//
// viewporteffect.h
//
// Copyright © 2020 Celestia Development Team. All rights reserved.
//
// 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 2
// of the License, or (at your option) any later version.

#pragma once

#include <string>
#include <celengine/glsupport.h>
#include <celengine/vertexobject.h>

class FramebufferObject;
class Renderer;
class CelestiaGLProgram;
class WarpMesh;

class ViewportEffect
{
 public:
    virtual ~ViewportEffect() = default;

    virtual bool preprocess(Renderer*, FramebufferObject*);
    virtual bool prerender(Renderer*, FramebufferObject*);
    virtual bool render(Renderer*, FramebufferObject*, int width, int height) = 0;
    virtual bool distortXY(float& x, float& y);

 private:
    GLint oldFboId;
};

class PassthroughViewportEffect : public ViewportEffect
{
 public:
    PassthroughViewportEffect();
    ~PassthroughViewportEffect() override = default;

    bool prerender(Renderer*, FramebufferObject* fbo) override;
    bool render(Renderer*, FramebufferObject*, int width, int height) override;

 private:
    celgl::VertexObject vo;

    void initializeVO(celgl::VertexObject&);
    void draw(celgl::VertexObject&);
};

class WarpMeshViewportEffect : public ViewportEffect
{
 public:
    WarpMeshViewportEffect(WarpMesh *mesh);
    ~WarpMeshViewportEffect() override = default;

    bool prerender(Renderer*, FramebufferObject* fbo) override;
    bool render(Renderer*, FramebufferObject*, int width, int height) override;
    bool distortXY(float& x, float& y) override;

 private:
    celgl::VertexObject vo;
    WarpMesh *mesh;

    void initializeVO(celgl::VertexObject&);
    void draw(celgl::VertexObject&);
};