Added distance attenuation and diffuse shading to PointLights

samplecode/SampleShadowing.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SampleCode.h"
 #include "SkPictureRecorder.h"
 #include "SkShadowPaintFilterCanvas.h"
 #include "SkShadowShader.h"
 #include "SkSurface.h"
 
 #ifdef SK_EXPERIMENTAL_SHADOWING
 
 class ShadowingView : public SampleView {
 public:
-    ShadowingView() {
+    ShadowingView()
+        : fSceneChanged(true)
+        , fLightsChanged(true)
+        , fMoveLight(false)
+        , fClearShadowMaps(false)
+        , fSelectedRectID(-1)
+        , fLightDepth(300.0f)  {
+        this->setBGColor(0xFFCCCCCC);
 
-        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;
         fTestRects[0].fGeometry = SkRect::MakeLTRB(200,150,350,300);
 
         fTestRects[1].fColor = 0xFF88EE88;
         fTestRects[1].fDepth = 160;
         fTestRects[1].fGeometry = SkRect::MakeLTRB(150,200,300,350);
 
         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:
     bool onQuery(SkEvent *evt) override {
         if (SampleCode::TitleQ(*evt)) {
             SampleCode::TitleR(evt, "shadowing");
             return true;
         }
 
         SkUnichar uni;
         if (SampleCode::CharQ(*evt, &uni)) {
             switch (uni) {
                 case 'L':
                     fMoveLight = !fMoveLight;
                     break;
                 case 'd':
                     // Raster generated shadow maps have their origin in the UL corner
                     // GPU shadow maps can have an arbitrary origin.
                     // We override the 'd' keypress so that when the device is cycled,
                     // 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;
             }
         }
         return this->INHERITED::onQuery(evt);
     }
 
     sk_sp<SkPicture> makeTestPicture(int width, int height) {
         SkPictureRecorder recorder;
 
@@ skipping 30 matching lines @@
         }
 
         if (fSceneChanged || fLightsChanged || fClearShadowMaps) {
             for (int i = 0; i < fLights->numLights(); i++) {
                 fLights->light(i).setShadowMap(nullptr);
             }
             fSceneChanged = false;
             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;
 
         SkScalar dx = x - click->fPrev.fX;
         SkScalar dy = y - click->fPrev.fY;
 
         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);
             }
             return true;
         }
 
         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);
             return true;
         }
 
         // 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;
                 this->inval(nullptr);
                 break;
             }
         }
 
         return true;
     }
 
 private:
     static constexpr int kNumTestRects = 3;
 
     static const int kWidth = 400;
     static const int kHeight = 400;
+
+    bool fSceneChanged;
+    bool fLightsChanged;
+    bool fMoveLight;
     bool fClearShadowMaps;
 
     struct {
         SkRect  fGeometry;
         int     fDepth;
         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;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 static SkView* MyFactory() { return new ShadowingView; }
 static SkViewRegister reg(MyFactory);
 
 #endif