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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrOvalRenderer.h"
#include "GrEffect.h"
#include "gl/GrGLEffect.h"
#include "gl/GrGLSL.h"
#include "GrTBackendEffectFactory.h"
#include "GrDrawState.h"
#include "GrDrawTarget.h"
#include "GrGpu.h"
#include "SkRRect.h"
#include "SkStrokeRec.h"
SK_DEFINE_INST_COUNT(GrOvalRenderer)
namespace {
struct CircleVertex {
GrPoint fPos;
GrPoint fOffset;
SkScalar fOuterRadius;
SkScalar fInnerRadius;
};
struct EllipseVertex {
GrPoint fPos;
GrPoint fOffset;
GrPoint fOuterRadii;
GrPoint fInnerRadii;
};
inline bool circle_stays_circle(const SkMatrix& m) {
return m.isSimilarity();
}
}
///////////////////////////////////////////////////////////////////////////////
/**
* The output of this effect is a modulation of the input color and coverage for a circle,
* specified as offset_x, offset_y (both from center point), outer radius and inner radius.
*/
class CircleEdgeEffect : public GrEffect {
public:
static GrEffectRef* Create(bool stroke) {
GR_CREATE_STATIC_EFFECT(gCircleStrokeEdge, CircleEdgeEffect, (true));
GR_CREATE_STATIC_EFFECT(gCircleFillEdge, CircleEdgeEffect, (false));
if (stroke) {
gCircleStrokeEdge->ref();
return gCircleStrokeEdge;
} else {
gCircleFillEdge->ref();
return gCircleFillEdge;
}
}
virtual void getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const SK_OVERRIDE {
*validFlags = 0;
}
virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
return GrTBackendEffectFactory<CircleEdgeEffect>::getInstance();
}
virtual ~CircleEdgeEffect() {}
static const char* Name() { return "CircleEdge"; }
inline bool isStroked() const { return fStroke; }
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 {
const CircleEdgeEffect& circleEffect = drawEffect.castEffect<CircleEdgeEffect>();
const char *vsName, *fsName;
builder->addVarying(kVec4f_GrSLType, "CircleEdge", &vsName, &fsName);
const SkString* attrName =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
builder->vsCodeAppendf("\t%s = %s;\n", vsName, attrName->c_str());
builder->fsCodeAppendf("\tfloat d = length(%s.xy);\n", fsName);
builder->fsCodeAppendf("\tfloat edgeAlpha = clamp(%s.z - d, 0.0, 1.0);\n", fsName);
if (circleEffect.isStroked()) {
builder->fsCodeAppendf("\tfloat innerAlpha = clamp(d - %s.w, 0.0, 1.0);\n", fsName);
builder->fsCodeAppend("\tedgeAlpha *= innerAlpha;\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 CircleEdgeEffect& circleEffect = drawEffect.castEffect<CircleEdgeEffect>();
return circleEffect.isStroked() ? 0x1 : 0x0;
}
virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {}
private:
typedef GrGLEffect INHERITED;
};
private:
CircleEdgeEffect(bool stroke) : GrEffect() {
this->addVertexAttrib(kVec4f_GrSLType);
fStroke = stroke;
}
virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
const CircleEdgeEffect& cee = CastEffect<CircleEdgeEffect>(other);
return cee.fStroke == fStroke;
}
bool fStroke;
GR_DECLARE_EFFECT_TEST;
typedef GrEffect INHERITED;
};
GR_DEFINE_EFFECT_TEST(CircleEdgeEffect);
GrEffectRef* CircleEdgeEffect::TestCreate(SkMWCRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
return CircleEdgeEffect::Create(random->nextBool());
}
///////////////////////////////////////////////////////////////////////////////
/**
* The output of this effect is a modulation of the input color and coverage for an axis-aligned
* ellipse, specified as a 2D offset from center, and the reciprocals of the outer and inner radii,
* in both x and y directions.
*
* We are using an implicit function of x^2/a^2 + y^2/b^2 - 1 = 0.
*/
class EllipseEdgeEffect : public GrEffect {
public:
static GrEffectRef* Create(bool stroke) {
GR_CREATE_STATIC_EFFECT(gEllipseStrokeEdge, EllipseEdgeEffect, (true));
GR_CREATE_STATIC_EFFECT(gEllipseFillEdge, EllipseEdgeEffect, (false));
if (stroke) {
gEllipseStrokeEdge->ref();
return gEllipseStrokeEdge;
} 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<EllipseEdgeEffect>::getInstance();
}
virtual ~EllipseEdgeEffect() {}
static const char* Name() { return "EllipseEdge"; }
inline bool isStroked() const { return fStroke; }
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 {
const EllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<EllipseEdgeEffect>();
const char *vsOffsetName, *fsOffsetName;
const char *vsRadiiName, *fsRadiiName;
builder->addVarying(kVec2f_GrSLType, "EllipseOffsets", &vsOffsetName, &fsOffsetName);
const SkString* attr0Name =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
builder->vsCodeAppendf("\t%s = %s;\n", vsOffsetName, attr0Name->c_str());
builder->addVarying(kVec4f_GrSLType, "EllipseRadii", &vsRadiiName, &fsRadiiName);
const SkString* attr1Name =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[1]);
builder->vsCodeAppendf("\t%s = %s;\n", vsRadiiName, attr1Name->c_str());
// for outer curve
builder->fsCodeAppendf("\tvec2 scaledOffset = %s*%s.xy;\n", fsOffsetName, fsRadiiName);
builder->fsCodeAppend("\tfloat test = dot(scaledOffset, scaledOffset) - 1.0;\n");
builder->fsCodeAppendf("\tvec2 grad = 2.0*scaledOffset*%s.xy;\n", fsRadiiName);
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");
builder->fsCodeAppend("\tfloat edgeAlpha = clamp(0.5-test*invlen, 0.0, 1.0);\n");
// for inner curve
if (ellipseEffect.isStroked()) {
builder->fsCodeAppendf("\tscaledOffset = %s*%s.zw;\n", fsOffsetName, fsRadiiName);
builder->fsCodeAppend("\ttest = dot(scaledOffset, scaledOffset) - 1.0;\n");
builder->fsCodeAppendf("\tgrad = 2.0*scaledOffset*%s.zw;\n", fsRadiiName);
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 EllipseEdgeEffect& ellipseEffect = drawEffect.castEffect<EllipseEdgeEffect>();
return ellipseEffect.isStroked() ? 0x1 : 0x0;
}
virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {
}
private:
typedef GrGLEffect INHERITED;
};
private:
EllipseEdgeEffect(bool stroke) : GrEffect() {
this->addVertexAttrib(kVec2f_GrSLType);
this->addVertexAttrib(kVec4f_GrSLType);
fStroke = stroke;
}
virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
const EllipseEdgeEffect& eee = CastEffect<EllipseEdgeEffect>(other);
return eee.fStroke == fStroke;
}
bool fStroke;
GR_DECLARE_EFFECT_TEST;
typedef GrEffect INHERITED;
};
GR_DEFINE_EFFECT_TEST(EllipseEdgeEffect);
GrEffectRef* EllipseEdgeEffect::TestCreate(SkMWCRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
return EllipseEdgeEffect::Create(random->nextBool());
}
///////////////////////////////////////////////////////////////////////////////
void GrOvalRenderer::reset() {
GrSafeSetNull(fRRectIndexBuffer);
}
bool GrOvalRenderer::drawOval(GrDrawTarget* target, const GrContext* context, bool useAA,
const GrRect& oval, const SkStrokeRec& stroke)
{
if (!useAA) {
return false;
}
const SkMatrix& vm = context->getMatrix();
// we can draw circles
if (SkScalarNearlyEqual(oval.width(), oval.height())
&& circle_stays_circle(vm)) {
this->drawCircle(target, useAA, oval, stroke);
// and axis-aligned ellipses only
} else if (vm.rectStaysRect()) {
return this->drawEllipse(target, useAA, oval, stroke);
} else {
return false;
}
return true;
}
namespace {
///////////////////////////////////////////////////////////////////////////////
// position + edge
extern const GrVertexAttrib gCircleVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding}
};
};
void GrOvalRenderer::drawCircle(GrDrawTarget* target,
bool useAA,
const GrRect& circle,
const SkStrokeRec& stroke)
{
GrDrawState* drawState = target->drawState();
const SkMatrix& vm = drawState->getViewMatrix();
GrPoint center = GrPoint::Make(circle.centerX(), circle.centerY());
vm.mapPoints(&center, 1);
SkScalar radius = vm.mapRadius(SkScalarHalf(circle.width()));
SkScalar strokeWidth = vm.mapRadius(stroke.getWidth());
GrDrawState::AutoViewMatrixRestore avmr;
if (!avmr.setIdentity(drawState)) {
return;
}
drawState->setVertexAttribs<gCircleVertexAttribs>(SK_ARRAY_COUNT(gCircleVertexAttribs));
GrAssert(sizeof(CircleVertex) == drawState->getVertexSize());
GrDrawTarget::AutoReleaseGeometry geo(target, 4, 0);
if (!geo.succeeded()) {
GrPrintf("Failed to get space for vertices!\n");
return;
}
CircleVertex* verts = reinterpret_cast<CircleVertex*>(geo.vertices());
SkStrokeRec::Style style = stroke.getStyle();
bool isStroked = (SkStrokeRec::kStroke_Style == style || SkStrokeRec::kHairline_Style == style);
GrEffectRef* effect = CircleEdgeEffect::Create(isStroked);
static const int kCircleEdgeAttrIndex = 1;
drawState->addCoverageEffect(effect, kCircleEdgeAttrIndex)->unref();
SkScalar innerRadius = 0.0f;
SkScalar outerRadius = radius;
SkScalar halfWidth = 0;
if (style != SkStrokeRec::kFill_Style) {
if (SkScalarNearlyZero(strokeWidth)) {
halfWidth = SK_ScalarHalf;
} else {
halfWidth = SkScalarHalf(strokeWidth);
}
outerRadius += halfWidth;
if (isStroked) {
innerRadius = radius - halfWidth;
isStroked = (innerRadius > 0);
}
}
// The radii are outset for two reasons. First, it allows the shader to simply perform
// clamp(distance-to-center - radius, 0, 1). Second, the outer radius is used to compute the
// verts of the bounding box that is rendered and the outset ensures the box will cover all
// pixels partially covered by the circle.
outerRadius += SK_ScalarHalf;
innerRadius -= SK_ScalarHalf;
SkRect bounds = SkRect::MakeLTRB(
center.fX - outerRadius,
center.fY - outerRadius,
center.fX + outerRadius,
center.fY + outerRadius
);
verts[0].fPos = SkPoint::Make(bounds.fLeft, bounds.fTop);
verts[0].fOffset = SkPoint::Make(-outerRadius, -outerRadius);
verts[0].fOuterRadius = outerRadius;
verts[0].fInnerRadius = innerRadius;
verts[1].fPos = SkPoint::Make(bounds.fRight, bounds.fTop);
verts[1].fOffset = SkPoint::Make(outerRadius, -outerRadius);
verts[1].fOuterRadius = outerRadius;
verts[1].fInnerRadius = innerRadius;
verts[2].fPos = SkPoint::Make(bounds.fLeft, bounds.fBottom);
verts[2].fOffset = SkPoint::Make(-outerRadius, outerRadius);
verts[2].fOuterRadius = outerRadius;
verts[2].fInnerRadius = innerRadius;
verts[3].fPos = SkPoint::Make(bounds.fRight, bounds.fBottom);
verts[3].fOffset = SkPoint::Make(outerRadius, outerRadius);
verts[3].fOuterRadius = outerRadius;
verts[3].fInnerRadius = innerRadius;
target->drawNonIndexed(kTriangleStrip_GrPrimitiveType, 0, 4, &bounds);
}
///////////////////////////////////////////////////////////////////////////////
namespace {
// position + edge
extern const GrVertexAttrib gEllipseVertexAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec2f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding},
{kVec4f_GrVertexAttribType, 2*sizeof(GrPoint), kEffect_GrVertexAttribBinding}
};
};
bool GrOvalRenderer::drawEllipse(GrDrawTarget* target,
bool useAA,
const GrRect& ellipse,
const SkStrokeRec& stroke)
{
GrDrawState* drawState = target->drawState();
#ifdef SK_DEBUG
{
// we should have checked for this previously
bool isAxisAlignedEllipse = drawState->getViewMatrix().rectStaysRect();
SkASSERT(useAA && isAxisAlignedEllipse);
}
#endif
// do any matrix crunching before we reset the draw state for device coords
const SkMatrix& vm = drawState->getViewMatrix();
GrPoint center = GrPoint::Make(ellipse.centerX(), ellipse.centerY());
vm.mapPoints(&center, 1);
SkScalar ellipseXRadius = SkScalarHalf(ellipse.width());
SkScalar ellipseYRadius = SkScalarHalf(ellipse.height());
SkScalar xRadius = SkScalarAbs(vm[SkMatrix::kMScaleX]*ellipseXRadius +
vm[SkMatrix::kMSkewY]*ellipseYRadius);
SkScalar yRadius = SkScalarAbs(vm[SkMatrix::kMSkewX]*ellipseXRadius +
vm[SkMatrix::kMScaleY]*ellipseYRadius);
// do (potentially) anisotropic mapping of stroke
SkVector scaledStroke;
SkScalar strokeWidth = stroke.getWidth();
scaledStroke.fX = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMScaleX] + vm[SkMatrix::kMSkewY]));
scaledStroke.fY = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMSkewX] + vm[SkMatrix::kMScaleY]));
SkStrokeRec::Style style = stroke.getStyle();
bool isStroked = (SkStrokeRec::kStroke_Style == style || SkStrokeRec::kHairline_Style == style);
SkScalar innerXRadius = 0.0f;
SkScalar innerYRadius = 0.0f;
if (SkStrokeRec::kFill_Style != style) {
if (SkScalarNearlyZero(scaledStroke.length())) {
scaledStroke.set(SK_ScalarHalf, SK_ScalarHalf);
} else {
scaledStroke.scale(SK_ScalarHalf);
}
// we only handle thick strokes for near-circular ellipses
if (scaledStroke.length() > 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 (scaledStroke.fX*(yRadius*yRadius) < (scaledStroke.fY*scaledStroke.fY)*xRadius ||
scaledStroke.fY*(xRadius*xRadius) < (scaledStroke.fX*scaledStroke.fX)*yRadius) {
return false;
}
// this is legit only if scale & translation (which should be the case at the moment)
if (isStroked) {
innerXRadius = xRadius - scaledStroke.fX;
innerYRadius = yRadius - scaledStroke.fY;
isStroked = (innerXRadius > 0 && innerYRadius > 0);
}
xRadius += scaledStroke.fX;
yRadius += scaledStroke.fY;
}
GrDrawState::AutoViewMatrixRestore avmr;
if (!avmr.setIdentity(drawState)) {
return false;
}
drawState->setVertexAttribs<gEllipseVertexAttribs>(SK_ARRAY_COUNT(gEllipseVertexAttribs));
GrAssert(sizeof(EllipseVertex) == drawState->getVertexSize());
GrDrawTarget::AutoReleaseGeometry geo(target, 4, 0);
if (!geo.succeeded()) {
GrPrintf("Failed to get space for vertices!\n");
return false;
}
EllipseVertex* verts = reinterpret_cast<EllipseVertex*>(geo.vertices());
GrEffectRef* effect = EllipseEdgeEffect::Create(isStroked);
static const int kEllipseCenterAttrIndex = 1;
static const int kEllipseEdgeAttrIndex = 2;
drawState->addCoverageEffect(effect, kEllipseCenterAttrIndex, kEllipseEdgeAttrIndex)->unref();
// Compute the reciprocals of the radii here to save time in the shader
SkScalar xRadRecip = SkScalarInvert(xRadius);
SkScalar yRadRecip = SkScalarInvert(yRadius);
SkScalar xInnerRadRecip = SkScalarInvert(innerXRadius);
SkScalar yInnerRadRecip = SkScalarInvert(innerYRadius);
// We've extended the outer x radius out half a pixel to antialias.
// This will also expand the rect so all the pixels will be captured.
// TODO: Consider if we should use sqrt(2)/2 instead
xRadius += SK_ScalarHalf;
yRadius += SK_ScalarHalf;
SkRect bounds = SkRect::MakeLTRB(
center.fX - xRadius,
center.fY - yRadius,
center.fX + xRadius,
center.fY + yRadius
);
verts[0].fPos = SkPoint::Make(bounds.fLeft, bounds.fTop);
verts[0].fOffset = SkPoint::Make(-xRadius, -yRadius);
verts[0].fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts[0].fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts[1].fPos = SkPoint::Make(bounds.fRight, bounds.fTop);
verts[1].fOffset = SkPoint::Make(xRadius, -yRadius);
verts[1].fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts[1].fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts[2].fPos = SkPoint::Make(bounds.fLeft, bounds.fBottom);
verts[2].fOffset = SkPoint::Make(-xRadius, yRadius);
verts[2].fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts[2].fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts[3].fPos = SkPoint::Make(bounds.fRight, bounds.fBottom);
verts[3].fOffset = SkPoint::Make(xRadius, yRadius);
verts[3].fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts[3].fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
target->drawNonIndexed(kTriangleStrip_GrPrimitiveType, 0, 4, &bounds);
return true;
}
///////////////////////////////////////////////////////////////////////////////
static const uint16_t gRRectIndices[] = {
// corners
0, 1, 5, 0, 5, 4,
2, 3, 7, 2, 7, 6,
8, 9, 13, 8, 13, 12,
10, 11, 15, 10, 15, 14,
// edges
1, 2, 6, 1, 6, 5,
4, 5, 9, 4, 9, 8,
6, 7, 11, 6, 11, 10,
9, 10, 14, 9, 14, 13,
// center
// we place this at the end so that we can ignore these indices when rendering stroke-only
5, 6, 10, 5, 10, 9
};
GrIndexBuffer* GrOvalRenderer::rRectIndexBuffer(GrGpu* gpu) {
if (NULL == fRRectIndexBuffer) {
fRRectIndexBuffer =
gpu->createIndexBuffer(sizeof(gRRectIndices), false);
if (NULL != fRRectIndexBuffer) {
#if GR_DEBUG
bool updated =
#endif
fRRectIndexBuffer->updateData(gRRectIndices,
sizeof(gRRectIndices));
GR_DEBUGASSERT(updated);
}
}
return fRRectIndexBuffer;
}
bool GrOvalRenderer::drawSimpleRRect(GrDrawTarget* target, GrContext* context, bool useAA,
const SkRRect& rrect, const SkStrokeRec& stroke)
{
// only anti-aliased rrects for now
if (!useAA) {
return false;
}
const SkMatrix& vm = context->getMatrix();
#ifdef SK_DEBUG
{
// we should have checked for this previously
SkASSERT(useAA && vm.rectStaysRect() && rrect.isSimple());
}
#endif
// do any matrix crunching before we reset the draw state for device coords
const SkRect& rrectBounds = rrect.getBounds();
SkRect bounds;
vm.mapRect(&bounds, rrectBounds);
SkVector radii = rrect.getSimpleRadii();
SkScalar xRadius = SkScalarAbs(vm[SkMatrix::kMScaleX]*radii.fX +
vm[SkMatrix::kMSkewY]*radii.fY);
SkScalar yRadius = SkScalarAbs(vm[SkMatrix::kMSkewX]*radii.fX +
vm[SkMatrix::kMScaleY]*radii.fY);
// if hairline stroke is greater than radius, we don't handle that right now
SkStrokeRec::Style style = stroke.getStyle();
if (SkStrokeRec::kHairline_Style == style &&
(SK_ScalarHalf >= xRadius || SK_ScalarHalf >= yRadius)) {
return false;
}
// do (potentially) anisotropic mapping of stroke
SkVector scaledStroke;
SkScalar strokeWidth = stroke.getWidth();
scaledStroke.fX = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMScaleX] + vm[SkMatrix::kMSkewY]));
scaledStroke.fY = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMSkewX] + vm[SkMatrix::kMScaleY]));
// if half of strokewidth is greater than radius, we don't handle that right now
if (SK_ScalarHalf*scaledStroke.fX >= xRadius || SK_ScalarHalf*scaledStroke.fY >= yRadius) {
return false;
}
// reset to device coordinates
GrDrawState* drawState = target->drawState();
GrDrawState::AutoViewMatrixRestore avmr;
if (!avmr.setIdentity(drawState)) {
return false;
}
bool isStroked = (SkStrokeRec::kStroke_Style == style || SkStrokeRec::kHairline_Style == style);
GrIndexBuffer* indexBuffer = this->rRectIndexBuffer(context->getGpu());
if (NULL == indexBuffer) {
GrPrintf("Failed to create index buffer!\n");
return false;
}
// if the corners are circles, use the circle renderer
if ((!isStroked || scaledStroke.fX == scaledStroke.fY) && xRadius == yRadius) {
drawState->setVertexAttribs<gCircleVertexAttribs>(SK_ARRAY_COUNT(gCircleVertexAttribs));
GrAssert(sizeof(CircleVertex) == drawState->getVertexSize());
GrDrawTarget::AutoReleaseGeometry geo(target, 16, 0);
if (!geo.succeeded()) {
GrPrintf("Failed to get space for vertices!\n");
return false;
}
CircleVertex* verts = reinterpret_cast<CircleVertex*>(geo.vertices());
SkScalar innerRadius = 0.0f;
SkScalar outerRadius = xRadius;
SkScalar halfWidth = 0;
if (style != SkStrokeRec::kFill_Style) {
if (SkScalarNearlyZero(scaledStroke.fX)) {
halfWidth = SK_ScalarHalf;
} else {
halfWidth = SkScalarHalf(scaledStroke.fX);
}
if (isStroked) {
innerRadius = xRadius - halfWidth;
isStroked = (innerRadius > 0);
}
outerRadius += halfWidth;
bounds.outset(halfWidth, halfWidth);
}
GrEffectRef* effect = CircleEdgeEffect::Create(isStroked);
static const int kCircleEdgeAttrIndex = 1;
drawState->addCoverageEffect(effect, kCircleEdgeAttrIndex)->unref();
// The radii are outset for two reasons. First, it allows the shader to simply perform
// clamp(distance-to-center - radius, 0, 1). Second, the outer radius is used to compute the
// verts of the bounding box that is rendered and the outset ensures the box will cover all
// pixels partially covered by the circle.
outerRadius += SK_ScalarHalf;
innerRadius -= SK_ScalarHalf;
// Expand the rect so all the pixels will be captured.
bounds.outset(SK_ScalarHalf, SK_ScalarHalf);
SkScalar yCoords[4] = {
bounds.fTop,
bounds.fTop + outerRadius,
bounds.fBottom - outerRadius,
bounds.fBottom
};
SkScalar yOuterRadii[4] = {
-outerRadius,
0,
0,
outerRadius
};
for (int i = 0; i < 4; ++i) {
verts->fPos = SkPoint::Make(bounds.fLeft, yCoords[i]);
verts->fOffset = SkPoint::Make(-outerRadius, yOuterRadii[i]);
verts->fOuterRadius = outerRadius;
verts->fInnerRadius = innerRadius;
verts++;
verts->fPos = SkPoint::Make(bounds.fLeft + outerRadius, yCoords[i]);
verts->fOffset = SkPoint::Make(0, yOuterRadii[i]);
verts->fOuterRadius = outerRadius;
verts->fInnerRadius = innerRadius;
verts++;
verts->fPos = SkPoint::Make(bounds.fRight - outerRadius, yCoords[i]);
verts->fOffset = SkPoint::Make(0, yOuterRadii[i]);
verts->fOuterRadius = outerRadius;
verts->fInnerRadius = innerRadius;
verts++;
verts->fPos = SkPoint::Make(bounds.fRight, yCoords[i]);
verts->fOffset = SkPoint::Make(outerRadius, yOuterRadii[i]);
verts->fOuterRadius = outerRadius;
verts->fInnerRadius = innerRadius;
verts++;
}
// drop out the middle quad if we're stroked
int indexCnt = isStroked ? GR_ARRAY_COUNT(gRRectIndices)-6 : GR_ARRAY_COUNT(gRRectIndices);
target->setIndexSourceToBuffer(indexBuffer);
target->drawIndexed(kTriangles_GrPrimitiveType, 0, 0, 16, indexCnt, &bounds);
// otherwise we use the ellipse renderer
} else {
drawState->setVertexAttribs<gEllipseVertexAttribs>(SK_ARRAY_COUNT(gEllipseVertexAttribs));
GrAssert(sizeof(EllipseVertex) == drawState->getVertexSize());
SkScalar innerXRadius = 0.0f;
SkScalar innerYRadius = 0.0f;
if (SkStrokeRec::kFill_Style != style) {
if (SkScalarNearlyZero(scaledStroke.length())) {
scaledStroke.set(SK_ScalarHalf, SK_ScalarHalf);
} else {
scaledStroke.scale(SK_ScalarHalf);
}
// we only handle thick strokes for near-circular ellipses
if (scaledStroke.length() > 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 (scaledStroke.fX*(yRadius*yRadius) < (scaledStroke.fY*scaledStroke.fY)*xRadius ||
scaledStroke.fY*(xRadius*xRadius) < (scaledStroke.fX*scaledStroke.fX)*yRadius) {
return false;
}
// this is legit only if scale & translation (which should be the case at the moment)
if (isStroked) {
innerXRadius = xRadius - scaledStroke.fX;
innerYRadius = yRadius - scaledStroke.fY;
isStroked = (innerXRadius > 0 && innerYRadius > 0);
}
xRadius += scaledStroke.fX;
yRadius += scaledStroke.fY;
bounds.outset(scaledStroke.fX, scaledStroke.fY);
}
GrDrawTarget::AutoReleaseGeometry geo(target, 16, 0);
if (!geo.succeeded()) {
GrPrintf("Failed to get space for vertices!\n");
return false;
}
EllipseVertex* verts = reinterpret_cast<EllipseVertex*>(geo.vertices());
GrEffectRef* effect = EllipseEdgeEffect::Create(isStroked);
static const int kEllipseOffsetAttrIndex = 1;
static const int kEllipseRadiiAttrIndex = 2;
drawState->addCoverageEffect(effect,
kEllipseOffsetAttrIndex, kEllipseRadiiAttrIndex)->unref();
// Compute the reciprocals of the radii here to save time in the shader
SkScalar xRadRecip = SkScalarInvert(xRadius);
SkScalar yRadRecip = SkScalarInvert(yRadius);
SkScalar xInnerRadRecip = SkScalarInvert(innerXRadius);
SkScalar yInnerRadRecip = SkScalarInvert(innerYRadius);
// Extend the radii out half a pixel to antialias.
SkScalar xOuterRadius = xRadius + SK_ScalarHalf;
SkScalar yOuterRadius = yRadius + SK_ScalarHalf;
// Expand the rect so all the pixels will be captured.
bounds.outset(SK_ScalarHalf, SK_ScalarHalf);
SkScalar yCoords[4] = {
bounds.fTop,
bounds.fTop + yOuterRadius,
bounds.fBottom - yOuterRadius,
bounds.fBottom
};
SkScalar yOuterOffsets[4] = {
yOuterRadius,
SK_ScalarNearlyZero, // we're using inversesqrt() in the shader, so can't be exactly 0
SK_ScalarNearlyZero,
yOuterRadius
};
for (int i = 0; i < 4; ++i) {
verts->fPos = SkPoint::Make(bounds.fLeft, yCoords[i]);
verts->fOffset = SkPoint::Make(xOuterRadius, yOuterOffsets[i]);
verts->fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts->fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts++;
verts->fPos = SkPoint::Make(bounds.fLeft + xOuterRadius, yCoords[i]);
verts->fOffset = SkPoint::Make(SK_ScalarNearlyZero, yOuterOffsets[i]);
verts->fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts->fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts++;
verts->fPos = SkPoint::Make(bounds.fRight - xOuterRadius, yCoords[i]);
verts->fOffset = SkPoint::Make(SK_ScalarNearlyZero, yOuterOffsets[i]);
verts->fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts->fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts++;
verts->fPos = SkPoint::Make(bounds.fRight, yCoords[i]);
verts->fOffset = SkPoint::Make(xOuterRadius, yOuterOffsets[i]);
verts->fOuterRadii = SkPoint::Make(xRadRecip, yRadRecip);
verts->fInnerRadii = SkPoint::Make(xInnerRadRecip, yInnerRadRecip);
verts++;
}
// drop out the middle quad if we're stroked
int indexCnt = isStroked ? GR_ARRAY_COUNT(gRRectIndices)-6 : GR_ARRAY_COUNT(gRRectIndices);
target->setIndexSourceToBuffer(indexBuffer);
target->drawIndexed(kTriangles_GrPrimitiveType, 0, 0, 16, indexCnt, &bounds);
}
return true;
}