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/* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef BACKENDS_GRAPHICS_OPENGL_FRAMEBUFFER_H
#define BACKENDS_GRAPHICS_OPENGL_FRAMEBUFFER_H
#include "backends/graphics/opengl/opengl-sys.h"
namespace OpenGL {
/**
* Object describing a framebuffer OpenGL can render to.
*/
class Framebuffer {
friend class Pipeline;
public:
Framebuffer();
virtual ~Framebuffer() {};
public:
enum BlendMode {
/**
* Newly drawn pixels overwrite the existing contents of the framebuffer
* without mixing with them
*/
kBlendModeDisabled,
/**
* Newly drawn pixels mix with the framebuffer based on their alpha value
* for transparency.
*/
kBlendModeTraditionalTransparency,
/**
* Newly drawn pixels mix with the framebuffer based on their alpha value
* for transparency.
*
* Requires the image data being drawn to have its color values pre-multipled
* with the alpha value.
*/
kBlendModePremultipliedTransparency
};
/**
* Set the clear color of the framebuffer.
*/
void setClearColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a);
/**
* Enable/disable GL_BLEND.
*/
void enableBlend(BlendMode mode);
/**
* Enable/disable GL_SCISSOR_TEST.
*/
void enableScissorTest(bool enable);
/**
* Set scissor box dimensions.
*/
void setScissorBox(GLint x, GLint y, GLsizei w, GLsizei h);
/**
* Obtain projection matrix of the framebuffer.
*/
const GLfloat *getProjectionMatrix() const { return _projectionMatrix; }
protected:
bool isActive() const { return _isActive; }
GLint _viewport[4];
void applyViewport();
GLfloat _projectionMatrix[4*4];
void applyProjectionMatrix();
/**
* Activate framebuffer.
*
* This is supposed to set all state associated with the framebuffer.
*/
virtual void activateInternal() = 0;
/**
* Deactivate framebuffer.
*
* This is supposed to make any cleanup required when unbinding the
* framebuffer.
*/
virtual void deactivateInternal() {}
private:
/**
* Accessor to activate framebuffer for pipeline.
*/
void activate();
/**
* Accessor to deactivate framebuffer from pipeline.
*/
void deactivate();
private:
bool _isActive;
GLfloat _clearColor[4];
void applyClearColor();
BlendMode _blendState;
void applyBlendState();
bool _scissorTestState;
void applyScissorTestState();
GLint _scissorBox[4];
void applyScissorBox();
};
/**
* Default back buffer implementation.
*/
class Backbuffer : public Framebuffer {
public:
/**
* Set the dimensions (a.k.a. size) of the back buffer.
*/
void setDimensions(uint width, uint height);
protected:
virtual void activateInternal();
};
#if !USE_FORCED_GLES
class GLTexture;
/**
* Render to texture framebuffer implementation.
*
* This target allows to render to a texture, which can then be used for
* further rendering.
*/
class TextureTarget : public Framebuffer {
public:
TextureTarget();
virtual ~TextureTarget();
/**
* Notify that the GL context is about to be destroyed.
*/
void destroy();
/**
* Notify that the GL context has been created.
*/
void create();
/**
* Set size of the texture target.
*/
void setSize(uint width, uint height);
/**
* Query pointer to underlying GL texture.
*/
GLTexture *getTexture() const { return _texture; }
protected:
virtual void activateInternal();
private:
GLTexture *_texture;
GLuint _glFBO;
bool _needUpdate;
};
#endif
} // End of namespace OpenGL
#endif
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