moved code into onDrawShadowedPic, only renders into shadow maps if needed

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
 
-static sk_sp<SkShader> make_shadow_shader(sk_sp<SkImage> povDepth,
-                                          sk_sp<SkImage> diffuse,
-                                          sk_sp<SkLights> lights) {
-
-    sk_sp<SkShader> povDepthShader = povDepth->makeShader(SkShader::kClamp_TileMode,
-                                                          SkShader::kClamp_TileMode);
-
-    sk_sp<SkShader> diffuseShader = diffuse->makeShader(SkShader::kClamp_TileMode,
-                                                        SkShader::kClamp_TileMode);
-
-    return SkShadowShader::Make(std::move(povDepthShader),
-                                std::move(diffuseShader),
-                                std::move(lights),
-                                diffuse->width(), diffuse->height());
-}
-
 class ShadowingView : public SampleView {
 public:
     ShadowingView() {
 
         this->setBGColor(0xFFCCCCCC);
         SkLights::Builder builder;
         builder.add(SkLights::Light(SkColor3f::Make(0.2f, 0.3f, 0.4f),
                                     SkVector3::Make(0.27f, 0.07f, 1.0f)));
         builder.add(SkLights::Light(SkColor3f::Make(0.4f, 0.3f, 0.2f),
                                     SkVector3::Make(0.03f, 0.27f, 1.0f)));
@@ skipping 62 matching lines @@
                 canvas->translateZ(fTestRects[0].fDepth);
             } else {
                 canvas->translateZ(fTestRects[i].fDepth - fTestRects[i-1].fDepth);
             }
             canvas->drawRect(fTestRects[i].fGeometry, paint);
         }
 
         return recorder.finishRecordingAsPicture();
     }
 
-    void updateDepthMaps(SkCanvas *canvas) {
-        for (int i = 0; i < fLights->numLights(); ++i) {
-            // skip over ambient lights; they don't cast shadows
-            if (SkLights::Light::kAmbient_LightType == fLights->light(i).type()) {
-                continue;
-            }
-
-            // TODO: maybe add a kDepth_8_SkColorType when vertices have depth
-            // assume max depth is 255.
-            // TODO: find actual max depth of picture
-            SkISize shMapSize = SkShadowPaintFilterCanvas::
-                                ComputeDepthMapSize(fLights->light(i), 255, kWidth, kHeight);
-
-            SkImageInfo info = SkImageInfo::Make(shMapSize.fWidth, shMapSize.fHeight,
-                                                 kBGRA_8888_SkColorType,
-                                                 kOpaque_SkAlphaType);
-
-            // Create a new surface (that matches the backend of canvas)
-            // for each shadow map
-            sk_sp<SkSurface> surf(canvas->makeSurface(info));
-
-            // Wrap another SPFCanvas around the surface
-            sk_sp<SkShadowPaintFilterCanvas> depthMapCanvas =
-                    sk_make_sp<SkShadowPaintFilterCanvas>(surf->getCanvas());
-
-            // set the depth map canvas to have the light we're drawing.
-            SkLights::Builder builder;
-            builder.add(fLights->light(i));
-            sk_sp<SkLights> curLight = builder.finish();
-
-            depthMapCanvas->setLights(std::move(curLight));
-            depthMapCanvas->drawPicture(fPicture);
-
-            fLights->light(i).setShadowMap(surf->makeImageSnapshot());
-        }
-    }
-
-    void updatePovDepthMap(SkCanvas* canvas) {
-        // TODO: pass the depth to the shader in vertices, or uniforms
-        //       so we don't have to render depth and color separately
-
-        SkLights::Builder builder;
-        builder.add(SkLights::Light(SkColor3f::Make(1.0f, 1.0f, 1.0f),
-                                    SkVector3::Make(0.0f, 0.0f, 1.0f)));
-        sk_sp<SkLights> povLight = builder.finish();
-
-        SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
-                                             kBGRA_8888_SkColorType,
-                                             kOpaque_SkAlphaType);
-
-        // Create a new surface (that matches the backend of canvas)
-        // to create the povDepthMap
-        sk_sp<SkSurface> surf(canvas->makeSurface(info));
-
-        // Wrap another SPFCanvas around the surface
-        sk_sp<SkShadowPaintFilterCanvas> depthMapCanvas =
-                sk_make_sp<SkShadowPaintFilterCanvas>(surf->getCanvas());
-
-        // set the depth map canvas to have the light as the user's POV
-        depthMapCanvas->setLights(std::move(povLight));
-
-        depthMapCanvas->drawPicture(fPicture);
-
-        fPovDepthMap = surf->makeImageSnapshot();
-    }
-
-    void updateDiffuseMap(SkCanvas* canvas) {
-        SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
-                                             kBGRA_8888_SkColorType,
-                                             kOpaque_SkAlphaType);
-
-        sk_sp<SkSurface> surf(canvas->makeSurface(info));
-        surf->getCanvas()->drawPicture(fPicture);
-
-        fDiffuseMap = surf->makeImageSnapshot();
-    }
-
     void onDrawContent(SkCanvas *canvas) override {
         if (fSceneChanged || !fPovDepthMap) {
             fPicture = this->makeTestPicture(kWidth, kHeight);
-            this->updateDepthMaps(canvas);
-            this->updatePovDepthMap(canvas);
-            this->updateDiffuseMap(canvas);
-        }
-
-        if (fLightsChanged) {
-            this->updateDepthMaps(canvas);
+            for (int i = 0; i < fLights->numLights(); i++) {
+                fLights->light(0).setShadowMap(nullptr);
+            }
         }
 
         if (fSceneChanged || fLightsChanged || !fShadowShader) {
-            fShadowShader = make_shadow_shader(fPovDepthMap, fDiffuseMap, fLights);
+            canvas->setLights(fLights);
+            SkPaint paint;
+            canvas->drawShadowedPicture(fPicture, nullptr, &paint);
         }
 
-        SkPaint paint;
-        paint.setShader(fShadowShader);
-
-        canvas->drawRect(SkRect::MakeIWH(kWidth, kHeight), 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 77 matching lines @@
     sk_sp<SkLights> fLights;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 static SkView* MyFactory() { return new ShadowingView; }
 static SkViewRegister reg(MyFactory);
 
 #endif