meemknight.PikaEngine/Pika/core/pikaSTD/pikaGL/frameBuffer.cpp

#include "frameBuffer.h"

namespace pika
{
	namespace GL
	{

		void PikaFramebuffer::createFramebuffer(unsigned int w, unsigned int h, bool hasDepth)
		{
			this->w = w;
			this->h = h;

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

			glGenTextures(1, &texture);
			glBindTexture(GL_TEXTURE_2D, texture);

			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);

			//glDrawBuffer(GL_COLOR_ATTACHMENT0); //todo look into this function

			if (hasDepth)
			{
				glGenTextures(1, &depthTexture); //todo add depth stuff
				glBindTexture(GL_TEXTURE_2D, depthTexture);

				glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32, w, h, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, nullptr);

				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

				glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTexture, 0);
			}
			

			glBindTexture(GL_TEXTURE_2D, 0);
			glBindFramebuffer(GL_FRAMEBUFFER, 0);

		}

		void PikaFramebuffer::deleteFramebuffer()
		{
			if (fbo)
			{
				glDeleteFramebuffers(1, &fbo);
				fbo = 0;
			}

			if (texture)
			{
				glDeleteTextures(1, &texture);
				texture = 0;
			}

			if (depthTexture)
			{
				glDeleteTextures(1, &depthTexture);
				depthTexture = 0;
			}
		}

		void PikaFramebuffer::resizeFramebuffer(unsigned int w, unsigned int h)
		{
			if (this->w != w || this->h != h)
			{
				this->w = w;
				this->h = h;

				glBindTexture(GL_TEXTURE_2D, texture);
				glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

				if (depthTexture)
				{
					glBindTexture(GL_TEXTURE_2D, depthTexture);
					glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
				}

				glBindTexture(GL_TEXTURE_2D, 0);
			}

		}

		void PikaFramebuffer::clear()
		{
			glBindFramebuffer(GL_FRAMEBUFFER, fbo);
			//glClearColor(1, 1, 1, 0);
			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
			//glClearColor(0, 0, 0, 0);

			glBindFramebuffer(GL_FRAMEBUFFER, 0);
		}

	}


}