frame_buffer.cpp

// SPDX-License-Identifier: MIT
// Author:  Giovanni Santini
// Mail:    giovanni.santini@proton.me
// Github:  @San7o
 
#include <brenta/frame_buffer.hpp>
#include <brenta/gl.hpp>
#include <brenta/logger.hpp>
#include <brenta/window.hpp>
 
#include <stdexcept>
 
using namespace brenta;
using namespace brenta::types;
 
framebuffer::framebuffer(int width, int height, GLenum format)
{
  this->format = format;
 
  glGenFramebuffers(1, &this->id);
  if (this->id == 0)
  {
    ERROR("framebuffer: error generating framebuffer");
    throw std::runtime_error("framebuffer: error generating framebuffer");
  }
  glBindFramebuffer(GL_FRAMEBUFFER, this->id);
  check_error();
 
  glGenTextures(1, &this->texture_id);
  if (this->texture_id == 0)
  {
    ERROR("framebuffer: error generating texture");
    exit(1);
  }
  glBindTexture(GL_TEXTURE_2D, this->texture_id);
  check_error();
 
  glTexImage2D(GL_TEXTURE_2D, 0, this->format, width, height, 0, GL_RGB,
               GL_UNSIGNED_BYTE, NULL);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                         this->texture_id, 0);
 
  glGenRenderbuffers(1, &this->render_buffer_id);
  glBindRenderbuffer(GL_RENDERBUFFER, this->render_buffer_id);
  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                            GL_RENDERBUFFER, this->render_buffer_id);
  check_error();
 
  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
  {
    ERROR("framebuffer: not complete");
    exit(1);
  }
 
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
  glBindTexture(GL_TEXTURE_2D, 0);
  glBindRenderbuffer(GL_RENDERBUFFER, 0);
}
 
framebuffer::~framebuffer()
{
  glDeleteFramebuffers(1, &this->id);
  glDeleteTextures(1, &this->texture_id);
}
 
void framebuffer::bind()
{
  glBindFramebuffer(GL_FRAMEBUFFER, this->id);
  check_error();
}
 
void framebuffer::unbind()
{
  glBindFramebuffer(GL_FRAMEBUFFER, 0);
  check_error();
}
 
void framebuffer::destroy()
{
  glDeleteFramebuffers(1, &this->id);
  glDeleteTextures(1, &this->texture_id);
}
 
void framebuffer::rescale(int width, int height)
{
  glBindFramebuffer(GL_FRAMEBUFFER, this->id);
  if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
  {
    ERROR("framebuffer: not complete");
    return;
  }
 
  glBindTexture(GL_TEXTURE_2D, this->texture_id);
  check_error();
 
  glTexImage2D(GL_TEXTURE_2D, 0, this->format, width, height, 0, GL_RGBA,
               GL_UNSIGNED_BYTE, NULL);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                         this->texture_id, 0);
  glBindTexture(GL_TEXTURE_2D, 0);
  check_error();
 
  glBindRenderbuffer(GL_RENDERBUFFER, this->render_buffer_id);
  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
  glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                            GL_RENDERBUFFER, this->render_buffer_id);
 
  window::set_width_height(width, height);
}
 
void framebuffer::set_format(GLenum format)
{
  this->format = format;
}