_scale)
{
    std::cout << "draw_light_source not implemented in cgv::render::context" << std::endl;
}
 
render_component::render_component()
{
    handle = 0;
    internal_format = 0;
    user_data = 0;
    ctx_ptr = 0;
}
 
bool render_component::is_created() const
{
    return handle != 0;
}
 
 
void render_component::put_id_void(void* ptr) const
{
    if (!ctx_ptr) {
        std::cerr << "no context set when render_component::put_id_void was called" << std::endl;
        return;
    }
    ctx_ptr->put_id(handle, ptr);
}
 
render_buffer_base::render_buffer_base()
{
}
 
texture_base::texture_base(TextureType _tt)
{
    mag_filter = TF_LINEAR;
    min_filter = TF_LINEAR_MIPMAP_LINEAR;
    wrap_s = TW_CLAMP_TO_EDGE;
    wrap_t = TW_CLAMP_TO_EDGE;
    wrap_r = TW_CLAMP_TO_EDGE;
    anisotropy = 1;
    priority = 0.5f;
    border_color[0] = 1;
    border_color[1] = 1;
    border_color[2] = 1;
    border_color[3] = 1;
    tt = _tt;
    compare_function = CF_LEQUAL;
    use_compare_function = false;
    have_mipmaps = false;
}
 
void shader_program_base::allow_context_to_set_color(bool allow)
{
    context_sets_color = allow;
}
 
shader_program_base::shader_program_base()
{
    is_enabled = false;
    geometry_shader_input_type = PT_POINTS;
    geometry_shader_output_type = PT_POINTS;
    geometry_shader_output_count = 1;
 
    auto_detect_uniforms = true;
    auto_detect_vertex_attributes = true;
 
    uses_view = false;
    uses_material = false;
    uses_lights = false;
    uses_gamma = false;
 
    position_index = -1;
    normal_index = -1;
    color_index = -1;
    context_sets_color = true;
    texcoord_index = -1;
}
 
// configure program
void shader_program_base::specify_standard_uniforms(bool view, bool material, bool lights, bool gamma)
{
    auto_detect_uniforms = false;
    uses_view = view;
    uses_material = material;
    uses_lights = lights;
    uses_gamma = gamma;
}
 
void shader_program_base::specify_standard_vertex_attribute_names(context& ctx, bool color, bool normal, bool texcoord)
{
    auto_detect_vertex_attributes = false;
    position_index = ctx.get_attribute_location(*this, "position");
    color_index = color ? ctx.get_attribute_location(*this, "color") : -1;
    normal_index = normal ? ctx.get_attribute_location(*this, "normal") : -1;
    texcoord_index = texcoord ? ctx.get_attribute_location(*this, "texcoord") : -1;
}
 
void shader_program_base::specify_vertex_attribute_names(context& ctx, const std::string& position, const std::string& color, const std::string& normal, const std::string& texcoord)
{
    auto_detect_vertex_attributes = false;
    position_index = position.empty() ? -1 : ctx.get_attribute_location(*this, position);
    color_index = color.empty() ? -1 : ctx.get_attribute_location(*this, color);
    normal_index = normal.empty() ? -1 : ctx.get_attribute_location(*this, normal);
    texcoord_index = texcoord.empty() ? -1 : ctx.get_attribute_location(*this, texcoord);
}
bool context::shader_program_link(shader_program_base& spb) const
{
    if (spb.handle == 0)
        return false;
    if (spb.auto_detect_vertex_attributes) {
        spb.position_index = get_attribute_location(spb, "position");
        spb.color_index = get_attribute_location(spb, "color");
        spb.normal_index = get_attribute_location(spb, "normal");
        spb.texcoord_index = get_attribute_location(spb, "texcoord");
        spb.auto_detect_vertex_attributes = false;
    }
    if (spb.auto_detect_uniforms) {
        spb.uses_lights = get_uniform_location(spb, "light_sources[0].light_source_type") != -1;
        spb.uses_material = get_uniform_location(spb, "material.brdf_type") != -1;
        spb.uses_view =
            get_uniform_location(spb, "modelview_matrix") != -1 ||
            get_uniform_location(spb, "projection_matrix") != -1 ||
            get_uniform_location(spb, "inverse_projection_matrix") != -1 ||
            get_uniform_location(spb, "normal_matrix") != -1 ||
            get_uniform_location(spb, "inverse_modelview_matrix") != -1 ||
            get_uniform_location(spb, "inverse_normal_matrix") != -1;
        spb.uses_gamma = get_uniform_location(spb, "gamma3") != -1 || get_uniform_location(spb, "gamma") != -1;
        spb.auto_detect_uniforms = false;
    }
    return true;
}
 
bool context::shader_program_enable(shader_program_base& spb)
{
    if (spb.is_enabled) {
        if (shader_program_stack.top() == &spb) {
            error("context::shader_program_enable() called with program that is currently active", &spb);
            return false;
        }
        error("context::shader_program_enable() called with program that is recursively reactivated", &spb);
        return false;
    }
    shader_program_stack.push(&spb);
    spb.is_enabled = true;
    return true;
}
 
bool context::shader_program_disable(shader_program_base& spb)
{
    if (shader_program_stack.empty()) {
        error("context::shader_program_disable() called with empty stack", &spb);
        return false;
    }
    if (!spb.is_enabled) {
        error("context::shader_program_disable() called with disabled program", &spb);
        return false;
    }
    if (shader_program_stack.top() != &spb) {
        error("context::shader_program_disable() called with program that was not on top of shader program stack", &spb);
        return false;
    }
    shader_program_stack.pop();
    spb.is_enabled = false;
    return true;
}
 
bool context::shader_program_destruct(shader_program_base& spb) const
{
    if (spb.is_enabled) {
        error("context::shader_program_destruct() on shader program that was still enabled", &spb);
/*      if (shader_program_stack.top() == &spb)
            shader_program_disable(spb);
        else {
            error("context::shader_program_destruct() on shader program that was still enabled", &spb);
            // remove destructed program from stack
            std::vector<shader_program_base*> tmp;
            while (!shader_program_stack.empty()) {
                shader_program_base* t = shader_program_stack.top();
                shader_program_stack.pop();
                if (t == &spb)
                    break;
                tmp.push_back(t);
            }
            while (!tmp.empty()) {
                shader_program_stack.push(tmp.back());
                tmp.pop_back();
            }
        }*/
        return false;
    }
    return true;
}
 
void context::shader_program_set_uniform_locations(shader_program_base& spb) const
{
    spb.uniform_locations.clear();
    std::vector<std::string> uniform_names;
    if(shader_program_get_active_uniforms(spb, uniform_names)) {
        for(size_t i = 0; i < uniform_names.size(); ++i) {
            int location = get_uniform_location(spb, uniform_names[i]);
            if(location > -1)
                spb.uniform_locations[uniform_names[i]] = location;
        }
    }
}
 
attribute_array_binding_base::attribute_array_binding_base()
{
    is_enabled = false;
}
 
 
bool context::attribute_array_binding_destruct(attribute_array_binding_base& aab) const
{
    if (aab.is_enabled) {
        error("context::attribute_array_binding_destruct() on array binding that was still enabled", &aab);
        /*
        if (attribute_array_binding_stack.top() == &aab)
            attribute_array_binding_disable(aab);
        else {
            // remove destructed binding from stack
            std::vector<attribute_array_binding_base*> tmp;
            while (!attribute_array_binding_stack.empty()) {
                attribute_array_binding_base* t = attribute_array_binding_stack.top();
                attribute_array_binding_stack.pop();
                if (t == &aab)
                    break;
                tmp.push_back(t);
            }
            while (!tmp.empty()) {
                attribute_array_binding_stack.push(tmp.back());
                tmp.pop_back();
            }
        }
        */
        return false;
    }
    return true;
}
 
bool context::attribute_array_binding_enable(attribute_array_binding_base& aab)
{
    if (!aab.handle) {
        error("context::attribute_array_binding_enable() called in not created attribute array binding.", &aab);
        return false;
    }
    if (aab.is_enabled) {
        if (attribute_array_binding_stack.top() == &aab) {
            error("context::attribute_array_binding_enable() called with array binding that is currently active", &aab);
            return false;
        }
        error("context::attribute_array_binding_enable() called with array binding that is recursively reactivated", &aab);
        return false;
    }
    attribute_array_binding_stack.push(&aab);
    aab.is_enabled = true;
    return true;
}
 
bool context::attribute_array_binding_disable(attribute_array_binding_base& aab)
{
    if (attribute_array_binding_stack.empty()) {
        error("context::attribute_array_binding_disable() called with empty stack", &aab);
        return false;
    }
    if (!aab.is_enabled) {
        error("context::attribute_array_binding_disable() called with disabled array binding", &aab);
        return false;
    }
    if (attribute_array_binding_stack.top() != &aab) {
        error("context::attribute_array_binding_disable() called with array binding that was not on top of array binding stack", &aab);
        return false;
    }
    attribute_array_binding_stack.pop();
    aab.is_enabled = false;
    return true;
}
 
vertex_buffer_base::vertex_buffer_base()
{
    type = VBT_VERTICES;
    usage = VBU_STATIC_DRAW;
}
 
 
frame_buffer_base::frame_buffer_base()
{
    is_enabled = false;
    width = -1;
    height = -1;
    depth_attached = false;
    std::fill(attached, attached+16,false);
}
 
void context::get_buffer_list(frame_buffer_base& fbb, bool& depth_buffer, std::vector<int>& buffers, int offset)
{
    if (fbb.enabled_color_attachments.size() == 0) {
        for (int i = 0; i < 16; ++i)
            if (fbb.attached[i])
                buffers.push_back(i + offset);
    }
    else {
        for (int i = 0; i < (int)fbb.enabled_color_attachments.size(); ++i)
            if (fbb.attached[fbb.enabled_color_attachments[i]])
                buffers.push_back(fbb.enabled_color_attachments[i]+offset);
    }
    depth_buffer = fbb.depth_attached;
}
 
bool context::frame_buffer_create(frame_buffer_base& fbb) const
{
    if (fbb.width == -1)
        fbb.width = get_width();
    if (fbb.height == -1)
        fbb.height = get_height();
    return true;
}
 
bool context::frame_buffer_attach(frame_buffer_base& fbb, const render_buffer_base& rb, bool is_depth, int i) const
{
    if (fbb.handle == 0) {
        error("gl_context::frame_buffer_attach: attempt to attach to frame buffer that is not created", &fbb);
        return false;
    }
    if (rb.handle == 0) {
        error("gl_context::frame_buffer_attach: attempt to attach empty render buffer", &fbb);
        return false;
    }
    if (is_depth)
        fbb.depth_attached = true;
    else
        fbb.attached[i] = true;
 
    return true;
}
 
bool context::frame_buffer_attach(frame_buffer_base& fbb, const texture_base& t, bool is_depth, int level, int i, int z_or_cube_side) const
{
    if (fbb.handle == 0) {
        error("context::frame_buffer_attach: attempt to attach to frame buffer that is not created", &fbb);
        return false;
    }
    if (t.handle == 0) {
        error("context::frame_buffer_attach: attempt to attach texture that is not created", &fbb);
        return false;
    }
    if(is_depth)
        fbb.depth_attached = true;
    else
        fbb.attached[i] = true;
    
    return true;
}
 
bool context::frame_buffer_enable(frame_buffer_base& fbb)
{
    if (fbb.handle == 0) {
        error("context::frame_buffer_enable: attempt to enable not created frame buffer", &fbb);
        return false;
    }
    if (fbb.is_enabled) {
        if (frame_buffer_stack.top() == &fbb) {
            error("context::frame_buffer_enable() called with frame buffer that is currently active", &fbb);
            return false;
        }
        error("context::frame_buffer_enable() called with frame buffer that is recursively reactivated", &fbb);
        return false;
    }
    frame_buffer_stack.push(&fbb);
    fbb.is_enabled = true;
    return true;
}
 
bool context::frame_buffer_disable(frame_buffer_base& fbb)
{
    if (frame_buffer_stack.size() == 1) {
        error("gl_context::frame_buffer_disable called with empty stack", &fbb);
        return false;
    }
    if (frame_buffer_stack.top() != &fbb) {
        error("gl_context::frame_buffer_disable called with different frame buffer enabled", &fbb);
        return false;
    }
    frame_buffer_stack.pop();
    fbb.is_enabled = false;
    return true;
}
 
bool context::frame_buffer_destruct(frame_buffer_base& fbb) const
{
    if (fbb.handle == 0) {
        error("context::frame_buffer_destruct: attempt to destruct not created frame buffer", &fbb);
        return false;
    }
    if (fbb.is_enabled) {
        error("context::frame_buffer_destruct() on frame buffer that was still enabled", &fbb);
        return false;
    }
    return true;
}
 
std::vector<context_creation_function_type>& ref_context_creation_functions()
{
    static std::vector<context_creation_function_type> ccfs;
    return ccfs;
}
 
void register_context_factory(context_creation_function_type fp)
{
    ref_context_creation_functions().push_back(fp);
}
 
context_factory_registration::context_factory_registration(context_creation_function_type fp)
{
    register_context_factory(fp);
};
 
context* create_context(RenderAPI api, 
        unsigned int w, unsigned int h, 
        const std::string& title, bool show)
{
    std::vector<context_creation_function_type>& ccfs = ref_context_creation_functions();
    for (unsigned i=0; i<ccfs.size(); ++i) {
        context* ctx = ccfs[i](api,w,h,title,show);
        if (ctx) {
            ctx->make_current();
            return ctx;
        }
    }
    std::cerr << "could not create context for given parameters" << std::endl;
    return 0;
}
 
 
    }
}
 
#include <cgv/base/register.h>
 
struct render_config_registration
{
    render_config_registration()
    {
        cgv::base::register_object(cgv::render::get_render_config(), "register global render config");
    }
};
 
render_config_registration render_config_registration_instance;
 
#undef SAFE_STACK_POP