#include "PrecompiledHeader.h"
#include "gBuffer.h"

bool GBuffer::Init(unsigned int WindowWidth, unsigned int WindowHeight)
{
	// Create the FBO
	glGenFramebuffers(1, &m_fbo); 
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_fbo);

	// Create the gbuffer textures
	glGenTextures(ARRAY_SIZE_IN_ELEMENTS(m_textures), m_textures);
	glGenTextures(1, &m_depthTexture);

	for (unsigned int i = 0 ; i < ARRAY_SIZE_IN_ELEMENTS(m_textures) ; i++) {
		glBindTexture(GL_TEXTURE_2D, m_textures[i]);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, WindowWidth, WindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
		glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, m_textures[i], 0);
	}

	// depth
	glBindTexture(GL_TEXTURE_2D, m_depthTexture);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, WindowWidth, WindowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT,
		NULL);
	glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, m_depthTexture, 0);

	GLenum DrawBuffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3 }; 
	glDrawBuffers(ARRAY_SIZE_IN_ELEMENTS(DrawBuffers), DrawBuffers);

	GLenum Status = glCheckFramebufferStatus(GL_FRAMEBUFFER);

	if (Status != GL_FRAMEBUFFER_COMPLETE) {
		printf("FB error, status: 0x%x\n", Status);
		return false;
	}

	// restore default FBO
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);

	return true;
}