framebuffer.h

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/* Conquer Space
 * Copyright (C) 2021-2025 Conquer Space
 *
 * 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/>.
 */
#pragma once
 
#include <glad/glad.h>
 
#include <memory>
#include <utility>
#include <vector>
 
#include "engine/renderer/renderer.h"
#include "engine/window.h"
 
namespace cqsp::engine {
class IFramebuffer {
 public:
    virtual ~IFramebuffer() {}
 
    virtual void InitTexture(int width = 1280, int height = 720) = 0;
    virtual void Clear() = 0;
    virtual void BeginDraw() = 0;
    virtual void EndDraw() = 0;
    virtual void RenderBuffer() = 0;
    virtual void Free() = 0;
    virtual void NewFrame(const Window& window) = 0;
 
    virtual Mesh& GetMeshOutput() = 0;
    virtual void SetMesh(Mesh_t) = 0;
    virtual void SetShader(asset::ShaderProgram_t shader) = 0;
};
 
class FramebufferRenderer : public IFramebuffer {
 public:
    FramebufferRenderer() : IFramebuffer(), width(0), height(0), framebuffer(0), colorbuffer(0), rbo(0) {}
    ~FramebufferRenderer();
 
    void InitTexture(int width, int height) override;
    void Clear() override;
    void BeginDraw() override;
    void EndDraw() override;
    void RenderBuffer() override;
    void Free() override;
    void NewFrame(const Window& window) override;
    void SetMesh(Mesh_t mesh) override { mesh_output = mesh; }
    Mesh& GetMeshOutput() override { return *mesh_output; }
    void SetShader(asset::ShaderProgram_t shader) override { buffer_shader = shader; }
    void FreeBuffer();
 
 private:
    unsigned int framebuffer;
    unsigned int colorbuffer;
    unsigned int rbo;
    int width;
    int height;
    asset::ShaderProgram_t buffer_shader;
    engine::Mesh_t mesh_output;
};
 
class AAFrameBufferRenderer : public IFramebuffer {
 public:
    AAFrameBufferRenderer()
        : IFramebuffer(), width(0), height(0), framebuffer(0), intermediateFBO(0), screenTexture(0), mscat(0), rbo(0) {}
    ~AAFrameBufferRenderer();
 
    void InitTexture(int width, int height) override;
    void Clear() override;
    void BeginDraw() override;
    void EndDraw() override;
    void Free() override;
    void RenderBuffer() override;
    void NewFrame(const Window& window) override;
    void FreeBuffer();
 
    engine::Mesh& GetMeshOutput() override { return *mesh_output; }
    void SetMesh(engine::Mesh_t mesh) override { mesh_output = mesh; }
    void SetShader(asset::ShaderProgram_t shader) override { buffer_shader = shader; }
 
 private:
    int width;
    int height;
 
    unsigned int framebuffer;
    unsigned int intermediateFBO;
    unsigned int screenTexture;
    unsigned int mscat;
    unsigned int rbo;
    asset::ShaderProgram_t buffer_shader;
    Mesh_t mesh_output;
};
 
class LayerRenderer {
 public:
    LayerRenderer();
    template <class T>
    int AddLayer(asset::ShaderProgram_t shader, const engine::Window& window) {
        std::unique_ptr<T> fb = std::make_unique<T>();
        InitFramebuffer(fb.get(), shader, window);
        framebuffers.push_back(std::move(fb));
        return framebuffers.size() - 1;
    }
 
    void BeginDraw(int layer);
    void EndDraw(int layer);
    void DrawAllLayers();
    void NewFrame(const cqsp::engine::Window& window);
    int GetLayerCount();
 
    IFramebuffer* GetFrameBuffer(int layer) { return framebuffers[layer].get(); }
 
 private:
    unsigned int blend_source_factor;
    unsigned int blend_dest_factor;
    std::vector<std::unique_ptr<IFramebuffer>> framebuffers;
    void InitFramebuffer(IFramebuffer* buffer, cqsp::asset::ShaderProgram_t shader, const cqsp::engine::Window& window);
};
 
const char* FramebufferStatusToString(GLenum error);
}  // namespace cqsp::engine