diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,1042 @@ +/* + * Copyright 2011 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include "GrAAHairLinePathRenderer.h" + +#include "GrContext.h" +#include "GrDrawState.h" +#include "GrDrawTargetCaps.h" +#include "GrEffect.h" +#include "GrGpu.h" +#include "GrIndexBuffer.h" +#include "GrPathUtils.h" +#include "GrTBackendEffectFactory.h" +#include "SkGeometry.h" +#include "SkStroke.h" +#include "SkTemplates.h" + +#include "effects/GrBezierEffect.h" + +namespace { +// quadratics are rendered as 5-sided polys in order to bound the +// AA stroke around the center-curve. See comments in push_quad_index_buffer and +// bloat_quad. Quadratics and conics share an index buffer +static const int kVertsPerQuad = 5; +static const int kIdxsPerQuad = 9; + +// lines are rendered as: +// *______________* +// |\ -_______ /| +// | \ \ / | +// | *--------* | +// | / ______/ \ | +// */_-__________\* +// For: 6 vertices and 18 indices (for 6 triangles) +static const int kVertsPerLineSeg = 6; +static const int kIdxsPerLineSeg = 18; + +static const int kNumQuadsInIdxBuffer = 256; +static const size_t kQuadIdxSBufize = kIdxsPerQuad * + sizeof(uint16_t) * + kNumQuadsInIdxBuffer; + +static const int kNumLineSegsInIdxBuffer = 256; +static const size_t kLineSegIdxSBufize = kIdxsPerLineSeg * + sizeof(uint16_t) * + kNumLineSegsInIdxBuffer; + +static bool push_quad_index_data(GrIndexBuffer* qIdxBuffer) { + uint16_t* data = (uint16_t*) qIdxBuffer->lock(); + bool tempData = NULL == data; + if (tempData) { + data = SkNEW_ARRAY(uint16_t, kNumQuadsInIdxBuffer * kIdxsPerQuad); + } + for (int i = 0; i < kNumQuadsInIdxBuffer; ++i) { + + // Each quadratic is rendered as a five sided polygon. This poly bounds + // the quadratic's bounding triangle but has been expanded so that the + // 1-pixel wide area around the curve is inside the poly. + // If a,b,c are the original control points then the poly a0,b0,c0,c1,a1 + // that is rendered would look like this: + // b0 + // b + // + // a0 c0 + // a c + // a1 c1 + // Each is drawn as three triangles specified by these 9 indices: + int baseIdx = i * kIdxsPerQuad; + uint16_t baseVert = (uint16_t)(i * kVertsPerQuad); + data[0 + baseIdx] = baseVert + 0; // a0 + data[1 + baseIdx] = baseVert + 1; // a1 + data[2 + baseIdx] = baseVert + 2; // b0 + data[3 + baseIdx] = baseVert + 2; // b0 + data[4 + baseIdx] = baseVert + 4; // c1 + data[5 + baseIdx] = baseVert + 3; // c0 + data[6 + baseIdx] = baseVert + 1; // a1 + data[7 + baseIdx] = baseVert + 4; // c1 + data[8 + baseIdx] = baseVert + 2; // b0 + } + if (tempData) { + bool ret = qIdxBuffer->updateData(data, kQuadIdxSBufize); + delete[] data; + return ret; + } else { + qIdxBuffer->unlock(); + return true; + } +} + +static bool push_line_index_data(GrIndexBuffer* lIdxBuffer) { + uint16_t* data = (uint16_t*) lIdxBuffer->lock(); + bool tempData = NULL == data; + if (tempData) { + data = SkNEW_ARRAY(uint16_t, kNumLineSegsInIdxBuffer * kIdxsPerLineSeg); + } + for (int i = 0; i < kNumLineSegsInIdxBuffer; ++i) { + // Each line segment is rendered as two quads and two triangles. + // p0 and p1 have alpha = 1 while all other points have alpha = 0. + // The four external points are offset 1 pixel perpendicular to the + // line and half a pixel parallel to the line. + // + // p4 p5 + // p0 p1 + // p2 p3 + // + // Each is drawn as six triangles specified by these 18 indices: + int baseIdx = i * kIdxsPerLineSeg; + uint16_t baseVert = (uint16_t)(i * kVertsPerLineSeg); + data[0 + baseIdx] = baseVert + 0; + data[1 + baseIdx] = baseVert + 1; + data[2 + baseIdx] = baseVert + 3; + + data[3 + baseIdx] = baseVert + 0; + data[4 + baseIdx] = baseVert + 3; + data[5 + baseIdx] = baseVert + 2; + + data[6 + baseIdx] = baseVert + 0; + data[7 + baseIdx] = baseVert + 4; + data[8 + baseIdx] = baseVert + 5; + + data[9 + baseIdx] = baseVert + 0; + data[10+ baseIdx] = baseVert + 5; + data[11+ baseIdx] = baseVert + 1; + + data[12 + baseIdx] = baseVert + 0; + data[13 + baseIdx] = baseVert + 2; + data[14 + baseIdx] = baseVert + 4; + + data[15 + baseIdx] = baseVert + 1; + data[16 + baseIdx] = baseVert + 5; + data[17 + baseIdx] = baseVert + 3; + } + if (tempData) { + bool ret = lIdxBuffer->updateData(data, kLineSegIdxSBufize); + delete[] data; + return ret; + } else { + lIdxBuffer->unlock(); + return true; + } +} +} + +GrPathRenderer* GrAAHairLinePathRenderer::Create(GrContext* context) { + GrGpu* gpu = context->getGpu(); + GrIndexBuffer* qIdxBuf = gpu->createIndexBuffer(kQuadIdxSBufize, false); + SkAutoTUnref qIdxBuffer(qIdxBuf); + if (NULL == qIdxBuf || !push_quad_index_data(qIdxBuf)) { + return NULL; + } + GrIndexBuffer* lIdxBuf = gpu->createIndexBuffer(kLineSegIdxSBufize, false); + SkAutoTUnref lIdxBuffer(lIdxBuf); + if (NULL == lIdxBuf || !push_line_index_data(lIdxBuf)) { + return NULL; + } + return SkNEW_ARGS(GrAAHairLinePathRenderer, + (context, lIdxBuf, qIdxBuf)); +} + +GrAAHairLinePathRenderer::GrAAHairLinePathRenderer( + const GrContext* context, + const GrIndexBuffer* linesIndexBuffer, + const GrIndexBuffer* quadsIndexBuffer) { + fLinesIndexBuffer = linesIndexBuffer; + linesIndexBuffer->ref(); + fQuadsIndexBuffer = quadsIndexBuffer; + quadsIndexBuffer->ref(); +} + +GrAAHairLinePathRenderer::~GrAAHairLinePathRenderer() { + fLinesIndexBuffer->unref(); + fQuadsIndexBuffer->unref(); +} + +namespace { + +#define PREALLOC_PTARRAY(N) SkSTArray<(N),SkPoint, true> + +// Takes 178th time of logf on Z600 / VC2010 +int get_float_exp(float x) { + GR_STATIC_ASSERT(sizeof(int) == sizeof(float)); +#ifdef SK_DEBUG + static bool tested; + if (!tested) { + tested = true; + SkASSERT(get_float_exp(0.25f) == -2); + SkASSERT(get_float_exp(0.3f) == -2); + SkASSERT(get_float_exp(0.5f) == -1); + SkASSERT(get_float_exp(1.f) == 0); + SkASSERT(get_float_exp(2.f) == 1); + SkASSERT(get_float_exp(2.5f) == 1); + SkASSERT(get_float_exp(8.f) == 3); + SkASSERT(get_float_exp(100.f) == 6); + SkASSERT(get_float_exp(1000.f) == 9); + SkASSERT(get_float_exp(1024.f) == 10); + SkASSERT(get_float_exp(3000000.f) == 21); + } +#endif + const int* iptr = (const int*)&x; + return (((*iptr) & 0x7f800000) >> 23) - 127; +} + +// Uses the max curvature function for quads to estimate +// where to chop the conic. If the max curvature is not +// found along the curve segment it will return 1 and +// dst[0] is the original conic. If it returns 2 the dst[0] +// and dst[1] are the two new conics. +int split_conic(const SkPoint src[3], SkConic dst[2], const SkScalar weight) { + SkScalar t = SkFindQuadMaxCurvature(src); + if (t == 0) { + if (dst) { + dst[0].set(src, weight); + } + return 1; + } else { + if (dst) { + SkConic conic; + conic.set(src, weight); + conic.chopAt(t, dst); + } + return 2; + } +} + +// Calls split_conic on the entire conic and then once more on each subsection. +// Most cases will result in either 1 conic (chop point is not within t range) +// or 3 points (split once and then one subsection is split again). +int chop_conic(const SkPoint src[3], SkConic dst[4], const SkScalar weight) { + SkConic dstTemp[2]; + int conicCnt = split_conic(src, dstTemp, weight); + if (2 == conicCnt) { + int conicCnt2 = split_conic(dstTemp[0].fPts, dst, dstTemp[0].fW); + conicCnt = conicCnt2 + split_conic(dstTemp[1].fPts, &dst[conicCnt2], dstTemp[1].fW); + } else { + dst[0] = dstTemp[0]; + } + return conicCnt; +} + +// returns 0 if quad/conic is degen or close to it +// in this case approx the path with lines +// otherwise returns 1 +int is_degen_quad_or_conic(const SkPoint p[3]) { + static const SkScalar gDegenerateToLineTol = SK_Scalar1; + static const SkScalar gDegenerateToLineTolSqd = + SkScalarMul(gDegenerateToLineTol, gDegenerateToLineTol); + + if (p[0].distanceToSqd(p[1]) < gDegenerateToLineTolSqd || + p[1].distanceToSqd(p[2]) < gDegenerateToLineTolSqd) { + return 1; + } + + SkScalar dsqd = p[1].distanceToLineBetweenSqd(p[0], p[2]); + if (dsqd < gDegenerateToLineTolSqd) { + return 1; + } + + if (p[2].distanceToLineBetweenSqd(p[1], p[0]) < gDegenerateToLineTolSqd) { + return 1; + } + return 0; +} + +// we subdivide the quads to avoid huge overfill +// if it returns -1 then should be drawn as lines +int num_quad_subdivs(const SkPoint p[3]) { + static const SkScalar gDegenerateToLineTol = SK_Scalar1; + static const SkScalar gDegenerateToLineTolSqd = + SkScalarMul(gDegenerateToLineTol, gDegenerateToLineTol); + + if (p[0].distanceToSqd(p[1]) < gDegenerateToLineTolSqd || + p[1].distanceToSqd(p[2]) < gDegenerateToLineTolSqd) { + return -1; + } + + SkScalar dsqd = p[1].distanceToLineBetweenSqd(p[0], p[2]); + if (dsqd < gDegenerateToLineTolSqd) { + return -1; + } + + if (p[2].distanceToLineBetweenSqd(p[1], p[0]) < gDegenerateToLineTolSqd) { + return -1; + } + + // tolerance of triangle height in pixels + // tuned on windows Quadro FX 380 / Z600 + // trade off of fill vs cpu time on verts + // maybe different when do this using gpu (geo or tess shaders) + static const SkScalar gSubdivTol = 175 * SK_Scalar1; + + if (dsqd <= SkScalarMul(gSubdivTol, gSubdivTol)) { + return 0; + } else { + static const int kMaxSub = 4; + // subdividing the quad reduces d by 4. so we want x = log4(d/tol) + // = log4(d*d/tol*tol)/2 + // = log2(d*d/tol*tol) + + // +1 since we're ignoring the mantissa contribution. + int log = get_float_exp(dsqd/(gSubdivTol*gSubdivTol)) + 1; + log = GrMin(GrMax(0, log), kMaxSub); + return log; + } +} + +/** + * Generates the lines and quads to be rendered. Lines are always recorded in + * device space. We will do a device space bloat to account for the 1pixel + * thickness. + * Quads are recorded in device space unless m contains + * perspective, then in they are in src space. We do this because we will + * subdivide large quads to reduce over-fill. This subdivision has to be + * performed before applying the perspective matrix. + */ +int generate_lines_and_quads(const SkPath& path, + const SkMatrix& m, + const SkIRect& devClipBounds, + GrAAHairLinePathRenderer::PtArray* lines, + GrAAHairLinePathRenderer::PtArray* quads, + GrAAHairLinePathRenderer::PtArray* conics, + GrAAHairLinePathRenderer::IntArray* quadSubdivCnts, + GrAAHairLinePathRenderer::FloatArray* conicWeights) { + SkPath::Iter iter(path, false); + + int totalQuadCount = 0; + SkRect bounds; + SkIRect ibounds; + + bool persp = m.hasPerspective(); + + for (;;) { + GrPoint pathPts[4]; + GrPoint devPts[4]; + SkPath::Verb verb = iter.next(pathPts); + switch (verb) { + case SkPath::kConic_Verb: { + SkConic dst[4]; + // We chop the conics to create tighter clipping to hide error + // that appears near max curvature of very thin conics. Thin + // hyperbolas with high weight still show error. + int conicCnt = chop_conic(pathPts, dst, iter.conicWeight()); + for (int i = 0; i < conicCnt; ++i) { + SkPoint* chopPnts = dst[i].fPts; + m.mapPoints(devPts, chopPnts, 3); + bounds.setBounds(devPts, 3); + bounds.outset(SK_Scalar1, SK_Scalar1); + bounds.roundOut(&ibounds); + if (SkIRect::Intersects(devClipBounds, ibounds)) { + if (is_degen_quad_or_conic(devPts)) { + SkPoint* pts = lines->push_back_n(4); + pts[0] = devPts[0]; + pts[1] = devPts[1]; + pts[2] = devPts[1]; + pts[3] = devPts[2]; + } else { + // when in perspective keep conics in src space + SkPoint* cPts = persp ? chopPnts : devPts; + SkPoint* pts = conics->push_back_n(3); + pts[0] = cPts[0]; + pts[1] = cPts[1]; + pts[2] = cPts[2]; + conicWeights->push_back() = dst[i].fW; + } + } + } + break; + } + case SkPath::kMove_Verb: + break; + case SkPath::kLine_Verb: + m.mapPoints(devPts, pathPts, 2); + bounds.setBounds(devPts, 2); + bounds.outset(SK_Scalar1, SK_Scalar1); + bounds.roundOut(&ibounds); + if (SkIRect::Intersects(devClipBounds, ibounds)) { + SkPoint* pts = lines->push_back_n(2); + pts[0] = devPts[0]; + pts[1] = devPts[1]; + } + break; + case SkPath::kQuad_Verb: { + SkPoint choppedPts[5]; + // Chopping the quad helps when the quad is either degenerate or nearly degenerate. + // When it is degenerate it allows the approximation with lines to work since the + // chop point (if there is one) will be at the parabola's vertex. In the nearly + // degenerate the QuadUVMatrix computed for the points is almost singular which + // can cause rendering artifacts. + int n = SkChopQuadAtMaxCurvature(pathPts, choppedPts); + for (int i = 0; i < n; ++i) { + SkPoint* quadPts = choppedPts + i * 2; + m.mapPoints(devPts, quadPts, 3); + bounds.setBounds(devPts, 3); + bounds.outset(SK_Scalar1, SK_Scalar1); + bounds.roundOut(&ibounds); + + if (SkIRect::Intersects(devClipBounds, ibounds)) { + int subdiv = num_quad_subdivs(devPts); + SkASSERT(subdiv >= -1); + if (-1 == subdiv) { + SkPoint* pts = lines->push_back_n(4); + pts[0] = devPts[0]; + pts[1] = devPts[1]; + pts[2] = devPts[1]; + pts[3] = devPts[2]; + } else { + // when in perspective keep quads in src space + SkPoint* qPts = persp ? quadPts : devPts; + SkPoint* pts = quads->push_back_n(3); + pts[0] = qPts[0]; + pts[1] = qPts[1]; + pts[2] = qPts[2]; + quadSubdivCnts->push_back() = subdiv; + totalQuadCount += 1 << subdiv; + } + } + } + break; + } + case SkPath::kCubic_Verb: + m.mapPoints(devPts, pathPts, 4); + bounds.setBounds(devPts, 4); + bounds.outset(SK_Scalar1, SK_Scalar1); + bounds.roundOut(&ibounds); + if (SkIRect::Intersects(devClipBounds, ibounds)) { + PREALLOC_PTARRAY(32) q; + // we don't need a direction if we aren't constraining the subdivision + static const SkPath::Direction kDummyDir = SkPath::kCCW_Direction; + // We convert cubics to quadratics (for now). + // In perspective have to do conversion in src space. + if (persp) { + SkScalar tolScale = + GrPathUtils::scaleToleranceToSrc(SK_Scalar1, m, + path.getBounds()); + GrPathUtils::convertCubicToQuads(pathPts, tolScale, false, kDummyDir, &q); + } else { + GrPathUtils::convertCubicToQuads(devPts, SK_Scalar1, false, kDummyDir, &q); + } + for (int i = 0; i < q.count(); i += 3) { + SkPoint* qInDevSpace; + // bounds has to be calculated in device space, but q is + // in src space when there is perspective. + if (persp) { + m.mapPoints(devPts, &q[i], 3); + bounds.setBounds(devPts, 3); + qInDevSpace = devPts; + } else { + bounds.setBounds(&q[i], 3); + qInDevSpace = &q[i]; + } + bounds.outset(SK_Scalar1, SK_Scalar1); + bounds.roundOut(&ibounds); + if (SkIRect::Intersects(devClipBounds, ibounds)) { + int subdiv = num_quad_subdivs(qInDevSpace); + SkASSERT(subdiv >= -1); + if (-1 == subdiv) { + SkPoint* pts = lines->push_back_n(4); + // lines should always be in device coords + pts[0] = qInDevSpace[0]; + pts[1] = qInDevSpace[1]; + pts[2] = qInDevSpace[1]; + pts[3] = qInDevSpace[2]; + } else { + SkPoint* pts = quads->push_back_n(3); + // q is already in src space when there is no + // perspective and dev coords otherwise. + pts[0] = q[0 + i]; + pts[1] = q[1 + i]; + pts[2] = q[2 + i]; + quadSubdivCnts->push_back() = subdiv; + totalQuadCount += 1 << subdiv; + } + } + } + } + break; + case SkPath::kClose_Verb: + break; + case SkPath::kDone_Verb: + return totalQuadCount; + } + } +} + +struct LineVertex { + GrPoint fPos; + GrColor fCoverage; +}; + +struct BezierVertex { + GrPoint fPos; + union { + struct { + SkScalar fK; + SkScalar fL; + SkScalar fM; + } fConic; + GrVec fQuadCoord; + struct { + SkScalar fBogus[4]; + }; + }; +}; + +GR_STATIC_ASSERT(sizeof(BezierVertex) == 3 * sizeof(GrPoint)); + +void intersect_lines(const SkPoint& ptA, const SkVector& normA, + const SkPoint& ptB, const SkVector& normB, + SkPoint* result) { + + SkScalar lineAW = -normA.dot(ptA); + SkScalar lineBW = -normB.dot(ptB); + + SkScalar wInv = SkScalarMul(normA.fX, normB.fY) - + SkScalarMul(normA.fY, normB.fX); + wInv = SkScalarInvert(wInv); + + result->fX = SkScalarMul(normA.fY, lineBW) - SkScalarMul(lineAW, normB.fY); + result->fX = SkScalarMul(result->fX, wInv); + + result->fY = SkScalarMul(lineAW, normB.fX) - SkScalarMul(normA.fX, lineBW); + result->fY = SkScalarMul(result->fY, wInv); +} + +void set_uv_quad(const SkPoint qpts[3], BezierVertex verts[kVertsPerQuad]) { + // this should be in the src space, not dev coords, when we have perspective + GrPathUtils::QuadUVMatrix DevToUV(qpts); + DevToUV.apply(verts); +} + +void bloat_quad(const SkPoint qpts[3], const SkMatrix* toDevice, + const SkMatrix* toSrc, BezierVertex verts[kVertsPerQuad], + SkRect* devBounds) { + SkASSERT(!toDevice == !toSrc); + // original quad is specified by tri a,b,c + SkPoint a = qpts[0]; + SkPoint b = qpts[1]; + SkPoint c = qpts[2]; + + if (toDevice) { + toDevice->mapPoints(&a, 1); + toDevice->mapPoints(&b, 1); + toDevice->mapPoints(&c, 1); + } + // make a new poly where we replace a and c by a 1-pixel wide edges orthog + // to edges ab and bc: + // + // before | after + // | b0 + // b | + // | + // | a0 c0 + // a c | a1 c1 + // + // edges a0->b0 and b0->c0 are parallel to original edges a->b and b->c, + // respectively. + BezierVertex& a0 = verts[0]; + BezierVertex& a1 = verts[1]; + BezierVertex& b0 = verts[2]; + BezierVertex& c0 = verts[3]; + BezierVertex& c1 = verts[4]; + + SkVector ab = b; + ab -= a; + SkVector ac = c; + ac -= a; + SkVector cb = b; + cb -= c; + + // We should have already handled degenerates + SkASSERT(ab.length() > 0 && cb.length() > 0); + + ab.normalize(); + SkVector abN; + abN.setOrthog(ab, SkVector::kLeft_Side); + if (abN.dot(ac) > 0) { + abN.negate(); + } + + cb.normalize(); + SkVector cbN; + cbN.setOrthog(cb, SkVector::kLeft_Side); + if (cbN.dot(ac) < 0) { + cbN.negate(); + } + + a0.fPos = a; + a0.fPos += abN; + a1.fPos = a; + a1.fPos -= abN; + + c0.fPos = c; + c0.fPos += cbN; + c1.fPos = c; + c1.fPos -= cbN; + + intersect_lines(a0.fPos, abN, c0.fPos, cbN, &b0.fPos); + devBounds->growToInclude(&verts[0].fPos, sizeof(BezierVertex), kVertsPerQuad); + + if (toSrc) { + toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(BezierVertex), kVertsPerQuad); + } +} + +// Equations based off of Loop-Blinn Quadratic GPU Rendering +// Input Parametric: +// P(t) = (P0*(1-t)^2 + 2*w*P1*t*(1-t) + P2*t^2) / (1-t)^2 + 2*w*t*(1-t) + t^2) +// Output Implicit: +// f(x, y, w) = f(P) = K^2 - LM +// K = dot(k, P), L = dot(l, P), M = dot(m, P) +// k, l, m are calculated in function GrPathUtils::getConicKLM +void set_conic_coeffs(const SkPoint p[3], BezierVertex verts[kVertsPerQuad], + const SkScalar weight) { + SkScalar klm[9]; + + GrPathUtils::getConicKLM(p, weight, klm); + + for (int i = 0; i < kVertsPerQuad; ++i) { + const SkPoint pnt = verts[i].fPos; + verts[i].fConic.fK = pnt.fX * klm[0] + pnt.fY * klm[1] + klm[2]; + verts[i].fConic.fL = pnt.fX * klm[3] + pnt.fY * klm[4] + klm[5]; + verts[i].fConic.fM = pnt.fX * klm[6] + pnt.fY * klm[7] + klm[8]; + } +} + +void add_conics(const SkPoint p[3], + const SkScalar weight, + const SkMatrix* toDevice, + const SkMatrix* toSrc, + BezierVertex** vert, + SkRect* devBounds) { + bloat_quad(p, toDevice, toSrc, *vert, devBounds); + set_conic_coeffs(p, *vert, weight); + *vert += kVertsPerQuad; +} + +void add_quads(const SkPoint p[3], + int subdiv, + const SkMatrix* toDevice, + const SkMatrix* toSrc, + BezierVertex** vert, + SkRect* devBounds) { + SkASSERT(subdiv >= 0); + if (subdiv) { + SkPoint newP[5]; + SkChopQuadAtHalf(p, newP); + add_quads(newP + 0, subdiv-1, toDevice, toSrc, vert, devBounds); + add_quads(newP + 2, subdiv-1, toDevice, toSrc, vert, devBounds); + } else { + bloat_quad(p, toDevice, toSrc, *vert, devBounds); + set_uv_quad(p, *vert); + *vert += kVertsPerQuad; + } +} + +void add_line(const SkPoint p[2], + const SkMatrix* toSrc, + GrColor coverage, + LineVertex** vert) { + const SkPoint& a = p[0]; + const SkPoint& b = p[1]; + + SkVector ortho, vec = b; + vec -= a; + + if (vec.setLength(SK_ScalarHalf)) { + // Create a vector orthogonal to 'vec' and of unit length + ortho.fX = 2.0f * vec.fY; + ortho.fY = -2.0f * vec.fX; + + (*vert)[0].fPos = a; + (*vert)[0].fCoverage = coverage; + (*vert)[1].fPos = b; + (*vert)[1].fCoverage = coverage; + (*vert)[2].fPos = a - vec + ortho; + (*vert)[2].fCoverage = 0; + (*vert)[3].fPos = b + vec + ortho; + (*vert)[3].fCoverage = 0; + (*vert)[4].fPos = a - vec - ortho; + (*vert)[4].fCoverage = 0; + (*vert)[5].fPos = b + vec - ortho; + (*vert)[5].fCoverage = 0; + + if (NULL != toSrc) { + toSrc->mapPointsWithStride(&(*vert)->fPos, + sizeof(LineVertex), + kVertsPerLineSeg); + } + } else { + // just make it degenerate and likely offscreen + for (int i = 0; i < kVertsPerLineSeg; ++i) { + (*vert)[i].fPos.set(SK_ScalarMax, SK_ScalarMax); + } + } + + *vert += kVertsPerLineSeg; +} + +} + +/////////////////////////////////////////////////////////////////////////////// + +namespace { + +// position + edge +extern const GrVertexAttrib gHairlineBezierAttribs[] = { + {kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding}, + {kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding} +}; + +// position + coverage +extern const GrVertexAttrib gHairlineLineAttribs[] = { + {kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding}, + {kVec4ub_GrVertexAttribType, sizeof(GrPoint), kCoverage_GrVertexAttribBinding}, +}; + +}; + +bool GrAAHairLinePathRenderer::createLineGeom(const SkPath& path, + GrDrawTarget* target, + const PtArray& lines, + int lineCnt, + GrDrawTarget::AutoReleaseGeometry* arg, + SkRect* devBounds) { + GrDrawState* drawState = target->drawState(); + + const SkMatrix& viewM = drawState->getViewMatrix(); + + int vertCnt = kVertsPerLineSeg * lineCnt; + + drawState->setVertexAttribs(SK_ARRAY_COUNT(gHairlineLineAttribs)); + SkASSERT(sizeof(LineVertex) == drawState->getVertexSize()); + + if (!arg->set(target, vertCnt, 0)) { + return false; + } + + LineVertex* verts = reinterpret_cast(arg->vertices()); + + const SkMatrix* toSrc = NULL; + SkMatrix ivm; + + if (viewM.hasPerspective()) { + if (viewM.invert(&ivm)) { + toSrc = &ivm; + } + } + devBounds->set(lines.begin(), lines.count()); + for (int i = 0; i < lineCnt; ++i) { + add_line(&lines[2*i], toSrc, drawState->getCoverageColor(), &verts); + } + // All the verts computed by add_line are within sqrt(1^2 + 0.5^2) of the end points. + static const SkScalar kSqrtOfOneAndAQuarter = 1.118f; + // Add a little extra to account for vector normalization precision. + static const SkScalar kOutset = kSqrtOfOneAndAQuarter + SK_Scalar1 / 20; + devBounds->outset(kOutset, kOutset); + + return true; +} + +bool GrAAHairLinePathRenderer::createBezierGeom( + const SkPath& path, + GrDrawTarget* target, + const PtArray& quads, + int quadCnt, + const PtArray& conics, + int conicCnt, + const IntArray& qSubdivs, + const FloatArray& cWeights, + GrDrawTarget::AutoReleaseGeometry* arg, + SkRect* devBounds) { + GrDrawState* drawState = target->drawState(); + + const SkMatrix& viewM = drawState->getViewMatrix(); + + int vertCnt = kVertsPerQuad * quadCnt + kVertsPerQuad * conicCnt; + + target->drawState()->setVertexAttribs(SK_ARRAY_COUNT(gHairlineBezierAttribs)); + SkASSERT(sizeof(BezierVertex) == target->getDrawState().getVertexSize()); + + if (!arg->set(target, vertCnt, 0)) { + return false; + } + + BezierVertex* verts = reinterpret_cast(arg->vertices()); + + const SkMatrix* toDevice = NULL; + const SkMatrix* toSrc = NULL; + SkMatrix ivm; + + if (viewM.hasPerspective()) { + if (viewM.invert(&ivm)) { + toDevice = &viewM; + toSrc = &ivm; + } + } + + // Seed the dev bounds with some pts known to be inside. Each quad and conic grows the bounding + // box to include its vertices. + SkPoint seedPts[2]; + if (quadCnt) { + seedPts[0] = quads[0]; + seedPts[1] = quads[2]; + } else if (conicCnt) { + seedPts[0] = conics[0]; + seedPts[1] = conics[2]; + } + if (NULL != toDevice) { + toDevice->mapPoints(seedPts, 2); + } + devBounds->set(seedPts[0], seedPts[1]); + + int unsubdivQuadCnt = quads.count() / 3; + for (int i = 0; i < unsubdivQuadCnt; ++i) { + SkASSERT(qSubdivs[i] >= 0); + add_quads(&quads[3*i], qSubdivs[i], toDevice, toSrc, &verts, devBounds); + } + + // Start Conics + for (int i = 0; i < conicCnt; ++i) { + add_conics(&conics[3*i], cWeights[i], toDevice, toSrc, &verts, devBounds); + } + return true; +} + +bool GrAAHairLinePathRenderer::canDrawPath(const SkPath& path, + const SkStrokeRec& stroke, + const GrDrawTarget* target, + bool antiAlias) const { + if (!antiAlias) { + return false; + } + + if (!IsStrokeHairlineOrEquivalent(stroke, + target->getDrawState().getViewMatrix(), + NULL)) { + return false; + } + + if (SkPath::kLine_SegmentMask == path.getSegmentMasks() || + target->caps()->shaderDerivativeSupport()) { + return true; + } + return false; +} + +template +bool check_bounds(GrDrawState* drawState, const SkRect& devBounds, void* vertices, int vCount) +{ + SkRect tolDevBounds = devBounds; + // The bounds ought to be tight, but in perspective the below code runs the verts + // through the view matrix to get back to dev coords, which can introduce imprecision. + if (drawState->getViewMatrix().hasPerspective()) { + tolDevBounds.outset(SK_Scalar1 / 1000, SK_Scalar1 / 1000); + } else { + // Non-persp matrices cause this path renderer to draw in device space. + SkASSERT(drawState->getViewMatrix().isIdentity()); + } + SkRect actualBounds; + + VertexType* verts = reinterpret_cast(vertices); + bool first = true; + for (int i = 0; i < vCount; ++i) { + SkPoint pos = verts[i].fPos; + // This is a hack to workaround the fact that we move some degenerate segments offscreen. + if (SK_ScalarMax == pos.fX) { + continue; + } + drawState->getViewMatrix().mapPoints(&pos, 1); + if (first) { + actualBounds.set(pos.fX, pos.fY, pos.fX, pos.fY); + first = false; + } else { + actualBounds.growToInclude(pos.fX, pos.fY); + } + } + if (!first) { + return tolDevBounds.contains(actualBounds); + } + + return true; +} + +bool GrAAHairLinePathRenderer::onDrawPath(const SkPath& path, + const SkStrokeRec& stroke, + GrDrawTarget* target, + bool antiAlias) { + GrDrawState* drawState = target->drawState(); + + SkScalar hairlineCoverage; + if (IsStrokeHairlineOrEquivalent(stroke, + target->getDrawState().getViewMatrix(), + &hairlineCoverage)) { + uint8_t newCoverage = SkScalarRoundToInt(hairlineCoverage * + target->getDrawState().getCoverage()); + target->drawState()->setCoverage(newCoverage); + } + + SkIRect devClipBounds; + target->getClip()->getConservativeBounds(drawState->getRenderTarget(), &devClipBounds); + + int lineCnt; + int quadCnt; + int conicCnt; + PREALLOC_PTARRAY(128) lines; + PREALLOC_PTARRAY(128) quads; + PREALLOC_PTARRAY(128) conics; + IntArray qSubdivs; + FloatArray cWeights; + quadCnt = generate_lines_and_quads(path, drawState->getViewMatrix(), devClipBounds, + &lines, &quads, &conics, &qSubdivs, &cWeights); + lineCnt = lines.count() / 2; + conicCnt = conics.count() / 3; + + // do lines first + if (lineCnt) { + GrDrawTarget::AutoReleaseGeometry arg; + SkRect devBounds; + + if (!this->createLineGeom(path, + target, + lines, + lineCnt, + &arg, + &devBounds)) { + return false; + } + + GrDrawTarget::AutoStateRestore asr; + + // createLineGeom transforms the geometry to device space when the matrix does not have + // perspective. + if (target->getDrawState().getViewMatrix().hasPerspective()) { + asr.set(target, GrDrawTarget::kPreserve_ASRInit); + } else if (!asr.setIdentity(target, GrDrawTarget::kPreserve_ASRInit)) { + return false; + } + GrDrawState* drawState = target->drawState(); + + // Check devBounds + SkASSERT(check_bounds(drawState, devBounds, arg.vertices(), + kVertsPerLineSeg * lineCnt)); + + { + GrDrawState::AutoRestoreEffects are(drawState); + target->setIndexSourceToBuffer(fLinesIndexBuffer); + int lines = 0; + while (lines < lineCnt) { + int n = GrMin(lineCnt - lines, kNumLineSegsInIdxBuffer); + target->drawIndexed(kTriangles_GrPrimitiveType, + kVertsPerLineSeg*lines, // startV + 0, // startI + kVertsPerLineSeg*n, // vCount + kIdxsPerLineSeg*n, // iCount + &devBounds); + lines += n; + } + } + } + + // then quadratics/conics + if (quadCnt || conicCnt) { + GrDrawTarget::AutoReleaseGeometry arg; + SkRect devBounds; + + if (!this->createBezierGeom(path, + target, + quads, + quadCnt, + conics, + conicCnt, + qSubdivs, + cWeights, + &arg, + &devBounds)) { + return false; + } + + GrDrawTarget::AutoStateRestore asr; + + // createGeom transforms the geometry to device space when the matrix does not have + // perspective. + if (target->getDrawState().getViewMatrix().hasPerspective()) { + asr.set(target, GrDrawTarget::kPreserve_ASRInit); + } else if (!asr.setIdentity(target, GrDrawTarget::kPreserve_ASRInit)) { + return false; + } + GrDrawState* drawState = target->drawState(); + + static const int kEdgeAttrIndex = 1; + + // Check devBounds + SkASSERT(check_bounds(drawState, devBounds, arg.vertices(), + kVertsPerQuad * quadCnt + kVertsPerQuad * conicCnt)); + + if (quadCnt > 0) { + GrEffectRef* hairQuadEffect = GrQuadEffect::Create(kHairlineAA_GrEffectEdgeType, + *target->caps()); + SkASSERT(NULL != hairQuadEffect); + GrDrawState::AutoRestoreEffects are(drawState); + target->setIndexSourceToBuffer(fQuadsIndexBuffer); + drawState->addCoverageEffect(hairQuadEffect, kEdgeAttrIndex)->unref(); + int quads = 0; + while (quads < quadCnt) { + int n = GrMin(quadCnt - quads, kNumQuadsInIdxBuffer); + target->drawIndexed(kTriangles_GrPrimitiveType, + kVertsPerQuad*quads, // startV + 0, // startI + kVertsPerQuad*n, // vCount + kIdxsPerQuad*n, // iCount + &devBounds); + quads += n; + } + } + + if (conicCnt > 0) { + GrDrawState::AutoRestoreEffects are(drawState); + GrEffectRef* hairConicEffect = GrConicEffect::Create(kHairlineAA_GrEffectEdgeType, + *target->caps()); + SkASSERT(NULL != hairConicEffect); + drawState->addCoverageEffect(hairConicEffect, 1, 2)->unref(); + int conics = 0; + while (conics < conicCnt) { + int n = GrMin(conicCnt - conics, kNumQuadsInIdxBuffer); + target->drawIndexed(kTriangles_GrPrimitiveType, + kVertsPerQuad*(quadCnt + conics), // startV + 0, // startI + kVertsPerQuad*n, // vCount + kIdxsPerQuad*n, // iCount + &devBounds); + conics += n; + } + } + } + + target->resetIndexSource(); + + return true; +}