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Add device-independent rendering of ovals, take two.

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This permits GPU support for arbitrary matrices. The only exception is 
not all stroked ovals are supported, as thin ovals + fat strokes do not
produce elliptical borders.

R=bsalomon@google.com, robertphillips@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23701013

git-svn-id: http://skia.googlecode.com/svn/trunk@11115 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
commit-bot@chromium.org 2013-09-05 19:26:51 +00:00
parent 40039a350b
commit 5242ed761f
2 changed files with 289 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/gpu/GrOvalRenderer.h
View File

@ -41,6 +41,9 @@ private:
bool drawEllipse(GrDrawTarget* target, bool useAA,
const SkRect& ellipse,
const SkStrokeRec& stroke);
bool drawDIEllipse(GrDrawTarget* target, bool useAA,
const SkRect& ellipse,
const SkStrokeRec& stroke);
void drawCircle(GrDrawTarget* target, bool useAA,
const SkRect& circle,
const SkStrokeRec& stroke);

302
src/gpu/GrOvalRenderer.cpp
View File

@ -37,6 +37,12 @@ struct EllipseVertex {
GrPoint fInnerRadii;
};
struct DIEllipseVertex {
GrPoint fPos;
GrPoint fOuterOffset;
GrPoint fInnerOffset;
};
inline bool circle_stays_circle(const SkMatrix& m) {
return m.isSimilarity();
}
@ -292,6 +298,158 @@ GrEffectRef* EllipseEdgeEffect::TestCreate(SkMWCRandom* random,
///////////////////////////////////////////////////////////////////////////////
/**
* The output of this effect is a modulation of the input color and coverage for an ellipse,
* specified as a 2D offset from center for both the outer and inner paths (if stroked). The
* implict equation used is for a unit circle (x^2 + y^2 - 1 = 0) and the edge corrected by
* using differentials.
*
* The result is device-independent and can be used with any affine matrix.
*/
class DIEllipseEdgeEffect : public GrEffect {
public:
enum Mode { kStroke = 0, kHairline, kFill };
static GrEffectRef* Create(Mode mode) {
GR_CREATE_STATIC_EFFECT(gEllipseStrokeEdge, DIEllipseEdgeEffect, (kStroke));
GR_CREATE_STATIC_EFFECT(gEllipseHairlineEdge, DIEllipseEdgeEffect, (kHairline));
GR_CREATE_STATIC_EFFECT(gEllipseFillEdge, DIEllipseEdgeEffect, (kFill));
if (kStroke == mode) {
gEllipseStrokeEdge->ref();
return gEllipseStrokeEdge;
} else if (kHairline == mode) {
gEllipseHairlineEdge->ref();
return gEllipseHairlineEdge;
} else {
gEllipseFillEdge->ref();
return gEllipseFillEdge;
}
}
virtual void getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const SK_OVERRIDE {
*validFlags = 0;
}
virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
return GrTBackendEffectFactory<DIEllipseEdgeEffect>::getInstance();
}
virtual ~DIEllipseEdgeEffect() {}
static const char* Name() { return "DIEllipseEdge"; }
inline Mode getMode() const { return fMode; }
class GLEffect : public GrGLEffect {
public:
GLEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
: INHERITED (factory) {}
virtual void emitCode(GrGLShaderBuilder* builder,
const GrDrawEffect& drawEffect,
EffectKey key,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) SK_OVERRIDE {
GrGLShaderBuilder::VertexBuilder* vertexBuilder = builder->getVertexBuilder();
SkASSERT(NULL != vertexBuilder);
const DIEllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<DIEllipseEdgeEffect>();
SkAssertResult(builder->enableFeature(
GrGLShaderBuilder::kStandardDerivatives_GLSLFeature));
const char *vsOffsetName, *fsOffsetName;
vertexBuilder->addVarying(kVec4f_GrSLType, "EllipseOffsets",
&vsOffsetName, &fsOffsetName);
const SkString* attr0Name =
vertexBuilder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
vertexBuilder->vsCodeAppendf("\t%s = %s;\n", vsOffsetName, attr0Name->c_str());
// for outer curve
builder->fsCodeAppendf("\tvec2 scaledOffset = %s.xy;\n", fsOffsetName);
builder->fsCodeAppend("\tfloat test = dot(scaledOffset, scaledOffset) - 1.0;\n");
builder->fsCodeAppendf("\tvec4 duvdx = dFdx(%s);\n", fsOffsetName);
builder->fsCodeAppendf("\tvec4 duvdy = dFdy(%s);\n", fsOffsetName);
builder->fsCodeAppendf("\tvec2 grad = vec2(2.0*%s.x*duvdx.x + 2.0*%s.y*duvdx.y,\n"
"\t 2.0*%s.x*duvdy.x + 2.0*%s.y*duvdy.y);\n",
fsOffsetName, fsOffsetName, fsOffsetName, fsOffsetName);
builder->fsCodeAppend("\tfloat grad_dot = dot(grad, grad);\n");
// we need to clamp the length^2 of the gradiant vector to a non-zero value, because
// on the Nexus 4 the undefined result of inversesqrt(0) drops out an entire tile
// TODO: restrict this to Adreno-only
builder->fsCodeAppend("\tgrad_dot = max(grad_dot, 1.0e-4);\n");
builder->fsCodeAppend("\tfloat invlen = inversesqrt(grad_dot);\n");
if (kHairline == ellipseEffect.getMode()) {
// can probably do this with one step
builder->fsCodeAppend("\tfloat edgeAlpha = clamp(1.0-test*invlen, 0.0, 1.0);\n");
builder->fsCodeAppend("\tedgeAlpha *= clamp(1.0+test*invlen, 0.0, 1.0);\n");
} else {
builder->fsCodeAppend("\tfloat edgeAlpha = clamp(0.5-test*invlen, 0.0, 1.0);\n");
}
// for inner curve
if (kStroke == ellipseEffect.getMode()) {
builder->fsCodeAppendf("\tscaledOffset = %s.zw;\n", fsOffsetName);
builder->fsCodeAppend("\ttest = dot(scaledOffset, scaledOffset) - 1.0;\n");
builder->fsCodeAppendf("\tgrad = vec2(2.0*%s.z*duvdx.z + 2.0*%s.w*duvdx.w,\n"
"\t 2.0*%s.z*duvdy.z + 2.0*%s.w*duvdy.w);\n",
fsOffsetName, fsOffsetName, fsOffsetName, fsOffsetName);
builder->fsCodeAppend("\tinvlen = inversesqrt(dot(grad, grad));\n");
builder->fsCodeAppend("\tedgeAlpha *= clamp(0.5+test*invlen, 0.0, 1.0);\n");
}
SkString modulate;
GrGLSLModulatef<4>(&modulate, inputColor, "edgeAlpha");
builder->fsCodeAppendf("\t%s = %s;\n", outputColor, modulate.c_str());
}
static inline EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
const DIEllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<DIEllipseEdgeEffect>();
return ellipseEffect.getMode();
}
virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {
}
private:
typedef GrGLEffect INHERITED;
};
private:
DIEllipseEdgeEffect(Mode mode) : GrEffect() {
this->addVertexAttrib(kVec4f_GrSLType);
fMode = mode;
}
virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
const DIEllipseEdgeEffect& eee = CastEffect<DIEllipseEdgeEffect>(other);
return eee.fMode == fMode;
}
Mode fMode;
GR_DECLARE_EFFECT_TEST;
typedef GrEffect INHERITED;
};
GR_DEFINE_EFFECT_TEST(DIEllipseEdgeEffect);
GrEffectRef* DIEllipseEdgeEffect::TestCreate(SkMWCRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
return DIEllipseEdgeEffect::Create((Mode)(random->nextRangeU(0,2)));
}
///////////////////////////////////////////////////////////////////////////////
void GrOvalRenderer::reset() {
GrSafeSetNull(fRRectIndexBuffer);
}
@ -309,11 +467,12 @@ bool GrOvalRenderer::drawOval(GrDrawTarget* target, const GrContext* context, bo
if (SkScalarNearlyEqual(oval.width(), oval.height())
&& circle_stays_circle(vm)) {
this->drawCircle(target, useAA, oval, stroke);
// and axis-aligned ellipses only
// if we have shader derivative support, render as device-independent
} else if (target->caps()->shaderDerivativeSupport()) {
return this->drawDIEllipse(target, useAA, oval, stroke);
// otherwise axis-aligned ellipses only
} else if (vm.rectStaysRect()) {
return this->drawEllipse(target, useAA, oval, stroke);
} else {
return false;
}
@ -321,8 +480,6 @@ bool GrOvalRenderer::drawOval(GrDrawTarget* target, const GrContext* context, bo
return true;
}
namespace {
///////////////////////////////////////////////////////////////////////////////
// position + edge
@ -331,8 +488,6 @@ extern const GrVertexAttrib gCircleVertexAttribs[] = {
{kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding}
};
};
void GrOvalRenderer::drawCircle(GrDrawTarget* target,
bool useAA,
const SkRect& circle,
@ -424,15 +579,17 @@ void GrOvalRenderer::drawCircle(GrDrawTarget* target,
///////////////////////////////////////////////////////////////////////////////
namespace {
// position + edge
// position + offset + 1/radii
extern const GrVertexAttrib gEllipseVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec2f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding},
{kVec4f_GrVertexAttribType, 2*sizeof(GrPoint), kEffect_GrVertexAttribBinding}
};
// position + offsets
extern const GrVertexAttrib gDIEllipseVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding},
};
bool GrOvalRenderer::drawEllipse(GrDrawTarget* target,
@ -469,8 +626,8 @@ bool GrOvalRenderer::drawEllipse(GrDrawTarget* target,
SkStrokeRec::Style style = stroke.getStyle();
bool isStroked = (SkStrokeRec::kStroke_Style == style || SkStrokeRec::kHairline_Style == style);
SkScalar innerXRadius = 0.0f;
SkScalar innerYRadius = 0.0f;
SkScalar innerXRadius = 0;
SkScalar innerYRadius = 0;
if (SkStrokeRec::kFill_Style != style) {
if (SkScalarNearlyZero(scaledStroke.length())) {
scaledStroke.set(SK_ScalarHalf, SK_ScalarHalf);
@ -520,8 +677,7 @@ bool GrOvalRenderer::drawEllipse(GrDrawTarget* target,
innerXRadius > 0 && innerYRadius > 0);
static const int kEllipseCenterAttrIndex = 1;
static const int kEllipseEdgeAttrIndex = 2;
drawState->addCoverageEffect(effect, kEllipseCenterAttrIndex, kEllipseEdgeAttrIndex)->unref();
drawState->addCoverageEffect(effect, kEllipseCenterAttrIndex)->unref();
// Compute the reciprocals of the radii here to save time in the shader
SkScalar xRadRecip = SkScalarInvert(xRadius);
@ -567,6 +723,120 @@ bool GrOvalRenderer::drawEllipse(GrDrawTarget* target,
return true;
}
bool GrOvalRenderer::drawDIEllipse(GrDrawTarget* target,
bool useAA,
const SkRect& ellipse,
const SkStrokeRec& stroke)
{
GrDrawState* drawState = target->drawState();
const SkMatrix& vm = drawState->getViewMatrix();
GrPoint center = GrPoint::Make(ellipse.centerX(), ellipse.centerY());
SkScalar xRadius = SkScalarHalf(ellipse.width());
SkScalar yRadius = SkScalarHalf(ellipse.height());
SkStrokeRec::Style style = stroke.getStyle();
DIEllipseEdgeEffect::Mode mode = (SkStrokeRec::kStroke_Style == style) ?
DIEllipseEdgeEffect::kStroke :
(SkStrokeRec::kHairline_Style == style) ?
DIEllipseEdgeEffect::kHairline : DIEllipseEdgeEffect::kFill;
SkScalar innerXRadius = 0;
SkScalar innerYRadius = 0;
if (SkStrokeRec::kFill_Style != style && SkStrokeRec::kHairline_Style != style) {
SkScalar strokeWidth = stroke.getWidth();
if (SkScalarNearlyZero(strokeWidth)) {
strokeWidth = SK_ScalarHalf;
} else {
strokeWidth *= SK_ScalarHalf;
}
// we only handle thick strokes for near-circular ellipses
if (strokeWidth > SK_ScalarHalf &&
(SK_ScalarHalf*xRadius > yRadius || SK_ScalarHalf*yRadius > xRadius)) {
return false;
}
// we don't handle it if curvature of the stroke is less than curvature of the ellipse
if (strokeWidth*(yRadius*yRadius) < (strokeWidth*strokeWidth)*xRadius ||
strokeWidth*(xRadius*xRadius) < (strokeWidth*strokeWidth)*yRadius) {
return false;
}
// set inner radius (if needed)
if (SkStrokeRec::kStroke_Style == style) {
innerXRadius = xRadius - strokeWidth;
innerYRadius = yRadius - strokeWidth;
}
xRadius += strokeWidth;
yRadius += strokeWidth;
}
if (DIEllipseEdgeEffect::kStroke == mode) {
mode = (innerXRadius > 0 && innerYRadius > 0) ? DIEllipseEdgeEffect::kStroke :
DIEllipseEdgeEffect::kFill;
}
SkScalar innerRatioX = SkScalarDiv(xRadius, innerXRadius);
SkScalar innerRatioY = SkScalarDiv(yRadius, innerYRadius);
drawState->setVertexAttribs<gDIEllipseVertexAttribs>(SK_ARRAY_COUNT(gDIEllipseVertexAttribs));
SkASSERT(sizeof(DIEllipseVertex) == drawState->getVertexSize());
GrDrawTarget::AutoReleaseGeometry geo(target, 4, 0);
if (!geo.succeeded()) {
GrPrintf("Failed to get space for vertices!\n");
return false;
}
DIEllipseVertex* verts = reinterpret_cast<DIEllipseVertex*>(geo.vertices());
GrEffectRef* effect = DIEllipseEdgeEffect::Create(mode);
static const int kEllipseOuterOffsetAttrIndex = 1;
static const int kEllipseInnerOffsetAttrIndex = 2;
drawState->addCoverageEffect(effect, kEllipseOuterOffsetAttrIndex,
kEllipseInnerOffsetAttrIndex)->unref();
// This expands the outer rect so that after CTM we end up with a half-pixel border
SkScalar a = vm[SkMatrix::kMScaleX];
SkScalar b = vm[SkMatrix::kMSkewX];
SkScalar c = vm[SkMatrix::kMSkewY];
SkScalar d = vm[SkMatrix::kMScaleY];
SkScalar geoDx = SkScalarDiv(SK_ScalarHalf, SkScalarSqrt(a*a + c*c));
SkScalar geoDy = SkScalarDiv(SK_ScalarHalf, SkScalarSqrt(b*b + d*d));
// This adjusts the "radius" to include the half-pixel border
SkScalar offsetDx = SkScalarDiv(geoDx, xRadius);
SkScalar offsetDy = SkScalarDiv(geoDy, yRadius);
SkRect bounds = SkRect::MakeLTRB(
center.fX - xRadius - geoDx,
center.fY - yRadius - geoDy,
center.fX + xRadius + geoDx,
center.fY + yRadius + geoDy
);
verts[0].fPos = SkPoint::Make(bounds.fLeft, bounds.fTop);
verts[0].fOuterOffset = SkPoint::Make(-1.0f - offsetDx, -1.0f - offsetDy);
verts[0].fInnerOffset = SkPoint::Make(-innerRatioX - offsetDx, -innerRatioY - offsetDy);
verts[1].fPos = SkPoint::Make(bounds.fRight, bounds.fTop);
verts[1].fOuterOffset = SkPoint::Make(1.0f + offsetDx, -1.0f - offsetDy);
verts[1].fInnerOffset = SkPoint::Make(innerRatioX + offsetDx, -innerRatioY - offsetDy);
verts[2].fPos = SkPoint::Make(bounds.fLeft, bounds.fBottom);
verts[2].fOuterOffset = SkPoint::Make(-1.0f - offsetDx, 1.0f + offsetDy);
verts[2].fInnerOffset = SkPoint::Make(-innerRatioX - offsetDx, innerRatioY + offsetDy);
verts[3].fPos = SkPoint::Make(bounds.fRight, bounds.fBottom);
verts[3].fOuterOffset = SkPoint::Make(1.0f + offsetDx, 1.0f + offsetDy);
verts[3].fInnerOffset = SkPoint::Make(innerRatioX + offsetDx, innerRatioY + offsetDy);
target->drawNonIndexed(kTriangleStrip_GrPrimitiveType, 0, 4, &bounds);
return true;
}
///////////////////////////////////////////////////////////////////////////////
static const uint16_t gRRectIndices[] = {
@ -693,7 +963,7 @@ bool GrOvalRenderer::drawSimpleRRect(GrDrawTarget* target, GrContext* context, b
bounds.outset(halfWidth, halfWidth);
}
isStroked = (isStroked && innerRadius > 0);
isStroked = (isStroked && innerRadius > 0);
GrEffectRef* effect = CircleEdgeEffect::Create(isStroked);
static const int kCircleEdgeAttrIndex = 1;
@ -789,7 +1059,7 @@ bool GrOvalRenderer::drawSimpleRRect(GrDrawTarget* target, GrContext* context, b
bounds.outset(scaledStroke.fX, scaledStroke.fY);
}
isStroked = (isStroked && innerXRadius > 0 && innerYRadius > 0);
isStroked = (isStroked && innerXRadius > 0 && innerYRadius > 0);
GrDrawTarget::AutoReleaseGeometry geo(target, 16, 0);
if (!geo.succeeded()) {