Added a lambda callback to OpenGLGraphicsContextCustomShader to allow custom set-up when the shader is activated

modules/juce_opengl/opengl/juce_OpenGLGraphicsContext.cpp

@@ -46,12 +46,12 @@ struct CachedImageList  : public ReferenceCountedObject,
                           private ImagePixelData::Listener
 {
     CachedImageList (OpenGLContext& c) noexcept
-        : context (c), totalSize (0), maxCacheSize (c.getImageCacheSize()) {}
+        : context (c), maxCacheSize (c.getImageCacheSize()) {}
 
     static CachedImageList* get (OpenGLContext& c)
     {
         const char cacheValueID[] = "CachedImages";
-        CachedImageList* list = static_cast<CachedImageList*> (c.getAssociatedObject (cacheValueID));
+        auto list = static_cast<CachedImageList*> (c.getAssociatedObject (cacheValueID));
 
         if (list == nullptr)
         {
@@ -64,13 +64,12 @@ struct CachedImageList  : public ReferenceCountedObject,
 
     TextureInfo getTextureFor (const Image& image)
     {
-        ImagePixelData* const pixelData = image.getPixelData();
-
-        CachedImage* c = findCachedImage (pixelData);
+        auto pixelData = image.getPixelData();
+        auto* c = findCachedImage (pixelData);
 
         if (c == nullptr)
         {
-            if (OpenGLFrameBuffer* const fb = OpenGLImageType::getFrameBufferFrom (image))
+            if (auto fb = OpenGLImageType::getFrameBufferFrom (image))
             {
                 TextureInfo t;
                 t.textureID = fb->getTextureID();
@@ -97,8 +96,7 @@ struct CachedImageList  : public ReferenceCountedObject,
         CachedImage (CachedImageList& list, ImagePixelData* im)
             : owner (list), pixelData (im),
               lastUsed (Time::getCurrentTime()),
-              imageSize ((size_t) (im->width * im->height)),
-              textureNeedsReloading (true)
+              imageSize ((size_t) (im->width * im->height))
         {
             pixelData->listeners.add (&owner);
         }
@@ -126,7 +124,6 @@ struct CachedImageList  : public ReferenceCountedObject,
             t.fullHeightProportion = t.imageHeight / (float) texture.getHeight();
 
             lastUsed = Time::getCurrentTime();
-
             return t;
         }
 
@@ -135,7 +132,7 @@ struct CachedImageList  : public ReferenceCountedObject,
         OpenGLTexture texture;
         Time lastUsed;
         const size_t imageSize;
-        bool textureNeedsReloading;
+        bool textureNeedsReloading = true;
 
         JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (CachedImage)
     };
@@ -145,7 +142,8 @@ struct CachedImageList  : public ReferenceCountedObject,
 private:
     OpenGLContext& context;
     OwnedArray<CachedImage> images;
-    size_t totalSize, maxCacheSize;
+    size_t totalSize = 0;
+    const size_t maxCacheSize;
 
     bool canUseContext() const noexcept
     {
@@ -154,7 +152,7 @@ private:
 
     void imageDataChanged (ImagePixelData* im) override
     {
-        if (CachedImage* c = findCachedImage (im))
+        if (auto* c = findCachedImage (im))
             c->textureNeedsReloading = true;
     }
 
@@ -162,7 +160,7 @@ private:
     {
         for (int i = images.size(); --i >= 0;)
         {
-            CachedImage& ci = *images.getUnchecked(i);
+            auto& ci = *images.getUnchecked(i);
 
             if (ci.pixelData == im)
             {
@@ -181,30 +179,22 @@ private:
         }
     }
 
-    CachedImage* findCachedImage (ImagePixelData* const pixelData) const
+    CachedImage* findCachedImage (ImagePixelData* pixelData) const
     {
-        for (int i = 0; i < images.size(); ++i)
-        {
-            CachedImage* c = images.getUnchecked(i);
-
-            if (c->pixelData == pixelData)
-                return c;
-        }
+        for (auto& i : images)
+            if (i->pixelData == pixelData)
+                return i;
 
-        return nullptr;
+        return {};
     }
 
     void removeOldestItem()
     {
         CachedImage* oldest = nullptr;
 
-        for (int i = 0; i < images.size(); ++i)
-        {
-            CachedImage* c = images.getUnchecked(i);
-
-            if (oldest == nullptr || c->lastUsed < oldest->lastUsed)
-                oldest = c;
-        }
+        for (auto& i : images)
+            if (oldest == nullptr || i->lastUsed < oldest->lastUsed)
+                oldest = i;
 
         if (oldest != nullptr)
         {
@@ -445,9 +435,8 @@ struct ShaderPrograms  : public ReferenceCountedObject
         }
 
         OpenGLShaderProgram::Attribute positionAttribute, colourAttribute;
-
-    private:
         OpenGLShaderProgram::Uniform screenBounds;
+        std::function<void(OpenGLShaderProgram&)> onShaderActivated;
     };
 
     struct MaskedShaderParams
@@ -831,9 +820,7 @@ struct StateHelpers
 {
     struct BlendingMode
     {
-        BlendingMode() noexcept
-            : blendingEnabled (false), srcFunction (0), dstFunction (0)
-        {}
+        BlendingMode() noexcept {}
 
         void resync() noexcept
         {
@@ -887,8 +874,8 @@ struct StateHelpers
         }
 
     private:
-        bool blendingEnabled;
-        GLenum srcFunction, dstFunction;
+        bool blendingEnabled = false;
+        GLenum srcFunction = 0, dstFunction = 0;
     };
 
     //==============================================================================
@@ -975,8 +962,7 @@ struct StateHelpers
     //==============================================================================
     struct ActiveTextures
     {
-        ActiveTextures (const OpenGLContext& c) noexcept
-            : texturesEnabled (0), currentActiveTexture (-1), context (c)
+        ActiveTextures (const OpenGLContext& c) noexcept  : context (c)
         {}
 
         void clear() noexcept
@@ -1048,6 +1034,7 @@ struct StateHelpers
                 setActiveTexture (0);
                 bindTexture (texture1);
             }
+
             JUCE_CHECK_OPENGL_ERROR
         }
 
@@ -1083,7 +1070,7 @@ struct StateHelpers
 
     private:
         GLuint currentTextureID[3];
-        int texturesEnabled, currentActiveTexture;
+        int texturesEnabled = 0, currentActiveTexture = -1;
         const OpenGLContext& context;
 
         ActiveTextures& operator= (const ActiveTextures&);
@@ -1330,6 +1317,9 @@ struct StateHelpers
                 shader.program.use();
                 shader.bindAttributes (context);
 
+                if (shader.onShaderActivated)
+                    shader.onShaderActivated (shader.program);
+
                 currentBounds = bounds;
                 shader.set2DBounds (bounds.toFloat());
 
@@ -1860,7 +1850,8 @@ struct CustomProgram  : public ReferenceCountedObject,
         return nullptr;
     }
 
-    static CustomProgram* getOrCreate (LowLevelGraphicsContext& gc, const String& hashName, const String& code, String& errorMessage)
+    static CustomProgram* getOrCreate (LowLevelGraphicsContext& gc, const String& hashName,
+                                       const String& code, String& errorMessage)
     {
         if (auto* c = get (hashName))
             return c;
@@ -1872,7 +1863,7 @@ struct CustomProgram  : public ReferenceCountedObject,
 
             if (errorMessage.isEmpty())
             {
-                if (OpenGLContext* context = OpenGLContext::getCurrentContext())
+                if (auto context = OpenGLContext::getCurrentContext())
                 {
                     context->setAssociatedObject (hashName.toRawUTF8(), c);
                     return c;
@@ -1904,19 +1895,24 @@ OpenGLShaderProgram* OpenGLGraphicsContextCustomShader::getProgram (LowLevelGrap
 {
     String errorMessage;
 
-    if (CustomProgram* c = CustomProgram::getOrCreate (gc, hashName, code, errorMessage))
+    if (auto c = CustomProgram::getOrCreate (gc, hashName, code, errorMessage))
         return &(c->program);
 
-    return nullptr;
+    return {};
 }
 
 void OpenGLGraphicsContextCustomShader::fillRect (LowLevelGraphicsContext& gc, Rectangle<int> area) const
 {
     String errorMessage;
 
-    if (OpenGLRendering::ShaderContext* sc = dynamic_cast<OpenGLRendering::ShaderContext*> (&gc))
-        if (CustomProgram* c = CustomProgram::getOrCreate (gc, hashName, code, errorMessage))
+    if (auto sc = dynamic_cast<OpenGLRendering::ShaderContext*> (&gc))
+    {
+        if (auto c = CustomProgram::getOrCreate (gc, hashName, code, errorMessage))
+        {
+            c->onShaderActivated = onShaderActivated;
             sc->fillRectWithCustomShader (*c, area);
+        }
+    }
 }
 
 Result OpenGLGraphicsContextCustomShader::checkCompilation (LowLevelGraphicsContext& gc)

modules/juce_opengl/opengl/juce_OpenGLGraphicsContext.h

@@ -30,19 +30,18 @@ namespace juce
 /** Creates a graphics context object that will render into the given OpenGL target.
     The caller is responsible for deleting this object when no longer needed.
 */
-LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext& target,
-                                                      int width, int height);
+LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext&, int width, int height);
 
-/** Creates a graphics context object that will render into the given OpenGL target.
+/** Creates a graphics context object that will render into the given OpenGL framebuffer.
     The caller is responsible for deleting this object when no longer needed.
 */
-LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext& context,
-                                                      OpenGLFrameBuffer& target);
+LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext&, OpenGLFrameBuffer&);
 
-/** Creates a graphics context object that will render into the given OpenGL target.
+/** Creates a graphics context object that will render into the given OpenGL framebuffer,
+    with the given size.
     The caller is responsible for deleting this object when no longer needed.
 */
-LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext& context,
+LowLevelGraphicsContext* createOpenGLGraphicsContext (OpenGLContext&,
                                                       unsigned int frameBufferID,
                                                       int width, int height);
 
@@ -89,6 +88,11 @@ struct JUCE_API  OpenGLGraphicsContextCustomShader
     /** Returns the code that was used to create this object. */
     const String& getFragmentShaderCode() const noexcept           { return code; }
 
+    /** Optional lambda that will be called when the shader is activated, to allow
+        user code to do setup tasks.
+    */
+    std::function<void(OpenGLShaderProgram&)> onShaderActivated;
+
 private:
     String code, hashName;