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Diffstat (limited to 'src/opengl/gl2paintengineex/qglengineshadermanager_p.h')
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diff --git a/src/opengl/gl2paintengineex/qglengineshadermanager_p.h b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h new file mode 100644 index 0000000..b8b2745 --- /dev/null +++ b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h @@ -0,0 +1,385 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtOpenGL module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, 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 1.0, 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. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +// +// 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 seperate 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 + qglslNonPremultipliedImageSrcFragShader + qglslSolidBrushSrcFragShader + qglslTextureBrushSrcFragShader + 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 + qglslRgbMaskFragmentShader + 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 (idea, depricated) + ================== + + 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 + (QGLCustomizedShader). The shader will implement a pre-defined method name + which Qt's fragment pipeline will call. There are two different hooks which + can be implemented as custom shader code: + + mediump vec4 customShader(sampler2d src, vec2 srcCoords) + mediump vec4 customShaderWithDest(sampler2d dest, sampler2d src, vec2 srcCoords) + +*/ + +#ifndef QGLENGINE_SHADER_MANAGER_H +#define QGLENGINE_SHADER_MANAGER_H + +#include <QGLShader> +#include <QGLShaderProgram> +#include <QPainter> + +QT_BEGIN_HEADER + +QT_BEGIN_NAMESPACE + +QT_MODULE(OpenGL) + + +struct QGLEngineShaderProg +{ + QGLShader* mainVertexShader; + QGLShader* positionVertexShader; + QGLShader* mainFragShader; + QGLShader* srcPixelFragShader; + QGLShader* maskFragShader; // Can be null for no mask + QGLShader* compositionFragShader; // Can be null for GL-handled mode + QGLShaderProgram* program; +}; + +/* +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; + +class QGLEngineShaderManager : public QObject +{ + Q_OBJECT; +public: + QGLEngineShaderManager(QGLContext* context); + ~QGLEngineShaderManager(); + + enum MaskType {NoMask, PixelMask, SubPixelMask, SubPixelWithGammaMask}; + enum PixelSrcType { + ImageSrc = Qt::TexturePattern+1, + NonPremultipliedImageSrc = Qt::TexturePattern+2 + }; + + // There are optimisations 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(const QTransform &transform); + void setSrcPixelType(Qt::BrushStyle); + void setSrcPixelType(PixelSrcType); // For non-brush sources, like pixmaps & images + void setTextureCoordsEnabled(bool); // For images & text glyphs + void setUseGlobalOpacity(bool); + void setMaskType(MaskType); + void setCompositionMode(QPainter::CompositionMode); + + bool useCorrectShaderProg(); // returns true if the shader program needed to be changed + + QGLShaderProgram* currentProgram(); // Returns pointer to the shader the manager has chosen + QGLShaderProgram* simpleProgram(); // Used to draw into e.g. stencil buffers + + enum ShaderName { + MainVertexShader, + MainWithTexCoordsVertexShader, + + PositionOnlyVertexShader, + PositionWithPatternBrushVertexShader, + PositionWithLinearGradientBrushVertexShader, + PositionWithConicalGradientBrushVertexShader, + PositionWithRadialGradientBrushVertexShader, + PositionWithTextureBrushVertexShader, + AffinePositionWithPatternBrushVertexShader, + AffinePositionWithLinearGradientBrushVertexShader, + AffinePositionWithConicalGradientBrushVertexShader, + AffinePositionWithRadialGradientBrushVertexShader, + AffinePositionWithTextureBrushVertexShader, + + MainFragmentShader_CMO, + MainFragmentShader_CM, + MainFragmentShader_MO, + MainFragmentShader_M, + MainFragmentShader_CO, + MainFragmentShader_C, + MainFragmentShader_O, + MainFragmentShader, + + ImageSrcFragmentShader, + NonPremultipliedImageSrcFragmentShader, + SolidBrushSrcFragmentShader, + TextureBrushSrcFragmentShader, + PatternBrushSrcFragmentShader, + LinearGradientBrushSrcFragmentShader, + RadialGradientBrushSrcFragmentShader, + ConicalGradientBrushSrcFragmentShader, + ShockingPinkSrcFragmentShader, + + MaskFragmentShader, + RgbMaskFragmentShader, + RgbMaskWithGammaFragmentShader, + + MultiplyCompositionModeFragmentShader, + ScreenCompositionModeFragmentShader, + OverlayCompositionModeFragmentShader, + DarkenCompositionModeFragmentShader, + LightenCompositionModeFragmentShader, + ColorDodgeCompositionModeFragmentShader, + ColorBurnCompositionModeFragmentShader, + HardLightCompositionModeFragmentShader, + SoftLightCompositionModeFragmentShader, + DifferenceCompositionModeFragmentShader, + ExclusionCompositionModeFragmentShader, + + TotalShaderCount, InvalidShaderName + }; + +/* + // 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; +*/ + +#if defined (QT_DEBUG) + Q_ENUMS(ShaderName); +#endif + + +private: + QGLContext* ctx; + bool shaderProgNeedsChanging; + + // Current state variables which influence the choice of shader: + QTransform brushTransform; + int srcPixelType; + bool useGlobalOpacity; + MaskType maskType; + bool useTextureCoords; + QPainter::CompositionMode compositionMode; + + QGLShaderProgram* simpleShaderProg; + QGLShaderProgram* currentShaderProg; + + // TODO: Possibly convert to a LUT + QList<QGLEngineShaderProg> cachedPrograms; + + QGLShader* compiledShaders[TotalShaderCount]; + + void compileNamedShader(QGLEngineShaderManager::ShaderName name, QGLShader::ShaderType type); + + static const char* qglEngineShaderSourceCode[TotalShaderCount]; +}; + +QT_END_NAMESPACE + +QT_END_HEADER + +#endif //QGLENGINE_SHADER_MANAGER_H |