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Unified Diff: samplecode/SampleSVGPong.cpp

Issue 2243853003: [SVGDom] SVGPong sample app (Closed) Base URL: https://chromium.googlesource.com/skia.git@master
Patch Set: win build fix Created 4 years, 4 months ago
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Index: samplecode/SampleSVGPong.cpp
diff --git a/samplecode/SampleSVGPong.cpp b/samplecode/SampleSVGPong.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..0a3fbd0f449aa82222de68aa83b3301a11bb70f4
--- /dev/null
+++ b/samplecode/SampleSVGPong.cpp
@@ -0,0 +1,288 @@
+/*
+ * 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 "SkAnimTimer.h"
+#include "SkColor.h"
+#include "SkRandom.h"
+#include "SkRRect.h"
+#include "SkSVGDOM.h"
+#include "SkSVGG.h"
+#include "SkSVGPath.h"
+#include "SkSVGRect.h"
+#include "SkSVGSVG.h"
+
+namespace {
+
+static const SkRect kBounds = SkRect::MakeLTRB(0.1f, 0.1f, 0.9f, 0.9f);
+static const SkSize kPaddleSize = SkSize::Make(0.03f, 0.1f);
+static const SkScalar kBallSize = 0.04f;
+static const SkScalar kShadowOpacity = 0.40f;
+static const SkScalar kShadowParallax = 0.04f;
+static const SkScalar kBackgroundStroke = 0.01f;
+static const uint32_t kBackgroundDashCount = 20;
+
+static const SkScalar kBallSpeedMax = 0.0020f;
+static const SkScalar kBallSpeedMin = 0.0005f;
+static const SkScalar kBallSpeedFuzz = 0.0002f;
+
+static const SkScalar kTimeScaleMin = 0.0f;
+static const SkScalar kTimeScaleMax = 5.0f;
+
+// Box the value within [min, max), by applying infinite reflection on the interval endpoints.
+SkScalar box_reflect(SkScalar v, SkScalar min, SkScalar max) {
+ const SkScalar intervalLen = max - min;
+ SkASSERT(intervalLen > 0);
+
+ // f(v) is periodic in 2 * intervalLen: one normal progression + one reflection
+ const SkScalar P = intervalLen * 2;
+ // relative to P origin
+ const SkScalar vP = v - min;
+ // map to [0, P)
robertphillips 2016/08/12 18:15:19 one line ?
f(malita) 2016/08/12 18:27:10 Done.
+ const SkScalar vMod = vP < 0
+ ? P - SkScalarMod(-vP, P)
+ : SkScalarMod(vP, P);
+ // reflect if needed, to map to [0, intervalLen)
+ const SkScalar vInterval = vMod < intervalLen ? vMod : P - vMod;
+ // finally, reposition relative to min
+ return vInterval + min;
+}
+
+// Compute <t, y> for the trajectory intersection with the next vertical edge.
+std::tuple<SkScalar, SkScalar> find_yintercept(const SkPoint& pos, const SkVector& spd,
+ const SkRect& box) {
+ const SkScalar edge = spd.fX > 0 ? box.fRight : box.fLeft;
robertphillips 2016/08/12 18:15:18 put assert on its own line ?
f(malita) 2016/08/12 18:27:10 Done.
+ const SkScalar t = (edge - pos.fX) / spd.fX; SkASSERT(t >= 0);
+ const SkScalar dY = t * spd.fY;
+
robertphillips 2016/08/12 18:15:19 one line ?
f(malita) 2016/08/12 18:27:10 Done.
+ return std::make_tuple(t,
+ box_reflect(pos.fY + dY, box.fTop, box.fBottom));
+}
+
+sk_sp<SkSVGRect> make_svg_rrect(const SkRRect& rrect) {
+ sk_sp<SkSVGRect> node = SkSVGRect::Make();
+ node->setX(SkSVGLength(rrect.rect().x()));
+ node->setY(SkSVGLength(rrect.rect().y()));
+ node->setWidth(SkSVGLength(rrect.width()));
+ node->setHeight(SkSVGLength(rrect.height()));
+ node->setRx(SkSVGLength(rrect.getSimpleRadii().x()));
+ node->setRy(SkSVGLength(rrect.getSimpleRadii().y()));
+
+ return node;
+}
+
+} // anonymous ns
+
+class SVGPongView final : public SampleView {
+public:
+ SVGPongView() {}
+
+protected:
+ void onOnceBeforeDraw() override {
+ const SkRect fieldBounds = kBounds.makeOutset(kBallSize / 2, kBallSize / 2);
+ const SkRRect ball = SkRRect::MakeOval(SkRect::MakeWH(kBallSize, kBallSize));
+ const SkRRect paddle = SkRRect::MakeRectXY(SkRect::MakeWH(kPaddleSize.width(),
+ kPaddleSize.height()),
+ kPaddleSize.width() / 2,
+ kPaddleSize.width() / 2);
+ fBall.initialize(ball,
+ SK_ColorGREEN,
+ SkPoint::Make(kBounds.centerX(), kBounds.centerY()),
+ SkVector::Make(fRand.nextRangeScalar(kBallSpeedMin, kBallSpeedMax),
+ fRand.nextRangeScalar(kBallSpeedMin, kBallSpeedMax)));
+ fPaddle0.initialize(paddle,
+ SK_ColorBLUE,
+ SkPoint::Make(fieldBounds.left() - kPaddleSize.width() / 2,
+ fieldBounds.centerY()),
+ SkVector::Make(0, 0));
+ fPaddle1.initialize(paddle,
+ SK_ColorRED,
+ SkPoint::Make(fieldBounds.right() + kPaddleSize.width() / 2,
+ fieldBounds.centerY()),
+ SkVector::Make(0, 0));
+
+ // Background decoration.
+ SkPath bgPath;
+ bgPath.moveTo(kBounds.left() , fieldBounds.top());
+ bgPath.lineTo(kBounds.right(), fieldBounds.top());
+ bgPath.moveTo(kBounds.left() , fieldBounds.bottom());
+ bgPath.lineTo(kBounds.right(), fieldBounds.bottom());
+ // TODO: stroke-dash support would come in handy right about now.
+ for (uint32_t i = 0; i < kBackgroundDashCount; ++i) {
+ bgPath.moveTo(kBounds.centerX(),
+ kBounds.top() + (i + 0.25f) * kBounds.height() / kBackgroundDashCount);
+ bgPath.lineTo(kBounds.centerX(),
+ kBounds.top() + (i + 0.75f) * kBounds.height() / kBackgroundDashCount);
+ }
+
+ sk_sp<SkSVGPath> bg = SkSVGPath::Make();
+ bg->setPath(bgPath);
+ bg->setFill(SkSVGPaint(SkSVGPaint::Type::kNone));
+ bg->setStroke(SkSVGPaint(SkSVGColorType(SK_ColorBLACK)));
+ bg->setStrokeWidth(SkSVGLength(kBackgroundStroke));
+
+ // Build the SVG DOM tree.
+ sk_sp<SkSVGSVG> root = SkSVGSVG::Make();
+ root->appendChild(std::move(bg));
+ root->appendChild(fPaddle0.shadowNode);
+ root->appendChild(fPaddle1.shadowNode);
+ root->appendChild(fBall.shadowNode);
+ root->appendChild(fPaddle0.objectNode);
+ root->appendChild(fPaddle1.objectNode);
+ root->appendChild(fBall.objectNode);
+
+ // Handle everything in a normalized 1x1 space.
+ root->setViewBox(SkSVGViewBoxType(SkRect::MakeWH(1, 1)));
+
+ fDom = sk_sp<SkSVGDOM>(new SkSVGDOM(SkSize::Make(this->width(), this->height())));
+ fDom->setRoot(std::move(root));
+
+ // Off we go.
+ this->updatePaddleStrategy();
+ }
+
+ bool onQuery(SkEvent* evt) override {
+ if (SampleCode::TitleQ(*evt)) {
+ SampleCode::TitleR(evt, "SVGPong");
+ return true;
+ }
+
+ SkUnichar uni;
+ if (SampleCode::CharQ(*evt, &uni)) {
+ switch (uni) {
+ case '[':
+ fTimeScale = SkTPin(fTimeScale - 0.1f, kTimeScaleMin, kTimeScaleMax);
+ return true;
+ case ']':
+ fTimeScale = SkTPin(fTimeScale + 0.1f, kTimeScaleMin, kTimeScaleMax);
+ return true;
+ default:
+ break;
+ }
+ }
+ return this->INHERITED::onQuery(evt);
+ }
+
+ void onSizeChange() override {
+ if (fDom) {
+ fDom->setContainerSize(SkSize::Make(this->width(), this->height()));
+ }
+
+ this->INHERITED::onSizeChange();
+ }
+
+ void onDrawContent(SkCanvas* canvas) override {
+ fDom->render(canvas);
+ }
+
+ bool onAnimate(const SkAnimTimer& timer) override {
+ SkScalar dt = (timer.msec() - fLastTick) * fTimeScale;
+ fLastTick = timer.msec();
+
+ fPaddle0.posTick(dt);
+ fPaddle1.posTick(dt);
+ fBall.posTick(dt);
+
+ this->enforceConstraints();
+
+ fPaddle0.updateDom();
+ fPaddle1.updateDom();
+ fBall.updateDom();
+
+ return true;
+ }
+
+private:
+ struct Object {
+ void initialize(const SkRRect& rrect, SkColor color,
+ const SkPoint& p, const SkVector& s) {
+ objectNode = make_svg_rrect(rrect);
+ objectNode->setFill(SkSVGPaint(SkSVGColorType(color)));
+
+ shadowNode = make_svg_rrect(rrect);
+ shadowNode->setFillOpacity(SkSVGNumberType(kShadowOpacity));
+
+ pos = p;
+ spd = s;
+ size = SkSize::Make(rrect.width(), rrect.height());
+ }
+
+ void posTick(SkScalar dt) {
+ pos += spd * dt;
+ }
+
+ void updateDom() {
+ const SkPoint corner = pos - SkPoint::Make(size.width() / 2, size.height() / 2);
+ objectNode->setX(SkSVGLength(corner.x()));
+ objectNode->setY(SkSVGLength(corner.y()));
+
+ // Simulate parallax shadow for a centered light source.
+ SkPoint shadowOffset = pos - SkPoint::Make(kBounds.centerX(), kBounds.centerY());
+ shadowOffset.scale(kShadowParallax);
+ const SkPoint shadowCorner = corner + shadowOffset;
+
+ shadowNode->setX(SkSVGLength(shadowCorner.x()));
+ shadowNode->setY(SkSVGLength(shadowCorner.y()));
+ }
+
+ sk_sp<SkSVGRect> objectNode;
+ sk_sp<SkSVGRect> shadowNode;
+ SkPoint pos;
+ SkVector spd;
+ SkSize size;
+ };
+
+ void enforceConstraints() {
+ // Perfect vertical reflection.
+ if (fBall.pos.fY < kBounds.fTop || fBall.pos.fY >= kBounds.fBottom) {
+ fBall.spd.fY = -fBall.spd.fY;
+ fBall.pos.fY = box_reflect(fBall.pos.fY, kBounds.fTop, kBounds.fBottom);
+ }
+
+ // Horizontal bounce - introduces a speed fuzz.
+ if (fBall.pos.fX < kBounds.fLeft || fBall.pos.fX >= kBounds.fRight) {
+ fBall.spd.fX = this->fuzzBallSpeed(-fBall.spd.fX);
+ fBall.spd.fY = this->fuzzBallSpeed(fBall.spd.fY);
+ fBall.pos.fX = box_reflect(fBall.pos.fX, kBounds.fLeft, kBounds.fRight);
+ this->updatePaddleStrategy();
+ }
+ }
+
+ SkScalar fuzzBallSpeed(SkScalar spd) {
+ // The speed limits are absolute values.
+ const SkScalar sign = spd >= 0 ? 1.0f : -1.0f;
+ const SkScalar fuzzed = fabs(spd) + fRand.nextRangeScalar(-kBallSpeedFuzz, kBallSpeedFuzz);
+
+ return sign * SkTPin(fuzzed, kBallSpeedMin, kBallSpeedMax);
+ }
+
+ void updatePaddleStrategy() {
+ Object* pitcher = fBall.spd.fX > 0 ? &fPaddle0 : &fPaddle1;
+ Object* catcher = fBall.spd.fX > 0 ? &fPaddle1 : &fPaddle0;
+
+ SkScalar t, yIntercept;
+ std::tie(t, yIntercept) = find_yintercept(fBall.pos, fBall.spd, kBounds);
+
+ // The pitcher aims for a neutral/centered position.
+ pitcher->spd.fY = (kBounds.centerY() - pitcher->pos.fY) / t;
+
+ // The catcher goes for the ball. Duh.
+ catcher->spd.fY = (yIntercept - catcher->pos.fY) / t;
+ }
+
+ sk_sp<SkSVGDOM> fDom;
+ Object fPaddle0, fPaddle1, fBall;
+ SkRandom fRand;
+
+ SkMSec fLastTick = 0;
+ SkScalar fTimeScale = 1.0f;
+
+ typedef SampleView INHERITED;
+};
+
+static SkView* SVGPongFactory() { return new SVGPongView; }
+static SkViewRegister reg(SVGPongFactory);
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