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Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ // // 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, QOpenGLShader & QOpenGLShaderProgram will make partial shaders work by concatenating the source in each QOpenGLShader and compiling it as a single shader. This is abstracted nicely by QOpenGLShaderProgram 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: qopenglslMainVertexShader qopenglslMainWithTexCoordsVertexShader And the following position vertex shaders: qopenglslPositionOnlyVertexShader qopenglslPositionWithTextureBrushVertexShader qopenglslPositionWithPatternBrushVertexShader qopenglslPositionWithLinearGradientBrushVertexShader qopenglslPositionWithRadialGradientBrushVertexShader qopenglslPositionWithConicalGradientBrushVertexShader qopenglslAffinePositionWithTextureBrushVertexShader qopenglslAffinePositionWithPatternBrushVertexShader qopenglslAffinePositionWithLinearGradientBrushVertexShader qopenglslAffinePositionWithRadialGradientBrushVertexShader qopenglslAffinePositionWithConicalGradientBrushVertexShader 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()": qopenglslImageSrcFragShader qopenglslImageSrcWithPatternFragShader qopenglslNonPremultipliedImageSrcFragShader qopenglslSolidBrushSrcFragShader qopenglslTextureBrushSrcFragShader qopenglslTextureBrushWithPatternFragShader qopenglslPatternBrushSrcFragShader qopenglslLinearGradientBrushSrcFragShader qopenglslRadialGradientBrushSrcFragShader qopenglslConicalGradientBrushSrcFragShader NOTE: It is assumed the colour returned by srcPixel() is pre-multiplied Masks are implementations of "qcolorp vec4 applyMask(qcolorp vec4 src)": qopenglslMaskFragmentShader qopenglslRgbMaskFragmentShaderPass1 qopenglslRgbMaskFragmentShaderPass2 qopenglslRgbMaskWithGammaFragmentShader Composition modes are "qcolorp vec4 compose(qcolorp vec4 src)": qopenglslColorBurnCompositionModeFragmentShader qopenglslColorDodgeCompositionModeFragmentShader qopenglslDarkenCompositionModeFragmentShader qopenglslDifferenceCompositionModeFragmentShader qopenglslExclusionCompositionModeFragmentShader qopenglslHardLightCompositionModeFragmentShader qopenglslLightenCompositionModeFragmentShader qopenglslMultiplyCompositionModeFragmentShader qopenglslOverlayCompositionModeFragmentShader qopenglslScreenCompositionModeFragmentShader qopenglslSoftLightCompositionModeFragmentShader 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: qopenglslMainFragmentShader_CMO qopenglslMainFragmentShader_CM qopenglslMainFragmentShader_MO qopenglslMainFragmentShader_M qopenglslMainFragmentShader_CO qopenglslMainFragmentShader_C qopenglslMainFragmentShader_O qopenglslMainFragmentShader 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 (QOpenGLCustomShaderStage). 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 QOPENGLENGINE_SHADER_MANAGER_H #define QOPENGLENGINE_SHADER_MANAGER_H #include #include #include #include #include #include QT_BEGIN_NAMESPACE /* struct QOpenGLEngineCachedShaderProg { QOpenGLEngineCachedShaderProg(QOpenGLEngineShaderManager::ShaderName vertexMain, QOpenGLEngineShaderManager::ShaderName vertexPosition, QOpenGLEngineShaderManager::ShaderName fragMain, QOpenGLEngineShaderManager::ShaderName pixelSrc, QOpenGLEngineShaderManager::ShaderName mask, QOpenGLEngineShaderManager::ShaderName composition); int cacheKey; QOpenGLShaderProgram* 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 QOpenGLEngineShaderProg; class Q_GUI_EXPORT QOpenGLEngineSharedShaders { Q_GADGET 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_MO, MainFragmentShader_M, MainFragmentShader_O, MainFragmentShader, MainFragmentShader_ImageArrays, // ImageSrcFragmentShader must be first in the list:: ImageSrcFragmentShader, ImageSrcWithPatternFragmentShader, NonPremultipliedImageSrcFragmentShader, GrayscaleImageSrcFragmentShader, AlphaImageSrcFragmentShader, 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_ENUM(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; */ QOpenGLEngineSharedShaders(QOpenGLContext *context); ~QOpenGLEngineSharedShaders(); QOpenGLShaderProgram *simpleProgram() { return simpleShaderProg; } QOpenGLShaderProgram *blitProgram() { return blitShaderProg; } // Compile the program if it's not already in the cache, return the item in the cache. QOpenGLEngineShaderProg *findProgramInCache(const QOpenGLEngineShaderProg &prog); // Compile the custom shader if it's not already in the cache, return the item in the cache. static QOpenGLEngineSharedShaders *shadersForContext(QOpenGLContext *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(QOpenGLCustomShaderStage* stage); private: QOpenGLShaderProgram *blitShaderProg; QOpenGLShaderProgram *simpleShaderProg; QList cachedPrograms; static const char* qShaderSnippets[TotalSnippetCount]; }; class QOpenGLEngineShaderProg { public: QOpenGLEngineShaderProg() : program(nullptr) {} ~QOpenGLEngineShaderProg() { if (program) delete program; } QOpenGLEngineSharedShaders::SnippetName mainVertexShader; QOpenGLEngineSharedShaders::SnippetName positionVertexShader; QOpenGLEngineSharedShaders::SnippetName mainFragShader; QOpenGLEngineSharedShaders::SnippetName srcPixelFragShader; QOpenGLEngineSharedShaders::SnippetName maskFragShader; QOpenGLEngineSharedShaders::SnippetName compositionFragShader; QByteArray customStageSource; //TODO: Decent cache key for custom stages QOpenGLShaderProgram* program; QVector uniformLocations; bool useTextureCoords; bool useOpacityAttribute; bool usePmvMatrixAttribute; bool operator==(const QOpenGLEngineShaderProg& other) const { // 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_GUI_EXPORT QOpenGLEngineShaderManager : public QObject { Q_OBJECT public: QOpenGLEngineShaderManager(QOpenGLContext* context); ~QOpenGLEngineShaderManager(); 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, GrayscaleImageSrc = Qt::TexturePattern+5, AlphaImageSrc = Qt::TexturePattern+6, }; enum Uniform { ImageTexture, PatternColor, GlobalOpacity, Depth, MaskTexture, FragmentColor, LinearData, Angle, HalfViewportSize, Fmp, Fmp2MRadius2, Inverse2Fmp2MRadius2, SqrFr, BRadius, 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(QOpenGLCustomShaderStage* 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; } QOpenGLShaderProgram* currentProgram(); // Returns pointer to the shader the manager has chosen QOpenGLShaderProgram* simpleProgram(); // Used to draw into e.g. stencil buffers QOpenGLShaderProgram* blitProgram(); // Used to blit a texture into the framebuffer QOpenGLEngineSharedShaders* sharedShaders; private: QOpenGLContext* 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; QOpenGLCustomShaderStage* customSrcStage; QOpenGLEngineShaderProg* currentShaderProg; }; QT_END_NAMESPACE #endif //QOPENGLENGINE_SHADER_MANAGER_H