framebuffer.hpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#pragma once

#include <gls/headercheck.hpp>
#include <gls/errorcheck.hpp>
#include <gls/objects/object.hpp>
#include <gls/objects/renderbuffer.hpp>
#include <type_traits>
#include <unordered_map>
#include <cassert>

namespace gls {

namespace priv {
    void gen_framebuffers( GLsizei size, GLuint* name ) { glGenFramebuffers( size, name ); }
    void delete_framebuffers( GLsizei size, const GLuint* name ) { glDeleteFramebuffers( size, name ); }
}

class framebuffer {
public:
    GLuint name() const {
        return m_object.name();
    }

    void bind() {
        check_gl_error( glBindFramebuffer( GL_FRAMEBUFFER, m_object.name() ) );
    }

    static void unbind() {
        check_gl_error( glBindFramebuffer( GL_FRAMEBUFFER, 0 ) );
    }

    void attach_texture( GLenum attachment, GLenum textarget, const texture<GL_TEXTURE_CUBE_MAP>& the_texture, GLint level ) {
        bind();
        check_gl_error( glFramebufferTexture2D( GL_FRAMEBUFFER, attachment, textarget, the_texture.name(), level ) );
        unbind();
    }

    template<GLenum Target>
    void attach_texture( GLenum attachment, const texture<Target>& the_texture, GLint level ) {
        static_assert( Target != GL_TEXTURE_CUBE_MAP, "glFramebufferTexture cannot take non-array cubemaps" );

        bind();
        check_gl_error( glFramebufferTexture( GL_FRAMEBUFFER, attachment, the_texture.name(), level ) );
        unbind();
    }

    template<GLenum Target>
    void attach_texture_layer( GLenum attachment, const texture<Target>& the_texture, GLint level, GLint layer ) {
        static_assert( Target != GL_TEXTURE_CUBE_MAP, "glFramebufferTextureLayer cannot take non-array cubemaps" );

        bind();
        check_gl_error( glFramebufferTextureLayer( GL_FRAMEBUFFER, attachment, the_texture.name(), level, layer ) );
        unbind();
    }

    void detach_texture( GLenum attachment ) {
        bind();
        check_gl_error( glFramebufferTexture( GL_FRAMEBUFFER, attachment, 0, 0 ) );
        unbind();
    }

    void add_renderbuffer( GLenum attachment, renderbuffer&& the_renderbuffer ) {
        bind();
        check_gl_error( glFramebufferRenderbuffer( GL_FRAMEBUFFER, attachment, GL_RENDERBUFFER, the_renderbuffer.name() ) );
        m_renderbuffers.emplace( attachment, std::forward<renderbuffer>( the_renderbuffer ) );
        unbind();
    }

    void remove_renderbuffer( GLenum attachment ) {
        bind();
        check_gl_error( glFramebufferRenderbuffer( GL_FRAMEBUFFER, attachment, GL_RENDERBUFFER, 0 ) );
        m_renderbuffers.erase( attachment );
        unbind();
    }

    GLenum status() {
        bind();
        auto status_value = check_gl_error( glCheckFramebufferStatus( GL_FRAMEBUFFER ) );
        unbind();

        return status_value;
    }

    bool complete() {
        return status() == GL_FRAMEBUFFER_COMPLETE;
    }

private:
    std::unordered_map<GLenum, renderbuffer> m_renderbuffers;
    object<priv::gen_framebuffers, priv::delete_framebuffers> m_object;
};

}