Add SkLights class

include/core/SkLights.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 SkLights_DEFINED
+#define SkLights_DEFINED
+
+#include "SkPoint3.h"
+#include "SkRefCnt.h"
+#include "SkTDArray.h"
+
+class SK_API SkLights  : public SkRefCnt {
+public:
+    class Light {
+    public:
+        enum LightType {
+            kAmbient_LightType,       // only 'fColor' is used
+            kInfinite_LightType

[bsalomon, 2015/08/05 14:58:38]

directional?

[robertphillips, 2015/08/05 15:40:24]

Done.

+        };
+
+        Light(const SkColor3f& color)
+            : fType(kAmbient_LightType)
+            , fColor(color) {
+            fDirection.set(0.0f, 0.0f, 1.0f);
+        }
+
+        Light(const SkColor3f& color, const SkVector3& dir)
+            : fType(kInfinite_LightType)
+            , fColor(color)
+            , fDirection(dir) {
+            if (!fDirection.normalize()) {
+                fDirection.set(0.0f, 0.0f, 1.0f);
+            }
+        }
+
+        LightType type() const { return fType; }
+        const SkColor3f& color() const { return fColor; }
+        const SkVector3& dir() const { 
+            SkASSERT(kAmbient_LightType != fType);
+            return fDirection; 
+        }
+
+    private:
+        LightType   fType;
+        SkColor3f   fColor;           // linear (unpremul) color. Range is 0..1 in each channel.
+        SkVector3   fDirection;       // direction towards the light (+Z is out of the screen).
+                                      // If degenerate, it will be replaced with (0, 0, 1).
+    };
+
+    class Editor {

[bsalomon, 2015/08/05 14:58:38]

Maybe just have a builder and immutable light set? I wish we had that pattern
for path rather than path/pathref/editor.

[robertphillips, 2015/08/05 15:40:24]

Done.

+    public:
+        Editor(SkAutoTUnref<SkLights>* lights) {
+            if (!(*lights)->unique()) {
+                SkLights* copy = SkNEW(SkLights);
+                copy->copy(**lights);
+                lights->reset(copy);
+            }
+            fLights = *lights;        
+        }
+    
+        void add(const Light& light) {
+            *fLights->fLights.push() = light;
+        }
+
+    private:
+        SkLights* fLights;
+    };
+
+    int numLights() const {
+        return fLights.count();
+    }
+
+    const Light& light(int index) const {
+        return fLights[index];
+    }
+
+private:
+    void copy(const SkLights& src) {
+        fLights.setCount(src.numLights());
+        src.fLights.copy(fLights.begin());
+    }
+
+    SkTDArray<Light> fLights;
+};
+
+#endif