Add ShadowUtils sample.

Also enables mouse support in Viewer.

Change-Id: Iaed08d42a64f591f0cd9b24684b3aee43404ed94
Reviewed-on: https://skia-review.googlesource.com/15313
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

1 files changed, 225 insertions, 0 deletions

diff --git a/samplecode/SampleShadowUtils.cpp b/samplecode/SampleShadowUtils.cpp
new file mode 100755
index 0000000000..858d212b85
--- /dev/null
+++ b/samplecode/SampleShadowUtils.cpp
@@ -0,0 +1,225 @@
+
+/*
+ * Copyright 2017 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 "SkAnimTimer.h"
+#include "SkBlurMask.h"
+#include "SkBlurMaskFilter.h"
+#include "SkColorFilter.h"
+#include "SkCamera.h"
+#include "SkCanvas.h"
+#include "SkGaussianEdgeShader.h"
+#include "SkPath.h"
+#include "SkPathOps.h"
+#include "SkPoint3.h"
+#include "SkShadowUtils.h"
+#include "SkUtils.h"
+#include "SkView.h"
+#include "sk_tool_utils.h"
+
+////////////////////////////////////////////////////////////////////////////
+
+class ShadowUtilsView : public SampleView {
+    SkTArray<SkPath> fPaths;
+    SkScalar         fZDelta;
+
+    bool      fShowAmbient;
+    bool      fShowSpot;
+    bool      fUseAlt;
+    bool      fShowObject;
+    bool      fIgnoreShadowAlpha;
+
+public:
+    ShadowUtilsView()
+        : fZDelta(0)
+        , fShowAmbient(true)
+        , fShowSpot(true)
+        , fUseAlt(false)
+        , fShowObject(false)
+        , fIgnoreShadowAlpha(false) {}
+
+protected:
+    void onOnceBeforeDraw() override {
+        fPaths.push_back().addRoundRect(SkRect::MakeWH(50, 50), 10, 10);
+        SkRRect oddRRect;
+        oddRRect.setNinePatch(SkRect::MakeWH(50, 50), 9, 13, 6, 16);
+        fPaths.push_back().addRRect(oddRRect);
+        fPaths.push_back().addRect(SkRect::MakeWH(50, 50));
+        fPaths.push_back().addCircle(25, 25, 25);
+        fPaths.push_back().cubicTo(100, 50, 20, 100, 0, 0);
+        fPaths.push_back().addOval(SkRect::MakeWH(20, 60));
+    }
+
+    // overrides from SkEventSink
+    bool onQuery(SkEvent* evt) override {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "ShadowUtils");
+            return true;
+        }
+
+        SkUnichar uni;
+        if (SampleCode::CharQ(*evt, &uni)) {
+            bool handled = false;
+            switch (uni) {
+                case 'W':
+                    fShowAmbient = !fShowAmbient;
+                    handled = true;
+                    break;
+                case 'S':
+                    fShowSpot = !fShowSpot;
+                    handled = true;
+                    break;
+                case 'T':
+                    fUseAlt = !fUseAlt;
+                    handled = true;
+                    break;
+                case 'O':
+                    fShowObject = !fShowObject;
+                    handled = true;
+                    break;
+                case '>':
+                    fZDelta += 0.5f;
+                    handled = true;
+                    break;
+                case '<':
+                    fZDelta -= 0.5f;
+                    handled = true;
+                    break;
+                case '?':
+                    fIgnoreShadowAlpha = !fIgnoreShadowAlpha;
+                    handled = true;
+                    break;
+                default:
+                    break;
+            }
+            if (handled) {
+                this->inval(nullptr);
+                return true;
+            }
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void drawBG(SkCanvas* canvas) {
+        canvas->drawColor(0xFFDDDDDD);
+    }
+
+    void drawShadowedPath(SkCanvas* canvas, const SkPath& path,
+                          std::function<SkScalar(SkScalar, SkScalar)> zFunc,
+                          const SkPaint& paint, SkScalar ambientAlpha,
+                          const SkPoint3& lightPos, SkScalar lightWidth, SkScalar spotAlpha,
+                          uint32_t flags) {
+        if (fIgnoreShadowAlpha) {
+            ambientAlpha = 255;
+            spotAlpha = 255;
+        }
+        if (!fShowAmbient) {
+            ambientAlpha = 0;
+        }
+        if (!fShowSpot) {
+            spotAlpha = 0;
+        }
+        if (fUseAlt) {
+            flags |= SkShadowFlags::kGeometricOnly_ShadowFlag;
+        }
+        //SkShadowUtils::DrawShadow(canvas, path,
+        //                          zValue,
+        //                          lightPos, lightWidth,
+        //                          ambientAlpha, spotAlpha, SK_ColorBLACK, flags);
+        SkShadowUtils::DrawUncachedShadow(canvas, path, zFunc,
+                                          lightPos, lightWidth,
+                                          ambientAlpha, 0, SK_ColorRED, flags);
+        SkShadowUtils::DrawUncachedShadow(canvas, path, zFunc,
+                                          lightPos, lightWidth,
+                                          0, spotAlpha, SK_ColorBLUE, flags);
+
+        if (fShowObject) {
+            canvas->drawPath(path, paint);
+        } else {
+            SkPaint strokePaint;
+
+            strokePaint.setColor(paint.getColor());
+            strokePaint.setStyle(SkPaint::kStroke_Style);
+
+            canvas->drawPath(path, strokePaint);
+        }
+    }
+
+    void onDrawContent(SkCanvas* canvas) override {
+        this->drawBG(canvas);
+
+        static constexpr int kW = 800;
+        static constexpr SkScalar kPad = 15.f;
+        static constexpr SkPoint3 kLightPos = { 250, 400, 500 };
+        static constexpr SkScalar kLightR = 100.f;
+        static constexpr SkScalar kHeight = 50.f;
+        static constexpr SkScalar kAmbientAlpha = 0.5f;
+        static constexpr SkScalar kSpotAlpha = 0.5f;
+
+        canvas->translate(3 * kPad, 3 * kPad);
+        canvas->save();
+        SkScalar x = 0;
+        SkScalar dy = 0;
+        SkTDArray<SkMatrix> matrices;
+        matrices.push()->reset();
+        SkMatrix* m = matrices.push();
+        m->setRotate(33.f, 25.f, 25.f);
+        m->postScale(1.2f, 0.8f, 25.f, 25.f);
+        SkPaint paint;
+        paint.setColor(SK_ColorGREEN);
+        paint.setAntiAlias(true);
+        SkScalar zValue = SkTMax(1.0f, kHeight + fZDelta);
+        std::function<SkScalar(SkScalar, SkScalar)> zFunc =
+            [zValue](SkScalar, SkScalar) { return zValue; };
+        for (auto& m : matrices) {
+            for (auto flags : { kNone_ShadowFlag, kTransparentOccluder_ShadowFlag }) {
+                for (const auto& path : fPaths) {
+                    SkRect postMBounds = path.getBounds();
+                    m.mapRect(&postMBounds);
+                    SkScalar w = postMBounds.width() + kHeight;
+                    SkScalar dx = w + kPad;
+                    if (x + dx > kW - 3 * kPad) {
+                        canvas->restore();
+                        canvas->translate(0, dy);
+                        canvas->save();
+                        x = 0;
+                        dy = 0;
+                    }
+
+                    canvas->save();
+                    canvas->concat(m);
+                    drawShadowedPath(canvas, path, zFunc, paint, kAmbientAlpha, kLightPos, kLightR,
+                                     kSpotAlpha, flags);
+                    canvas->restore();
+
+                    canvas->translate(dx, 0);
+                    x += dx;
+                    dy = SkTMax(dy, postMBounds.height() + kPad + kHeight);
+                }
+            }
+        }
+        // Show where the light is in x,y as a circle (specified in device space).
+        SkMatrix invCanvasM = canvas->getTotalMatrix();
+        if (invCanvasM.invert(&invCanvasM)) {
+            canvas->save();
+            canvas->concat(invCanvasM);
+            SkPaint paint;
+            paint.setColor(SK_ColorBLACK);
+            paint.setAntiAlias(true);
+            canvas->drawCircle(kLightPos.fX, kLightPos.fY, kLightR / 10.f, paint);
+            canvas->restore();
+        }
+    }
+
+private:
+    typedef SampleView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new ShadowUtilsView; }
+static SkViewRegister reg(MyFactory);