Restore SkLightingShader and associated classes

This reverts https://skia-review.googlesource.com/c/skia/+/31140 (Remove SkLightingShader and associated classes) and updates the classes to ToT

Change-Id: I3b1df1704cca8907aa00f081a7e93339b65ad4fa
Reviewed-on: https://skia-review.googlesource.com/141545
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

2 files changed, 196 insertions, 1 deletions

diff --git a/include/core/SkFlattenable.h b/include/core/SkFlattenable.h
index 1bee00a403..af3d5870a8 100644
--- a/include/core/SkFlattenable.h
+++ b/include/core/SkFlattenable.h
@@ -37,7 +37,7 @@ public:
         kSkShaderBase_Type,
         kSkUnused_Type,     // used to be SkUnitMapper
         kSkUnused_Type2,
-        kSkUnused_Type3,    // used to be SkNormalSource
+        kSkNormalSource_Type,
     };
 
     typedef sk_sp<SkFlattenable> (*Factory)(SkReadBuffer&);
diff --git a/include/core/SkLights.h b/include/core/SkLights.h
new file mode 100644
index 0000000000..c4262a0fc0
--- /dev/null
+++ b/include/core/SkLights.h
@@ -0,0 +1,195 @@
+
+/*
+ * 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 "../private/SkTArray.h"
+
+class SkColorSpaceXformer;
+class SkReadBuffer;
+class SkWriteBuffer;
+
+/** \class SkLights
+    SkLights encapsulates a set of directional, point and ambient lights for use with the
+    SkLightingShader.
+*/
+class SK_API SkLights  : public SkRefCnt {
+public:
+    class Light {
+    public:
+        enum LightType {
+            kDirectional_LightType,
+            kPoint_LightType
+        };
+
+        Light(const Light& other)
+                : fType(other.fType)
+                , fColor(other.fColor)
+                , fDirOrPos(other.fDirOrPos)
+                , fIntensity(other.fIntensity) {}
+
+        Light(Light&& other)
+                : fType(other.fType)
+                , fColor(other.fColor)
+                , fDirOrPos(other.fDirOrPos)
+                , fIntensity(other.fIntensity) {}
+
+        static Light MakeDirectional(const SkColor3f& color, const SkVector3& dir) {
+            Light light(kDirectional_LightType, color, dir, 0.0f);
+            if (!light.fDirOrPos.normalize()) {
+                light.fDirOrPos.set(0.0f, 0.0f, 1.0f);
+            }
+            return light;
+        }
+
+        static Light MakePoint(const SkColor3f& color, const SkPoint3& pos, SkScalar intensity) {
+            return Light(kPoint_LightType, color, pos, intensity);
+        }
+
+        LightType type() const { return fType; }
+        const SkColor3f& color() const { return fColor; }
+        const SkVector3& dir() const {
+            SkASSERT(kDirectional_LightType == fType);
+            return fDirOrPos;
+        }
+        const SkPoint3& pos() const {
+            SkASSERT(kPoint_LightType == fType);
+            return fDirOrPos;
+        }
+        SkScalar intensity() const {
+            SkASSERT(kPoint_LightType == fType);
+            return fIntensity;
+        }
+
+        Light& operator=(const Light& other) {
+            if (this == &other) {
+                return *this;
+            }
+
+            fType = other.fType;
+            fColor = other.fColor;
+            fDirOrPos = other.fDirOrPos;
+            fIntensity = other.fIntensity;
+            return *this;
+        }
+
+        bool operator==(const Light& other) {
+            return (fType      == other.fType) &&
+                   (fColor     == other.fColor) &&
+                   (fDirOrPos  == other.fDirOrPos) &&
+                   (fIntensity == other.fIntensity);
+        }
+
+        bool operator!=(const Light& other) { return !(this->operator==(other)); }
+
+    private:
+        friend class SkLights;
+
+        Light(LightType type, const SkColor3f& color, const SkVector3& dirOrPos,
+              SkScalar intensity)
+                : fType(type)
+                , fColor(color)
+                , fDirOrPos(dirOrPos)
+                , fIntensity(intensity) {}
+
+        LightType   fType;
+        SkColor3f   fColor;           // linear (unpremul) color. Range is 0..1 in each channel.
+
+        SkVector3   fDirOrPos;        // For directional lights, holds the direction towards the
+                                      // light (+Z is out of the screen).
+                                      // If degenerate, it will be replaced with (0, 0, 1).
+                                      // For point lights, holds location of point light
+
+        SkScalar    fIntensity;       // For point lights, dictates the light intensity.
+                                      // Simply a multiplier to the final light output value.
+    };
+
+    class Builder {
+    public:
+        Builder() : fLights(new SkLights) {}
+
+        void add(const Light& light) {
+            if (fLights) {
+                fLights->fLights.push_back(light);
+            }
+        }
+
+        void add(Light&& light) {
+            if (fLights) {
+                fLights->fLights.push_back(std::move(light));
+            }
+        }
+
+        void setAmbientLightColor(const SkColor3f& color) {
+            if (fLights) {
+                fLights->fAmbientLightColor = color;
+            }
+        }
+
+        sk_sp<SkLights> finish() {
+            return std::move(fLights);
+        }
+
+    private:
+        sk_sp<SkLights> fLights;
+    };
+
+    /** Returns number of lights not including the ambient light.
+
+        @return number of lights not including the ambient light
+    */
+    int numLights() const { return fLights.count(); }
+
+    /** Returns the index-th light.
+
+        @param index  the index of the desired light
+        @return       the index-th light
+    */
+    const Light& light(int index) const { return fLights[index]; }
+
+    /** Returns the ambient light.
+
+        @return the ambient light
+    */
+    const SkColor3f& ambientLightColor() const {
+        return fAmbientLightColor;
+    }
+
+    /**
+     *  Recreate an SkLights object that was serialized into a buffer.
+     *
+     *  @param  SkReadBuffer Serialized blob data.
+     *  @return A new SkLights representing the serialized data, or NULL if the buffer is
+     *          invalid.
+     */
+    static sk_sp<SkLights> MakeFromBuffer(SkReadBuffer& buf);
+
+    /**
+     *  Serialize to a buffer.
+     *
+     *  @param  buffer the write buffer to write out to
+     */
+    void flatten(SkWriteBuffer& buf) const;
+
+private:
+    friend class SkLightingShaderImpl;
+
+    SkLights() : fAmbientLightColor(SkColor3f::Make(0.0f, 0.0f, 0.0f)) {}
+
+    sk_sp<SkLights> makeColorSpace(SkColorSpaceXformer* xformer) const;
+
+    SkTArray<Light> fLights;
+    SkColor3f       fAmbientLightColor;
+
+    typedef SkRefCnt INHERITED;
+};
+
+#endif