#include "FBO.h"

FBO::FBO()
{
	glGenFramebuffers(1, &mFBO);
}

void FBO::AttachColorBuffer(const char*bufferName, GLenum attachment, GLenum dataType, int width, int height)
{
	GLuint colorBuffer;
	glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
	glGenTextures(1, &colorBuffer);
	glBindTexture(GL_TEXTURE_2D, colorBuffer);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

	if (dataType == GL_RGBA16F) {
		glTexImage2D(GL_TEXTURE_2D, 0, dataType, width, height, 0, GL_RGBA, GL_UNSIGNED_SHORT, NULL);
	}
	else {
		glTexImage2D(GL_TEXTURE_2D, 0, dataType, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	}
	glBindTexture(GL_TEXTURE_2D, 0);
	glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GL_TEXTURE_2D, colorBuffer, 0);
	
	mDrawBuffers.push_back(attachment);
	mBuffers.insert(std::pair<std::string,GLuint>(bufferName,colorBuffer));
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void FBO::AttachDepthBuffer(const char*bufferName, int width, int height)
{
	GLuint depthMap;
	glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
	glGenTextures(1, &depthMap);
	glBindTexture(GL_TEXTURE_2D, depthMap);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
	glBindTexture(GL_TEXTURE_2D, 0);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
	mBuffers.insert(std::pair<std::string, GLuint>(bufferName, depthMap));
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void FBO::Finish()
{
	int nCount = (int)mDrawBuffers.size();
	if (nCount>0)
	{
		GLenum *buffers = new GLenum[nCount];
		int i = 0;
		while (i < nCount)
		{
			buffers[i++] = mDrawBuffers[i];
		}
		glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
		glDrawBuffers(nCount, buffers);
		glBindFramebuffer(GL_FRAMEBUFFER, 0);
	}
}

void FBO::Bind()
{
	glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
}

void FBO::Unbind()
{
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

GLuint FBO::GetBuffer(const char*bufferName)
{
	auto iter = mBuffers.find(bufferName);
	if (iter!=mBuffers.end())
	{
		return iter->second;
	}
	return 0;
}