spg-project/LayeredFramebuffer.cpp

#include <iostream>

#include "LayeredFramebuffer.h"

LayeredFramebuffer::LayeredFramebuffer(int width, int height, int depth)
    : texture(0), buffer(0) {
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_3D, texture);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
    glTexImage3D(GL_TEXTURE_3D, 0, GL_R32F, width, height, depth, 0, GL_RED,
                 GL_FLOAT, nullptr);

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

    GLenum c = GL_COLOR_ATTACHMENT0;
    glFramebufferTexture3D(GL_FRAMEBUFFER, c, GL_TEXTURE_3D, texture, 0, 0);
    glDrawBuffers(1, &c);
}

LayeredFramebuffer::~LayeredFramebuffer() {
    glDeleteFramebuffers(1, &buffer);
    glDeleteTextures(1, &texture);
}

void LayeredFramebuffer::bindAndClear() {
    glBindFramebuffer(GL_FRAMEBUFFER, buffer);
    glClear(GL_COLOR_BUFFER_BIT);
}

void LayeredFramebuffer::bindTextureTo(int unit) const {
    glActiveTexture(GL_TEXTURE0 + unit);
    glBindTexture(GL_TEXTURE_3D, texture);
}

void LayeredFramebuffer::bindLayer(int layer) {
    glBindFramebuffer(GL_FRAMEBUFFER, buffer);
    glFramebufferTexture3D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_3D,
                           texture, 0, layer);
}

bool LayeredFramebuffer::hasError() const {
    GLenum error = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    if(error == GL_FRAMEBUFFER_COMPLETE) {
        return false;
    }
    switch(error) {
        case GL_FRAMEBUFFER_UNDEFINED:
            std::cout << "undefined framebuffer\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
            std::cout << "incomplete framebuffer attachment\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
            std::cout << "incomplete missing framebuffer attachment\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
            std::cout << "incomplete framebuffer draw buffer\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
            std::cout << "incomplete framebuffer read buffer\n";
            return true;
        case GL_FRAMEBUFFER_UNSUPPORTED:
            std::cout << "unsupported framebuffer\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE:
            std::cout << "incomplete framebuffer multisample\n";
            return true;
        case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS:
            std::cout << "incomplete framebuffer layer targets\n";
            return true;
    }
    return "unknown error";
}