#include <poly/Log.h>
#include <TestFboChangeBuffer.h>

using namespace poly;

TestFboChangeBuffer::TestFboChangeBuffer()
  :fbo(0)
  ,dx(0)
{
  tex[0] = 0;
  tex[1] = 0;
}

TestFboChangeBuffer::~TestFboChangeBuffer() {
}

int TestFboChangeBuffer::init() {

  if (0 != fbo) {
    SX_ERROR("Cannot initialize because we're already initialized.");
    return -1;
  }


  glGenTextures(2, tex);

  glBindTexture(GL_TEXTURE_2D, tex[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1024, 1024, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glBindTexture(GL_TEXTURE_2D, tex[1]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1024, 1024, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  glBindTexture(GL_TEXTURE_2D, 0);

  glGenFramebuffers(1, &fbo);
  glBindFramebuffer(GL_FRAMEBUFFER, fbo);

  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex[0], 0);
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, tex[1], 0);

  if (GL_FRAMEBUFFER_COMPLETE != glCheckFramebufferStatus(GL_FRAMEBUFFER)) {
    SX_ERROR("Framebuffer not yet complete.");
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    return -1;
  }

  glBindFramebuffer(GL_FRAMEBUFFER, 0);
  
  return 0;
}

void TestFboChangeBuffer::activate() {

  glBindFramebuffer(GL_FRAMEBUFFER, fbo);
  
  if (0 == dx) {
    glDrawBuffer(GL_COLOR_ATTACHMENT1);
    glReadBuffer(GL_COLOR_ATTACHMENT0);
  }
  else {
    glDrawBuffer(GL_COLOR_ATTACHMENT0);
    glReadBuffer(GL_COLOR_ATTACHMENT1);
  }

  glViewport(0, 0, 1024, 1024);
}

void TestFboChangeBuffer::swap() {
  dx = 1 - dx;
}

GLuint TestFboChangeBuffer::getReadTexture() {
  return tex[dx]; 
}