Made shadows blurry (thru implementing variance mapping)

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"
@@ skipping 20 matching lines @@
         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.fBiasingConstant = 0.3f;
+        fShadowParams.fMinVariance = 1024;
+        fShadowParams.fType = SkShadowParams::kVariance_BlurAlgorithm;
     }
 
 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 'B':
+                    if (fShadowParams.fType == SkShadowParams::kVariance_BlurAlgorithm) {
+                        fShadowParams.fType = SkShadowParams::kNoBlur_BlurAlgorithm;
+                    } else if (fShadowParams.fType ==
+                               SkShadowParams::kNoBlur_BlurAlgorithm) {
+                        fShadowParams.fType = SkShadowParams::kVariance_BlurAlgorithm;
+                    }
+                    fLightsChanged = true;
+                    break;
                 default:
                     break;
             }
         }
         return this->INHERITED::onQuery(evt);
     }
 
     sk_sp<SkPicture> makeTestPicture(int width, int height) {
         SkPictureRecorder recorder;
 
@@ skipping 26 matching lines @@
 
     void onDrawContent(SkCanvas *canvas) override {
         if (fSceneChanged) {
             fPicture = this->makeTestPicture(kWidth, kHeight);
         }
 
         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->drawShadowedPicture(fPicture, nullptr, nullptr, fShadowParams);
+
+        for (int i = 0; i < kNumSliders; i++) {
+            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);
     }
 
     bool onClick(Click *click) override {
         SkScalar x = click->fCurr.fX;
         SkScalar y = click->fCurr.fY;
 
@@ skipping 21 matching lines @@
                 fLights = builder.finish();
 
                 fLightsChanged = true;
                 this->inval(nullptr);
             }
             return true;
         }
 
         if (click->fState == Click::State::kUp_State) {
             fSelectedRect = -1;
+            fSelectedSlider = -1;
             return true;
         }
 
         if (fSelectedRect > -1) {
             fTestRects[fSelectedRect].fGeometry.offset(dx, dy);
 
             fSceneChanged = true;
             this->inval(nullptr);
             return true;
         }
 
+        if (fSelectedSlider > -1) {
+            fSliders[fSelectedSlider].fGeometry.offset(dx, 0);
+
+            SkScalar newValue = fSliders[fSelectedSlider].fGeometry.fLeft *
+                                fSliders[fSelectedSlider].fScale +
+                                fSliders[fSelectedSlider].fOffset;
+
+            switch (fSelectedSlider) {
+                case 0:
+                    fShadowParams.fShadowRadius = newValue;
+                    break;
+                case 1:
+                    fShadowParams.fMinVariance = newValue;
+                    break;
+                case 2:
+                    fShadowParams.fBiasingConstant = newValue;
+                    break;
+                default:
+                    break;
+            }
+
+            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;
                 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;
+                fSliders[i].fGeometry.offset(dx, dy);
+
+                SkScalar newValue = fSliders[fSelectedSlider].fGeometry.fLeft *
+                                    fSliders[fSelectedSlider].fScale +
+                                    fSliders[fSelectedSlider].fOffset;
+
+                switch (fSelectedSlider) {
+                    case 0:
+                        fShadowParams.fShadowRadius = newValue;
+                        break;
+                    case 1:
+                        fShadowParams.fMinVariance = newValue;
+                        break;
+                    case 2:
+                        fShadowParams.fBiasingConstant = newValue;
+                        break;
+                    default:
+                        break;
+                }
+
+                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 fClearShadowMaps;
 
     struct {
         SkRect  fGeometry;
         int     fDepth;
         SkColor fColor;
     } fTestRects[kNumTestRects];
+    int fSelectedRect;
 
-    int fSelectedRect;
+    struct {
+        SkRect   fGeometry;
+        SkScalar fOffset;
+        SkScalar fScale;
+    } fSliders[kNumSliders];
+    int fSelectedSlider;
+
+    bool fClearShadowMaps;
     bool fMoveLight;
-
-    sk_sp<SkPicture> fPicture;
-
     bool fSceneChanged;
     bool fLightsChanged;
 
+    sk_sp<SkPicture> fPicture;
+    SkShadowParams fShadowParams;
     sk_sp<SkLights> fLights;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 static SkView* MyFactory() { return new ShadowingView; }
 static SkViewRegister reg(MyFactory);
 
 #endif