Adding 3D lut color filter

include/effects/SkColorCubeFilter.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkColorCubeFilter_DEFINED
+#define SkColorCubeFilter_DEFINED
+
+#include "SkColorFilter.h"
+#include "SkData.h"
+
+class SK_API SkColorCubeFilter : public SkColorFilter {
+public:
+    /** cubeData must containt a 3D data in the form of cube of the size:
+     *  cubeDimension * cubeDimension * cubeDimension * sizeof(SkColor)
+     *  This cube contains a transform where (x,y,z) maps to the (r,g,b).
+     *  The alpha components of the colors are ignored (treated as 0xFF).
+     */
+    static SkColorFilter* Create(SkData* cubeData, int cubeDimension);
+
+    virtual void filterSpan(const SkPMColor src[], int count, SkPMColor[]) const SK_OVERRIDE;
+    virtual uint32_t getFlags() const SK_OVERRIDE;
+
+#if SK_SUPPORT_GPU
+   virtual GrFragmentProcessor* asFragmentProcessor(GrContext*) const SK_OVERRIDE;
+#endif
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkColorCubeFilter)
+
+protected:
+    SkColorCubeFilter(SkData* cubeData, int cubeDimension);
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
+    SkColorCubeFilter(SkReadBuffer& buffer);
+#endif
+    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+
+private:
+    /** The cache is initialized on-demand when getProcessingLuts is called.
+     */
+    class ColorCubeProcesingCache {
+    public:
+        ColorCubeProcesingCache(int cubeDimension);
+
+        void getProcessingLuts(const int* (*colorToIndex)[2],
+                               const SkScalar* (*colorToFactors)[2],
+                               const SkScalar** colorToScalar);
+
+        int cubeDimension() const { return fCubeDimension; }
+
+    private:
+        // Working pointers. If any of these is NULL,
+        // we need to recompute the corresponding cache values.
+        int* fColorToIndex[2];
+        SkScalar* fColorToFactors[2];
+        SkScalar* fColorToScalar;
+
+        SkAutoMalloc fLutStorage;
+
+        const int fCubeDimension;
+
+        // Make sure we only initialize the caches once.
+        SkMutex fLutsMutex;
+        bool fLutsInited;
+
+        static void initProcessingLuts(ColorCubeProcesingCache* cache);
+    };
+
+    SkAutoDataUnref fCubeData;
+    int32_t fUniqueID;
+
+    mutable ColorCubeProcesingCache fCache;
+
+    typedef SkColorFilter INHERITED;
+};
+
+#endif