Update SkLightingShader to support rotation

This also:
makes the SkLightingShader handle normal maps where the rects aren't aligned between the diffuse and normal maps.

adds a light aggregating class (Lights) to SkLightingShader (along with a Builder nested class).

Split out of https://codereview.chromium.org/1261433009/ (Add SkCanvas::drawLitAtlas call)

Review URL: https://codereview.chromium.org/1291783003

1 files changed, 22 insertions, 15 deletions

diff --git a/samplecode/SampleLighting.cpp b/samplecode/SampleLighting.cpp
index 5b4f2e0931..4838cf8183 100755
--- a/samplecode/SampleLighting.cpp
+++ b/samplecode/SampleLighting.cpp
@@ -11,6 +11,21 @@
 #include "SkCanvas.h"
 #include "SkImageDecoder.h"
 #include "SkLightingShader.h"
+#include "SkPoint3.h"
+
+static const SkLightingShader::Lights* create_lights(SkScalar angle, SkScalar blue) {
+
+    const SkVector3 dir = SkVector3::Make(SkScalarSin(angle)*SkScalarSin(SK_ScalarPI*0.25f),
+                                          SkScalarCos(angle)*SkScalarSin(SK_ScalarPI*0.25f),
+                                          SkScalarCos(SK_ScalarPI*0.25f));
+
+    SkLightingShader::Lights::Builder builder;
+
+    builder.add(SkLight(SkColor3f::Make(1.0f, 1.0f, blue), dir));
+    builder.add(SkLight(SkColor3f::Make(0.1f, 0.1f, 0.1f)));
+
+    return builder.finish();
+}
 
 ////////////////////////////////////////////////////////////////////////////
 
@@ -21,7 +36,6 @@ public:
     SkBitmap               fNormalBitmap;
     SkScalar               fLightAngle;
     SkScalar               fColorFactor;
-    SkColor3f              fAmbientColor;
 
     LightingView() {
         SkString diffusePath = GetResourcePath("brickwork-texture.jpg");
@@ -32,16 +46,11 @@ public:
         fLightAngle = 0.0f;
         fColorFactor = 0.0f;
 
-        SkLightingShader::Light light;
-        light.fColor = SkColor3f::Make(1.0f, 1.0f, 1.0f);
-        light.fDirection.fX = SkScalarSin(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
-        light.fDirection.fY = SkScalarCos(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
-        light.fDirection.fZ = SkScalarCos(SK_ScalarPI*0.25f);
-
-        fAmbientColor = SkColor3f::Make(0.1f, 0.1f, 0.1f);
+        SkAutoTUnref<const SkLightingShader::Lights> lights(create_lights(fLightAngle, 1.0f));
 
         fShader.reset(SkLightingShader::Create(fDiffuseBitmap, fNormalBitmap,
-                                               light, fAmbientColor, nullptr));
+                                               lights, SkVector::Make(1.0f, 0.0f),
+                                               nullptr, nullptr));
     }
 
     virtual ~LightingView() {}
@@ -63,14 +72,12 @@ protected:
             fColorFactor = 0.0f;
         }
 
-        SkLightingShader::Light light;
-        light.fColor = SkColor3f::Make(1.0f, 1.0f, fColorFactor);
-        light.fDirection.fX = SkScalarSin(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
-        light.fDirection.fY = SkScalarCos(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
-        light.fDirection.fZ = SkScalarCos(SK_ScalarPI*0.25f);
+        SkAutoTUnref<const SkLightingShader::Lights> lights(create_lights(fLightAngle,
+                                                                          fColorFactor));
 
         fShader.reset(SkLightingShader::Create(fDiffuseBitmap, fNormalBitmap,
-                                               light, fAmbientColor, nullptr));
+                                               lights, SkVector::Make(1.0f, 0.0f),
+                                               nullptr, nullptr));
 
         SkPaint paint;
         paint.setShader(fShader);