Added custom shader hook to the GL 2 paint engine.

This will make it easier to implement pixmap filters, YUV->RGB
conversions, etc in other parts of Qt.

5 files changed, 107 insertions, 24 deletions

diff --git a/src/opengl/gl2paintengineex/qglengineshadermanager.cpp b/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
index 4b73ca9..068f804 100644
--- a/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
+++ b/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
@@ -49,6 +49,30 @@
 
 QT_BEGIN_NAMESPACE
 
+QGLCustomShader::QGLCustomShader(QGLShader *shader)
+    : m_shader(shader)
+{
+}
+
+QGLCustomShader::~QGLCustomShader()
+{
+    delete m_shader;
+}
+
+void QGLCustomShader::updateUniforms(QGLShaderProgram *)
+{
+}
+
+void QGLCustomShader::setShader(QGLShader *shader)
+{
+    m_shader = shader;
+}
+
+QGLShader *QGLCustomShader::shader() const
+{
+    return m_shader;
+}
+
 const char* QGLEngineShaderManager::qglEngineShaderSourceCode[] = {
     0,0,0,0,0,0,0,0,0,0,
     0,0,0,0,0,0,0,0,0,0,
@@ -66,7 +90,8 @@ QGLEngineShaderManager::QGLEngineShaderManager(QGLContext* context)
       compositionMode(QPainter::CompositionMode_SourceOver),
       blitShaderProg(0),
       simpleShaderProg(0),
-      currentShaderProg(0)
+      currentShaderProg(0),
+      customShader(0)
 {
     memset(compiledShaders, 0, sizeof(compiledShaders));
 
@@ -107,6 +132,7 @@ QGLEngineShaderManager::QGLEngineShaderManager(QGLContext* context)
         code[MainFragmentShader] = qglslMainFragmentShader;
 
         code[ImageSrcFragmentShader] = qglslImageSrcFragmentShader;
+        code[CustomSrcFragmentShader] = qglslCustomSrcFragmentShader;
         code[ImageSrcWithPatternFragmentShader] = qglslImageSrcWithPatternFragmentShader;
         code[NonPremultipliedImageSrcFragmentShader] = qglslNonPremultipliedImageSrcFragmentShader;
         code[SolidBrushSrcFragmentShader] = qglslSolidBrushSrcFragmentShader;
@@ -228,7 +254,7 @@ void QGLEngineShaderManager::setDirty()
 
 void QGLEngineShaderManager::setSrcPixelType(Qt::BrushStyle style)
 {
-    if (srcPixelType == PixelSrcType(style))
+    if (customShader || srcPixelType == PixelSrcType(style))
         return;
 
     srcPixelType = style;
@@ -237,13 +263,20 @@ void QGLEngineShaderManager::setSrcPixelType(Qt::BrushStyle style)
 
 void QGLEngineShaderManager::setSrcPixelType(PixelSrcType type)
 {
-    if (srcPixelType == type)
+    if (customShader || srcPixelType == type)
         return;
 
     srcPixelType = type;
     shaderProgNeedsChanging = true; //###
 }
 
+void QGLEngineShaderManager::setCustomShader(QGLCustomShader *shader)
+{
+    srcPixelType = CustomSrc;
+    shaderProgNeedsChanging = true;
+    customShader = shader;
+}
+
 void QGLEngineShaderManager::setTextureCoordsEnabled(bool enabled)
 {
     if (useTextureCoords == enabled)
@@ -338,6 +371,10 @@ bool QGLEngineShaderManager::useCorrectShaderProg()
             srcPixelFragShaderName = ImageSrcFragmentShader;
             positionVertexShaderName = PositionOnlyVertexShader;
             break;
+        case QGLEngineShaderManager::CustomSrc:
+            srcPixelFragShaderName = CustomSrcFragmentShader;
+            positionVertexShaderName = PositionOnlyVertexShader;
+            break;
         case QGLEngineShaderManager::PatternSrc:
             srcPixelFragShaderName = ImageSrcWithPatternFragmentShader;
             positionVertexShaderName = PositionOnlyVertexShader;
@@ -381,7 +418,6 @@ bool QGLEngineShaderManager::useCorrectShaderProg()
     requiredProgram.positionVertexShader = compiledShaders[positionVertexShaderName];
     requiredProgram.srcPixelFragShader = compiledShaders[srcPixelFragShaderName];
 
-
     const bool hasCompose = compositionMode > QPainter::CompositionMode_Plus;
     const bool hasMask = maskType != QGLEngineShaderManager::NoMask;
 
@@ -483,6 +519,7 @@ bool QGLEngineShaderManager::useCorrectShaderProg()
             currentShaderProg = &prog;
             currentShaderProg->program->enable();
             shaderProgNeedsChanging = false;
+
             return true;
         }
     }
@@ -496,6 +533,9 @@ bool QGLEngineShaderManager::useCorrectShaderProg()
     requiredProgram.program->addShader(requiredProgram.maskFragShader);
     requiredProgram.program->addShader(requiredProgram.compositionFragShader);
 
+    if (customShader)
+        requiredProgram.program->addShader(customShader->shader());
+
     // We have to bind the vertex attribute names before the program is linked:
     requiredProgram.program->bindAttributeLocation("vertexCoordsArray", QT_VERTEX_COORDS_ATTR);
     if (useTextureCoords)
@@ -520,11 +560,20 @@ bool QGLEngineShaderManager::useCorrectShaderProg()
         qWarning() << error;
     }
     else {
-        cachedPrograms.append(requiredProgram);
-        // taking the address here is safe since
-        // cachePrograms isn't resized anywhere else
-        currentShaderProg = &cachedPrograms.last();
+        if (customShader) {
+            // don't cache custom shaders
+            customShaderProg = requiredProgram;
+            currentShaderProg = &customShaderProg;
+        } else {
+            cachedPrograms.append(requiredProgram);
+            // taking the address here is safe since
+            // cachePrograms isn't resized anywhere else
+            currentShaderProg = &cachedPrograms.last();
+        }
         currentShaderProg->program->enable();
+
+        if (customShader)
+            customShader->updateUniforms(currentShaderProg->program);
     }
     shaderProgNeedsChanging = false;
     return true;
diff --git a/src/opengl/gl2paintengineex/qglengineshadermanager_p.h b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
index 34f0768..891776f 100644
--- a/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
+++ b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
@@ -199,18 +199,19 @@
         O = Global Opacity
 
 
-    CUSTOM SHADER CODE (idea, depricated)
+    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
-    (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:
+    The custom shader is passed to the shader manager as a partial fragment shader
+    by calling setCustomShader(). Qt's fragment pipeline will call the following
+    method name in the custom shader:
 
         mediump vec4 customShader(sampler2d src, vec2 srcCoords)
-        mediump vec4 customShaderWithDest(sampler2d dest, sampler2d src, vec2 srcCoords)
+
+    Transformations, clipping, opacity, and composition modes set using QPainter
+    will be respected when using the custom shader hook.
 
 */
 
@@ -227,6 +228,22 @@ QT_BEGIN_NAMESPACE
 
 QT_MODULE(OpenGL)
 
+class Q_OPENGL_EXPORT QGLCustomShader
+{
+public:
+    QGLCustomShader(QGLShader *shader = 0);
+    virtual ~QGLCustomShader();
+
+    virtual void updateUniforms(QGLShaderProgram *program);
+
+    void setShader(QGLShader *shader);
+    QGLShader *shader() const;
+
+private:
+    Q_DISABLE_COPY(QGLCustomShader)
+
+    QGLShader *m_shader;
+};
 
 struct QGLEngineShaderProg
 {
@@ -259,7 +276,7 @@ struct QGLEngineCachedShaderProg
 static const GLuint QT_VERTEX_COORDS_ATTR  = 0;
 static const GLuint QT_TEXTURE_COORDS_ATTR = 1;
 
-class QGLEngineShaderManager : public QObject
+class Q_OPENGL_EXPORT QGLEngineShaderManager : public QObject
 {
     Q_OBJECT
 public:
@@ -271,7 +288,8 @@ public:
         ImageSrc = Qt::TexturePattern+1,
         NonPremultipliedImageSrc = Qt::TexturePattern+2,
         PatternSrc = Qt::TexturePattern+3,
-        TextureSrcWithPattern = Qt::TexturePattern+4
+        TextureSrcWithPattern = Qt::TexturePattern+4,
+        CustomSrc = Qt::TexturePattern + 5
     };
 
     // There are optimisations we can do, depending on the brush transform:
@@ -285,6 +303,8 @@ public:
     void setMaskType(MaskType);
     void setCompositionMode(QPainter::CompositionMode);
 
+    void setCustomShader(QGLCustomShader *shader);
+
     uint getUniformIdentifier(const char *uniformName);
     uint getUniformLocation(uint id);
 
@@ -322,6 +342,7 @@ public:
         MainFragmentShader,
 
         ImageSrcFragmentShader,
+        CustomSrcFragmentShader,
         ImageSrcWithPatternFragmentShader,
         NonPremultipliedImageSrcFragmentShader,
         SolidBrushSrcFragmentShader,
@@ -366,7 +387,6 @@ public:
     Q_ENUMS(ShaderName)
 #endif
 
-
 private:
     QGLContext*     ctx;
     bool            shaderProgNeedsChanging;
@@ -383,6 +403,9 @@ private:
     QGLShaderProgram*     simpleShaderProg;
     QGLEngineShaderProg*  currentShaderProg;
 
+    QGLEngineShaderProg customShaderProg;
+    QGLCustomShader* customShader;
+
     // TODO: Possibly convert to a LUT
     QList<QGLEngineShaderProg> cachedPrograms;
 
diff --git a/src/opengl/gl2paintengineex/qglengineshadersource_p.h b/src/opengl/gl2paintengineex/qglengineshadersource_p.h
index 4e32f91..e379aa3 100644
--- a/src/opengl/gl2paintengineex/qglengineshadersource_p.h
+++ b/src/opengl/gl2paintengineex/qglengineshadersource_p.h
@@ -290,6 +290,14 @@ static const char* const qglslImageSrcFragmentShader = "\
         return texture2D(imageTexture, textureCoords); \
     }";
 
+static const char* const qglslCustomSrcFragmentShader = "\
+    varying highp vec2      textureCoords; \
+    uniform       sampler2D imageTexture; \
+    lowp vec4 customShader(sampler2D texture, vec2 coords); \
+    lowp vec4 srcPixel() { \
+        return customShader(imageTexture, textureCoords); \
+    }";
+
 static const char* const qglslImageSrcWithPatternFragmentShader = "\
     varying highp vec2      textureCoords; \
     uniform lowp  vec4      patternColor; \
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index 4bf5d4c..a679a62 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -130,10 +130,6 @@ QGLTextureGlyphCache::QGLTextureGlyphCache(QGLContext *context, QFontEngineGlyph
 
 QGLTextureGlyphCache::~QGLTextureGlyphCache()
 {
-    glDeleteFramebuffers(1, &m_fbo);
-
-    if (m_width || m_height)
-        glDeleteTextures(1, &m_texture);
 }
 
 void QGLTextureGlyphCache::createTextureData(int width, int height)
@@ -251,7 +247,7 @@ QGL2PaintEngineExPrivate::~QGL2PaintEngineExPrivate()
 void QGL2PaintEngineExPrivate::updateTextureFilter(GLenum target, GLenum wrapMode, bool smoothPixmapTransform, GLuint id)
 {
 //    glActiveTexture(GL_TEXTURE0 + QT_BRUSH_TEXTURE_UNIT); //### Is it always this texture unit?
-    if (id != -1 && id == lastTexture)
+    if (id != GLuint(-1) && id == lastTexture)
         return;
 
     lastTexture = id;
@@ -1605,4 +1601,10 @@ QOpenGL2PaintEngineState::~QOpenGL2PaintEngineState()
 {
 }
 
+QGLEngineShaderManager *QGL2PaintEngineEx::shaderManager() const
+{
+    Q_D(const QGL2PaintEngineEx);
+    return d->shaderManager;
+}
+
 QT_END_NAMESPACE
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
index 0d28a49..f8d3b53 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
@@ -88,8 +88,7 @@ public:
     bool canRestoreClip;
 };
 
-
-class QGL2PaintEngineEx : public QPaintEngineEx
+class Q_OPENGL_EXPORT QGL2PaintEngineEx : public QPaintEngineEx
 {
     Q_DECLARE_PRIVATE(QGL2PaintEngineEx)
 public:
@@ -133,6 +132,8 @@ public:
     }
     virtual void sync();
 
+    QGLEngineShaderManager *shaderManager() const;
+
 private:
     Q_DISABLE_COPY(QGL2PaintEngineEx)
 };