| |
| /* |
| * 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 "GrGpu.h" |
| #include "GrIndexBuffer.h" |
| #include "GrPathUtils.h" |
| #include "SkGeometry.h" |
| #include "SkStroke.h" |
| #include "SkTemplates.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. |
| static const int kVertsPerQuad = 5; |
| static const int kIdxsPerQuad = 9; |
| |
| static const int kVertsPerLineSeg = 4; |
| static const int kIdxsPerLineSeg = 6; |
| |
| static const int kNumQuadsInIdxBuffer = 256; |
| static const size_t kQuadIdxSBufize = kIdxsPerQuad * |
| sizeof(uint16_t) * |
| kNumQuadsInIdxBuffer; |
| |
| 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; |
| } |
| } |
| } |
| |
| GrPathRenderer* GrAAHairLinePathRenderer::Create(GrContext* context) { |
| const GrIndexBuffer* lIdxBuffer = context->getQuadIndexBuffer(); |
| if (NULL == lIdxBuffer) { |
| return NULL; |
| } |
| GrGpu* gpu = context->getGpu(); |
| GrIndexBuffer* qIdxBuf = gpu->createIndexBuffer(kQuadIdxSBufize, false); |
| SkAutoTUnref<GrIndexBuffer> qIdxBuffer(qIdxBuf); |
| if (NULL == qIdxBuf || |
| !push_quad_index_data(qIdxBuf)) { |
| return NULL; |
| } |
| return SkNEW_ARGS(GrAAHairLinePathRenderer, |
| (context, lIdxBuffer, 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 { |
| |
| typedef SkTArray<SkPoint, true> PtArray; |
| #define PREALLOC_PTARRAY(N) SkSTArray<(N),SkPoint, true> |
| typedef SkTArray<int, true> IntArray; |
| |
| // Takes 178th time of logf on Z600 / VC2010 |
| int get_float_exp(float x) { |
| GR_STATIC_ASSERT(sizeof(int) == sizeof(float)); |
| #if GR_DEBUG |
| static bool tested; |
| if (!tested) { |
| tested = true; |
| GrAssert(get_float_exp(0.25f) == -2); |
| GrAssert(get_float_exp(0.3f) == -2); |
| GrAssert(get_float_exp(0.5f) == -1); |
| GrAssert(get_float_exp(1.f) == 0); |
| GrAssert(get_float_exp(2.f) == 1); |
| GrAssert(get_float_exp(2.5f) == 1); |
| GrAssert(get_float_exp(8.f) == 3); |
| GrAssert(get_float_exp(100.f) == 6); |
| GrAssert(get_float_exp(1000.f) == 9); |
| GrAssert(get_float_exp(1024.f) == 10); |
| GrAssert(get_float_exp(3000000.f) == 21); |
| } |
| #endif |
| const int* iptr = (const int*)&x; |
| return (((*iptr) & 0x7f800000) >> 23) - 127; |
| } |
| |
| // 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; |
| } |
| |
| static const int kMaxSub = 4; |
| // 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 { |
| // 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) |
| |
| #ifdef SK_SCALAR_IS_FLOAT |
| // +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; |
| #else |
| SkScalar log = SkScalarLog( |
| SkScalarDiv(dsqd, |
| SkScalarMul(gSubdivTol, gSubdivTol))); |
| static const SkScalar conv = SkScalarInvert(SkScalarLog(2)); |
| log = SkScalarMul(log, conv); |
| return GrMin(GrMax(0, SkScalarCeilToInt(log)),kMaxSub); |
| #endif |
| } |
| } |
| |
| /** |
| * 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 GrIRect& devClipBounds, |
| PtArray* lines, |
| PtArray* quads, |
| IntArray* quadSubdivCnts) { |
| SkPath::Iter iter(path, false); |
| |
| int totalQuadCount = 0; |
| GrRect bounds; |
| GrIRect ibounds; |
| |
| bool persp = m.hasPerspective(); |
| |
| for (;;) { |
| GrPoint pts[4]; |
| GrPoint devPts[4]; |
| GrPathCmd cmd = (GrPathCmd)iter.next(pts); |
| switch (cmd) { |
| case kMove_PathCmd: |
| break; |
| case kLine_PathCmd: |
| m.mapPoints(devPts, pts, 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 kQuadratic_PathCmd: |
| m.mapPoints(devPts, pts, 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); |
| GrAssert(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 ? pts : 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 kCubic_PathCmd: |
| m.mapPoints(devPts, pts, 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(pts, 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); |
| GrAssert(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 kClose_PathCmd: |
| break; |
| case kEnd_PathCmd: |
| return totalQuadCount; |
| } |
| } |
| } |
| |
| struct Vertex { |
| GrPoint fPos; |
| union { |
| struct { |
| SkScalar fA; |
| SkScalar fB; |
| SkScalar fC; |
| } fLine; |
| GrVec fQuadCoord; |
| struct { |
| SkScalar fBogus[4]; |
| }; |
| }; |
| }; |
| GR_STATIC_ASSERT(sizeof(Vertex) == 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 bloat_quad(const SkPoint qpts[3], const SkMatrix* toDevice, |
| const SkMatrix* toSrc, Vertex verts[kVertsPerQuad]) { |
| GrAssert(!toDevice == !toSrc); |
| // original quad is specified by tri a,b,c |
| SkPoint a = qpts[0]; |
| SkPoint b = qpts[1]; |
| SkPoint c = qpts[2]; |
| |
| // this should be in the src space, not dev coords, when we have perspective |
| GrPathUtils::QuadUVMatrix DevToUV(qpts); |
| |
| 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. |
| Vertex& a0 = verts[0]; |
| Vertex& a1 = verts[1]; |
| Vertex& b0 = verts[2]; |
| Vertex& c0 = verts[3]; |
| Vertex& c1 = verts[4]; |
| |
| SkVector ab = b; |
| ab -= a; |
| SkVector ac = c; |
| ac -= a; |
| SkVector cb = b; |
| cb -= c; |
| |
| // We should have already handled degenerates |
| GrAssert(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); |
| |
| if (toSrc) { |
| toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(Vertex), kVertsPerQuad); |
| } |
| DevToUV.apply<kVertsPerQuad, sizeof(Vertex), sizeof(GrPoint)>(verts); |
| } |
| |
| void add_quads(const SkPoint p[3], |
| int subdiv, |
| const SkMatrix* toDevice, |
| const SkMatrix* toSrc, |
| Vertex** vert) { |
| GrAssert(subdiv >= 0); |
| if (subdiv) { |
| SkPoint newP[5]; |
| SkChopQuadAtHalf(p, newP); |
| add_quads(newP + 0, subdiv-1, toDevice, toSrc, vert); |
| add_quads(newP + 2, subdiv-1, toDevice, toSrc, vert); |
| } else { |
| bloat_quad(p, toDevice, toSrc, *vert); |
| *vert += kVertsPerQuad; |
| } |
| } |
| |
| void add_line(const SkPoint p[2], |
| int rtHeight, |
| const SkMatrix* toSrc, |
| Vertex** vert) { |
| const SkPoint& a = p[0]; |
| const SkPoint& b = p[1]; |
| |
| SkVector orthVec = b; |
| orthVec -= a; |
| |
| if (orthVec.setLength(SK_Scalar1)) { |
| orthVec.setOrthog(orthVec); |
| |
| SkScalar lineC = -(a.dot(orthVec)); |
| for (int i = 0; i < kVertsPerLineSeg; ++i) { |
| (*vert)[i].fPos = (i < 2) ? a : b; |
| if (0 == i || 3 == i) { |
| (*vert)[i].fPos -= orthVec; |
| } else { |
| (*vert)[i].fPos += orthVec; |
| } |
| (*vert)[i].fLine.fA = orthVec.fX; |
| (*vert)[i].fLine.fB = orthVec.fY; |
| (*vert)[i].fLine.fC = lineC; |
| } |
| if (NULL != toSrc) { |
| toSrc->mapPointsWithStride(&(*vert)->fPos, |
| sizeof(Vertex), |
| kVertsPerLineSeg); |
| } |
| } else { |
| // just make it degenerate and likely offscreen |
| (*vert)[0].fPos.set(SK_ScalarMax, SK_ScalarMax); |
| (*vert)[1].fPos.set(SK_ScalarMax, SK_ScalarMax); |
| (*vert)[2].fPos.set(SK_ScalarMax, SK_ScalarMax); |
| (*vert)[3].fPos.set(SK_ScalarMax, SK_ScalarMax); |
| } |
| |
| *vert += kVertsPerLineSeg; |
| } |
| |
| } |
| |
| bool GrAAHairLinePathRenderer::createGeom( |
| const SkPath& path, |
| GrDrawTarget* target, |
| int* lineCnt, |
| int* quadCnt, |
| GrDrawTarget::AutoReleaseGeometry* arg) { |
| const GrDrawState& drawState = target->getDrawState(); |
| int rtHeight = drawState.getRenderTarget()->height(); |
| |
| GrIRect devClipBounds; |
| target->getClip()->getConservativeBounds(drawState.getRenderTarget(), |
| &devClipBounds); |
| |
| GrVertexLayout layout = GrDrawState::kEdge_VertexLayoutBit; |
| SkMatrix viewM = drawState.getViewMatrix(); |
| |
| PREALLOC_PTARRAY(128) lines; |
| PREALLOC_PTARRAY(128) quads; |
| IntArray qSubdivs; |
| *quadCnt = generate_lines_and_quads(path, viewM, devClipBounds, |
| &lines, &quads, &qSubdivs); |
| |
| *lineCnt = lines.count() / 2; |
| int vertCnt = kVertsPerLineSeg * *lineCnt + kVertsPerQuad * *quadCnt; |
| |
| GrAssert(sizeof(Vertex) == GrDrawState::VertexSize(layout)); |
| |
| if (!arg->set(target, layout, vertCnt, 0)) { |
| return false; |
| } |
| |
| Vertex* verts = reinterpret_cast<Vertex*>(arg->vertices()); |
| |
| const SkMatrix* toDevice = NULL; |
| const SkMatrix* toSrc = NULL; |
| SkMatrix ivm; |
| |
| if (viewM.hasPerspective()) { |
| if (viewM.invert(&ivm)) { |
| toDevice = &viewM; |
| toSrc = &ivm; |
| } |
| } |
| |
| for (int i = 0; i < *lineCnt; ++i) { |
| add_line(&lines[2*i], rtHeight, toSrc, &verts); |
| } |
| |
| int unsubdivQuadCnt = quads.count() / 3; |
| for (int i = 0; i < unsubdivQuadCnt; ++i) { |
| GrAssert(qSubdivs[i] >= 0); |
| add_quads(&quads[3*i], qSubdivs[i], toDevice, toSrc, &verts); |
| } |
| |
| return true; |
| } |
| |
| bool GrAAHairLinePathRenderer::canDrawPath(const SkPath& path, |
| const SkStrokeRec& stroke, |
| const GrDrawTarget* target, |
| bool antiAlias) const { |
| if (!stroke.isHairlineStyle() || !antiAlias) { |
| return false; |
| } |
| |
| static const uint32_t gReqDerivMask = SkPath::kCubic_SegmentMask | |
| SkPath::kQuad_SegmentMask; |
| if (!target->getCaps().shaderDerivativeSupport() && |
| (gReqDerivMask & path.getSegmentMasks())) { |
| return false; |
| } |
| return true; |
| } |
| |
| bool GrAAHairLinePathRenderer::onDrawPath(const SkPath& path, |
| const SkStrokeRec&, |
| GrDrawTarget* target, |
| bool antiAlias) { |
| |
| int lineCnt; |
| int quadCnt; |
| GrDrawTarget::AutoReleaseGeometry arg; |
| if (!this->createGeom(path, |
| target, |
| &lineCnt, |
| &quadCnt, |
| &arg)) { |
| return false; |
| } |
| |
| GrDrawState::AutoDeviceCoordDraw adcd; |
| GrDrawState* drawState = target->drawState(); |
| // createGeom transforms the geometry to device space when the matrix does not have |
| // perspective. |
| if (!drawState->getViewMatrix().hasPerspective()) { |
| adcd.set(drawState); |
| if (!adcd.succeeded()) { |
| return false; |
| } |
| } |
| |
| // TODO: See whether rendering lines as degenerate quads improves perf |
| // when we have a mix |
| |
| GrDrawState::VertexEdgeType oldEdgeType = drawState->getVertexEdgeType(); |
| |
| target->setIndexSourceToBuffer(fLinesIndexBuffer); |
| int lines = 0; |
| int nBufLines = fLinesIndexBuffer->maxQuads(); |
| drawState->setVertexEdgeType(GrDrawState::kHairLine_EdgeType); |
| while (lines < lineCnt) { |
| int n = GrMin(lineCnt - lines, nBufLines); |
| target->drawIndexed(kTriangles_GrPrimitiveType, |
| kVertsPerLineSeg*lines, // startV |
| 0, // startI |
| kVertsPerLineSeg*n, // vCount |
| kIdxsPerLineSeg*n); // iCount |
| lines += n; |
| } |
| |
| target->setIndexSourceToBuffer(fQuadsIndexBuffer); |
| int quads = 0; |
| drawState->setVertexEdgeType(GrDrawState::kHairQuad_EdgeType); |
| while (quads < quadCnt) { |
| int n = GrMin(quadCnt - quads, kNumQuadsInIdxBuffer); |
| target->drawIndexed(kTriangles_GrPrimitiveType, |
| 4 * lineCnt + kVertsPerQuad*quads, // startV |
| 0, // startI |
| kVertsPerQuad*n, // vCount |
| kIdxsPerQuad*n); // iCount |
| quads += n; |
| } |
| drawState->setVertexEdgeType(oldEdgeType); |
| return true; |
| } |
