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1 /*
2  * Copyright 2020 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "include/core/SkCanvas.h"
9 #include "include/core/SkM44.h"
10 #include "include/core/SkPaint.h"
11 #include "include/core/SkRRect.h"
12 #include "include/core/SkVertices.h"
13 #include "include/utils/SkRandom.h"
14 #include "samplecode/Sample.h"
15 #include "tools/Resources.h"
16 
17 struct VSphere {
18     SkV2     fCenter;
19     SkScalar fRadius;
20 
VSphereVSphere21     VSphere(SkV2 center, SkScalar radius) : fCenter(center), fRadius(radius) {}
22 
containsVSphere23     bool contains(SkV2 v) const {
24         return (v - fCenter).length() <= fRadius;
25     }
26 
pinLocVSphere27     SkV2 pinLoc(SkV2 p) const {
28         auto v = p - fCenter;
29         if (v.length() > fRadius) {
30             v *= (fRadius / v.length());
31         }
32         return fCenter + v;
33     }
34 
computeUnitV3VSphere35     SkV3 computeUnitV3(SkV2 v) const {
36         v = (v - fCenter) * (1 / fRadius);
37         SkScalar len2 = v.lengthSquared();
38         if (len2 > 1) {
39             v = v.normalize();
40             len2 = 1;
41         }
42         SkScalar z = SkScalarSqrt(1 - len2);
43         return {v.x, v.y, z};
44     }
45 
46     struct RotateInfo {
47         SkV3    fAxis;
48         SkScalar fAngle;
49     };
50 
computeRotationInfoVSphere51     RotateInfo computeRotationInfo(SkV2 a, SkV2 b) const {
52         SkV3 u = this->computeUnitV3(a);
53         SkV3 v = this->computeUnitV3(b);
54         SkV3 axis = u.cross(v);
55         SkScalar length = axis.length();
56 
57         if (!SkScalarNearlyZero(length)) {
58             return {axis * (1.0f / length), acos(u.dot(v))};
59         }
60         return {{0, 0, 0}, 0};
61     }
62 
computeRotationVSphere63     SkM44 computeRotation(SkV2 a, SkV2 b) const {
64         auto [axis, angle] = this->computeRotationInfo(a, b);
65         return SkM44::Rotate(axis, angle);
66     }
67 };
68 
inv(const SkM44 & m)69 static SkM44 inv(const SkM44& m) {
70     SkM44 inverse;
71     SkAssertResult(m.invert(&inverse));
72     return inverse;
73 }
74 
75 // Compute the inverse transpose (of the upper-left 3x3) of a matrix, used to transform vectors
normals(SkM44 m)76 static SkM44 normals(SkM44 m) {
77     m.setRow(3, {0, 0, 0, 1});
78     m.setCol(3, {0, 0, 0, 1});
79     SkAssertResult(m.invert(&m));
80     return m.transpose();
81 }
82 
83 class Sample3DView : public Sample {
84 protected:
85     float   fNear = 0.05f;
86     float   fFar = 4;
87     float   fAngle = SK_ScalarPI / 12;
88 
89     SkV3    fEye { 0, 0, 1.0f/tan(fAngle/2) - 1 };
90     SkV3    fCOA { 0, 0, 0 };
91     SkV3    fUp  { 0, 1, 0 };
92 
93 public:
concatCamera(SkCanvas * canvas,const SkRect & area,SkScalar zscale)94     void concatCamera(SkCanvas* canvas, const SkRect& area, SkScalar zscale) {
95         SkM44 camera = SkM44::LookAt(fEye, fCOA, fUp),
96               perspective = SkM44::Perspective(fNear, fFar, fAngle),
97               viewport = SkM44::Translate(area.centerX(), area.centerY(), 0) *
98                          SkM44::Scale(area.width()*0.5f, area.height()*0.5f, zscale);
99 
100         canvas->concat(viewport * perspective * camera * inv(viewport));
101     }
102 };
103 
104 struct Face {
105     SkScalar fRx, fRy;
106     SkColor  fColor;
107 
TFace108     static SkM44 T(SkScalar x, SkScalar y, SkScalar z) {
109         return SkM44::Translate(x, y, z);
110     }
111 
RFace112     static SkM44 R(SkV3 axis, SkScalar rad) {
113         return SkM44::Rotate(axis, rad);
114     }
115 
asM44Face116     SkM44 asM44(SkScalar scale) const {
117         return R({0,1,0}, fRy) * R({1,0,0}, fRx) * T(0, 0, scale);
118     }
119 };
120 
front(const SkM44 & m)121 static bool front(const SkM44& m) {
122     SkM44 m2(SkM44::kUninitialized_Constructor);
123     if (!m.invert(&m2)) {
124         m2.setIdentity();
125     }
126     /*
127      *  Classically we want to dot the transpose(inverse(ctm)) with our surface normal.
128      *  In this case, the normal is known to be {0, 0, 1}, so we only actually need to look
129      *  at the z-scale of the inverse (the transpose doesn't change the main diagonal, so
130      *  no need to actually transpose).
131      */
132     return m2.rc(2,2) > 0;
133 }
134 
135 const Face faces[] = {
136     {             0,             0,  SK_ColorRED }, // front
137     {             0,   SK_ScalarPI,  SK_ColorGREEN }, // back
138 
139     { SK_ScalarPI/2,             0,  SK_ColorBLUE }, // top
140     {-SK_ScalarPI/2,             0,  SK_ColorCYAN }, // bottom
141 
142     {             0, SK_ScalarPI/2,  SK_ColorMAGENTA }, // left
143     {             0,-SK_ScalarPI/2,  SK_ColorYELLOW }, // right
144 };
145 
146 #include "include/effects/SkRuntimeEffect.h"
147 
148 struct LightOnSphere {
149     SkV2     fLoc;
150     SkScalar fDistance;
151     SkScalar fRadius;
152 
computeWorldPosLightOnSphere153     SkV3 computeWorldPos(const VSphere& s) const {
154         return s.computeUnitV3(fLoc) * fDistance;
155     }
156 
drawLightOnSphere157     void draw(SkCanvas* canvas) const {
158         SkPaint paint;
159         paint.setAntiAlias(true);
160         paint.setColor(SK_ColorWHITE);
161         canvas->drawCircle(fLoc.x, fLoc.y, fRadius + 2, paint);
162         paint.setColor(SK_ColorBLACK);
163         canvas->drawCircle(fLoc.x, fLoc.y, fRadius, paint);
164     }
165 };
166 
167 #include "include/core/SkTime.h"
168 
169 class RotateAnimator {
170     SkV3        fAxis = {0, 0, 0};
171     SkScalar    fAngle = 0,
172                 fPrevAngle = 1234567;
173     double      fNow = 0,
174                 fPrevNow = 0;
175 
176     SkScalar    fAngleSpeed = 0,
177                 fAngleSign = 1;
178 
179     inline static constexpr double kSlowDown = 4;
180     inline static constexpr SkScalar kMaxSpeed = 16;
181 
182 public:
update(SkV3 axis,SkScalar angle)183     void update(SkV3 axis, SkScalar angle) {
184         if (angle != fPrevAngle) {
185             fPrevAngle = fAngle;
186             fAngle = angle;
187 
188             fPrevNow = fNow;
189             fNow = SkTime::GetSecs();
190 
191             fAxis = axis;
192         }
193     }
194 
rotation()195     SkM44 rotation() {
196         if (fAngleSpeed > 0) {
197             double now = SkTime::GetSecs();
198             double dtime = now - fPrevNow;
199             fPrevNow = now;
200             double delta = fAngleSign * fAngleSpeed * dtime;
201             fAngle += delta;
202             fAngleSpeed -= kSlowDown * dtime;
203             if (fAngleSpeed < 0) {
204                 fAngleSpeed = 0;
205             }
206         }
207         return SkM44::Rotate(fAxis, fAngle);
208 
209     }
210 
start()211     void start() {
212         if (fPrevNow != fNow) {
213             fAngleSpeed = (fAngle - fPrevAngle) / (fNow - fPrevNow);
214             fAngleSign = fAngleSpeed < 0 ? -1 : 1;
215             fAngleSpeed = std::min(kMaxSpeed, std::abs(fAngleSpeed));
216         } else {
217             fAngleSpeed = 0;
218         }
219         fPrevNow = SkTime::GetSecs();
220         fAngle = 0;
221     }
222 
reset()223     void reset() {
224         fAngleSpeed = 0;
225         fAngle = 0;
226         fPrevAngle = 1234567;
227     }
228 
isAnimating() const229     bool isAnimating() const { return fAngleSpeed != 0; }
230 };
231 
232 class SampleCubeBase : public Sample3DView {
233     enum {
234         DX = 400,
235         DY = 300
236     };
237 
238     SkM44 fRotation;        // part of model
239 
240     RotateAnimator fRotateAnimator;
241 
242 protected:
243     enum Flags {
244         kCanRunOnCPU    = 1 << 0,
245         kShowLightDome  = 1 << 1,
246     };
247 
248     LightOnSphere fLight = {{200 + DX, 200 + DY}, 800, 12};
249 
250     VSphere fSphere;
251     Flags   fFlags;
252 
253 public:
SampleCubeBase(Flags flags)254     SampleCubeBase(Flags flags)
255         : fSphere({200 + DX, 200 + DY}, 400)
256         , fFlags(flags)
257     {}
258 
onChar(SkUnichar uni)259     bool onChar(SkUnichar uni) override {
260         switch (uni) {
261             case 'Z': fLight.fDistance += 10; return true;
262             case 'z': fLight.fDistance -= 10; return true;
263         }
264         return this->Sample3DView::onChar(uni);
265     }
266 
267     virtual void drawContent(
268             SkCanvas* canvas, SkColor, int index, bool drawFront, const SkM44& localToWorld) = 0;
269 
onDrawContent(SkCanvas * canvas)270     void onDrawContent(SkCanvas* canvas) override {
271         if (!canvas->recordingContext() && !(fFlags & kCanRunOnCPU)) {
272             return;
273         }
274 
275         canvas->save();
276         canvas->translate(DX, DY);
277 
278         this->concatCamera(canvas, {0, 0, 400, 400}, 200);
279 
280         for (bool drawFront : {false, true}) {
281             int index = 0;
282             for (auto f : faces) {
283                 SkAutoCanvasRestore acr(canvas, true);
284 
285                 SkM44 trans = SkM44::Translate(200, 200, 0);   // center of the rotation
286                 SkM44 m = fRotateAnimator.rotation() * fRotation * f.asM44(200);
287 
288                 canvas->concat(trans);
289 
290                 // "World" space - content is centered at the origin, in device scale (+-200)
291                 SkM44 localToWorld = m * inv(trans);
292 
293                 canvas->concat(localToWorld);
294                 this->drawContent(canvas, f.fColor, index++, drawFront, localToWorld);
295             }
296         }
297 
298         canvas->restore();  // camera & center the content in the window
299 
300         if (fFlags & kShowLightDome){
301             fLight.draw(canvas);
302 
303             SkPaint paint;
304             paint.setAntiAlias(true);
305             paint.setStyle(SkPaint::kStroke_Style);
306             paint.setColor(0x40FF0000);
307             canvas->drawCircle(fSphere.fCenter.x, fSphere.fCenter.y, fSphere.fRadius, paint);
308             canvas->drawLine(fSphere.fCenter.x, fSphere.fCenter.y - fSphere.fRadius,
309                              fSphere.fCenter.x, fSphere.fCenter.y + fSphere.fRadius, paint);
310             canvas->drawLine(fSphere.fCenter.x - fSphere.fRadius, fSphere.fCenter.y,
311                              fSphere.fCenter.x + fSphere.fRadius, fSphere.fCenter.y, paint);
312         }
313     }
314 
onFindClickHandler(SkScalar x,SkScalar y,skui::ModifierKey modi)315     Click* onFindClickHandler(SkScalar x, SkScalar y, skui::ModifierKey modi) override {
316         SkV2 p = fLight.fLoc - SkV2{x, y};
317         if (p.length() <= fLight.fRadius) {
318             Click* c = new Click();
319             c->fMeta.setS32("type", 0);
320             return c;
321         }
322         if (fSphere.contains({x, y})) {
323             Click* c = new Click();
324             c->fMeta.setS32("type", 1);
325 
326             fRotation = fRotateAnimator.rotation() * fRotation;
327             fRotateAnimator.reset();
328             return c;
329         }
330         return nullptr;
331     }
onClick(Click * click)332     bool onClick(Click* click) override {
333         if (click->fMeta.hasS32("type", 0)) {
334             fLight.fLoc = fSphere.pinLoc({click->fCurr.fX, click->fCurr.fY});
335             return true;
336         }
337         if (click->fMeta.hasS32("type", 1)) {
338             if (click->fState == skui::InputState::kUp) {
339                 fRotation = fRotateAnimator.rotation() * fRotation;
340                 fRotateAnimator.start();
341             } else {
342                 auto [axis, angle] = fSphere.computeRotationInfo(
343                                                 {click->fOrig.fX, click->fOrig.fY},
344                                                 {click->fCurr.fX, click->fCurr.fY});
345                 fRotateAnimator.update(axis, angle);
346             }
347             return true;
348         }
349         return true;
350     }
351 
onAnimate(double nanos)352     bool onAnimate(double nanos) override {
353         return fRotateAnimator.isAnimating();
354     }
355 
356 private:
357     using INHERITED = Sample3DView;
358 };
359 
360 class SampleBump3D : public SampleCubeBase {
361     sk_sp<SkShader>        fBmpShader, fImgShader;
362     sk_sp<SkRuntimeEffect> fEffect;
363     SkRRect                fRR;
364 
365 public:
SampleBump3D()366     SampleBump3D() : SampleCubeBase(Flags(kCanRunOnCPU | kShowLightDome)) {}
367 
name()368     SkString name() override { return SkString("bump3d"); }
369 
onOnceBeforeDraw()370     void onOnceBeforeDraw() override {
371         fRR = SkRRect::MakeRectXY({20, 20, 380, 380}, 50, 50);
372         auto img = GetResourceAsImage("images/brickwork-texture.jpg");
373         fImgShader = img->makeShader(SkSamplingOptions(), SkMatrix::Scale(2, 2));
374         img = GetResourceAsImage("images/brickwork_normal-map.jpg");
375         fBmpShader = img->makeShader(SkSamplingOptions(), SkMatrix::Scale(2, 2));
376 
377         const char code[] = R"(
378             uniform shader color_map;
379             uniform shader normal_map;
380 
381             uniform float4x4 localToWorld;
382             uniform float4x4 localToWorldAdjInv;
383             uniform float3   lightPos;
384 
385             float3 convert_normal_sample(half4 c) {
386                 float3 n = 2 * c.rgb - 1;
387                 n.y = -n.y;
388                 return n;
389             }
390 
391             half4 main(float2 p) {
392                 float3 norm = convert_normal_sample(normal_map.eval(p));
393                 float3 plane_norm = normalize(localToWorldAdjInv * norm.xyz0).xyz;
394 
395                 float3 plane_pos = (localToWorld * p.xy01).xyz;
396                 float3 light_dir = normalize(lightPos - plane_pos);
397 
398                 float ambient = 0.2;
399                 float dp = dot(plane_norm, light_dir);
400                 float scale = min(ambient + max(dp, 0), 1);
401 
402                 return color_map.eval(p) * scale.xxx1;
403             }
404         )";
405         auto [effect, error] = SkRuntimeEffect::MakeForShader(SkString(code));
406         if (!effect) {
407             SkDebugf("runtime error %s\n", error.c_str());
408         }
409         fEffect = effect;
410     }
411 
drawContent(SkCanvas * canvas,SkColor color,int index,bool drawFront,const SkM44 & localToWorld)412     void drawContent(SkCanvas* canvas,
413                      SkColor color,
414                      int index,
415                      bool drawFront,
416                      const SkM44& localToWorld) override {
417         if (!drawFront || !front(canvas->getLocalToDevice())) {
418             return;
419         }
420 
421         SkRuntimeShaderBuilder builder(fEffect);
422         builder.uniform("lightPos") = fLight.computeWorldPos(fSphere);
423         builder.uniform("localToWorld") = localToWorld;
424         builder.uniform("localToWorldAdjInv") = normals(localToWorld);
425 
426         builder.child("color_map")  = fImgShader;
427         builder.child("normal_map") = fBmpShader;
428 
429         SkPaint paint;
430         paint.setColor(color);
431         paint.setShader(builder.makeShader(nullptr, true));
432 
433         canvas->drawRRect(fRR, paint);
434     }
435 };
436 DEF_SAMPLE( return new SampleBump3D; )
437 
438 #include "modules/skottie/include/Skottie.h"
439 
440 class SampleSkottieCube : public SampleCubeBase {
441     sk_sp<skottie::Animation> fAnim[6];
442 
443 public:
SampleSkottieCube()444     SampleSkottieCube() : SampleCubeBase(kCanRunOnCPU) {}
445 
name()446     SkString name() override { return SkString("skottie3d"); }
447 
onOnceBeforeDraw()448     void onOnceBeforeDraw() override {
449         const char* files[] = {
450             "skottie/skottie-chained-mattes.json",
451             "skottie/skottie-gradient-ramp.json",
452             "skottie/skottie_sample_2.json",
453             "skottie/skottie-3d-3planes.json",
454             "skottie/skottie-text-animator-4.json",
455             "skottie/skottie-motiontile-effect-phase.json",
456 
457         };
458         for (unsigned i = 0; i < SK_ARRAY_COUNT(files); ++i) {
459             if (auto stream = GetResourceAsStream(files[i])) {
460                 fAnim[i] = skottie::Animation::Make(stream.get());
461             }
462         }
463     }
464 
drawContent(SkCanvas * canvas,SkColor color,int index,bool drawFront,const SkM44 &)465     void drawContent(
466             SkCanvas* canvas, SkColor color, int index, bool drawFront, const SkM44&) override {
467         if (!drawFront || !front(canvas->getLocalToDevice())) {
468             return;
469         }
470 
471         SkPaint paint;
472         paint.setColor(color);
473         SkRect r = {0, 0, 400, 400};
474         canvas->drawRect(r, paint);
475         fAnim[index]->render(canvas, &r);
476     }
477 
onAnimate(double nanos)478     bool onAnimate(double nanos) override {
479         for (auto& anim : fAnim) {
480             SkScalar dur = anim->duration();
481             SkScalar t = fmod(1e-9 * nanos, dur) / dur;
482             anim->seek(t);
483         }
484         return true;
485     }
486 };
487 DEF_SAMPLE( return new SampleSkottieCube; )
488