framebuffer.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 <http://www.gnu.org/licenses/>.
 *
 */

#ifndef BACKENDS_GRAPHICS_OPENGL_FRAMEBUFFER_H
#define BACKENDS_GRAPHICS_OPENGL_FRAMEBUFFER_H

#include "graphics/opengl/system_headers.h"

#include "math/matrix4.h"

namespace OpenGL {

class Pipeline;

class Framebuffer {
public:
    Framebuffer();
    virtual ~Framebuffer() {};

public:
    enum BlendMode {
        kBlendModeDisabled,

        kBlendModeOpaque,

        kBlendModeTraditionalTransparency,

        kBlendModePremultipliedTransparency,

        kBlendModeAdditive,

        kBlendModeMaskAlphaAndInvertByColor,
    };

    void setClearColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a);

    void enableBlend(BlendMode mode);

    void enableScissorTest(bool enable);

    void setScissorBox(GLint x, GLint y, GLsizei w, GLsizei h);

    const Math::Matrix4 &getProjectionMatrix() const { return _projectionMatrix; }

    enum CopyMask {
        kCopyMaskClearColor   = (1 << 0),
        kCopyMaskBlendState   = (1 << 1),
        kCopyMaskScissorState = (1 << 2),
        kCopyMaskScissorBox   = (1 << 4),

        kCopyMaskAll          = kCopyMaskClearColor | kCopyMaskBlendState |
                                kCopyMaskScissorState | kCopyMaskScissorBox,
    };

    void copyRenderStateFrom(const Framebuffer &other, uint copyMask);

protected:
    bool isActive() const { return _pipeline != nullptr; }

    GLint _viewport[4];
    void applyViewport();

    Math::Matrix4 _projectionMatrix;
    void applyProjectionMatrix();

    virtual void activateInternal() = 0;

    virtual void deactivateInternal() {}

public:
    virtual bool setSize(uint width, uint height) = 0;

    void activate(Pipeline *pipeline);

    void deactivate();

private:
    Pipeline *_pipeline;

    GLfloat _clearColor[4];
    void applyClearColor();

    BlendMode _blendState;
    void applyBlendState();

    bool _scissorTestState;
    void applyScissorTestState();

    GLint _scissorBox[4];
    void applyScissorBox();
};

class Backbuffer : public Framebuffer {
public:
    bool setSize(uint width, uint height) override;

protected:
    void activateInternal() override;
};

#if !USE_FORCED_GLES
class GLTexture;

class TextureTarget : public Framebuffer {
public:
    TextureTarget();
    ~TextureTarget() override;

    void destroy();

    void create();

    bool setSize(uint width, uint height) override;

    GLTexture *getTexture() const { return _texture; }

protected:
    void activateInternal() override;

private:
    GLTexture *_texture;
    GLuint _glFBO;
    bool _needUpdate;
};
#endif

} // End of namespace OpenGL

#endif