Move LightingShader to effects

src/effects/SkLightingShader.h

+
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkLightingShader_DEFINED
+#define SkLightingShader_DEFINED
+
+#include "SkPoint3.h"
+#include "SkShader.h"
+
+class SK_API SkLightingShader {
+public:
+    struct Light {
+        SkVector3   fDirection;       // direction towards the light (+Z is out of the screen).
+                                      // If degenerate, it will be replaced with (0, 0, 1).
+        SkColor     fColor;           // linear (unpremul) color. Note: alpha assumed to be 255.
+    };
+
+    /** Returns a shader that lights the diffuse and normal maps with a single light.
+
+        It returns a shader with a reference count of 1.
+        The caller should decrement the shader's reference count when done with the shader.
+        It is an error for count to be < 2.
+        @param  diffuse the diffuse bitmap
+        @param  normal  the normal map
+        @param  light   the light applied to the normal map
+        @param  ambient the linear (unpremul) ambient light color. Note: alpha assumed to be 255.
+
+        NULL will be returned if:
+            either 'diffuse' or 'normal' are empty
+            either 'diffuse' or 'normal' are too big (> 65535 on a side)
+            'diffuse' and 'normal' aren't the same size
+    */
+    static SkShader* Create(const SkBitmap& diffuse, const SkBitmap& normal,
+                            const SkLightingShader::Light& light, const SkColor ambient);
+
+    SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
+};
+
+#endif