/* * Copyright 2014 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "GrDashingEffect.h" #include "../GrAARectRenderer.h" #include "effects/GrVertexEffect.h" #include "gl/GrGLEffect.h" #include "gl/GrGLVertexEffect.h" #include "gl/GrGLSL.h" #include "GrContext.h" #include "GrCoordTransform.h" #include "GrDrawTarget.h" #include "GrDrawTargetCaps.h" #include "GrEffect.h" #include "GrGpu.h" #include "GrStrokeInfo.h" #include "GrTBackendEffectFactory.h" #include "SkGr.h" /////////////////////////////////////////////////////////////////////////////// // Returns whether or not the gpu can fast path the dash line effect. static bool can_fast_path_dash(const SkPoint pts[2], const GrStrokeInfo& strokeInfo, const GrDrawTarget& target, const SkMatrix& viewMatrix) { if (target.getDrawState().getRenderTarget()->isMultisampled()) { return false; } // Pts must be either horizontal or vertical in src space if (pts[0].fX != pts[1].fX && pts[0].fY != pts[1].fY) { return false; } // May be able to relax this to include skew. As of now cannot do perspective // because of the non uniform scaling of bloating a rect if (!viewMatrix.preservesRightAngles()) { return false; } if (!strokeInfo.isDashed() || 2 != strokeInfo.dashCount()) { return false; } const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo(); if (0 == info.fIntervals[0] && 0 == info.fIntervals[1]) { return false; } SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap(); // Current we do don't handle Round or Square cap dashes if (SkPaint::kRound_Cap == cap) { return false; } return true; } namespace { struct DashLineVertex { SkPoint fPos; SkPoint fDashPos; }; extern const GrVertexAttrib gDashLineVertexAttribs[] = { { kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding }, { kVec2f_GrVertexAttribType, sizeof(SkPoint), kEffect_GrVertexAttribBinding }, }; }; static void calc_dash_scaling(SkScalar* parallelScale, SkScalar* perpScale, const SkMatrix& viewMatrix, const SkPoint pts[2]) { SkVector vecSrc = pts[1] - pts[0]; SkScalar magSrc = vecSrc.length(); SkScalar invSrc = magSrc ? SkScalarInvert(magSrc) : 0; vecSrc.scale(invSrc); SkVector vecSrcPerp; vecSrc.rotateCW(&vecSrcPerp); viewMatrix.mapVectors(&vecSrc, 1); viewMatrix.mapVectors(&vecSrcPerp, 1); // parallelScale tells how much to scale along the line parallel to the dash line // perpScale tells how much to scale in the direction perpendicular to the dash line *parallelScale = vecSrc.length(); *perpScale = vecSrcPerp.length(); } // calculates the rotation needed to aligned pts to the x axis with pts[0] < pts[1] // Stores the rotation matrix in rotMatrix, and the mapped points in ptsRot static void align_to_x_axis(const SkPoint pts[2], SkMatrix* rotMatrix, SkPoint ptsRot[2] = NULL) { SkVector vec = pts[1] - pts[0]; SkScalar mag = vec.length(); SkScalar inv = mag ? SkScalarInvert(mag) : 0; vec.scale(inv); rotMatrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY); if (ptsRot) { rotMatrix->mapPoints(ptsRot, pts, 2); // correction for numerical issues if map doesn't make ptsRot exactly horizontal ptsRot[1].fY = pts[0].fY; } } // Assumes phase < sum of all intervals static SkScalar calc_start_adjustment(const SkPathEffect::DashInfo& info) { SkASSERT(info.fPhase < info.fIntervals[0] + info.fIntervals[1]); if (info.fPhase >= info.fIntervals[0] && info.fPhase != 0) { SkScalar srcIntervalLen = info.fIntervals[0] + info.fIntervals[1]; return srcIntervalLen - info.fPhase; } return 0; } static SkScalar calc_end_adjustment(const SkPathEffect::DashInfo& info, const SkPoint pts[2], SkScalar phase, SkScalar* endingInt) { if (pts[1].fX <= pts[0].fX) { return 0; } SkScalar srcIntervalLen = info.fIntervals[0] + info.fIntervals[1]; SkScalar totalLen = pts[1].fX - pts[0].fX; SkScalar temp = SkScalarDiv(totalLen, srcIntervalLen); SkScalar numFullIntervals = SkScalarFloorToScalar(temp); *endingInt = totalLen - numFullIntervals * srcIntervalLen + phase; temp = SkScalarDiv(*endingInt, srcIntervalLen); *endingInt = *endingInt - SkScalarFloorToScalar(temp) * srcIntervalLen; if (0 == *endingInt) { *endingInt = srcIntervalLen; } if (*endingInt > info.fIntervals[0]) { if (0 == info.fIntervals[0]) { *endingInt -= 0.01f; // make sure we capture the last zero size pnt (used if has caps) } return *endingInt - info.fIntervals[0]; } return 0; } static void setup_dashed_rect(const SkRect& rect, DashLineVertex* verts, int idx, const SkMatrix& matrix, SkScalar offset, SkScalar bloat, SkScalar len, SkScalar stroke) { SkScalar startDashX = offset - bloat; SkScalar endDashX = offset + len + bloat; SkScalar startDashY = -stroke - bloat; SkScalar endDashY = stroke + bloat; verts[idx].fDashPos = SkPoint::Make(startDashX , startDashY); verts[idx + 1].fDashPos = SkPoint::Make(startDashX, endDashY); verts[idx + 2].fDashPos = SkPoint::Make(endDashX, endDashY); verts[idx + 3].fDashPos = SkPoint::Make(endDashX, startDashY); verts[idx].fPos = SkPoint::Make(rect.fLeft, rect.fTop); verts[idx + 1].fPos = SkPoint::Make(rect.fLeft, rect.fBottom); verts[idx + 2].fPos = SkPoint::Make(rect.fRight, rect.fBottom); verts[idx + 3].fPos = SkPoint::Make(rect.fRight, rect.fTop); matrix.mapPointsWithStride(&verts[idx].fPos, sizeof(DashLineVertex), 4); } bool GrDashingEffect::DrawDashLine(const SkPoint pts[2], const GrPaint& paint, const GrStrokeInfo& strokeInfo, GrGpu* gpu, GrDrawTarget* target, const SkMatrix& vm) { if (!can_fast_path_dash(pts, strokeInfo, *target, vm)) { return false; } const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo(); SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap(); SkScalar srcStrokeWidth = strokeInfo.getStrokeRec().getWidth(); // the phase should be normalized to be [0, sum of all intervals) SkASSERT(info.fPhase >= 0 && info.fPhase < info.fIntervals[0] + info.fIntervals[1]); SkScalar srcPhase = info.fPhase; // Rotate the src pts so they are aligned horizontally with pts[0].fX < pts[1].fX SkMatrix srcRotInv; SkPoint ptsRot[2]; if (pts[0].fY != pts[1].fY || pts[0].fX > pts[1].fX) { SkMatrix rotMatrix; align_to_x_axis(pts, &rotMatrix, ptsRot); if(!rotMatrix.invert(&srcRotInv)) { GrPrintf("Failed to create invertible rotation matrix!\n"); return false; } } else { srcRotInv.reset(); memcpy(ptsRot, pts, 2 * sizeof(SkPoint)); } bool useAA = paint.isAntiAlias(); // Scale corrections of intervals and stroke from view matrix SkScalar parallelScale; SkScalar perpScale; calc_dash_scaling(¶llelScale, &perpScale, vm, ptsRot); bool hasCap = SkPaint::kSquare_Cap == cap && 0 != srcStrokeWidth; // We always want to at least stroke out half a pixel on each side in device space // so 0.5f / perpScale gives us this min in src space SkScalar halfSrcStroke = SkMaxScalar(srcStrokeWidth * 0.5f, 0.5f / perpScale); SkScalar strokeAdj; if (!hasCap) { strokeAdj = 0.f; } else { strokeAdj = halfSrcStroke; } SkScalar startAdj = 0; SkMatrix combinedMatrix = srcRotInv; combinedMatrix.postConcat(vm); bool lineDone = false; SkRect startRect; bool hasStartRect = false; // If we are using AA, check to see if we are drawing a partial dash at the start. If so // draw it separately here and adjust our start point accordingly if (useAA) { if (srcPhase > 0 && srcPhase < info.fIntervals[0]) { SkPoint startPts[2]; startPts[0] = ptsRot[0]; startPts[1].fY = startPts[0].fY; startPts[1].fX = SkMinScalar(startPts[0].fX + info.fIntervals[0] - srcPhase, ptsRot[1].fX); startRect.set(startPts, 2); startRect.outset(strokeAdj, halfSrcStroke); hasStartRect = true; startAdj = info.fIntervals[0] + info.fIntervals[1] - srcPhase; } } // adjustments for start and end of bounding rect so we only draw dash intervals // contained in the original line segment. startAdj += calc_start_adjustment(info); if (startAdj != 0) { ptsRot[0].fX += startAdj; srcPhase = 0; } SkScalar endingInterval = 0; SkScalar endAdj = calc_end_adjustment(info, ptsRot, srcPhase, &endingInterval); ptsRot[1].fX -= endAdj; if (ptsRot[0].fX >= ptsRot[1].fX) { lineDone = true; } SkRect endRect; bool hasEndRect = false; // If we are using AA, check to see if we are drawing a partial dash at then end. If so // draw it separately here and adjust our end point accordingly if (useAA && !lineDone) { // If we adjusted the end then we will not be drawing a partial dash at the end. // If we didn't adjust the end point then we just need to make sure the ending // dash isn't a full dash if (0 == endAdj && endingInterval != info.fIntervals[0]) { SkPoint endPts[2]; endPts[1] = ptsRot[1]; endPts[0].fY = endPts[1].fY; endPts[0].fX = endPts[1].fX - endingInterval; endRect.set(endPts, 2); endRect.outset(strokeAdj, halfSrcStroke); hasEndRect = true; endAdj = endingInterval + info.fIntervals[1]; ptsRot[1].fX -= endAdj; if (ptsRot[0].fX >= ptsRot[1].fX) { lineDone = true; } } } if (startAdj != 0) { srcPhase = 0; } // Change the dashing info from src space into device space SkScalar devIntervals[2]; devIntervals[0] = info.fIntervals[0] * parallelScale; devIntervals[1] = info.fIntervals[1] * parallelScale; SkScalar devPhase = srcPhase * parallelScale; SkScalar strokeWidth = srcStrokeWidth * perpScale; if ((strokeWidth < 1.f && !useAA) || 0.f == strokeWidth) { strokeWidth = 1.f; } SkScalar halfDevStroke = strokeWidth * 0.5f; if (SkPaint::kSquare_Cap == cap && 0 != srcStrokeWidth) { // add cap to on interveal and remove from off interval devIntervals[0] += strokeWidth; devIntervals[1] -= strokeWidth; } SkScalar startOffset = devIntervals[1] * 0.5f + devPhase; SkScalar bloatX = useAA ? 0.5f / parallelScale : 0.f; SkScalar bloatY = useAA ? 0.5f / perpScale : 0.f; SkScalar devBloat = useAA ? 0.5f : 0.f; GrDrawState* drawState = target->drawState(); if (devIntervals[1] <= 0.f && useAA) { // Case when we end up drawing a solid AA rect // Reset the start rect to draw this single solid rect // but it requires to upload a new intervals uniform so we can mimic // one giant dash ptsRot[0].fX -= hasStartRect ? startAdj : 0; ptsRot[1].fX += hasEndRect ? endAdj : 0; startRect.set(ptsRot, 2); startRect.outset(strokeAdj, halfSrcStroke); hasStartRect = true; hasEndRect = false; lineDone = true; SkPoint devicePts[2]; vm.mapPoints(devicePts, ptsRot, 2); SkScalar lineLength = SkPoint::Distance(devicePts[0], devicePts[1]); if (hasCap) { lineLength += 2.f * halfDevStroke; } devIntervals[0] = lineLength; } if (devIntervals[1] > 0.f || useAA) { SkPathEffect::DashInfo devInfo; devInfo.fPhase = devPhase; devInfo.fCount = 2; devInfo.fIntervals = devIntervals; GrEffectEdgeType edgeType= useAA ? kFillAA_GrEffectEdgeType : kFillBW_GrEffectEdgeType; drawState->addCoverageEffect( GrDashingEffect::Create(edgeType, devInfo, strokeWidth), 1)->unref(); } // Set up the vertex data for the line and start/end dashes drawState->setVertexAttribs<gDashLineVertexAttribs>(SK_ARRAY_COUNT(gDashLineVertexAttribs)); int totalRectCnt = 0; totalRectCnt += !lineDone ? 1 : 0; totalRectCnt += hasStartRect ? 1 : 0; totalRectCnt += hasEndRect ? 1 : 0; GrDrawTarget::AutoReleaseGeometry geo(target, totalRectCnt * 4, 0); if (!geo.succeeded()) { GrPrintf("Failed to get space for vertices!\n"); return false; } DashLineVertex* verts = reinterpret_cast<DashLineVertex*>(geo.vertices()); int curVIdx = 0; // Draw interior part of dashed line if (!lineDone) { SkPoint devicePts[2]; vm.mapPoints(devicePts, ptsRot, 2); SkScalar lineLength = SkPoint::Distance(devicePts[0], devicePts[1]); if (hasCap) { lineLength += 2.f * halfDevStroke; } SkRect bounds; bounds.set(ptsRot[0].fX, ptsRot[0].fY, ptsRot[1].fX, ptsRot[1].fY); bounds.outset(bloatX + strokeAdj, bloatY + halfSrcStroke); setup_dashed_rect(bounds, verts, curVIdx, combinedMatrix, startOffset, devBloat, lineLength, halfDevStroke); curVIdx += 4; } if (hasStartRect) { SkASSERT(useAA); // so that we know bloatX and bloatY have been set startRect.outset(bloatX, bloatY); setup_dashed_rect(startRect, verts, curVIdx, combinedMatrix, startOffset, devBloat, devIntervals[0], halfDevStroke); curVIdx += 4; } if (hasEndRect) { SkASSERT(useAA); // so that we know bloatX and bloatY have been set endRect.outset(bloatX, bloatY); setup_dashed_rect(endRect, verts, curVIdx, combinedMatrix, startOffset, devBloat, devIntervals[0], halfDevStroke); } target->setIndexSourceToBuffer(gpu->getContext()->getQuadIndexBuffer()); target->drawIndexedInstances(kTriangles_GrPrimitiveType, totalRectCnt, 4, 6); target->resetIndexSource(); return true; } ////////////////////////////////////////////////////////////////////////////// class GLDashingLineEffect; class DashingLineEffect : public GrVertexEffect { public: typedef SkPathEffect::DashInfo DashInfo; /** * The effect calculates the coverage for the case of a horizontal line in device space. * The matrix that is passed in should be able to convert a line in source space to a * horizontal line in device space. Additionally, the coord transform matrix should translate * the the start of line to origin, and the shift it along the positive x-axis by the phase * and half the off interval. */ static GrEffectRef* Create(GrEffectEdgeType edgeType, const DashInfo& info, SkScalar strokeWidth); virtual ~DashingLineEffect(); static const char* Name() { return "DashingEffect"; } GrEffectEdgeType getEdgeType() const { return fEdgeType; } const SkRect& getRect() const { return fRect; } SkScalar getIntervalLength() const { return fIntervalLength; } typedef GLDashingLineEffect GLEffect; virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE; virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE; private: DashingLineEffect(GrEffectEdgeType edgeType, const DashInfo& info, SkScalar strokeWidth); virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE; GrEffectEdgeType fEdgeType; SkRect fRect; SkScalar fIntervalLength; GR_DECLARE_EFFECT_TEST; typedef GrEffect INHERITED; }; ////////////////////////////////////////////////////////////////////////////// class GLDashingLineEffect : public GrGLVertexEffect { public: GLDashingLineEffect(const GrBackendEffectFactory&, const GrDrawEffect&); virtual void emitCode(GrGLFullShaderBuilder* builder, const GrDrawEffect& drawEffect, EffectKey key, const char* outputColor, const char* inputColor, const TransformedCoordsArray&, const TextureSamplerArray&) SK_OVERRIDE; static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&); virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE; private: GrGLUniformManager::UniformHandle fRectUniform; GrGLUniformManager::UniformHandle fIntervalUniform; SkRect fPrevRect; SkScalar fPrevIntervalLength; typedef GrGLVertexEffect INHERITED; }; GLDashingLineEffect::GLDashingLineEffect(const GrBackendEffectFactory& factory, const GrDrawEffect& drawEffect) : INHERITED (factory) { fPrevRect.fLeft = SK_ScalarNaN; fPrevIntervalLength = SK_ScalarMax; } void GLDashingLineEffect::emitCode(GrGLFullShaderBuilder* builder, const GrDrawEffect& drawEffect, EffectKey key, const char* outputColor, const char* inputColor, const TransformedCoordsArray&, const TextureSamplerArray& samplers) { const DashingLineEffect& de = drawEffect.castEffect<DashingLineEffect>(); const char *rectName; // The rect uniform's xyzw refer to (left + 0.5, top + 0.5, right - 0.5, bottom - 0.5), // respectively. fRectUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility, kVec4f_GrSLType, "rect", &rectName); const char *intervalName; // The interval uniform's refers to the total length of the interval (on + off) fIntervalUniform = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility, kFloat_GrSLType, "interval", &intervalName); const char *vsCoordName, *fsCoordName; builder->addVarying(kVec2f_GrSLType, "Coord", &vsCoordName, &fsCoordName); const SkString* attr0Name = builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0]); builder->vsCodeAppendf("\t%s = %s;\n", vsCoordName, attr0Name->c_str()); // transforms all points so that we can compare them to our test rect builder->fsCodeAppendf("\t\tfloat xShifted = %s.x - floor(%s.x / %s) * %s;\n", fsCoordName, fsCoordName, intervalName, intervalName); builder->fsCodeAppendf("\t\tvec2 fragPosShifted = vec2(xShifted, %s.y);\n", fsCoordName); if (GrEffectEdgeTypeIsAA(de.getEdgeType())) { // The amount of coverage removed in x and y by the edges is computed as a pair of negative // numbers, xSub and ySub. builder->fsCodeAppend("\t\tfloat xSub, ySub;\n"); builder->fsCodeAppendf("\t\txSub = min(fragPosShifted.x - %s.x, 0.0);\n", rectName); builder->fsCodeAppendf("\t\txSub += min(%s.z - fragPosShifted.x, 0.0);\n", rectName); builder->fsCodeAppendf("\t\tySub = min(fragPosShifted.y - %s.y, 0.0);\n", rectName); builder->fsCodeAppendf("\t\tySub += min(%s.w - fragPosShifted.y, 0.0);\n", rectName); // Now compute coverage in x and y and multiply them to get the fraction of the pixel // covered. builder->fsCodeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n"); } else { // Assuming the bounding geometry is tight so no need to check y values builder->fsCodeAppendf("\t\tfloat alpha = 1.0;\n"); builder->fsCodeAppendf("\t\talpha *= (fragPosShifted.x - %s.x) > -0.5 ? 1.0 : 0.0;\n", rectName); builder->fsCodeAppendf("\t\talpha *= (%s.z - fragPosShifted.x) >= -0.5 ? 1.0 : 0.0;\n", rectName); } builder->fsCodeAppendf("\t\t%s = %s;\n", outputColor, (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str()); } void GLDashingLineEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) { const DashingLineEffect& de = drawEffect.castEffect<DashingLineEffect>(); const SkRect& rect = de.getRect(); SkScalar intervalLength = de.getIntervalLength(); if (rect != fPrevRect || intervalLength != fPrevIntervalLength) { uman.set4f(fRectUniform, rect.fLeft + 0.5f, rect.fTop + 0.5f, rect.fRight - 0.5f, rect.fBottom - 0.5f); uman.set1f(fIntervalUniform, intervalLength); fPrevRect = rect; fPrevIntervalLength = intervalLength; } } GrGLEffect::EffectKey GLDashingLineEffect::GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) { const DashingLineEffect& de = drawEffect.castEffect<DashingLineEffect>(); return de.getEdgeType(); } ////////////////////////////////////////////////////////////////////////////// GrEffectRef* DashingLineEffect::Create(GrEffectEdgeType edgeType, const DashInfo& info, SkScalar strokeWidth) { if (info.fCount != 2) { return NULL; } return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(DashingLineEffect, (edgeType, info, strokeWidth)))); } DashingLineEffect::~DashingLineEffect() {} void DashingLineEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const { *validFlags = 0; } const GrBackendEffectFactory& DashingLineEffect::getFactory() const { return GrTBackendEffectFactory<DashingLineEffect>::getInstance(); } DashingLineEffect::DashingLineEffect(GrEffectEdgeType edgeType, const DashInfo& info, SkScalar strokeWidth) : fEdgeType(edgeType) { SkScalar onLen = info.fIntervals[0]; SkScalar offLen = info.fIntervals[1]; SkScalar halfOffLen = SkScalarHalf(offLen); SkScalar halfStroke = SkScalarHalf(strokeWidth); fIntervalLength = onLen + offLen; fRect.set(halfOffLen, -halfStroke, halfOffLen + onLen, halfStroke); this->addVertexAttrib(kVec2f_GrSLType); } bool DashingLineEffect::onIsEqual(const GrEffect& other) const { const DashingLineEffect& de = CastEffect<DashingLineEffect>(other); return (fEdgeType == de.fEdgeType && fRect == de.fRect && fIntervalLength == de.fIntervalLength); } GR_DEFINE_EFFECT_TEST(DashingLineEffect); GrEffectRef* DashingLineEffect::TestCreate(SkRandom* random, GrContext*, const GrDrawTargetCaps& caps, GrTexture*[]) { GrEffectRef* effect; GrEffectEdgeType edgeType = static_cast<GrEffectEdgeType>(random->nextULessThan( kGrEffectEdgeTypeCnt)); SkScalar strokeWidth = random->nextRangeScalar(0, 100.f); DashInfo info; info.fCount = 2; SkAutoTArray<SkScalar> intervals(info.fCount); info.fIntervals = intervals.get(); info.fIntervals[0] = random->nextRangeScalar(0, 10.f); info.fIntervals[1] = random->nextRangeScalar(0, 10.f); info.fPhase = random->nextRangeScalar(0, info.fIntervals[0] + info.fIntervals[1]); effect = DashingLineEffect::Create(edgeType, info, strokeWidth); return effect; } ////////////////////////////////////////////////////////////////////////////// GrEffectRef* GrDashingEffect::Create(GrEffectEdgeType edgeType, const SkPathEffect::DashInfo& info, SkScalar strokeWidth) { return DashingLineEffect::Create(edgeType, info, strokeWidth); }