/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrAAConvexPathRenderer.h"
#include "GrContext.h"
#include "GrDrawState.h"
#include "GrDrawTargetCaps.h"
#include "GrEffect.h"
#include "GrPathUtils.h"
#include "GrTBackendEffectFactory.h"
#include "SkString.h"
#include "SkStrokeRec.h"
#include "SkTraceEvent.h"
#include "gl/GrGLEffect.h"
#include "gl/GrGLSL.h"
#include "gl/GrGLVertexEffect.h"
#include "effects/GrVertexEffect.h"
GrAAConvexPathRenderer::GrAAConvexPathRenderer() {
}
struct Segment {
enum {
// These enum values are assumed in member functions below.
kLine = 0,
kQuad = 1,
} fType;
// line uses one pt, quad uses 2 pts
SkPoint fPts[2];
// normal to edge ending at each pt
SkVector fNorms[2];
// is the corner where the previous segment meets this segment
// sharp. If so, fMid is a normalized bisector facing outward.
SkVector fMid;
int countPoints() {
GR_STATIC_ASSERT(0 == kLine && 1 == kQuad);
return fType + 1;
}
const SkPoint& endPt() const {
GR_STATIC_ASSERT(0 == kLine && 1 == kQuad);
return fPts[fType];
};
const SkPoint& endNorm() const {
GR_STATIC_ASSERT(0 == kLine && 1 == kQuad);
return fNorms[fType];
};
};
typedef SkTArray<Segment, true> SegmentArray;
static void center_of_mass(const SegmentArray& segments, SkPoint* c) {
SkScalar area = 0;
SkPoint center = {0, 0};
int count = segments.count();
SkPoint p0 = {0, 0};
if (count > 2) {
// We translate the polygon so that the first point is at the origin.
// This avoids some precision issues with small area polygons far away
// from the origin.
p0 = segments[0].endPt();
SkPoint pi;
SkPoint pj;
// the first and last iteration of the below loop would compute
// zeros since the starting / ending point is (0,0). So instead we start
// at i=1 and make the last iteration i=count-2.
pj = segments[1].endPt() - p0;
for (int i = 1; i < count - 1; ++i) {
pi = pj;
const SkPoint pj = segments[i + 1].endPt() - p0;
SkScalar t = SkScalarMul(pi.fX, pj.fY) - SkScalarMul(pj.fX, pi.fY);
area += t;
center.fX += (pi.fX + pj.fX) * t;
center.fY += (pi.fY + pj.fY) * t;
}
}
// If the poly has no area then we instead return the average of
// its points.
if (SkScalarNearlyZero(area)) {
SkPoint avg;
avg.set(0, 0);
for (int i = 0; i < count; ++i) {
const SkPoint& pt = segments[i].endPt();
avg.fX += pt.fX;
avg.fY += pt.fY;
}
SkScalar denom = SK_Scalar1 / count;
avg.scale(denom);
*c = avg;
} else {
area *= 3;
area = SkScalarDiv(SK_Scalar1, area);
center.fX = SkScalarMul(center.fX, area);
center.fY = SkScalarMul(center.fY, area);
// undo the translate of p0 to the origin.
*c = center + p0;
}
SkASSERT(!SkScalarIsNaN(c->fX) && !SkScalarIsNaN(c->fY));
}
static void compute_vectors(SegmentArray* segments,
SkPoint* fanPt,
SkPath::Direction dir,
int* vCount,
int* iCount) {
center_of_mass(*segments, fanPt);
int count = segments->count();
// Make the normals point towards the outside
SkPoint::Side normSide;
if (dir == SkPath::kCCW_Direction) {
normSide = SkPoint::kRight_Side;
} else {
normSide = SkPoint::kLeft_Side;
}
*vCount = 0;
*iCount = 0;
// compute normals at all points
for (int a = 0; a < count; ++a) {
Segment& sega = (*segments)[a];
int b = (a + 1) % count;
Segment& segb = (*segments)[b];
const SkPoint* prevPt = &sega.endPt();
int n = segb.countPoints();
for (int p = 0; p < n; ++p) {
segb.fNorms[p] = segb.fPts[p] - *prevPt;
segb.fNorms[p].normalize();
segb.fNorms[p].setOrthog(segb.fNorms[p], normSide);
prevPt = &segb.fPts[p];
}
if (Segment::kLine == segb.fType) {
*vCount += 5;
*iCount += 9;
} else {
*vCount += 6;
*iCount += 12;
}
}
// compute mid-vectors where segments meet. TODO: Detect shallow corners
// and leave out the wedges and close gaps by stitching segments together.
for (int a = 0; a < count; ++a) {
const Segment& sega = (*segments)[a];
int b = (a + 1) % count;
Segment& segb = (*segments)[b];
segb.fMid = segb.fNorms[0] + sega.endNorm();
segb.fMid.normalize();
// corner wedges
*vCount += 4;
*iCount += 6;
}
}
struct DegenerateTestData {
DegenerateTestData() { fStage = kInitial; }
bool isDegenerate() const { return kNonDegenerate != fStage; }
enum {
kInitial,
kPoint,
kLine,
kNonDegenerate
} fStage;
SkPoint fFirstPoint;
SkVector fLineNormal;
SkScalar fLineC;
};
static const SkScalar kClose = (SK_Scalar1 / 16);
static const SkScalar kCloseSqd = SkScalarMul(kClose, kClose);
static void update_degenerate_test(DegenerateTestData* data, const SkPoint& pt) {
switch (data->fStage) {
case DegenerateTestData::kInitial:
data->fFirstPoint = pt;
data->fStage = DegenerateTestData::kPoint;
break;
case DegenerateTestData::kPoint:
if (pt.distanceToSqd(data->fFirstPoint) > kCloseSqd) {
data->fLineNormal = pt - data->fFirstPoint;
data->fLineNormal.normalize();
data->fLineNormal.setOrthog(data->fLineNormal);
data->fLineC = -data->fLineNormal.dot(data->fFirstPoint);
data->fStage = DegenerateTestData::kLine;
}
break;
case DegenerateTestData::kLine:
if (SkScalarAbs(data->fLineNormal.dot(pt) + data->fLineC) > kClose) {
data->fStage = DegenerateTestData::kNonDegenerate;
}
case DegenerateTestData::kNonDegenerate:
break;
default:
SkFAIL("Unexpected degenerate test stage.");
}
}
static inline bool get_direction(const SkPath& path, const SkMatrix& m, SkPath::Direction* dir) {
if (!path.cheapComputeDirection(dir)) {
return false;
}
// check whether m reverses the orientation
SkASSERT(!m.hasPerspective());
SkScalar det2x2 = SkScalarMul(m.get(SkMatrix::kMScaleX), m.get(SkMatrix::kMScaleY)) -
SkScalarMul(m.get(SkMatrix::kMSkewX), m.get(SkMatrix::kMSkewY));
if (det2x2 < 0) {
*dir = SkPath::OppositeDirection(*dir);
}
return true;
}
static inline void add_line_to_segment(const SkPoint& pt,
SegmentArray* segments,
SkRect* devBounds) {
segments->push_back();
segments->back().fType = Segment::kLine;
segments->back().fPts[0] = pt;
devBounds->growToInclude(pt.fX, pt.fY);
}
#ifdef SK_DEBUG
static inline bool contains_inclusive(const SkRect& rect, const SkPoint& p) {
return p.fX >= rect.fLeft && p.fX <= rect.fRight && p.fY >= rect.fTop && p.fY <= rect.fBottom;
}
#endif
static inline void add_quad_segment(const SkPoint pts[3],
SegmentArray* segments,
SkRect* devBounds) {
if (pts[0].distanceToSqd(pts[1]) < kCloseSqd || pts[1].distanceToSqd(pts[2]) < kCloseSqd) {
if (pts[0] != pts[2]) {
add_line_to_segment(pts[2], segments, devBounds);
}
} else {
segments->push_back();
segments->back().fType = Segment::kQuad;
segments->back().fPts[0] = pts[1];
segments->back().fPts[1] = pts[2];
SkASSERT(contains_inclusive(*devBounds, pts[0]));
devBounds->growToInclude(pts + 1, 2);
}
}
static inline void add_cubic_segments(const SkPoint pts[4],
SkPath::Direction dir,
SegmentArray* segments,
SkRect* devBounds) {
SkSTArray<15, SkPoint, true> quads;
GrPathUtils::convertCubicToQuads(pts, SK_Scalar1, true, dir, &quads);
int count = quads.count();
for (int q = 0; q < count; q += 3) {
add_quad_segment(&quads[q], segments, devBounds);
}
}
static bool get_segments(const SkPath& path,
const SkMatrix& m,
SegmentArray* segments,
SkPoint* fanPt,
int* vCount,
int* iCount,
SkRect* devBounds) {
SkPath::Iter iter(path, true);
// This renderer over-emphasizes very thin path regions. We use the distance
// to the path from the sample to compute coverage. Every pixel intersected
// by the path will be hit and the maximum distance is sqrt(2)/2. We don't
// notice that the sample may be close to a very thin area of the path and
// thus should be very light. This is particularly egregious for degenerate
// line paths. We detect paths that are very close to a line (zero area) and
// draw nothing.
DegenerateTestData degenerateData;
SkPath::Direction dir;
// get_direction can fail for some degenerate paths.
if (!get_direction(path, m, &dir)) {
return false;
}
for (;;) {
SkPoint pts[4];
SkPath::Verb verb = iter.next(pts);
switch (verb) {
case SkPath::kMove_Verb:
m.mapPoints(pts, 1);
update_degenerate_test(°enerateData, pts[0]);
devBounds->set(pts->fX, pts->fY, pts->fX, pts->fY);
break;
case SkPath::kLine_Verb: {
m.mapPoints(&pts[1], 1);
update_degenerate_test(°enerateData, pts[1]);
add_line_to_segment(pts[1], segments, devBounds);
break;
}
case SkPath::kQuad_Verb:
m.mapPoints(pts, 3);
update_degenerate_test(°enerateData, pts[1]);
update_degenerate_test(°enerateData, pts[2]);
add_quad_segment(pts, segments, devBounds);
break;
case SkPath::kCubic_Verb: {
m.mapPoints(pts, 4);
update_degenerate_test(°enerateData, pts[1]);
update_degenerate_test(°enerateData, pts[2]);
update_degenerate_test(°enerateData, pts[3]);
add_cubic_segments(pts, dir, segments, devBounds);
break;
};
case SkPath::kDone_Verb:
if (degenerateData.isDegenerate()) {
return false;
} else {
compute_vectors(segments, fanPt, dir, vCount, iCount);
return true;
}
default:
break;
}
}
}
struct QuadVertex {
SkPoint fPos;
SkPoint fUV;
SkScalar fD0;
SkScalar fD1;
};
struct Draw {
Draw() : fVertexCnt(0), fIndexCnt(0) {}
int fVertexCnt;
int fIndexCnt;
};
typedef SkTArray<Draw, true> DrawArray;
static void create_vertices(const SegmentArray& segments,
const SkPoint& fanPt,
DrawArray* draws,
QuadVertex* verts,
uint16_t* idxs) {
Draw* draw = &draws->push_back();
// alias just to make vert/index assignments easier to read.
int* v = &draw->fVertexCnt;
int* i = &draw->fIndexCnt;
int count = segments.count();
for (int a = 0; a < count; ++a) {
const Segment& sega = segments[a];
int b = (a + 1) % count;
const Segment& segb = segments[b];
// Check whether adding the verts for this segment to the current draw would cause index
// values to overflow.
int vCount = 4;
if (Segment::kLine == segb.fType) {
vCount += 5;
} else {
vCount += 6;
}
if (draw->fVertexCnt + vCount > (1 << 16)) {
verts += *v;
idxs += *i;
draw = &draws->push_back();
v = &draw->fVertexCnt;
i = &draw->fIndexCnt;
}
// FIXME: These tris are inset in the 1 unit arc around the corner
verts[*v + 0].fPos = sega.endPt();
verts[*v + 1].fPos = verts[*v + 0].fPos + sega.endNorm();
verts[*v + 2].fPos = verts[*v + 0].fPos + segb.fMid;
verts[*v + 3].fPos = verts[*v + 0].fPos + segb.fNorms[0];
verts[*v + 0].fUV.set(0,0);
verts[*v + 1].fUV.set(0,-SK_Scalar1);
verts[*v + 2].fUV.set(0,-SK_Scalar1);
verts[*v + 3].fUV.set(0,-SK_Scalar1);
verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;
idxs[*i + 0] = *v + 0;
idxs[*i + 1] = *v + 2;
idxs[*i + 2] = *v + 1;
idxs[*i + 3] = *v + 0;
idxs[*i + 4] = *v + 3;
idxs[*i + 5] = *v + 2;
*v += 4;
*i += 6;
if (Segment::kLine == segb.fType) {
verts[*v + 0].fPos = fanPt;
verts[*v + 1].fPos = sega.endPt();
verts[*v + 2].fPos = segb.fPts[0];
verts[*v + 3].fPos = verts[*v + 1].fPos + segb.fNorms[0];
verts[*v + 4].fPos = verts[*v + 2].fPos + segb.fNorms[0];
// we draw the line edge as a degenerate quad (u is 0, v is the
// signed distance to the edge)
SkScalar dist = fanPt.distanceToLineBetween(verts[*v + 1].fPos,
verts[*v + 2].fPos);
verts[*v + 0].fUV.set(0, dist);
verts[*v + 1].fUV.set(0, 0);
verts[*v + 2].fUV.set(0, 0);
verts[*v + 3].fUV.set(0, -SK_Scalar1);
verts[*v + 4].fUV.set(0, -SK_Scalar1);
verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;
verts[*v + 4].fD0 = verts[*v + 4].fD1 = -SK_Scalar1;
idxs[*i + 0] = *v + 0;
idxs[*i + 1] = *v + 2;
idxs[*i + 2] = *v + 1;
idxs[*i + 3] = *v + 3;
idxs[*i + 4] = *v + 1;
idxs[*i + 5] = *v + 2;
idxs[*i + 6] = *v + 4;
idxs[*i + 7] = *v + 3;
idxs[*i + 8] = *v + 2;
*v += 5;
*i += 9;
} else {
SkPoint qpts[] = {sega.endPt(), segb.fPts[0], segb.fPts[1]};
SkVector midVec = segb.fNorms[0] + segb.fNorms[1];
midVec.normalize();
verts[*v + 0].fPos = fanPt;
verts[*v + 1].fPos = qpts[0];
verts[*v + 2].fPos = qpts[2];
verts[*v + 3].fPos = qpts[0] + segb.fNorms[0];
verts[*v + 4].fPos = qpts[2] + segb.fNorms[1];
verts[*v + 5].fPos = qpts[1] + midVec;
SkScalar c = segb.fNorms[0].dot(qpts[0]);
verts[*v + 0].fD0 = -segb.fNorms[0].dot(fanPt) + c;
verts[*v + 1].fD0 = 0.f;
verts[*v + 2].fD0 = -segb.fNorms[0].dot(qpts[2]) + c;
verts[*v + 3].fD0 = -SK_ScalarMax/100;
verts[*v + 4].fD0 = -SK_ScalarMax/100;
verts[*v + 5].fD0 = -SK_ScalarMax/100;
c = segb.fNorms[1].dot(qpts[2]);
verts[*v + 0].fD1 = -segb.fNorms[1].dot(fanPt) + c;
verts[*v + 1].fD1 = -segb.fNorms[1].dot(qpts[0]) + c;
verts[*v + 2].fD1 = 0.f;
verts[*v + 3].fD1 = -SK_ScalarMax/100;
verts[*v + 4].fD1 = -SK_ScalarMax/100;
verts[*v + 5].fD1 = -SK_ScalarMax/100;
GrPathUtils::QuadUVMatrix toUV(qpts);
toUV.apply<6, sizeof(QuadVertex), sizeof(SkPoint)>(verts + *v);
idxs[*i + 0] = *v + 3;
idxs[*i + 1] = *v + 1;
idxs[*i + 2] = *v + 2;
idxs[*i + 3] = *v + 4;
idxs[*i + 4] = *v + 3;
idxs[*i + 5] = *v + 2;
idxs[*i + 6] = *v + 5;
idxs[*i + 7] = *v + 3;
idxs[*i + 8] = *v + 4;
idxs[*i + 9] = *v + 0;
idxs[*i + 10] = *v + 2;
idxs[*i + 11] = *v + 1;
*v += 6;
*i += 12;
}
}
}
///////////////////////////////////////////////////////////////////////////////
/*
* Quadratic specified by 0=u^2-v canonical coords. u and v are the first
* two components of the vertex attribute. Coverage is based on signed
* distance with negative being inside, positive outside. The edge is specified in
* window space (y-down). If either the third or fourth component of the interpolated
* vertex coord is > 0 then the pixel is considered outside the edge. This is used to
* attempt to trim to a portion of the infinite quad.
* Requires shader derivative instruction support.
*/
class QuadEdgeEffect : public GrVertexEffect {
public:
static GrEffectRef* Create() {
GR_CREATE_STATIC_EFFECT(gQuadEdgeEffect, QuadEdgeEffect, ());
gQuadEdgeEffect->ref();
return gQuadEdgeEffect;
}
virtual ~QuadEdgeEffect() {}
static const char* Name() { return "QuadEdge"; }
virtual void getConstantColorComponents(GrColor* color,
uint32_t* validFlags) const SK_OVERRIDE {
*validFlags = 0;
}
virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
return GrTBackendEffectFactory<QuadEdgeEffect>::getInstance();
}
class GLEffect : public GrGLVertexEffect {
public:
GLEffect(const GrBackendEffectFactory& factory, const GrDrawEffect&)
: INHERITED (factory) {}
virtual void emitCode(GrGLFullShaderBuilder* builder,
const GrDrawEffect& drawEffect,
EffectKey key,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray&,
const TextureSamplerArray& samplers) SK_OVERRIDE {
const char *vsName, *fsName;
const SkString* attrName =
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]);
builder->fsCodeAppendf("\t\tfloat edgeAlpha;\n");
SkAssertResult(builder->enableFeature(
GrGLShaderBuilder::kStandardDerivatives_GLSLFeature));
builder->addVarying(kVec4f_GrSLType, "QuadEdge", &vsName, &fsName);
// keep the derivative instructions outside the conditional
builder->fsCodeAppendf("\t\tvec2 duvdx = dFdx(%s.xy);\n", fsName);
builder->fsCodeAppendf("\t\tvec2 duvdy = dFdy(%s.xy);\n", fsName);
builder->fsCodeAppendf("\t\tif (%s.z > 0.0 && %s.w > 0.0) {\n", fsName, fsName);
// today we know z and w are in device space. We could use derivatives
builder->fsCodeAppendf("\t\t\tedgeAlpha = min(min(%s.z, %s.w) + 0.5, 1.0);\n", fsName,
fsName);
builder->fsCodeAppendf ("\t\t} else {\n");
builder->fsCodeAppendf("\t\t\tvec2 gF = vec2(2.0*%s.x*duvdx.x - duvdx.y,\n"
"\t\t\t 2.0*%s.x*duvdy.x - duvdy.y);\n",
fsName, fsName);
builder->fsCodeAppendf("\t\t\tedgeAlpha = (%s.x*%s.x - %s.y);\n", fsName, fsName,
fsName);
builder->fsCodeAppendf("\t\t\tedgeAlpha = "
"clamp(0.5 - edgeAlpha / length(gF), 0.0, 1.0);\n\t\t}\n");
builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
(GrGLSLExpr4(inputColor) * GrGLSLExpr1("edgeAlpha")).c_str());
builder->vsCodeAppendf("\t%s = %s;\n", vsName, attrName->c_str());
}
static inline EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
return 0x0;
}
virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE {}
private:
typedef GrGLVertexEffect INHERITED;
};
private:
QuadEdgeEffect() {
this->addVertexAttrib(kVec4f_GrSLType);
}
virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
return true;
}
GR_DECLARE_EFFECT_TEST;
typedef GrVertexEffect INHERITED;
};
GR_DEFINE_EFFECT_TEST(QuadEdgeEffect);
GrEffectRef* QuadEdgeEffect::TestCreate(SkRandom* random,
GrContext*,
const GrDrawTargetCaps& caps,
GrTexture*[]) {
// Doesn't work without derivative instructions.
return caps.shaderDerivativeSupport() ? QuadEdgeEffect::Create() : NULL;
}
///////////////////////////////////////////////////////////////////////////////
bool GrAAConvexPathRenderer::canDrawPath(const SkPath& path,
const SkStrokeRec& stroke,
const GrDrawTarget* target,
bool antiAlias) const {
return (target->caps()->shaderDerivativeSupport() && antiAlias &&
stroke.isFillStyle() && !path.isInverseFillType() && path.isConvex());
}
namespace {
// position + edge
extern const GrVertexAttrib gPathAttribs[] = {
{kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
{kVec4f_GrVertexAttribType, sizeof(SkPoint), kEffect_GrVertexAttribBinding}
};
};
bool GrAAConvexPathRenderer::onDrawPath(const SkPath& origPath,
const SkStrokeRec&,
GrDrawTarget* target,
bool antiAlias) {
const SkPath* path = &origPath;
if (path->isEmpty()) {
return true;
}
SkMatrix viewMatrix = target->getDrawState().getViewMatrix();
GrDrawTarget::AutoStateRestore asr;
if (!asr.setIdentity(target, GrDrawTarget::kPreserve_ASRInit)) {
return false;
}
GrDrawState* drawState = target->drawState();
// We use the fact that SkPath::transform path does subdivision based on
// perspective. Otherwise, we apply the view matrix when copying to the
// segment representation.
SkPath tmpPath;
if (viewMatrix.hasPerspective()) {
origPath.transform(viewMatrix, &tmpPath);
path = &tmpPath;
viewMatrix = SkMatrix::I();
}
QuadVertex *verts;
uint16_t* idxs;
int vCount;
int iCount;
enum {
kPreallocSegmentCnt = 512 / sizeof(Segment),
kPreallocDrawCnt = 4,
};
SkSTArray<kPreallocSegmentCnt, Segment, true> segments;
SkPoint fanPt;
// We can't simply use the path bounds because we may degenerate cubics to quads which produces
// new control points outside the original convex hull.
SkRect devBounds;
if (!get_segments(*path, viewMatrix, &segments, &fanPt, &vCount, &iCount, &devBounds)) {
return false;
}
// Our computed verts should all be within one pixel of the segment control points.
devBounds.outset(SK_Scalar1, SK_Scalar1);
drawState->setVertexAttribs<gPathAttribs>(SK_ARRAY_COUNT(gPathAttribs));
static const int kEdgeAttrIndex = 1;
GrEffectRef* quadEffect = QuadEdgeEffect::Create();
drawState->addCoverageEffect(quadEffect, kEdgeAttrIndex)->unref();
GrDrawTarget::AutoReleaseGeometry arg(target, vCount, iCount);
if (!arg.succeeded()) {
return false;
}
SkASSERT(sizeof(QuadVertex) == drawState->getVertexSize());
verts = reinterpret_cast<QuadVertex*>(arg.vertices());
idxs = reinterpret_cast<uint16_t*>(arg.indices());
SkSTArray<kPreallocDrawCnt, Draw, true> draws;
create_vertices(segments, fanPt, &draws, verts, idxs);
// Check devBounds
#ifdef SK_DEBUG
SkRect tolDevBounds = devBounds;
tolDevBounds.outset(SK_Scalar1 / 10000, SK_Scalar1 / 10000);
SkRect actualBounds;
actualBounds.set(verts[0].fPos, verts[1].fPos);
for (int i = 2; i < vCount; ++i) {
actualBounds.growToInclude(verts[i].fPos.fX, verts[i].fPos.fY);
}
SkASSERT(tolDevBounds.contains(actualBounds));
#endif
int vOffset = 0;
for (int i = 0; i < draws.count(); ++i) {
const Draw& draw = draws[i];
target->drawIndexed(kTriangles_GrPrimitiveType,
vOffset, // start vertex
0, // start index
draw.fVertexCnt,
draw.fIndexCnt,
&devBounds);
vOffset += draw.fVertexCnt;
}
return true;
}