gistfile1.cpp

struct FramebufferWraper {
    glm::uvec2 size;
    GLuint fbo{ 0 };
    GLuint color{ 0 };
    GLuint depth{ 0 };

    virtual ~FramebufferWraper() {
        release();
    }

    void allocate() {
        release();
        glGenRenderbuffers(1, &depth);
        assert(depth);
        glGenTextures(1, &color);
        assert(color);
        glGenFramebuffers(1, &fbo);
        assert(fbo);
    }

    void release() {
        if (fbo) {
            glDeleteFramebuffers(1, &fbo);
            fbo = 0;
        }
        if (color) {
            glDeleteTextures(1, &color);
            color = 0;
        }
        if (depth) {
            glDeleteRenderbuffers(1, &depth);
            depth = 0;
        }
    }

    static bool checkStatus(GLenum target = GL_FRAMEBUFFER) {
        GLuint status = glCheckFramebufferStatus(target);
        switch (status) {
        case GL_FRAMEBUFFER_COMPLETE:
            return true;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
            std::cerr << "framebuffer incomplete attachment" << std::endl;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
            std::cerr << "framebuffer missing attachment" << std::endl;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
            std::cerr << "framebuffer incomplete draw buffer" << std::endl;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
            std::cerr << "framebuffer incomplete read buffer" << std::endl;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
            std::cerr << "framebuffer incomplete multisample" << std::endl;
            break;

        case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:
            std::cerr << "framebuffer incomplete layer targets" << std::endl;
            break;

        case GL_FRAMEBUFFER_UNSUPPORTED:
            std::cerr << "framebuffer unsupported internal format or image" << std::endl;
            break;

        default:
            std::cerr << "other framebuffer error" << std::endl;
            break;
        }

        return false;
    }

    void init(const glm::ivec2 & size) {
        this->size = size;
        allocate();

        glBindFramebuffer(GL_FRAMEBUFFER, fbo);

        glBindTexture(GL_TEXTURE_2D, color);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
        glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, size.x, size.y);
        glBindTexture(GL_TEXTURE_2D, 0);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);

        glBindRenderbuffer(GL_RENDERBUFFER, depth);
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, size.x, size.y);
        glBindRenderbuffer(GL_RENDERBUFFER, 0);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth);

        if (!checkStatus()) {
            FAIL("Could not create a valid framebuffer");
        }
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
    }

    void activate() {
        assert(fbo);
        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
        glViewport(0, 0, size.x, size.y);
    }
};