The Tor Browser: gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /*
  * 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<GrIndexBuffer> qIdxBuffer(qIdxBuf);
     if (NULL == qIdxBuf || !push_quad_index_data(qIdxBuf)) {
         return NULL;
     }
     GrIndexBuffer* lIdxBuf = gpu->createIndexBuffer(kLineSegIdxSBufize, false);
     SkAutoTUnref<GrIndexBuffer> 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<kVertsPerQuad, sizeof(BezierVertex), sizeof(GrPoint)>(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<gHairlineLineAttribs>(SK_ARRAY_COUNT(gHairlineLineAttribs));
     SkASSERT(sizeof(LineVertex) == drawState->getVertexSize());
     if (!arg->set(target, vertCnt, 0)) {
         return false;
     }
     LineVertex* verts = reinterpret_cast<LineVertex*>(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<gHairlineBezierAttribs>(SK_ARRAY_COUNT(gHairlineBezierAttribs));
     SkASSERT(sizeof(BezierVertex) == target->getDrawState().getVertexSize());
     if (!arg->set(target, vertCnt, 0)) {
         return false;
     }
     BezierVertex* verts = reinterpret_cast<BezierVertex*>(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 <class VertexType>
 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<VertexType*>(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<LineVertex>(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
 ,                          // 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<BezierVertex>(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
 ,                                 // 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
 ,                                 // startI
                                     kVertsPerQuad*n,                   // vCount
                                     kIdxsPerQuad*n,                    // iCount
                                     &devBounds);
                 conics += n;
             }
         }
     }
     target->resetIndexSource();
     return true;
 }

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gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/gpu/GrAAHairLinePathRenderer.cpp