a_buffer.h

#pragma once 
 
#include <cgv/render/shader_program.h>
#include <cgv/render/texture.h>
#include <cgv/render/vertex_buffer.h>
#include <cgv_gl/gl/gl.h>
 
#include "gl/lib_begin.h"
 
namespace cgv {
    namespace render {

class CGV_API a_buffer
{
    shader_compile_options prog_options;
    shader_compile_options last_prog_options;
    bool init_frame_called;
protected:
    texture depth_tex;
    cgv::render::vertex_buffer node_counter_buffer = { cgv::render::VertexBufferType::VBT_ATOMIC_COUNTER };
    cgv::render::vertex_buffer head_pointer_buffer = { cgv::render::VertexBufferType::VBT_STORAGE };
    cgv::render::vertex_buffer node_buffer = { cgv::render::VertexBufferType::VBT_STORAGE };
    int depth_tex_unit;
    int node_counter_binding_point; 
    int head_pointers_binding_point;
    int nodes_binding_point;
    // GPU objects
    shader_program clear_ssbo_prog;
    shader_program a_buffer_prog;
 
    void ensure_buffers(context& ctx);
 
    void update_shader_program_options(shader_compile_options& options, bool include_binding_points);
public:
    bool pre_multiply_opacity = true;
    int z_fight_removal = 0;
    float z_fight_removal_exp = -5.0f;
    unsigned z_fight_window_width = 8;
    a_buffer(unsigned _fragments_per_pixel = 32, unsigned _nodes_per_pixel = 64, int _depth_tex_unit = 0, 
        int _node_counter_binding_point = 0, int _head_pointers_binding_point = 0, int _nodes_binding_point = 1);
    unsigned fragments_per_pixel;
    unsigned nodes_per_pixel;
    bool init(context& ctx);
    void destruct(context& ctx);
    void init_frame(context& ctx);
    void update_shader_program_options(shader_compile_options& options);

    bool enable(context& ctx, shader_program& prog, int tex_unit = -1);
    void disable(context& ctx, size_t* out_node_count = nullptr);
    void finish_frame(context& ctx);
 
    int& ref_depth_tex_unit() { return depth_tex_unit; }
    int& ref_node_counter_binding_point () { return  node_counter_binding_point  ; }
    int& ref_head_pointers_binding_point() { return  head_pointers_binding_point ; }
    int& ref_nodes_binding_point        () { return  nodes_binding_point         ; }
};
    }
}
 
#include <cgv/config/lib_end.h>