RenderTarget.cpp

#include "RenderTarget.h"

#include <GL/glew.h>
#include <exception>
#include <iostream>

using namespace glm;

RenderTarget::RenderTarget(int width, int height) : width(width), height(height) {
	glGenFramebuffers(1, &framebuffer);
	glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
	glGenTextures(2, renderedTextures);
	glBindTexture(GL_TEXTURE_2D, renderedTextures[0]);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glBindTexture(GL_TEXTURE_2D, renderedTextures[1]);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
	glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, renderedTextures[0], 0);
	glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, renderedTextures[1], 0);
	glGenRenderbuffers(1, &rbo);
	glBindRenderbuffer(GL_RENDERBUFFER, rbo);
	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
	GLenum drawBuffers[2] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };
	glDrawBuffers(2, drawBuffers);
	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) throw std::exception("Couldn't create framebuffer!");
	data = new float[3 * width * height];
}

void RenderTarget::resize(int width, int height) {
	this->width = width;
	this->height = height;
	delete[] data;
	glBindTexture(GL_TEXTURE_2D, renderedTextures[0]);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
	glBindTexture(GL_TEXTURE_2D, renderedTextures[1]);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
	glBindRenderbuffer(GL_RENDERBUFFER, rbo);
	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
	data = new float[3 * width * height];
}

void RenderTarget::bind() {
	glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
}

void RenderTarget::unbind() {
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);
}

void RenderTarget::texApply() {
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, renderedTextures[0]);
}

unsigned RenderTarget::getWidth() {
	return this->width;
}

unsigned RenderTarget::getHeight() {
	return this->height;
}

float RenderTarget::get(vec2 loc) {
	return data[int(width * loc.y + loc.x)];
}

float RenderTarget::sample(vec2 v) {
	return data[int(width * (v.y * height + v.x))];
}

RenderTarget::~RenderTarget() {
	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glDeleteFramebuffers(1, &framebuffer);
	glBindTexture(GL_TEXTURE_2D, 0);
	glDeleteTextures(1, renderedTextures);
	glBindRenderbuffer(GL_RENDERBUFFER, 0);
	glDeleteRenderbuffers(1, &rbo);
	delete[] data;
}