Windows-4.7.4/src/opengl/gl2paintengineex/qglengineshadermanager_p.h - platform/external/qt - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the QtOpenGL module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** GNU Lesser General Public License Usage
 ** This file may be used under the terms of the GNU Lesser General Public
 ** License version 2.1 as published by the Free Software Foundation and
 ** appearing in the file LICENSE.LGPL included in the packaging of this
 ** file. Please review the following information to ensure the GNU Lesser
 ** General Public License version 2.1 requirements will be met:
 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** In addition, as a special exception, Nokia gives you certain additional
 ** rights. These rights are described in the Nokia Qt LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU General
 ** Public License version 3.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of this
 ** file. Please review the following information to ensure the GNU General
 ** Public License version 3.0 requirements will be met:
 ** http://www.gnu.org/copyleft/gpl.html.
 **
 ** Other Usage
 ** Alternatively, this file may be used in accordance with the terms and
 ** conditions contained in a signed written agreement between you and Nokia.
 **
 **
 **
 **
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 //
 //  W A R N I N G
 //  -------------
 //
 // This file is not part of the Qt API.  It exists purely as an
 // implementation detail.  This header file may change from version to
 // version without notice, or even be removed.
 //
 // We mean it.
 //

 /*
     VERTEX SHADERS
     ==============

     Vertex shaders are specified as multiple (partial) shaders. On desktop,
     this works fine. On ES, QGLShader & QGLShaderProgram will make partial
     shaders work by concatenating the source in each QGLShader and compiling
     it as a single shader. This is abstracted nicely by QGLShaderProgram and
     the GL2 engine doesn't need to worry about it.

     Generally, there's two vertex shader objects. The position shaders are
     the ones which set gl_Position. There's also two "main" vertex shaders,
     one which just calls the position shader and another which also passes
     through some texture coordinates from a vertex attribute array to a
     varying. These texture coordinates are used for mask position in text
     rendering and for the source coordinates in drawImage/drawPixmap. There's
     also a "Simple" vertex shader for rendering a solid colour (used to render
     into the stencil buffer where the actual colour value is discarded).

     The position shaders for brushes look scary. This is because many of the
     calculations which logically belong in the fragment shader have been moved
     into the vertex shader to improve performance. This is why the position
     calculation is in a separate shader. Not only does it calculate the
     position, but it also calculates some data to be passed to the fragment
     shader as a varying. It is optimal to move as much of the calculation as
     possible into the vertex shader as this is executed less often.

     The varyings passed to the fragment shaders are interpolated (which is
     cheap). Unfortunately, GL will apply perspective correction to the
     interpolation calusing errors. To get around this, the vertex shader must
     apply perspective correction itself and set the w-value of gl_Position to
     zero. That way, GL will be tricked into thinking it doesn't need to apply a
     perspective correction and use linear interpolation instead (which is what
     we want). Of course, if the brush transform is affeine, no perspective
     correction is needed and a simpler vertex shader can be used instead.

     So there are the following "main" vertex shaders:
         qglslMainVertexShader
         qglslMainWithTexCoordsVertexShader

     And the the following position vertex shaders:
         qglslPositionOnlyVertexShader
         qglslPositionWithTextureBrushVertexShader
         qglslPositionWithPatternBrushVertexShader
         qglslPositionWithLinearGradientBrushVertexShader
         qglslPositionWithRadialGradientBrushVertexShader
         qglslPositionWithConicalGradientBrushVertexShader
         qglslAffinePositionWithTextureBrushVertexShader
         qglslAffinePositionWithPatternBrushVertexShader
         qglslAffinePositionWithLinearGradientBrushVertexShader
         qglslAffinePositionWithRadialGradientBrushVertexShader
         qglslAffinePositionWithConicalGradientBrushVertexShader

     Leading to 23 possible vertex shaders


     FRAGMENT SHADERS
     ================

     Fragment shaders are also specified as multiple (partial) shaders. The
     different fragment shaders represent the different stages in Qt's fragment
     pipeline. There are 1-3 stages in this pipeline: First stage is to get the
     fragment's colour value. The next stage is to get the fragment's mask value
     (coverage value for anti-aliasing) and the final stage is to blend the
     incoming fragment with the background (for composition modes not supported
     by GL).

     Of these, the first stage will always be present. If Qt doesn't need to
     apply anti-aliasing (because it's off or handled by multisampling) then
     the coverage value doesn't need to be applied. (Note: There are two types
     of mask, one for regular anti-aliasing and one for sub-pixel anti-
     aliasing.) If the composition mode is one which GL supports natively then
     the blending stage doesn't need to be applied.

     As eash stage can have multiple implementations, they are abstracted as
     GLSL function calls with the following signatures:

     Brushes & image drawing are implementations of "qcolorp vec4 srcPixel()":
         qglslImageSrcFragShader
         qglslImageSrcWithPatternFragShader
         qglslNonPremultipliedImageSrcFragShader
         qglslSolidBrushSrcFragShader
         qglslTextureBrushSrcFragShader
         qglslTextureBrushWithPatternFragShader
         qglslPatternBrushSrcFragShader
         qglslLinearGradientBrushSrcFragShader
         qglslRadialGradientBrushSrcFragShader
         qglslConicalGradientBrushSrcFragShader
     NOTE: It is assumed the colour returned by srcPixel() is pre-multiplied

     Masks are implementations of "qcolorp vec4 applyMask(qcolorp vec4 src)":
         qglslMaskFragmentShader
         qglslRgbMaskFragmentShaderPass1
         qglslRgbMaskFragmentShaderPass2
         qglslRgbMaskWithGammaFragmentShader

     Composition modes are "qcolorp vec4 compose(qcolorp vec4 src)":
         qglslColorBurnCompositionModeFragmentShader
         qglslColorDodgeCompositionModeFragmentShader
         qglslDarkenCompositionModeFragmentShader
         qglslDifferenceCompositionModeFragmentShader
         qglslExclusionCompositionModeFragmentShader
         qglslHardLightCompositionModeFragmentShader
         qglslLightenCompositionModeFragmentShader
         qglslMultiplyCompositionModeFragmentShader
         qglslOverlayCompositionModeFragmentShader
         qglslScreenCompositionModeFragmentShader
         qglslSoftLightCompositionModeFragmentShader


     Note: In the future, some GLSL compilers will support an extension allowing
           a new 'color' precision specifier. To support this, qcolorp is used for
           all color components so it can be defined to colorp or lowp depending upon
           the implementation.

     So there are differnt frament shader main functions, depending on the
     number & type of pipelines the fragment needs to go through.

     The choice of which main() fragment shader string to use depends on:
         - Use of global opacity
         - Brush style (some brushes apply opacity themselves)
         - Use & type of mask (TODO: Need to support high quality anti-aliasing & text)
         - Use of non-GL Composition mode

     Leading to the following fragment shader main functions:
         gl_FragColor = compose(applyMask(srcPixel()*globalOpacity));
         gl_FragColor = compose(applyMask(srcPixel()));
         gl_FragColor = applyMask(srcPixel()*globalOpacity);
         gl_FragColor = applyMask(srcPixel());
         gl_FragColor = compose(srcPixel()*globalOpacity);
         gl_FragColor = compose(srcPixel());
         gl_FragColor = srcPixel()*globalOpacity;
         gl_FragColor = srcPixel();

     Called:
         qglslMainFragmentShader_CMO
         qglslMainFragmentShader_CM
         qglslMainFragmentShader_MO
         qglslMainFragmentShader_M
         qglslMainFragmentShader_CO
         qglslMainFragmentShader_C
         qglslMainFragmentShader_O
         qglslMainFragmentShader

     Where:
         M = Mask
         C = Composition
         O = Global Opacity


     CUSTOM SHADER CODE
     ==================

     The use of custom shader code is supported by the engine for drawImage and
     drawPixmap calls. This is implemented via hooks in the fragment pipeline.

     The custom shader is passed to the engine as a partial fragment shader
     (QGLCustomShaderStage). The shader will implement a pre-defined method name
     which Qt's fragment pipeline will call:

         lowp vec4 customShader(lowp sampler2d imageTexture, highp vec2 textureCoords)

     The provided src and srcCoords parameters can be used to sample from the
     source image.

     Transformations, clipping, opacity, and composition modes set using QPainter
     will be respected when using the custom shader hook.
 */

 #ifndef QGLENGINE_SHADER_MANAGER_H
 #define QGLENGINE_SHADER_MANAGER_H

 #include <QGLShader>
 #include <QGLShaderProgram>
 #include <QPainter>
 #include <private/qgl_p.h>
 #include <private/qglcustomshaderstage_p.h>

 QT_BEGIN_HEADER

 QT_BEGIN_NAMESPACE

 QT_MODULE(OpenGL)


 /*
 struct QGLEngineCachedShaderProg
 {
     QGLEngineCachedShaderProg(QGLEngineShaderManager::ShaderName vertexMain,
                               QGLEngineShaderManager::ShaderName vertexPosition,
                               QGLEngineShaderManager::ShaderName fragMain,
                               QGLEngineShaderManager::ShaderName pixelSrc,
                               QGLEngineShaderManager::ShaderName mask,
                               QGLEngineShaderManager::ShaderName composition);

     int cacheKey;
     QGLShaderProgram* program;
 }
 */

 static const GLuint QT_VERTEX_COORDS_ATTR  = 0;
 static const GLuint QT_TEXTURE_COORDS_ATTR = 1;
 static const GLuint QT_OPACITY_ATTR = 2;
 static const GLuint QT_PMV_MATRIX_1_ATTR = 3;
 static const GLuint QT_PMV_MATRIX_2_ATTR = 4;
 static const GLuint QT_PMV_MATRIX_3_ATTR = 5;

 class QGLEngineShaderProg;

 class QGLEngineSharedShaders : public QObject
 {
     Q_OBJECT
 public:

     enum SnippetName {
         MainVertexShader,
         MainWithTexCoordsVertexShader,
         MainWithTexCoordsAndOpacityVertexShader,

         // UntransformedPositionVertexShader must be first in the list:
         UntransformedPositionVertexShader,
         PositionOnlyVertexShader,
         ComplexGeometryPositionOnlyVertexShader,
         PositionWithPatternBrushVertexShader,
         PositionWithLinearGradientBrushVertexShader,
         PositionWithConicalGradientBrushVertexShader,
         PositionWithRadialGradientBrushVertexShader,
         PositionWithTextureBrushVertexShader,
         AffinePositionWithPatternBrushVertexShader,
         AffinePositionWithLinearGradientBrushVertexShader,
         AffinePositionWithConicalGradientBrushVertexShader,
         AffinePositionWithRadialGradientBrushVertexShader,
         AffinePositionWithTextureBrushVertexShader,

         // MainFragmentShader_CMO must be first in the list:
         MainFragmentShader_CMO,
         MainFragmentShader_CM,
         MainFragmentShader_MO,
         MainFragmentShader_M,
         MainFragmentShader_CO,
         MainFragmentShader_C,
         MainFragmentShader_O,
         MainFragmentShader,
         MainFragmentShader_ImageArrays,

         // ImageSrcFragmentShader must be first in the list::
         ImageSrcFragmentShader,
         ImageSrcWithPatternFragmentShader,
         NonPremultipliedImageSrcFragmentShader,
         CustomImageSrcFragmentShader,
         SolidBrushSrcFragmentShader,
         TextureBrushSrcFragmentShader,
         TextureBrushSrcWithPatternFragmentShader,
         PatternBrushSrcFragmentShader,
         LinearGradientBrushSrcFragmentShader,
         RadialGradientBrushSrcFragmentShader,
         ConicalGradientBrushSrcFragmentShader,
         ShockingPinkSrcFragmentShader,

         // NoMaskFragmentShader must be first in the list:
         NoMaskFragmentShader,
         MaskFragmentShader,
         RgbMaskFragmentShaderPass1,
         RgbMaskFragmentShaderPass2,
         RgbMaskWithGammaFragmentShader,

         // NoCompositionModeFragmentShader must be first in the list:
         NoCompositionModeFragmentShader,
         MultiplyCompositionModeFragmentShader,
         ScreenCompositionModeFragmentShader,
         OverlayCompositionModeFragmentShader,
         DarkenCompositionModeFragmentShader,
         LightenCompositionModeFragmentShader,
         ColorDodgeCompositionModeFragmentShader,
         ColorBurnCompositionModeFragmentShader,
         HardLightCompositionModeFragmentShader,
         SoftLightCompositionModeFragmentShader,
         DifferenceCompositionModeFragmentShader,
         ExclusionCompositionModeFragmentShader,

         TotalSnippetCount, InvalidSnippetName
     };
 #if defined (QT_DEBUG)
     Q_ENUMS(SnippetName)
     static QByteArray snippetNameStr(SnippetName snippetName);
 #endif

 /*
     // These allow the ShaderName enum to be used as a cache key
     const int mainVertexOffset = 0;
     const int positionVertexOffset = (1<<2) - PositionOnlyVertexShader;
     const int mainFragOffset = (1<<6) - MainFragmentShader_CMO;
     const int srcPixelOffset = (1<<10) - ImageSrcFragmentShader;
     const int maskOffset = (1<<14) - NoMaskShader;
     const int compositionOffset = (1 << 16) - MultiplyCompositionModeFragmentShader;
 */

     QGLEngineSharedShaders(const QGLContext *context);
     ~QGLEngineSharedShaders();

     QGLShaderProgram *simpleProgram() { return simpleShaderProg; }
     QGLShaderProgram *blitProgram() { return blitShaderProg; }
     // Compile the program if it's not already in the cache, return the item in the cache.
     QGLEngineShaderProg *findProgramInCache(const QGLEngineShaderProg &prog);
     // Compile the custom shader if it's not already in the cache, return the item in the cache.

     static QGLEngineSharedShaders *shadersForContext(const QGLContext *context);

     // Ideally, this would be static and cleanup all programs in all contexts which
     // contain the custom code. Currently it is just a hint and we rely on deleted
     // custom shaders being cleaned up by being kicked out of the cache when it's
     // full.
     void cleanupCustomStage(QGLCustomShaderStage* stage);

 signals:
     void shaderProgNeedsChanging();

 private:
     QGLSharedResourceGuard ctxGuard;
     QGLShaderProgram *blitShaderProg;
     QGLShaderProgram *simpleShaderProg;
     QList<QGLEngineShaderProg*> cachedPrograms;

     static const char* qShaderSnippets[TotalSnippetCount];
 };


 class QGLEngineShaderProg
 {
 public:
     QGLEngineShaderProg() : program(0) {}

     ~QGLEngineShaderProg() {
         if (program)
             delete program;
     }

     QGLEngineSharedShaders::SnippetName mainVertexShader;
     QGLEngineSharedShaders::SnippetName positionVertexShader;
     QGLEngineSharedShaders::SnippetName mainFragShader;
     QGLEngineSharedShaders::SnippetName srcPixelFragShader;
     QGLEngineSharedShaders::SnippetName maskFragShader;
     QGLEngineSharedShaders::SnippetName compositionFragShader;

     QByteArray          customStageSource; //TODO: Decent cache key for custom stages
     QGLShaderProgram*   program;

     QVector<uint> uniformLocations;

     bool                useTextureCoords;
     bool                useOpacityAttribute;
     bool                usePmvMatrixAttribute;

     bool operator==(const QGLEngineShaderProg& other) {
         // We don't care about the program
         return ( mainVertexShader      == other.mainVertexShader &&
                  positionVertexShader  == other.positionVertexShader &&
                  mainFragShader        == other.mainFragShader &&
                  srcPixelFragShader    == other.srcPixelFragShader &&
                  maskFragShader        == other.maskFragShader &&
                  compositionFragShader == other.compositionFragShader &&
                  customStageSource     == other.customStageSource
                );
     }
 };

 class Q_OPENGL_EXPORT QGLEngineShaderManager : public QObject
 {
     Q_OBJECT
 public:
     QGLEngineShaderManager(QGLContext* context);
     ~QGLEngineShaderManager();

     enum MaskType {NoMask, PixelMask, SubPixelMaskPass1, SubPixelMaskPass2, SubPixelWithGammaMask};
     enum PixelSrcType {
         ImageSrc = Qt::TexturePattern+1,
         NonPremultipliedImageSrc = Qt::TexturePattern+2,
         PatternSrc = Qt::TexturePattern+3,
         TextureSrcWithPattern = Qt::TexturePattern+4
     };

     enum Uniform {
         ImageTexture,
         PatternColor,
         GlobalOpacity,
         Depth,
         MaskTexture,
         FragmentColor,
         LinearData,
         Angle,
         HalfViewportSize,
         Fmp,
         Fmp2MRadius2,
         Inverse2Fmp2MRadius2,
         InvertedTextureSize,
         BrushTransform,
         BrushTexture,
         Matrix,
         NumUniforms
     };

     enum OpacityMode {
         NoOpacity,
         UniformOpacity,
         AttributeOpacity
     };

     // There are optimizations we can do, depending on the brush transform:
     //    1) May not have to apply perspective-correction
     //    2) Can use lower precision for matrix
     void optimiseForBrushTransform(QTransform::TransformationType transformType);
     void setSrcPixelType(Qt::BrushStyle);
     void setSrcPixelType(PixelSrcType); // For non-brush sources, like pixmaps & images
     void setOpacityMode(OpacityMode);
     void setMaskType(MaskType);
     void setCompositionMode(QPainter::CompositionMode);
     void setCustomStage(QGLCustomShaderStage* stage);
     void removeCustomStage();

     GLuint getUniformLocation(Uniform id);

     void setDirty(); // someone has manually changed the current shader program
     bool useCorrectShaderProg(); // returns true if the shader program needed to be changed

     void useSimpleProgram();
     void useBlitProgram();
     void setHasComplexGeometry(bool hasComplexGeometry)
     {
         complexGeometry = hasComplexGeometry;
         shaderProgNeedsChanging = true;
     }
     bool hasComplexGeometry() const
     {
         return complexGeometry;
     }

     QGLShaderProgram* currentProgram(); // Returns pointer to the shader the manager has chosen
     QGLShaderProgram* simpleProgram(); // Used to draw into e.g. stencil buffers
     QGLShaderProgram* blitProgram(); // Used to blit a texture into the framebuffer

     QGLEngineSharedShaders* sharedShaders;

 private slots:
     void shaderProgNeedsChangingSlot() { shaderProgNeedsChanging = true; }

 private:
     QGLContext*     ctx;
     bool            shaderProgNeedsChanging;
     bool            complexGeometry;

     // Current state variables which influence the choice of shader:
     QTransform                  brushTransform;
     int                         srcPixelType;
     OpacityMode                 opacityMode;
     MaskType                    maskType;
     QPainter::CompositionMode   compositionMode;
     QGLCustomShaderStage*       customSrcStage;

     QGLEngineShaderProg*    currentShaderProg;
 };

 QT_END_NAMESPACE

 QT_END_HEADER

 #endif //QGLENGINE_SHADER_MANAGER_H
	/****************************************************************************
	**
	** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
	** All rights reserved.
	** Contact: Nokia Corporation (qt-info@nokia.com)
	**
	** This file is part of the QtOpenGL module of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:LGPL$
	** GNU Lesser General Public License Usage
	** This file may be used under the terms of the GNU Lesser General Public
	** License version 2.1 as published by the Free Software Foundation and
	** appearing in the file LICENSE.LGPL included in the packaging of this
	** file. Please review the following information to ensure the GNU Lesser
	** General Public License version 2.1 requirements will be met:
	** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
	**
	** In addition, as a special exception, Nokia gives you certain additional
	** rights. These rights are described in the Nokia Qt LGPL Exception
	** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
	**
	** GNU General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU General
	** Public License version 3.0 as published by the Free Software Foundation
	** and appearing in the file LICENSE.GPL included in the packaging of this
	** file. Please review the following information to ensure the GNU General
	** Public License version 3.0 requirements will be met:
	** http://www.gnu.org/copyleft/gpl.html.
	**
	** Other Usage
	** Alternatively, this file may be used in accordance with the terms and
	** conditions contained in a signed written agreement between you and Nokia.
	**
	**
	**
	**
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	//
	// W A R N I N G
	// -------------
	//
	// This file is not part of the Qt API. It exists purely as an
	// implementation detail. This header file may change from version to
	// version without notice, or even be removed.
	//
	// We mean it.
	//

	/*
	VERTEX SHADERS
	==============

	Vertex shaders are specified as multiple (partial) shaders. On desktop,
	this works fine. On ES, QGLShader & QGLShaderProgram will make partial
	shaders work by concatenating the source in each QGLShader and compiling
	it as a single shader. This is abstracted nicely by QGLShaderProgram and
	the GL2 engine doesn't need to worry about it.

	Generally, there's two vertex shader objects. The position shaders are
	the ones which set gl_Position. There's also two "main" vertex shaders,
	one which just calls the position shader and another which also passes
	through some texture coordinates from a vertex attribute array to a
	varying. These texture coordinates are used for mask position in text
	rendering and for the source coordinates in drawImage/drawPixmap. There's
	also a "Simple" vertex shader for rendering a solid colour (used to render
	into the stencil buffer where the actual colour value is discarded).

	The position shaders for brushes look scary. This is because many of the
	calculations which logically belong in the fragment shader have been moved
	into the vertex shader to improve performance. This is why the position
	calculation is in a separate shader. Not only does it calculate the
	position, but it also calculates some data to be passed to the fragment
	shader as a varying. It is optimal to move as much of the calculation as
	possible into the vertex shader as this is executed less often.

	The varyings passed to the fragment shaders are interpolated (which is
	cheap). Unfortunately, GL will apply perspective correction to the
	interpolation calusing errors. To get around this, the vertex shader must
	apply perspective correction itself and set the w-value of gl_Position to
	zero. That way, GL will be tricked into thinking it doesn't need to apply a
	perspective correction and use linear interpolation instead (which is what
	we want). Of course, if the brush transform is affeine, no perspective
	correction is needed and a simpler vertex shader can be used instead.

	So there are the following "main" vertex shaders:
	qglslMainVertexShader
	qglslMainWithTexCoordsVertexShader

	And the the following position vertex shaders:
	qglslPositionOnlyVertexShader
	qglslPositionWithTextureBrushVertexShader
	qglslPositionWithPatternBrushVertexShader
	qglslPositionWithLinearGradientBrushVertexShader
	qglslPositionWithRadialGradientBrushVertexShader
	qglslPositionWithConicalGradientBrushVertexShader
	qglslAffinePositionWithTextureBrushVertexShader
	qglslAffinePositionWithPatternBrushVertexShader
	qglslAffinePositionWithLinearGradientBrushVertexShader
	qglslAffinePositionWithRadialGradientBrushVertexShader
	qglslAffinePositionWithConicalGradientBrushVertexShader

	Leading to 23 possible vertex shaders


	FRAGMENT SHADERS
	================

	Fragment shaders are also specified as multiple (partial) shaders. The
	different fragment shaders represent the different stages in Qt's fragment
	pipeline. There are 1-3 stages in this pipeline: First stage is to get the
	fragment's colour value. The next stage is to get the fragment's mask value
	(coverage value for anti-aliasing) and the final stage is to blend the
	incoming fragment with the background (for composition modes not supported
	by GL).

	Of these, the first stage will always be present. If Qt doesn't need to
	apply anti-aliasing (because it's off or handled by multisampling) then
	the coverage value doesn't need to be applied. (Note: There are two types
	of mask, one for regular anti-aliasing and one for sub-pixel anti-
	aliasing.) If the composition mode is one which GL supports natively then
	the blending stage doesn't need to be applied.

	As eash stage can have multiple implementations, they are abstracted as
	GLSL function calls with the following signatures:

	Brushes & image drawing are implementations of "qcolorp vec4 srcPixel()":
	qglslImageSrcFragShader
	qglslImageSrcWithPatternFragShader
	qglslNonPremultipliedImageSrcFragShader
	qglslSolidBrushSrcFragShader
	qglslTextureBrushSrcFragShader
	qglslTextureBrushWithPatternFragShader
	qglslPatternBrushSrcFragShader
	qglslLinearGradientBrushSrcFragShader
	qglslRadialGradientBrushSrcFragShader
	qglslConicalGradientBrushSrcFragShader
	NOTE: It is assumed the colour returned by srcPixel() is pre-multiplied

	Masks are implementations of "qcolorp vec4 applyMask(qcolorp vec4 src)":
	qglslMaskFragmentShader
	qglslRgbMaskFragmentShaderPass1
	qglslRgbMaskFragmentShaderPass2
	qglslRgbMaskWithGammaFragmentShader

	Composition modes are "qcolorp vec4 compose(qcolorp vec4 src)":
	qglslColorBurnCompositionModeFragmentShader
	qglslColorDodgeCompositionModeFragmentShader
	qglslDarkenCompositionModeFragmentShader
	qglslDifferenceCompositionModeFragmentShader
	qglslExclusionCompositionModeFragmentShader
	qglslHardLightCompositionModeFragmentShader
	qglslLightenCompositionModeFragmentShader
	qglslMultiplyCompositionModeFragmentShader
	qglslOverlayCompositionModeFragmentShader
	qglslScreenCompositionModeFragmentShader
	qglslSoftLightCompositionModeFragmentShader


	Note: In the future, some GLSL compilers will support an extension allowing
	a new 'color' precision specifier. To support this, qcolorp is used for
	all color components so it can be defined to colorp or lowp depending upon
	the implementation.

	So there are differnt frament shader main functions, depending on the
	number & type of pipelines the fragment needs to go through.

	The choice of which main() fragment shader string to use depends on:
	- Use of global opacity
	- Brush style (some brushes apply opacity themselves)
	- Use & type of mask (TODO: Need to support high quality anti-aliasing & text)
	- Use of non-GL Composition mode

	Leading to the following fragment shader main functions:
	gl_FragColor = compose(applyMask(srcPixel()*globalOpacity));
	gl_FragColor = compose(applyMask(srcPixel()));
	gl_FragColor = applyMask(srcPixel()*globalOpacity);
	gl_FragColor = applyMask(srcPixel());
	gl_FragColor = compose(srcPixel()*globalOpacity);
	gl_FragColor = compose(srcPixel());
	gl_FragColor = srcPixel()*globalOpacity;
	gl_FragColor = srcPixel();

	Called:
	qglslMainFragmentShader_CMO
	qglslMainFragmentShader_CM
	qglslMainFragmentShader_MO
	qglslMainFragmentShader_M
	qglslMainFragmentShader_CO
	qglslMainFragmentShader_C
	qglslMainFragmentShader_O
	qglslMainFragmentShader

	Where:
	M = Mask
	C = Composition
	O = Global Opacity


	CUSTOM SHADER CODE
	==================

	The use of custom shader code is supported by the engine for drawImage and
	drawPixmap calls. This is implemented via hooks in the fragment pipeline.

	The custom shader is passed to the engine as a partial fragment shader
	(QGLCustomShaderStage). The shader will implement a pre-defined method name
	which Qt's fragment pipeline will call:

	lowp vec4 customShader(lowp sampler2d imageTexture, highp vec2 textureCoords)

	The provided src and srcCoords parameters can be used to sample from the
	source image.

	Transformations, clipping, opacity, and composition modes set using QPainter
	will be respected when using the custom shader hook.
	*/

	#ifndef QGLENGINE_SHADER_MANAGER_H
	#define QGLENGINE_SHADER_MANAGER_H

	#include <QGLShader>
	#include <QGLShaderProgram>
	#include <QPainter>
	#include <private/qgl_p.h>
	#include <private/qglcustomshaderstage_p.h>

	QT_BEGIN_HEADER

	QT_BEGIN_NAMESPACE

	QT_MODULE(OpenGL)


	/*
	struct QGLEngineCachedShaderProg
	{
	QGLEngineCachedShaderProg(QGLEngineShaderManager::ShaderName vertexMain,
	QGLEngineShaderManager::ShaderName vertexPosition,
	QGLEngineShaderManager::ShaderName fragMain,
	QGLEngineShaderManager::ShaderName pixelSrc,
	QGLEngineShaderManager::ShaderName mask,
	QGLEngineShaderManager::ShaderName composition);

	int cacheKey;
	QGLShaderProgram* program;
	}
	*/

	static const GLuint QT_VERTEX_COORDS_ATTR = 0;
	static const GLuint QT_TEXTURE_COORDS_ATTR = 1;
	static const GLuint QT_OPACITY_ATTR = 2;
	static const GLuint QT_PMV_MATRIX_1_ATTR = 3;
	static const GLuint QT_PMV_MATRIX_2_ATTR = 4;
	static const GLuint QT_PMV_MATRIX_3_ATTR = 5;

	class QGLEngineShaderProg;

	class QGLEngineSharedShaders : public QObject
	{
	Q_OBJECT
	public:

	enum SnippetName {
	MainVertexShader,
	MainWithTexCoordsVertexShader,
	MainWithTexCoordsAndOpacityVertexShader,

	// UntransformedPositionVertexShader must be first in the list:
	UntransformedPositionVertexShader,
	PositionOnlyVertexShader,
	ComplexGeometryPositionOnlyVertexShader,
	PositionWithPatternBrushVertexShader,
	PositionWithLinearGradientBrushVertexShader,
	PositionWithConicalGradientBrushVertexShader,
	PositionWithRadialGradientBrushVertexShader,
	PositionWithTextureBrushVertexShader,
	AffinePositionWithPatternBrushVertexShader,
	AffinePositionWithLinearGradientBrushVertexShader,
	AffinePositionWithConicalGradientBrushVertexShader,
	AffinePositionWithRadialGradientBrushVertexShader,
	AffinePositionWithTextureBrushVertexShader,

	// MainFragmentShader_CMO must be first in the list:
	MainFragmentShader_CMO,
	MainFragmentShader_CM,
	MainFragmentShader_MO,
	MainFragmentShader_M,
	MainFragmentShader_CO,
	MainFragmentShader_C,
	MainFragmentShader_O,
	MainFragmentShader,
	MainFragmentShader_ImageArrays,

	// ImageSrcFragmentShader must be first in the list::
	ImageSrcFragmentShader,
	ImageSrcWithPatternFragmentShader,
	NonPremultipliedImageSrcFragmentShader,
	CustomImageSrcFragmentShader,
	SolidBrushSrcFragmentShader,
	TextureBrushSrcFragmentShader,
	TextureBrushSrcWithPatternFragmentShader,
	PatternBrushSrcFragmentShader,
	LinearGradientBrushSrcFragmentShader,
	RadialGradientBrushSrcFragmentShader,
	ConicalGradientBrushSrcFragmentShader,
	ShockingPinkSrcFragmentShader,

	// NoMaskFragmentShader must be first in the list:
	NoMaskFragmentShader,
	MaskFragmentShader,
	RgbMaskFragmentShaderPass1,
	RgbMaskFragmentShaderPass2,
	RgbMaskWithGammaFragmentShader,

	// NoCompositionModeFragmentShader must be first in the list:
	NoCompositionModeFragmentShader,
	MultiplyCompositionModeFragmentShader,
	ScreenCompositionModeFragmentShader,
	OverlayCompositionModeFragmentShader,
	DarkenCompositionModeFragmentShader,
	LightenCompositionModeFragmentShader,
	ColorDodgeCompositionModeFragmentShader,
	ColorBurnCompositionModeFragmentShader,
	HardLightCompositionModeFragmentShader,
	SoftLightCompositionModeFragmentShader,
	DifferenceCompositionModeFragmentShader,
	ExclusionCompositionModeFragmentShader,

	TotalSnippetCount, InvalidSnippetName
	};
	#if defined (QT_DEBUG)
	Q_ENUMS(SnippetName)
	static QByteArray snippetNameStr(SnippetName snippetName);
	#endif

	/*
	// These allow the ShaderName enum to be used as a cache key
	const int mainVertexOffset = 0;
	const int positionVertexOffset = (1<<2) - PositionOnlyVertexShader;
	const int mainFragOffset = (1<<6) - MainFragmentShader_CMO;
	const int srcPixelOffset = (1<<10) - ImageSrcFragmentShader;
	const int maskOffset = (1<<14) - NoMaskShader;
	const int compositionOffset = (1 << 16) - MultiplyCompositionModeFragmentShader;
	*/

	QGLEngineSharedShaders(const QGLContext *context);
	~QGLEngineSharedShaders();

	QGLShaderProgram *simpleProgram() { return simpleShaderProg; }
	QGLShaderProgram *blitProgram() { return blitShaderProg; }
	// Compile the program if it's not already in the cache, return the item in the cache.
	QGLEngineShaderProg *findProgramInCache(const QGLEngineShaderProg &prog);
	// Compile the custom shader if it's not already in the cache, return the item in the cache.

	static QGLEngineSharedShaders shadersForContext(const QGLContext context);

	// Ideally, this would be static and cleanup all programs in all contexts which
	// contain the custom code. Currently it is just a hint and we rely on deleted
	// custom shaders being cleaned up by being kicked out of the cache when it's
	// full.
	void cleanupCustomStage(QGLCustomShaderStage* stage);

	signals:
	void shaderProgNeedsChanging();

	private:
	QGLSharedResourceGuard ctxGuard;
	QGLShaderProgram *blitShaderProg;
	QGLShaderProgram *simpleShaderProg;
	QList<QGLEngineShaderProg*> cachedPrograms;

	static const char* qShaderSnippets[TotalSnippetCount];
	};


	class QGLEngineShaderProg
	{
	public:
	QGLEngineShaderProg() : program(0) {}

	~QGLEngineShaderProg() {
	if (program)
	delete program;
	}

	QGLEngineSharedShaders::SnippetName mainVertexShader;
	QGLEngineSharedShaders::SnippetName positionVertexShader;
	QGLEngineSharedShaders::SnippetName mainFragShader;
	QGLEngineSharedShaders::SnippetName srcPixelFragShader;
	QGLEngineSharedShaders::SnippetName maskFragShader;
	QGLEngineSharedShaders::SnippetName compositionFragShader;

	QByteArray customStageSource; //TODO: Decent cache key for custom stages
	QGLShaderProgram* program;

	QVector<uint> uniformLocations;

	bool useTextureCoords;
	bool useOpacityAttribute;
	bool usePmvMatrixAttribute;

	bool operator==(const QGLEngineShaderProg& other) {
	// We don't care about the program
	return ( mainVertexShader == other.mainVertexShader &&
	positionVertexShader == other.positionVertexShader &&
	mainFragShader == other.mainFragShader &&
	srcPixelFragShader == other.srcPixelFragShader &&
	maskFragShader == other.maskFragShader &&
	compositionFragShader == other.compositionFragShader &&
	customStageSource == other.customStageSource
	);
	}
	};

	class Q_OPENGL_EXPORT QGLEngineShaderManager : public QObject
	{
	Q_OBJECT
	public:
	QGLEngineShaderManager(QGLContext* context);
	~QGLEngineShaderManager();

	enum MaskType {NoMask, PixelMask, SubPixelMaskPass1, SubPixelMaskPass2, SubPixelWithGammaMask};
	enum PixelSrcType {
	ImageSrc = Qt::TexturePattern+1,
	NonPremultipliedImageSrc = Qt::TexturePattern+2,
	PatternSrc = Qt::TexturePattern+3,
	TextureSrcWithPattern = Qt::TexturePattern+4
	};

	enum Uniform {
	ImageTexture,
	PatternColor,
	GlobalOpacity,
	Depth,
	MaskTexture,
	FragmentColor,
	LinearData,
	Angle,
	HalfViewportSize,
	Fmp,
	Fmp2MRadius2,
	Inverse2Fmp2MRadius2,
	InvertedTextureSize,
	BrushTransform,
	BrushTexture,
	Matrix,
	NumUniforms
	};

	enum OpacityMode {
	NoOpacity,
	UniformOpacity,
	AttributeOpacity
	};

	// There are optimizations we can do, depending on the brush transform:
	// 1) May not have to apply perspective-correction
	// 2) Can use lower precision for matrix
	void optimiseForBrushTransform(QTransform::TransformationType transformType);
	void setSrcPixelType(Qt::BrushStyle);
	void setSrcPixelType(PixelSrcType); // For non-brush sources, like pixmaps & images
	void setOpacityMode(OpacityMode);
	void setMaskType(MaskType);
	void setCompositionMode(QPainter::CompositionMode);
	void setCustomStage(QGLCustomShaderStage* stage);
	void removeCustomStage();

	GLuint getUniformLocation(Uniform id);

	void setDirty(); // someone has manually changed the current shader program
	bool useCorrectShaderProg(); // returns true if the shader program needed to be changed

	void useSimpleProgram();
	void useBlitProgram();
	void setHasComplexGeometry(bool hasComplexGeometry)
	{
	complexGeometry = hasComplexGeometry;
	shaderProgNeedsChanging = true;
	}
	bool hasComplexGeometry() const
	{
	return complexGeometry;
	}

	QGLShaderProgram* currentProgram(); // Returns pointer to the shader the manager has chosen
	QGLShaderProgram* simpleProgram(); // Used to draw into e.g. stencil buffers
	QGLShaderProgram* blitProgram(); // Used to blit a texture into the framebuffer

	QGLEngineSharedShaders* sharedShaders;

	private slots:
	void shaderProgNeedsChangingSlot() { shaderProgNeedsChanging = true; }

	private:
	QGLContext* ctx;
	bool shaderProgNeedsChanging;
	bool complexGeometry;

	// Current state variables which influence the choice of shader:
	QTransform brushTransform;
	int srcPixelType;
	OpacityMode opacityMode;
	MaskType maskType;
	QPainter::CompositionMode compositionMode;
	QGLCustomShaderStage* customSrcStage;

	QGLEngineShaderProg* currentShaderProg;
	};

	QT_END_NAMESPACE

	QT_END_HEADER

	#endif //QGLENGINE_SHADER_MANAGER_H