Added distance attenuation and diffuse shading to PointLights

samplecode/SampleShadowing.cpp

Index: samplecode/SampleShadowing.cpp
diff --git a/samplecode/SampleShadowing.cpp b/samplecode/SampleShadowing.cpp
index d0b37fb15ab7921f259a93f2ed2c236f3fb124cf..b2d24e182bde6d2c10b3773c7e3a1f2a7f7510ba 100644
--- a/samplecode/SampleShadowing.cpp
+++ b/samplecode/SampleShadowing.cpp
@@ -15,16 +15,16 @@
 
 class ShadowingView : public SampleView {
 public:
-    ShadowingView() {
-
+    ShadowingView()
+        : fSceneChanged(true)
+        , fLightsChanged(true)
+        , fMoveLight(false)
+        , fClearShadowMaps(false)
+        , fSelectedRectID(-1)
+        , fLightDepth(300.0f)  {
         this->setBGColor(0xFFCCCCCC);
-        SkLights::Builder builder;
-        builder.add(SkLights::Light::MakeDirectional(SkColor3f::Make(0.2f, 0.3f, 0.4f),
-                                                     SkVector3::Make(0.2f, 0.05f, 1.0f)));
-        builder.add(SkLights::Light::MakeDirectional(SkColor3f::Make(0.4f, 0.3f, 0.2f),
-                                                     SkVector3::Make(0.05f, 0.2f, 1.0f)));
-        builder.add(SkLights::Light::MakeAmbient(SkColor3f::Make(0.4f, 0.4f, 0.4f)));
-        fLights = builder.finish();
+
+        this->updateLights(200, 200);
 
         fTestRects[0].fColor = 0xFFEE8888;
         fTestRects[0].fDepth = 80;
@@ -37,14 +37,6 @@ public:
         fTestRects[2].fColor = 0xFF8888EE;
         fTestRects[2].fDepth = 240;
         fTestRects[2].fGeometry = SkRect::MakeLTRB(100,100,250,250);
-
-        fSceneChanged = true;
-        fLightsChanged = true;
-
-        fSelectedRect = -1;
-        fMoveLight = false;
-
-        fClearShadowMaps = false;
     }
 
 protected:
@@ -67,6 +59,14 @@ protected:
                     // the shadow maps will be re-generated according to the new backend.
                     fClearShadowMaps = true;
                     break;
+                case 'q':
+                    fLightDepth += 5.0f;
+                    fMoveLight = true;
+                    break;
+                case 'w':
+                    fLightDepth -= 5.0f;
+                    fMoveLight = true;
+                    break;
                 default:
                     break;
             }
@@ -117,15 +117,31 @@ protected:
             fLightsChanged = false;
             fClearShadowMaps = false;
 
-            canvas->setLights(fLights);
-            canvas->drawShadowedPicture(fPicture, nullptr, nullptr);
         }
+        canvas->setLights(fLights);
+        canvas->drawShadowedPicture(fPicture, nullptr, nullptr);
     }
 
     SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
         return new SkView::Click(this);
     }
 
+    void updateLights(int x, int y) {
+        SkLights::Builder builder;
+        builder.add(SkLights::Light::MakePoint(SkColor3f::Make(0.3f, 0.5f, 0.7f),
+                                               SkVector3::Make(x - 50,
+                                                               350 - y,
+                                                               fLightDepth),
+                                               1024));
+
+        builder.add(SkLights::Light::MakePoint(SkColor3f::Make(0.7f, 0.5f, 0.3f),
+                                               SkVector3::Make(x + 50,
+                                                               450 - y,
+                                                               fLightDepth),
+                                               1024));
+        fLights = builder.finish();
+    }
+
     bool onClick(Click *click) override {
         SkScalar x = click->fCurr.fX;
         SkScalar y = click->fCurr.fY;
@@ -135,24 +151,7 @@ protected:
 
         if (fMoveLight) {
             if (dx != 0 || dy != 0) {
-                float recipX = 1.0f / kWidth;
-                float recipY = 1.0f / kHeight;
-
-                SkLights::Builder builder;
-                builder.add(SkLights::Light::MakeDirectional(
-                        SkColor3f::Make(0.2f, 0.3f, 0.4f),
-                        SkVector3::Make(0.2f + (200.0f - x) * recipX,
-                                        0.05f + (200.0f - y) * recipY,
-                                        1.0f)));
-                builder.add(SkLights::Light::MakeDirectional(
-                        SkColor3f::Make(0.4f, 0.3f, 0.2f),
-                        SkVector3::Make(0.05f + (200.0f - x) * recipX,
-                                        0.2f + (200.0f - y) * recipY,
-                                        1.0f)));
-                builder.add(SkLights::Light::MakeAmbient(
-                        SkColor3f::Make(0.4f, 0.4f, 0.4f)));
-                fLights = builder.finish();
-
+                this->updateLights(x, y);
                 fLightsChanged = true;
                 this->inval(nullptr);
             }
@@ -160,12 +159,12 @@ protected:
         }
 
         if (click->fState == Click::State::kUp_State) {
-            fSelectedRect = -1;
+            fSelectedRectID = -1;
             return true;
         }
 
-        if (fSelectedRect > -1) {
-            fTestRects[fSelectedRect].fGeometry.offset(dx, dy);
+        if (fSelectedRectID > -1) {
+            fTestRects[fSelectedRectID].fGeometry.offset(dx, dy);
 
             fSceneChanged = true;
             this->inval(nullptr);
@@ -175,7 +174,7 @@ protected:
         // assume last elements are highest
         for (int i = kNumTestRects - 1; i >= 0; i--) {
             if (fTestRects[i].fGeometry.contains(SkRect::MakeXYWH(x, y, 1, 1))) {
-                fSelectedRect = i;
+                fSelectedRectID = i;
                 fTestRects[i].fGeometry.offset(dx, dy);
 
                 fSceneChanged = true;
@@ -192,6 +191,10 @@ private:
 
     static const int kWidth = 400;
     static const int kHeight = 400;
+
+    bool fSceneChanged;
+    bool fLightsChanged;
+    bool fMoveLight;
     bool fClearShadowMaps;
 
     struct {
@@ -200,14 +203,11 @@ private:
         SkColor fColor;
     } fTestRects[kNumTestRects];
 
-    int fSelectedRect;
-    bool fMoveLight;
+    int fSelectedRectID;
+    SkScalar fLightDepth;
 
     sk_sp<SkPicture> fPicture;
 
-    bool fSceneChanged;
-    bool fLightsChanged;
-
     sk_sp<SkLights> fLights;
 
     typedef SampleView INHERITED;