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)
+        , fSelectedSliderID(-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);
 
         fSliders[0].fGeometry = SkRect::MakeLTRB(20, 400, 30, 420);
         fSliders[0].fOffset = 0.0f;
         fSliders[0].fScale = 0.1f;
 
         fSliders[1].fGeometry = SkRect::MakeLTRB(100, 420, 110, 440);
         fSliders[1].fOffset = 0.0f;
         fSliders[1].fScale = 10.0f;
 
         fSliders[2].fGeometry = SkRect::MakeLTRB(0, 440, 10, 460);
         fSliders[2].fOffset = 0.0f;
         fSliders[2].fScale = 0.0025f;
 
-        fSceneChanged = true;
-        fLightsChanged = true;
-
-        fSelectedRect = -1;
-        fSelectedSlider = -1;
-        fMoveLight = false;
-
-        fClearShadowMaps = false;
-
-        fShadowParams.fShadowRadius = 2.0f;
+        fShadowParams.fShadowRadius = 4.0f;
         fShadowParams.fBiasingConstant = 0.3f;
         fShadowParams.fMinVariance = 1024;
         fShadowParams.fType = SkShadowParams::kVariance_ShadowType;
     }
 
 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;
                 case 'B':
                     if (SkShadowParams::kVariance_ShadowType == fShadowParams.fType) {
                         fShadowParams.fType = SkShadowParams::kNoBlur_ShadowType;
                     } else if (SkShadowParams::kNoBlur_ShadowType ==
                                fShadowParams.fType) {
                         fShadowParams.fType = SkShadowParams::kVariance_ShadowType;
                     }
                     fLightsChanged = 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 46 matching lines @@
             SkPaint paint;
             paint.setColor(SK_ColorBLACK);
             canvas->drawRect(fSliders[i].fGeometry, paint);
         }
     }
 
     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(0.2f, 0.4f, 0.6f),
+                                               SkVector3::Make(x - 50,
+                                                               350 - y,
+                                                               fLightDepth),
+                                               1024));
+        builder.add(SkLights::Light::MakePoint(SkColor3f::Make(0.6f, 0.4f, 0.2f),
+                                               SkVector3::Make(x + 50,
+                                                               450 - y,
+                                                               fLightDepth),
+                                               1024));
+        builder.add(SkLights::Light::MakeDirectional(SkColor3f::Make(0.2f, 0.2f, 0.2f),
+                                                     SkVector3::Make(0.2f, 0.2f, 1.0f)));
+        fLights = builder.finish();
+    }
+
     void updateFromSelectedSlider() {
-        SkScalar newValue = fSliders[fSelectedSlider].fGeometry.fLeft *
-                            fSliders[fSelectedSlider].fScale +
-                            fSliders[fSelectedSlider].fOffset;
+        SkScalar newValue = fSliders[fSelectedSliderID].fGeometry.fLeft *
+                            fSliders[fSelectedSliderID].fScale +
+                            fSliders[fSelectedSliderID].fOffset;
 
-        switch (fSelectedSlider) {
+        switch (fSelectedSliderID) {
             case 0:
                 fShadowParams.fShadowRadius = newValue;
                 break;
             case 1:
                 fShadowParams.fMinVariance = newValue;
                 break;
             case 2:
                 fShadowParams.fBiasingConstant = newValue;
                 break;
             default:
                 break;
         }
     }
 
     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;
-            fSelectedSlider = -1;
+            fSelectedRectID = -1;
+            fSelectedSliderID = -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;
         }
 
-        if (fSelectedSlider > -1) {
-            fSliders[fSelectedSlider].fGeometry.offset(dx, 0);
+        if (fSelectedSliderID > -1) {
+            fSliders[fSelectedSliderID].fGeometry.offset(dx, 0);
 
             this->updateFromSelectedSlider();
 
             fLightsChanged = 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;
             }
         }
 
         for (int i = 0; i <= kNumSliders; i++) {
             if (fSliders[i].fGeometry.contains(SkRect::MakeXYWH(x, y, 1, 1))) {
-                fSelectedSlider = i;
+                fSelectedSliderID = i;
                 fSliders[i].fGeometry.offset(dx, 0);
 
                 this->updateFromSelectedSlider();
 
                 fLightsChanged = true;
 
                 this->inval(nullptr);
                 break;
             }
         }
 
         return true;
     }
 
 private:
     static constexpr int kNumTestRects = 3;
     static constexpr int kNumSliders = 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;
+    int fSelectedRectID;
 
     struct {
         SkRect   fGeometry;
         SkScalar fOffset;
         SkScalar fScale;
     } fSliders[kNumSliders];
-    int fSelectedSlider;
+    int fSelectedSliderID;
 
-    bool fClearShadowMaps;
-    bool fMoveLight;
-    bool fSceneChanged;
-    bool fLightsChanged;
+    SkScalar fLightDepth;
 
     sk_sp<SkPicture> fPicture;
     SkShadowParams fShadowParams;
     sk_sp<SkLights> fLights;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 static SkView* MyFactory() { return new ShadowingView; }
 static SkViewRegister reg(MyFactory);
 
 #endif