cellular-shader/fbo.h

#ifndef FBO_H
#define FBO_H

#include <stdexcept>

#include <GL/glew.h>
#include <GL/freeglut.h>


class fbo {
	int width, height;
	GLuint fbo_number;
	std::map<GLenum, GLuint> renderbuffers;
	GLuint texture_id;

public:
	fbo(int width, int height) : width(width), height(height) {
		check_status();
		glGenBuffers(1, &fbo_number);
		begin();

		// generate texture
		glGenTextures(1, &texture_id);
		glEnable(GL_TEXTURE_2D);
		glBindTexture(GL_TEXTURE_2D, texture_id);
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_BYTE, 0);
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_id, 0);

		// attach depth
		create_attach_renderbuffer(GL_DEPTH_COMPONENT, GL_DEPTH_ATTACHMENT);

		// attach stencil
		create_attach_renderbuffer(GL_STENCIL_INDEX, GL_STENCIL_ATTACHMENT);

		check_status();
	}
	~fbo() {
		end();

		glDeleteFramebuffers(1, &fbo_number);

		for(auto& it : renderbuffers){
			glDeleteFramebuffers(1, &it.second);
		}

		glDeleteTextures(1, &texture_id);
	}

	void begin(){
		glBindFramebuffer(GL_FRAMEBUFFER, fbo_number);
	}

	void end(){
		glBindFramebuffer(GL_FRAMEBUFFER, 0);
	}

private:
	void create_attach_renderbuffer(GLenum format, GLenum attachment_point) {
		GLuint buffer;
		glGenRenderbuffers(1, &buffer);
		glBindRenderbuffer(GL_RENDERBUFFER, buffer);
		glRenderbufferStorage(GL_RENDERBUFFER, format, width, height);
		glFramebufferRenderbuffer(GL_FRAMEBUFFER, attachment_point, GL_RENDERBUFFER, buffer);

		renderbuffers[format] = buffer;
	}

	void check_status() {
		GLenum status = glGetError();
		if(status != GL_NO_ERROR) {
			status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
			switch(status) {
			case GL_FRAMEBUFFER_COMPLETE:
				std::cout << "FRAMEBUFFER_COMPLETE - OK" << std::endl;
				return;
			case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
				std::cout << "FRAMEBUFFER_INCOMPLETE_ATTACHMENT" << std::endl;
				break;
			case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
				std::cout << "FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT" << std::endl;
				break;
			/*case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
				std::cout << "FRAMEBUFFER_INCOMPLETE_DIMENSIONS" << std::endl;
				break;
			case GL_FRAMEBUFFER_INCOMPLETE_FORMATS:
				std::cout << "FRAMEBUFFER_INCOMPLETE_FORMATS" << std::endl;
				break;*/
			case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
				std::cout << "FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER" << std::endl;
				break;
			case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
				std::cout << "FRAMEBUFFER_INCOMPLETE_READ_BUFFER" << std::endl;
				break;
			case GL_FRAMEBUFFER_UNSUPPORTED:
				std::cout << "FRAMEBUFFER_UNSUPPORTED" << std::endl;
				break;
			case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
				std::cout << "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE" << std::endl;
				break;
			default:
				std::cout << "UNKNOWN FRAMEBUFFER ERROR" << std::endl;
				break;
			}
			throw std::runtime_error("I will not continu..");
		}
	}

};

#endif // FBO_H