gl_vr_display.cxx

#include "gl_vr_display.h"
 
#include <GL/glew.h>
 
namespace vr {
 
gl_vr_display::gl_vr_display(unsigned _width, unsigned _height, unsigned _nr_multi_samples)
    : width(_width), height(_height), nr_multi_samples(_nr_multi_samples)
{
    for (unsigned i = 0; i < 2; ++i) {
        multi_depth_buffer_id[i] = 0;
        multi_tex_id[i] = 0;
        multi_fbo_id[i] = 0;
        tex_id[i] = 0;
        fbo_id[i] = 0;
    }
}
 
gl_vr_display::~gl_vr_display() 
{
}
 
const std::string& gl_vr_display::get_last_error() const 
{
    return last_error; 
}
 
void gl_vr_display::set_size(int new_width, int new_height)
{
    width = new_width;
    height = new_height;
}
 
int gl_vr_display::get_width() const
{
    return width;
}
int gl_vr_display::get_height() const
{
    return height;
}
 
bool gl_vr_display::fbos_initialized(EyeSelection es) const
{
    switch (es) {
    case ES_BOTH :
        return fbo_id[0] != 0 && fbo_id[1] != 0 && multi_fbo_id[0] != 0 && multi_fbo_id[1] != 0;
    case ES_LEFT:
        return fbo_id[0] != 0 && multi_fbo_id[0];
    case ES_RIGHT:
        return fbo_id[1] != 0 && multi_fbo_id[1] != 0;
    }
    return false;
}
 
void gl_vr_display::destruct_fbos(EyeSelection es)
{
    for (unsigned i = 0; i < 2; ++i) {
        if (es == ES_LEFT && i == 1)
            continue;
        if (es == ES_RIGHT && i == 0)
            continue;
        if (multi_depth_buffer_id[i] != 0) {
            glDeleteRenderbuffers(1, &multi_depth_buffer_id[i]);
            multi_depth_buffer_id[i] = 0;
        }
        if (multi_tex_id[i] != 0) {
            glDeleteTextures(1, &multi_tex_id[i]);
            multi_tex_id[i] = 0;
        }
        if (multi_fbo_id[i] != 0) {
            glDeleteFramebuffers(1, &multi_fbo_id[i]);
            multi_fbo_id[i] = 0;
        }
        if (tex_id[i] != 0) {
            glDeleteTextures(1, &tex_id[i]);
            tex_id[i] = 0;
        }
        if (fbo_id[i] != 0) {
            glDeleteFramebuffers(1, &fbo_id[i]);
            fbo_id[i] = 0;
        }
    }
}
 
bool gl_vr_display::init_fbos(EyeSelection es)
{
    for (unsigned i = 0; i < 2; ++i) {
        if (es == ES_LEFT && i == 1)
            continue;
        if (es == ES_RIGHT && i == 0)
            continue;
 
        glGenFramebuffers(1, &multi_fbo_id[i]);
        glBindFramebuffer(GL_FRAMEBUFFER, multi_fbo_id[i]);
 
        glGenRenderbuffers(1, &multi_depth_buffer_id[i]);
        glBindRenderbuffer(GL_RENDERBUFFER, multi_depth_buffer_id[i]);
        glRenderbufferStorageMultisample(GL_RENDERBUFFER, nr_multi_samples, GL_DEPTH_COMPONENT, width, height);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, multi_depth_buffer_id[i]);
 
        glGenTextures(1, &multi_tex_id[i]);
        glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, multi_tex_id[i]);
        glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, nr_multi_samples, GL_RGBA8, width, height, true);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, multi_tex_id[i], 0);
 
        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
            destruct_fbos();
            glBindFramebuffer(GL_FRAMEBUFFER, 0);
            last_error = "check status of multi framebuffer failed";
            return false;
        }
 
        glGenFramebuffers(1, &fbo_id[i]);
        glBindFramebuffer(GL_FRAMEBUFFER, fbo_id[i]);
 
        glGenTextures(1, &tex_id[i]);
        glBindTexture(GL_TEXTURE_2D, tex_id[i]);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex_id[i], 0);
 
        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
            destruct_fbos();
            glBindFramebuffer(GL_FRAMEBUFFER, 0);
            last_error = "check status of framebuffer failed";
            return false;
        }
    }
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    return true;
}
void gl_vr_display::bind_texture(int eye)
{
    glBindTexture(GL_TEXTURE_2D, tex_id[eye]);
}
 
void gl_vr_display::enable_fbo(int eye)
{
    old_msaa = (int)glIsEnabled(GL_MULTISAMPLE);
    if (old_msaa == GL_FALSE)
        glEnable(GL_MULTISAMPLE);
    // Left Eye
    glBindFramebuffer(GL_FRAMEBUFFER, multi_fbo_id[eye]);
    glGetIntegerv(GL_VIEWPORT, vp);
    glViewport(0, 0, width, height);
}
 
bool gl_vr_display::blit_fbo(int eye, int x, int y, int w, int h)
{
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo_id[eye]);
    glBlitFramebuffer(0, 0, width, height, x, y, x+w, y+h,
        GL_COLOR_BUFFER_BIT, GL_NEAREST);
    glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
    return true;
}
 
void gl_vr_display::disable_fbo(int eye)
{
    glViewport(vp[0], vp[1], vp[2], vp[3]);
 
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glDisable(GL_MULTISAMPLE);
 
    glBindFramebuffer(GL_READ_FRAMEBUFFER, multi_fbo_id[eye]);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo_id[eye]);
    glBlitFramebuffer(0, 0, width, height, 0, 0, width, height,
        GL_COLOR_BUFFER_BIT, GL_LINEAR);
    glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 
    if (old_msaa == GL_TRUE)
        glEnable(GL_MULTISAMPLE);
}
 
}