BLT-With-Graphics-Template/src/blt/gfx/framebuffer.cpp

/*
 *  Copyright (C) 2024  Brett Terpstra
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include <blt/gfx/framebuffer.h>

namespace blt::gfx
{
    void rbo_t::create()
    {
        glGenRenderbuffers(1, &rboID);
    }
    
    void rbo_t::bind() const
    {
        glBindRenderbuffer(GL_RENDERBUFFER, rboID);
    }
    
    void rbo_t::unbind()
    {
        glBindRenderbuffer(GL_RENDERBUFFER, 0);
    }
    
    void rbo_t::destroy()
    {
        glDeleteRenderbuffers(1, &rboID);
    }
    
    void rbo_t::updateStorage(blt::i32 width, blt::i32 height)
    {
        width_ = width;
        height_ = height;
        glRenderbufferStorage(GL_RENDERBUFFER, storage_type, width, height);
    }
    
    void rbo_t::setStorage(GLuint s_type, blt::i32 width, blt::i32 height)
    {
        storage_type = s_type;
        updateStorage(width, height);
    }
    
    rbo_t rbo_t::make_render_buffer(GLuint storage_type, blt::i32 width, blt::i32 height)
    {
        rbo_t rbo{};
        rbo.create();
        rbo.bind();
        rbo.setStorage(storage_type, width, height);
        rbo_t::unbind();
        return rbo;
    }
    
    void fbo_t::create(fbo_t::draw_t type)
    {
        generic_bind_type = static_cast<GLuint>(type);
        glGenFramebuffers(1, &fboID);
    }
    
    void fbo_t::bind(draw_t type) const
    {
        glBindFramebuffer(static_cast<GLuint>(type), fboID);
    }
    
    void fbo_t::unbind()
    {
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
    }
    
    void fbo_t::destroy()
    {
        glDeleteFramebuffers(1, &fboID);
        for (auto& v : render_buffers)
            v.destroy();
        for (auto* texture : texture_buffers)
            delete texture;
    }
    
    bool fbo_t::validate()
    {
        return glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE;
    }
    
    void fbo_t::attachTexture(blt::gfx::texture_gl* texture, attachment_t attachment, int level)
    {
        texture_buffers.push_back(texture);
        glFramebufferTexture2D(generic_bind_type, static_cast<GLuint>(attachment), texture->getBindType(), texture->getTextureID(), level);
    }
    
    void fbo_t::attachRenderBuffer(rbo_t rbo, fbo_t::attachment_t attachment)
    {
        rbo.bind();
        glFramebufferRenderbuffer(generic_bind_type, static_cast<GLuint>(attachment), GL_RENDERBUFFER, rbo.rboID);
        render_buffers.push_back(rbo);
    }
    
    void fbo_t::updateBuffersStorage(blt::i32 width, blt::i32 height)
    {
        for (auto& rbo : render_buffers)
        {
            rbo.bind();
            rbo.updateStorage(width, height);
        }
        
        for (auto& texture : texture_buffers)
            texture->updateSize(width, height);
    }
    
    void fbo_t::blitTexture(const fbo_t& draw, blt::i32 x1_offset, blt::i32 y1_offset, blt::i32 x2_offset, blt::i32 y2_offset)
    {
        if (texture_buffers.empty())
        {
            BLT_ERROR("Trying to blit texture with no texture attached!");
            return;
        }
        glBindFramebuffer(GL_READ_FRAMEBUFFER, fboID);
        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, draw.fboID);
        //glBlitFramebuffer(x1_offset, y1_offset, texture_buffers[0].)
    }
    
    void fbo_t::blitDepth(fbo_t draw, blt::i32 x1_offset, blt::i32 y1_offset, blt::i32 x2_offset, blt::i32 y2_offset)
    {
    
    }
    
    fbo_t fbo_t::make_render_texture(blt::i32 width, blt::i32 height)
    {
        fbo_t fbo;
        
        fbo.create();
        fbo.bind();
        
        auto* texture = new texture_gl2D(width, height);
        fbo.attachTexture(texture, attachment_t::COLOR0);
        
        rbo_t depth_rbo;
        depth_rbo.create();
        depth_rbo.bind();
        depth_rbo.setStorage(GL_DEPTH24_STENCIL8, width, height);
        
        fbo.attachRenderBuffer(depth_rbo, attachment_t::DEPTH_STENCIL);
        
        if (!fbo_t::validate())
            BLT_ERROR("Failed to create render texture framebuffer!");
        fbo_t::unbind();
        
        return fbo;
    }
}