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Add alternative spot shadow to Android shadow sample

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BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2246273003

Review-Url: https://codereview.chromium.org/2256713002
This commit is contained in:
jvanverth 2016-08-17 10:06:18 -07:00 committed by Commit bot
parent 28341fad84
commit d7315f9133
2 changed files with 160 additions and 80 deletions
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219
samplecode/SampleAndroidShadows.cpp
View File

@ -25,15 +25,15 @@ class ShadowsView : public SampleView {
SkPoint3 fLightPos;
bool fShowAmbient;
bool fUseAltAmbient;
bool fShowSpot;
bool fUseAlt;
bool fShowObject;
public:
ShadowsView()
: fShowAmbient(true)
, fUseAltAmbient(true)
, fShowSpot(true)
, fUseAlt(true)
, fShowObject(true) {}
protected:
@ -41,7 +41,7 @@ protected:
fCirclePath.addCircle(0, 0, 50);
fRectPath.addRect(SkRect::MakeXYWH(-100, -50, 200, 100));
fRRPath.addRRect(SkRRect::MakeRectXY(SkRect::MakeXYWH(-100, -50, 200, 100), 4, 4));
fLightPos = SkPoint3::Make(-220, -330, 150);
fLightPos = SkPoint3::Make(-2, -2, 6);
}
// overrides from SkEventSink
@ -57,12 +57,12 @@ protected:
case 'B':
fShowAmbient = !fShowAmbient;
break;
case 'T':
fUseAltAmbient = !fUseAltAmbient;
break;
case 'S':
fShowSpot = !fShowSpot;
break;
case 'T':
fUseAlt = !fUseAlt;
break;
case 'O':
fShowObject = !fShowObject;
break;
@ -143,64 +143,48 @@ protected:
return;
}
SkRect pathRect;
SkRRect pathRRect;
if ((!path.isOval(&pathRect) || pathRect.width() != pathRect.height()) &&
(!path.isRRect(&pathRRect) || !pathRRect.allCornersCircular()) &&
!path.isRect(&pathRect)) {
this->drawAmbientShadow(canvas, path, zValue, ambientAlpha);
return;
}
const SkScalar kHeightFactor = 1.f / 128.f;
const SkScalar kGeomFactor = 64;
SkScalar umbraAlpha = 1 / (1 + SkMaxScalar(zValue*kHeightFactor, 0));
SkScalar radius = zValue*kHeightFactor*kGeomFactor;
// fast path
SkRect pathRect;
SkRRect pathRRect;
if ((path.isOval(&pathRect) && pathRect.width() == pathRect.height()) ||
(path.isRRect(&pathRRect) && pathRRect.allCornersCircular()) ||
path.isRect(&pathRect)) {
// For all of these, we outset the rect by half the radius to get our stroke shape.
if (path.isOval(nullptr)) {
pathRect.outset(0.5f*radius, 0.5f*radius);
pathRRect = SkRRect::MakeOval(pathRect);
} else if (path.isRect(nullptr)) {
pathRect.outset(0.5f*radius, 0.5f*radius);
pathRRect = SkRRect::MakeRectXY(pathRect, 0.5f*radius, 0.5f*radius);
} else {
pathRRect.outset(0.5f*radius, 0.5f*radius);
}
SkPaint paint;
paint.setAntiAlias(true);
paint.setColor(SkColorSetARGB((unsigned char)(ambientAlpha*umbraAlpha*255.999f),
0, 0, 0));
paint.setStrokeWidth(radius);
paint.setStyle(SkPaint::kStroke_Style);
paint.setShader(SkGaussianEdgeShader::Make());
canvas->drawRRect(pathRRect, paint);
// For all of these, we outset the rect by the radius to get our coverage shape.
if (path.isOval(nullptr)) {
pathRect.outset(radius, radius);
pathRRect = SkRRect::MakeOval(pathRect);
} else if (path.isRect(nullptr)) {
pathRect.outset(radius, radius);
pathRRect = SkRRect::MakeRectXY(pathRect, radius, radius);
} else {
// occlude blur
SkRect occlRect;
GetOcclRect(path, &occlRect);
sk_sp<SkMaskFilter> f = SkBlurMaskFilter::Make(kNormal_SkBlurStyle,
SkBlurMask::ConvertRadiusToSigma(radius),
occlRect,
SkBlurMaskFilter::kNone_BlurFlag);
SkPaint paint;
paint.setAntiAlias(true);
paint.setMaskFilter(std::move(f));
paint.setColor(SkColorSetARGB((unsigned char)(ambientAlpha*umbraAlpha*255.999f),
0, 0, 0));
canvas->drawPath(path, paint);
// draw occlusion rect
#if DRAW_OCCL_RECT
SkPaint stroke;
stroke.setStyle(SkPaint::kStroke_Style);
stroke.setColor(SK_ColorBLUE);
canvas->drawRect(occlRect, stroke);
#endif
pathRRect.outset(radius, radius);
}
SkPaint paint;
paint.setAntiAlias(true);
// handle scale of radius due to CTM
SkScalar maxScale = canvas->getTotalMatrix().getMaxScale();
radius *= maxScale;
unsigned char gray = (unsigned char)(ambientAlpha*umbraAlpha*255.999f);
SkASSERT(radius < 256);
// convert the radius to fixed point 8.8 and
// place it in the G,B components of the color
unsigned char intPart = (unsigned char)radius;
SkScalar fracPart = radius - intPart;
paint.setColor(SkColorSetARGB(1, gray, intPart, (unsigned char)(fracPart*256.f)));
sk_sp<SkShader> gaussShader = std::move(SkGaussianEdgeShader::Make());
paint.setShader(gaussShader);
canvas->drawRRect(pathRRect, paint);
}
void drawSpotShadow(SkCanvas* canvas, const SkPath& path, SkScalar zValue,
@ -235,10 +219,19 @@ protected:
GetOcclRect(path, &occlRect);
// apply inverse transform
occlRect.offset(-offset);
#if 0
// It looks like the scale may be invalid
SkScalar scale = lightPos.fZ / (lightPos.fZ - zValue);
if (scale < 1.0f) {
scale = 1.0f;
} else if (scale > 1024.f) {
scale = 1024.f;
}
occlRect.fLeft /= scale;
occlRect.fRight /= scale;
occlRect.fTop /= scale;
occlRect.fBottom /= scale;
#endif
sk_sp<SkMaskFilter> mf = SkBlurMaskFilter::Make(kNormal_SkBlurStyle,
SkBlurMask::ConvertRadiusToSigma(radius),
occlRect,
@ -251,7 +244,10 @@ protected:
// apply transformation to shadow
canvas->translate(offset.fX, offset.fY);
#if 0
// It looks like the scale may be invalid
canvas->scale(scale, scale);
#endif
canvas->drawPath(path, paint);
// draw occlusion rect
@ -263,21 +259,93 @@ protected:
#endif
}
void drawShadowedPath(SkCanvas* canvas, const SkPath& path, SkScalar zValue,
const SkPaint& paint) {
const SkScalar kLightWidth = 3;
const SkScalar kAmbientAlpha = 0.25f;
const SkScalar kSpotAlpha = 0.25f;
void drawSpotShadowAlt(SkCanvas* canvas, const SkPath& path, SkScalar zValue,
SkPoint3 lightPos, SkScalar lightWidth, SkScalar spotAlpha) {
if (spotAlpha <= 0) {
return;
}
SkRect pathRect;
SkRRect pathRRect;
if ((!path.isOval(&pathRect) || pathRect.width() != pathRect.height()) &&
(!path.isRRect(&pathRRect) || !pathRRect.allCornersCircular()) &&
!path.isRect(&pathRect)) {
this->drawSpotShadow(canvas, path, zValue, lightPos, lightWidth, spotAlpha);
return;
}
SkScalar zRatio = zValue / (lightPos.fZ - zValue);
if (zRatio < 0.0f) {
zRatio = 0.0f;
} else if (zRatio > 0.95f) {
zRatio = 0.95f;
}
SkScalar radius = lightWidth*zRatio;
// For all of these, we outset the rect by the radius to get our coverage shape.
if (path.isOval(nullptr)) {
pathRect.outset(radius, radius);
pathRRect = SkRRect::MakeOval(pathRect);
} else if (path.isRect(nullptr)) {
pathRect.outset(radius, radius);
pathRRect = SkRRect::MakeRectXY(pathRect, radius, radius);
} else {
pathRRect.outset(radius, radius);
}
// compute the transformation params
SkPoint center = SkPoint::Make(path.getBounds().centerX(), path.getBounds().centerY());
canvas->getTotalMatrix().mapPoints(&center, 1);
SkPoint offset = SkPoint::Make(-zRatio*(lightPos.fX - center.fX),
-zRatio*(lightPos.fY - center.fY));
SkAutoCanvasRestore acr(canvas, true);
SkPaint paint;
paint.setAntiAlias(true);
sk_sp<SkShader> gaussShader = std::move(SkGaussianEdgeShader::Make());
paint.setShader(gaussShader);
// handle scale of radius due to CTM
SkScalar maxScale = canvas->getTotalMatrix().getMaxScale();
radius *= maxScale;
unsigned char gray = (unsigned char)(spotAlpha*255.999f);
SkASSERT(radius < 256);
// convert the radius to fixed point 8.8 and
// place it in the G,B components of the color
unsigned char intPart = (unsigned char)radius;
SkScalar fracPart = radius - intPart;
paint.setColor(SkColorSetARGB(1, gray, intPart, (unsigned char)(fracPart*256.f)));
// apply transformation to shadow
canvas->translate(offset.fX, offset.fY);
#if 0
// It looks like the scale may be invalid
SkScalar scale = lightPos.fZ / (lightPos.fZ - zValue);
if (scale < 1.0f) {
scale = 1.0f;
} else if (scale > 1024.f) {
scale = 1024.f;
}
canvas->scale(scale, scale);
#endif
canvas->drawRRect(pathRRect, paint);
}
void drawShadowedPath(SkCanvas* canvas, const SkPath& path, SkScalar zValue,
const SkPaint& paint, SkScalar ambientAlpha,
const SkPoint3& lightPos, SkScalar lightWidth, SkScalar spotAlpha) {
if (fShowAmbient) {
if (fUseAltAmbient) {
this->drawAmbientShadowAlt(canvas, path, zValue, kAmbientAlpha);
if (fUseAlt) {
this->drawAmbientShadowAlt(canvas, path, zValue, ambientAlpha);
} else {
this->drawAmbientShadow(canvas, path, zValue, kAmbientAlpha);
this->drawAmbientShadow(canvas, path, zValue, ambientAlpha);
}
}
if (fShowSpot) {
this->drawSpotShadow(canvas, path, zValue, fLightPos, kLightWidth, kSpotAlpha);
if (fUseAlt) {
this->drawSpotShadowAlt(canvas, path, zValue, lightPos, lightWidth, spotAlpha);
} else {
this->drawSpotShadow(canvas, path, zValue, lightPos, lightWidth, spotAlpha);
}
}
if (fShowObject) {
canvas->drawPath(path, paint);
@ -286,25 +354,40 @@ protected:
void onDrawContent(SkCanvas* canvas) override {
this->drawBG(canvas);
const SkScalar kLightWidth = 3;
const SkScalar kAmbientAlpha = 0.25f;
const SkScalar kSpotAlpha = 0.25f;
SkPaint paint;
paint.setAntiAlias(true);
SkPoint3 lightPos = fLightPos;
paint.setColor(SK_ColorWHITE);
canvas->translate(200, 90);
this->drawShadowedPath(canvas, fRectPath, 5, paint);
lightPos.fX += 200;
lightPos.fY += 90;
this->drawShadowedPath(canvas, fRectPath, 5, paint, kAmbientAlpha,
lightPos, kLightWidth, kSpotAlpha);
paint.setColor(SK_ColorRED);
canvas->translate(250, 0);
this->drawShadowedPath(canvas, fRRPath, 5, paint);
lightPos.fX += 250;
this->drawShadowedPath(canvas, fRRPath, 5, paint, kAmbientAlpha,
lightPos, kLightWidth, kSpotAlpha);
paint.setColor(SK_ColorBLUE);
canvas->translate(-250, 110);
this->drawShadowedPath(canvas, fCirclePath, 5, paint);
lightPos.fX -= 250;
lightPos.fY += 110;
this->drawShadowedPath(canvas, fCirclePath, 5, paint, 0.0f,
lightPos, kLightWidth, 0.5f);
paint.setColor(SK_ColorGREEN);
canvas->translate(250, 0);
this->drawShadowedPath(canvas, fRRPath, 5, paint);
lightPos.fX += 250;
this->drawShadowedPath(canvas, fRRPath, 5, paint, kAmbientAlpha,
lightPos, kLightWidth, kSpotAlpha);
}
protected:

21
src/effects/SkGaussianEdgeShader.cpp
View File

@ -11,6 +11,10 @@
/** \class SkGaussianEdgeShaderImpl
This subclass of shader applies a Gaussian to shadow edge
The radius of the Gaussian blur is specified by the g and b values of the color,
where g is the integer component and b is the fractional component. The r value
represents the max final alpha.
*/
class SkGaussianEdgeShaderImpl : public SkShader {
public:
@ -65,20 +69,13 @@ public:
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
fragBuilder->codeAppendf("vec4 output = %s;", args.fInputColor);
// outside the outer edge
fragBuilder->codeAppendf("if (%s.z <= 0) {", fragBuilder->distanceVectorName());
fragBuilder->codeAppend("output *= 0.0;");
// inside the stroke
fragBuilder->codeAppendf("} else if (%s.w > 0) {", fragBuilder->distanceVectorName());
fragBuilder->codeAppendf("float factor = %s.w/(%s.z + %s.w);",
fragBuilder->distanceVectorName(),
fragBuilder->distanceVectorName(),
fragBuilder->codeAppendf("vec4 color = %s;", args.fInputColor);
fragBuilder->codeAppend("float radius = color.g*255.0 + color.b;");
fragBuilder->codeAppendf("float factor = 1.0 - clamp(%s.z/radius, 0.0, 1.0);",
fragBuilder->distanceVectorName());
fragBuilder->codeAppend("factor = exp(-factor * factor * 4.0) - 0.018;");
fragBuilder->codeAppend("output *= factor;");
fragBuilder->codeAppend("}");
fragBuilder->codeAppendf("%s = output;", args.fOutputColor);
fragBuilder->codeAppendf("%s = factor*vec4(0.0, 0.0, 0.0, color.r);", args.fOutputColor);
}
static void GenKey(const GrProcessor& proc, const GrGLSLCaps&,