ccpr: Implement conics
TBR=egdaniel@google.com
Bug: skia:
Change-Id: Idf7811dc285961db52db41c9ff145afda40c274d
Reviewed-on: https://skia-review.googlesource.com/122127
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/ccpr/GrCCConicShader.cpp b/src/gpu/ccpr/GrCCConicShader.cpp
new file mode 100644
index 0000000..01568de
--- /dev/null
+++ b/src/gpu/ccpr/GrCCConicShader.cpp
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrCCConicShader.h"
+
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
+
+void GrCCConicShader::emitSetupCode(GrGLSLVertexGeoBuilder* s, const char* pts, const char* wind,
+ const char** outHull4) const {
+ // K is distance from the line P2 -> P0. L is distance from the line P0 -> P1, scaled by 2w.
+ // M is distance from the line P1 -> P2, scaled by 2w. We do this in a space where P1=0.
+ s->declareGlobal(fKLMMatrix);
+ s->codeAppendf("float x0 = %s[0].x - %s[1].x, x2 = %s[2].x - %s[1].x;", pts, pts, pts, pts);
+ s->codeAppendf("float y0 = %s[0].y - %s[1].y, y2 = %s[2].y - %s[1].y;", pts, pts, pts, pts);
+ s->codeAppendf("float w = %s[3].x;", pts);
+ s->codeAppendf("%s = float3x3(y2 - y0, x0 - x2, x2*y0 - x0*y2, "
+ "2*w * float2(+y0, -x0), 0, "
+ "2*w * float2(-y2, +x2), 0);", fKLMMatrix.c_str());
+
+ s->declareGlobal(fControlPoint);
+ s->codeAppendf("%s = %s[1];", fControlPoint.c_str(), pts);
+
+ // Scale KLM by the inverse Manhattan width of K. This allows K to double as the flat opposite
+ // edge AA. kwidth will not be 0 because we cull degenerate conics on the CPU.
+ s->codeAppendf("float kwidth = 2*bloat * %s * (abs(%s[0].x) + abs(%s[0].y));",
+ wind, fKLMMatrix.c_str(), fKLMMatrix.c_str());
+ s->codeAppendf("%s *= 1/kwidth;", fKLMMatrix.c_str());
+
+ if (outHull4) {
+ // Clip the conic triangle by the tangent line at maximum height. Conics have the nice
+ // property that maximum height always occurs at T=.5. This is a simple application for
+ // De Casteljau's algorithm.
+ s->codeAppendf("float2 p1w = %s[1]*w;", pts);
+ s->codeAppend ("float r = 1 / (1 + w);");
+ s->codeAppendf("float2 conic_hull[4] = float2[4](%s[0], "
+ "(%s[0] + p1w) * r, "
+ "(p1w + %s[2]) * r, "
+ "%s[2]);", pts, pts, pts, pts);
+ *outHull4 = "conic_hull";
+ }
+}
+
+void GrCCConicShader::onEmitVaryings(GrGLSLVaryingHandler* varyingHandler,
+ GrGLSLVarying::Scope scope, SkString* code,
+ const char* position, const char* coverage,
+ const char* cornerCoverage) {
+ fKLM_fWind.reset(kFloat4_GrSLType, scope);
+ varyingHandler->addVarying("klm_and_wind", &fKLM_fWind);
+ code->appendf("float3 klm = float3(%s - %s, 1) * %s;",
+ position, fControlPoint.c_str(), fKLMMatrix.c_str());
+ code->appendf("%s.xyz = klm;", OutName(fKLM_fWind));
+ code->appendf("%s.w = %s;", OutName(fKLM_fWind), coverage); // coverage == wind.
+
+ fGrad_fCorner.reset(cornerCoverage ? kFloat4_GrSLType : kFloat2_GrSLType, scope);
+ varyingHandler->addVarying(cornerCoverage ? "grad_and_corner" : "grad", &fGrad_fCorner);
+ code->appendf("%s.xy = 2*bloat * (float3x2(%s) * float3(2*klm[0], -klm[2], -klm[1]));",
+ OutName(fGrad_fCorner), fKLMMatrix.c_str());
+
+ if (cornerCoverage) {
+ code->appendf("half hull_coverage;");
+ this->calcHullCoverage(code, "klm", OutName(fGrad_fCorner), "hull_coverage");
+ code->appendf("%s.zw = half2(hull_coverage, 1) * %s;",
+ OutName(fGrad_fCorner), cornerCoverage);
+ }
+}
+
+void GrCCConicShader::onEmitFragmentCode(GrGLSLFPFragmentBuilder* f,
+ const char* outputCoverage) const {
+ this->calcHullCoverage(&AccessCodeString(f), fKLM_fWind.fsIn(), fGrad_fCorner.fsIn(),
+ outputCoverage);
+ f->codeAppendf("%s *= %s.w;", outputCoverage, fKLM_fWind.fsIn()); // Wind.
+
+ if (kFloat4_GrSLType == fGrad_fCorner.type()) {
+ f->codeAppendf("%s = %s.z * %s.w + %s;", // Attenuated corner coverage.
+ outputCoverage, fGrad_fCorner.fsIn(), fGrad_fCorner.fsIn(),
+ outputCoverage);
+ }
+}
+
+void GrCCConicShader::calcHullCoverage(SkString* code, const char* klm, const char* grad,
+ const char* outputCoverage) const {
+ code->appendf("float k = %s.x, l = %s.y, m = %s.z;", klm, klm, klm);
+ code->append ("float f = k*k - l*m;");
+ code->appendf("float fwidth = abs(%s.x) + abs(%s.y);", grad, grad);
+ code->appendf("%s = min(0.5 - f/fwidth, 1);", outputCoverage); // Curve coverage.
+ code->append ("half d = min(k - 0.5, 0);"); // K doubles as the flat opposite edge's AA.
+ code->appendf("%s = max(%s + d, 0);", outputCoverage, outputCoverage); // Total hull coverage.
+}
diff --git a/src/gpu/ccpr/GrCCConicShader.h b/src/gpu/ccpr/GrCCConicShader.h
new file mode 100644
index 0000000..16b70e7
--- /dev/null
+++ b/src/gpu/ccpr/GrCCConicShader.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrCCConicShader_DEFINED
+#define GrCCConicShader_DEFINED
+
+#include "ccpr/GrCCCoverageProcessor.h"
+
+/**
+ * This class renders the coverage of closed conic curves using the techniques outlined in
+ * "Resolution Independent Curve Rendering using Programmable Graphics Hardware" by Charles Loop and
+ * Jim Blinn:
+ *
+ * https://www.microsoft.com/en-us/research/wp-content/uploads/2005/01/p1000-loop.pdf
+ *
+ * The provided curves must be monotonic with respect to the vector of their closing edge [P2 - P0].
+ * (Use GrCCGeometry::conicTo().)
+ */
+class GrCCConicShader : public GrCCCoverageProcessor::Shader {
+public:
+ void emitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* wind,
+ const char** outHull4) const override;
+
+ void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code,
+ const char* position, const char* coverage,
+ const char* cornerCoverage) override;
+
+ void onEmitFragmentCode(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const override;
+
+private:
+ void calcHullCoverage(SkString* code, const char* klm, const char* grad,
+ const char* outputCoverage) const;
+
+ const GrShaderVar fKLMMatrix{"klm_matrix", kFloat3x3_GrSLType};
+ const GrShaderVar fControlPoint{"control_point", kFloat2_GrSLType};
+ GrGLSLVarying fKLM_fWind;
+ GrGLSLVarying fGrad_fCorner;
+};
+
+#endif
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor.cpp b/src/gpu/ccpr/GrCCCoverageProcessor.cpp
index b94b188..d38db27 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor.cpp
@@ -10,6 +10,7 @@
#include "GrGpuCommandBuffer.h"
#include "GrOpFlushState.h"
#include "SkMakeUnique.h"
+#include "ccpr/GrCCConicShader.h"
#include "ccpr/GrCCCubicShader.h"
#include "ccpr/GrCCQuadraticShader.h"
#include "glsl/GrGLSLVertexGeoBuilder.h"
@@ -174,6 +175,9 @@
case PrimitiveType::kCubics:
shader = skstd::make_unique<GrCCCubicShader>();
break;
+ case PrimitiveType::kConics:
+ shader = skstd::make_unique<GrCCConicShader>();
+ break;
}
return Impl::kGeometryShader == fImpl ? this->createGSImpl(std::move(shader))
: this->createVSImpl(std::move(shader));
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor.h b/src/gpu/ccpr/GrCCCoverageProcessor.h
index 6818027..454e728 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor.h
+++ b/src/gpu/ccpr/GrCCCoverageProcessor.h
@@ -40,6 +40,7 @@
kWeightedTriangles, // Triangles (from the tessellator) whose winding magnitude > 1.
kQuadratics,
kCubics,
+ kConics
};
static const char* PrimitiveTypeName(PrimitiveType);
@@ -53,14 +54,15 @@
void set(const SkPoint&, const SkPoint&, const SkPoint&, const Sk2f& trans);
};
- // Defines a single primitive shape with 4 input points, or 3 input points plus a W parameter
- // duplicated in both 4th components (i.e. Cubics or Triangles with a custom winding number).
- // X,Y point values are transposed.
+ // Defines a single primitive shape with 4 input points, or 3 input points plus a "weight"
+ // parameter duplicated in both lanes of the 4th input (i.e. Cubics, Conics, and Triangles with
+ // a weighted winding number). X,Y point values are transposed.
struct QuadPointInstance {
float fX[4];
float fY[4];
void set(const SkPoint[4], float dx, float dy);
+ void setW(const SkPoint[3], const Sk2f& trans, float w);
void setW(const SkPoint&, const SkPoint&, const SkPoint&, const Sk2f& trans, float w);
};
@@ -205,6 +207,11 @@
// Number of bezier points for curves, or 3 for triangles.
int numInputPoints() const { return PrimitiveType::kCubics == fPrimitiveType ? 4 : 3; }
+ int hasInputWeight() const {
+ return PrimitiveType::kWeightedTriangles == fPrimitiveType ||
+ PrimitiveType::kConics == fPrimitiveType;
+ }
+
enum class Impl : bool {
kGeometryShader,
kVertexShader
@@ -259,6 +266,7 @@
case PrimitiveType::kWeightedTriangles: return "kWeightedTriangles";
case PrimitiveType::kQuadratics: return "kQuadratics";
case PrimitiveType::kCubics: return "kCubics";
+ case PrimitiveType::kConics: return "kConics";
}
SK_ABORT("Invalid PrimitiveType");
return "";
@@ -283,6 +291,11 @@
(Y + dy).store(&fY);
}
+inline void GrCCCoverageProcessor::QuadPointInstance::setW(const SkPoint p[3], const Sk2f& trans,
+ float w) {
+ this->setW(p[0], p[1], p[2], trans, w);
+}
+
inline void GrCCCoverageProcessor::QuadPointInstance::setW(const SkPoint& p0, const SkPoint& p1,
const SkPoint& p2, const Sk2f& trans,
float w) {
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp b/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
index f933030..b1d886c 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor_GSImpl.cpp
@@ -52,9 +52,10 @@
int numInputPoints = proc.numInputPoints();
SkASSERT(3 == numInputPoints || 4 == numInputPoints);
- const char* posValues = (4 == numInputPoints) ? "sk_Position" : "sk_Position.xyz";
+ int inputWidth = (4 == numInputPoints || proc.hasInputWeight()) ? 4 : 3;
+ const char* posValues = (4 == inputWidth) ? "sk_Position" : "sk_Position.xyz";
g->codeAppendf("float%ix2 pts = transpose(float2x%i(sk_in[0].%s, sk_in[1].%s));",
- numInputPoints, numInputPoints, posValues, posValues);
+ inputWidth, inputWidth, posValues, posValues);
GrShaderVar wind("wind", kHalf_GrSLType);
g->declareGlobal(wind);
@@ -389,8 +390,7 @@
void GrCCCoverageProcessor::initGS() {
SkASSERT(Impl::kGeometryShader == fImpl);
- if (PrimitiveType::kCubics == fPrimitiveType ||
- PrimitiveType::kWeightedTriangles == fPrimitiveType) {
+ if (4 == this->numInputPoints() || this->hasInputWeight()) {
this->addVertexAttrib("x_or_y_values", kFloat4_GrVertexAttribType);
SkASSERT(sizeof(QuadPointInstance) == this->getVertexStride() * 2);
SkASSERT(offsetof(QuadPointInstance, fY) == this->getVertexStride());
diff --git a/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp b/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
index a1f180b..dd8da96 100644
--- a/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
+++ b/src/gpu/ccpr/GrCCCoverageProcessor_VSImpl.cpp
@@ -257,9 +257,10 @@
GrGLSLVertexBuilder* v = args.fVertBuilder;
int numInputPoints = proc.numInputPoints();
- const char* swizzle = (4 == numInputPoints) ? "xyzw" : "xyz";
+ int inputWidth = (4 == numInputPoints || proc.hasInputWeight()) ? 4 : 3;
+ const char* swizzle = (4 == inputWidth) ? "xyzw" : "xyz";
v->codeAppendf("float%ix2 pts = transpose(float2x%i(%s.%s, %s.%s));",
- numInputPoints, numInputPoints, proc.getAttrib(kAttribIdx_X).fName, swizzle,
+ inputWidth, inputWidth, proc.getAttrib(kAttribIdx_X).fName, swizzle,
proc.getAttrib(kAttribIdx_Y).fName, swizzle);
if (PrimitiveType::kWeightedTriangles != proc.fPrimitiveType) {
@@ -476,7 +477,8 @@
}
case PrimitiveType::kQuadratics:
- case PrimitiveType::kCubics: {
+ case PrimitiveType::kCubics:
+ case PrimitiveType::kConics: {
GR_DEFINE_STATIC_UNIQUE_KEY(gCurveVertexBufferKey);
fVSVertexBuffer = rp->findOrMakeStaticBuffer(kVertex_GrBufferType,
sizeof(kCurveVertices), kCurveVertices,
@@ -499,8 +501,7 @@
}
}
- if (PrimitiveType::kCubics == fPrimitiveType ||
- PrimitiveType::kWeightedTriangles == fPrimitiveType) {
+ if (4 == this->numInputPoints() || this->hasInputWeight()) {
SkASSERT(kAttribIdx_X == this->numAttribs());
this->addInstanceAttrib("X", kFloat4_GrVertexAttribType);
@@ -550,6 +551,7 @@
return new VSImpl(std::move(shadr), 3);
case PrimitiveType::kQuadratics:
case PrimitiveType::kCubics:
+ case PrimitiveType::kConics:
return new VSImpl(std::move(shadr), 4);
}
SK_ABORT("Invalid RenderPass");
diff --git a/src/gpu/ccpr/GrCCGeometry.cpp b/src/gpu/ccpr/GrCCGeometry.cpp
index 5d7fc69..302cfe2 100644
--- a/src/gpu/ccpr/GrCCGeometry.cpp
+++ b/src/gpu/ccpr/GrCCGeometry.cpp
@@ -27,7 +27,7 @@
SkASSERT(!fBuildingContour);
// Store the current verb count in the fTriangles field for now. When we close the contour we
// will use this value to calculate the actual number of triangles in its fan.
- fCurrContourTallies = {fVerbs.count(), 0, 0, 0};
+ fCurrContourTallies = {fVerbs.count(), 0, 0, 0, 0};
fPoints.push_back(pt);
fVerbs.push_back(Verb::kBeginContour);
@@ -125,7 +125,8 @@
return dot0 >= tolerance && dot1 >= tolerance;
}
-static inline Sk2f lerp(const Sk2f& a, const Sk2f& b, const Sk2f& t) {
+template<int N> static inline SkNx<N,float> lerp(const SkNx<N,float>& a, const SkNx<N,float>& b,
+ const SkNx<N,float>& t) {
return SkNx_fma(t, b - a, a);
}
@@ -328,6 +329,54 @@
return ((c1 - c2).abs() <= 1).allTrue();
}
+// Given a convex curve segment with the following order-2 tangent function:
+//
+// |C2x C2y|
+// tan = some_scale * |dx/dt dy/dt| = |t^2 t 1| * |C1x C1y|
+// |C0x C0y|
+//
+// This function finds the T value whose tangent angle is halfway between the tangents at T=0 and
+// T=1 (tan0 and tan1).
+static inline float find_midtangent(const Sk2f& tan0, const Sk2f& tan1,
+ float scale2, const Sk2f& C2,
+ float scale1, const Sk2f& C1,
+ float scale0, const Sk2f& C0) {
+ // Tangents point in the direction of increasing T, so tan0 and -tan1 both point toward the
+ // midtangent. 'n' will therefore bisect tan0 and -tan1, giving us the normal to the midtangent.
+ //
+ // n dot midtangent = 0
+ //
+ Sk2f n = normalize(tan0) - normalize(tan1);
+
+ // Find the T value at the midtangent. This is a simple quadratic equation:
+ //
+ // midtangent dot n = 0
+ //
+ // (|t^2 t 1| * C) dot n = 0
+ //
+ // |t^2 t 1| dot C*n = 0
+ //
+ // First find coeffs = C*n.
+ Sk4f C[2];
+ Sk2f::Store4(C, C2, C1, C0, 0);
+ Sk4f coeffs = C[0]*n[0] + C[1]*n[1];
+ if (1 != scale2 || 1 != scale1 || 1 != scale0) {
+ coeffs *= Sk4f(scale2, scale1, scale0, 0);
+ }
+
+ // Now solve the quadratic.
+ float a = coeffs[0], b = coeffs[1], c = coeffs[2];
+ float discr = b*b - 4*a*c;
+ if (discr < 0) {
+ return 0; // This will only happen if the curve is a line.
+ }
+
+ // The roots are q/a and c/q. Pick the one closer to T=.5.
+ float q = -.5f * (b + copysignf(std::sqrt(discr), b));
+ float r = .5f*q*a;
+ return std::abs(q*q - r) < std::abs(a*c - r) ? q/a : c/q;
+}
+
void GrCCGeometry::cubicTo(const SkPoint P[4], float inflectPad, float loopIntersectPad) {
SkASSERT(fBuildingContour);
SkASSERT(P[0] == fPoints.back());
@@ -486,7 +535,7 @@
this->appendMonotonicCubics(p0, ab2, abc2, abcd2);
} else if (T2 > T1) {
// Section 3 (middle section).
- Sk2f midp2 = lerp(abc2, abcd2, T1/T2);
+ Sk2f midp2 = lerp(abc2, abcd2, Sk2f(T1/T2));
this->appendMonotonicCubics(midp0, midp1, midp2, abcd2);
}
@@ -499,25 +548,18 @@
inline void GrCCGeometry::chopCubicAtMidTangent(const Sk2f& p0, const Sk2f& p1, const Sk2f& p2,
const Sk2f& p3, const Sk2f& tan0,
const Sk2f& tan1, int maxFutureSubdivisions) {
- // Find the T value whose tangent is perpendicular to the vector that bisects tan0 and -tan1.
- Sk2f n = normalize(tan0) - normalize(tan1);
-
- float a = 3 * dot(p3 + (p1 - p2)*3 - p0, n);
- float b = 6 * dot(p0 - p1*2 + p2, n);
- float c = 3 * dot(p1 - p0, n);
-
- float discr = b*b - 4*a*c;
- if (discr < 0) {
- // If this is the case then the cubic must be nearly flat.
- (this->*AppendLeftRight)(p0, p1, p2, p3, maxFutureSubdivisions);
+ float midT = find_midtangent(tan0, tan1, 3, p3 + (p1 - p2)*3 - p0,
+ 6, p0 - p1*2 + p2,
+ 3, p1 - p0);
+ // Use positive logic since NaN fails comparisons. (However midT should not be NaN since we cull
+ // near-flat cubics in cubicTo().)
+ if (!(midT > 0 && midT < 1)) {
+ // The cubic is flat. Otherwise there would be a real midtangent inside T=0..1.
+ this->appendLine(p3);
return;
}
- float q = -.5f * (b + copysignf(std::sqrt(discr), b));
- float m = .5f*q*a;
- float T = std::abs(q*q - m) < std::abs(a*c - m) ? q/a : c/q;
-
- this->chopCubic<AppendLeftRight, AppendLeftRight>(p0, p1, p2, p3, T, maxFutureSubdivisions);
+ this->chopCubic<AppendLeftRight, AppendLeftRight>(p0, p1, p2, p3, midT, maxFutureSubdivisions);
}
template<GrCCGeometry::AppendCubicFn AppendLeft, GrCCGeometry::AppendCubicFn AppendRight>
@@ -610,6 +652,87 @@
}
}
+void GrCCGeometry::conicTo(const SkPoint P[3], float w) {
+ SkASSERT(fBuildingContour);
+ SkASSERT(P[0] == fPoints.back());
+ Sk2f p0 = Sk2f::Load(P);
+ Sk2f p1 = Sk2f::Load(P+1);
+ Sk2f p2 = Sk2f::Load(P+2);
+
+ // Don't crunch on the curve if it is nearly flat (or just very small). Collinear control points
+ // can break the midtangent-finding math below.
+ if (are_collinear(p0, p1, p2)) {
+ this->appendLine(p2);
+ return;
+ }
+
+ Sk2f tan0 = p1 - p0;
+ Sk2f tan1 = p2 - p1;
+ // The derivative of a conic has a cumbersome order-4 denominator. However, this isn't necessary
+ // if we are only interested in a vector in the same *direction* as a given tangent line. Since
+ // the denominator scales dx and dy uniformly, we can throw it out completely after evaluating
+ // the derivative with the standard quotient rule. This leaves us with a simpler quadratic
+ // function that we use to find the midtangent.
+ float midT = find_midtangent(tan0, tan1, 1, (w - 1) * (p2 - p0),
+ 1, (p2 - p0) - 2*w*(p1 - p0),
+ 1, w*(p1 - p0));
+ // Use positive logic since NaN fails comparisons. (However midT should not be NaN since we cull
+ // near-linear conics above. And while w=0 is flat, it's not a line and has valid midtangents.)
+ if (!(midT > 0 && midT < 1)) {
+ // The conic is flat. Otherwise there would be a real midtangent inside T=0..1.
+ this->appendLine(p2);
+ return;
+ }
+
+ // Evaluate the conic at midT.
+ Sk4f p3d0 = Sk4f(p0[0], p0[1], 1, 0);
+ Sk4f p3d1 = Sk4f(p1[0], p1[1], 1, 0) * w;
+ Sk4f p3d2 = Sk4f(p2[0], p2[1], 1, 0);
+ Sk4f midT4 = midT;
+
+ Sk4f p3d01 = lerp(p3d0, p3d1, midT4);
+ Sk4f p3d12 = lerp(p3d1, p3d2, midT4);
+ Sk4f p3d012 = lerp(p3d01, p3d12, midT4);
+
+ Sk2f midpoint = Sk2f(p3d012[0], p3d012[1]) / p3d012[2];
+
+ if (are_collinear(p0, midpoint, p2, 1) || // Check if the curve is within one pixel of flat.
+ ((midpoint - p1).abs() < 1).allTrue()) { // Check if the curve is almost a triangle.
+ // Draw the conic as a triangle instead. Our AA approximation won't do well if the curve
+ // gets wrapped too tightly, and if we get too close to p1 we will pick up artifacts from
+ // the implicit function's reflection.
+ this->appendLine(midpoint);
+ this->appendLine(p2);
+ return;
+ }
+
+ if (!is_convex_curve_monotonic(p0, tan0, p2, tan1)) {
+ // Chop the conic at midtangent to produce two monotonic segments.
+ Sk2f ww = Sk2f(p3d01[2], p3d12[2]) * Sk2f(p3d012[2]).rsqrt();
+ this->appendMonotonicConic(p0, Sk2f(p3d01[0], p3d01[1]) / p3d01[2], midpoint, ww[0]);
+ this->appendMonotonicConic(midpoint, Sk2f(p3d12[0], p3d12[1]) / p3d12[2], p2, ww[1]);
+ return;
+ }
+
+ this->appendMonotonicConic(p0, p1, p2, w);
+}
+
+void GrCCGeometry::appendMonotonicConic(const Sk2f& p0, const Sk2f& p1, const Sk2f& p2, float w) {
+ SkASSERT(fPoints.back() == SkPoint::Make(p0[0], p0[1]));
+
+ // Don't send curves to the GPU if we know they are nearly flat (or just very small).
+ if (are_collinear(p0, p1, p2)) {
+ this->appendLine(p2);
+ return;
+ }
+
+ p1.store(&fPoints.push_back());
+ p2.store(&fPoints.push_back());
+ fConicWeights.push_back(w);
+ fVerbs.push_back(Verb::kMonotonicConicTo);
+ ++fCurrContourTallies.fConics;
+}
+
GrCCGeometry::PrimitiveTallies GrCCGeometry::endContour() {
SkASSERT(fBuildingContour);
SkASSERT(fVerbs.count() >= fCurrContourTallies.fTriangles);
diff --git a/src/gpu/ccpr/GrCCGeometry.h b/src/gpu/ccpr/GrCCGeometry.h
index 01cf16c..7f098f9 100644
--- a/src/gpu/ccpr/GrCCGeometry.h
+++ b/src/gpu/ccpr/GrCCGeometry.h
@@ -31,6 +31,7 @@
kLineTo,
kMonotonicQuadraticTo, // Monotonic relative to the vector between its endpoints [P2 - P0].
kMonotonicCubicTo,
+ kMonotonicConicTo,
kEndClosedContour, // endPt == startPt.
kEndOpenContour // endPt != startPt.
};
@@ -41,6 +42,7 @@
int fWeightedTriangles; // Triangles (from the tessellator) whose winding magnitude > 1.
int fQuadratics;
int fCubics;
+ int fConics;
void operator+=(const PrimitiveTallies&);
PrimitiveTallies operator-(const PrimitiveTallies&) const;
@@ -53,6 +55,7 @@
const SkTArray<SkPoint, true>& points() const { SkASSERT(!fBuildingContour); return fPoints; }
const SkTArray<Verb, true>& verbs() const { SkASSERT(!fBuildingContour); return fVerbs; }
+ float getConicWeight(int idx) const { SkASSERT(!fBuildingContour); return fConicWeights[idx]; }
void reset() {
SkASSERT(!fBuildingContour);
@@ -89,6 +92,8 @@
// intersection vs. 1.489 on the tiger).
void cubicTo(const SkPoint[4], float inflectPad = 0.55f, float loopIntersectPad = 2);
+ void conicTo(const SkPoint[3], float w);
+
PrimitiveTallies endContour(); // Returns the numbers of primitives needed to draw the contour.
private:
@@ -116,15 +121,17 @@
void appendCubicApproximation(const Sk2f& p0, const Sk2f& p1, const Sk2f& p2, const Sk2f& p3,
int maxSubdivisions = kMaxSubdivionsPerCubicSection);
+ void appendMonotonicConic(const Sk2f& p0, const Sk2f& p1, const Sk2f& p2, float w);
+
// Transient state used while building a contour.
SkPoint fCurrAnchorPoint;
PrimitiveTallies fCurrContourTallies;
SkCubicType fCurrCubicType;
SkDEBUGCODE(bool fBuildingContour = false);
- // TODO: These points could eventually be written directly to block-allocated GPU buffers.
- SkSTArray<128, SkPoint, true> fPoints;
- SkSTArray<128, Verb, true> fVerbs;
+ SkSTArray<128, SkPoint, true> fPoints;
+ SkSTArray<32, float, true> fConicWeights;
+ SkSTArray<128, Verb, true> fVerbs;
};
inline void GrCCGeometry::PrimitiveTallies::operator+=(const PrimitiveTallies& b) {
@@ -132,6 +139,7 @@
fWeightedTriangles += b.fWeightedTriangles;
fQuadratics += b.fQuadratics;
fCubics += b.fCubics;
+ fConics += b.fConics;
}
GrCCGeometry::PrimitiveTallies
@@ -139,12 +147,13 @@
return {fTriangles - b.fTriangles,
fWeightedTriangles - b.fWeightedTriangles,
fQuadratics - b.fQuadratics,
- fCubics - b.fCubics};
+ fCubics - b.fCubics,
+ fConics - b.fConics};
}
inline bool GrCCGeometry::PrimitiveTallies::operator==(const PrimitiveTallies& b) {
return fTriangles == b.fTriangles && fWeightedTriangles == b.fWeightedTriangles &&
- fQuadratics == b.fQuadratics && fCubics == b.fCubics;
+ fQuadratics == b.fQuadratics && fCubics == b.fCubics && fConics == b.fConics;
}
#endif
diff --git a/src/gpu/ccpr/GrCCPathParser.cpp b/src/gpu/ccpr/GrCCPathParser.cpp
index f77c52e..2740569 100644
--- a/src/gpu/ccpr/GrCCPathParser.cpp
+++ b/src/gpu/ccpr/GrCCPathParser.cpp
@@ -114,7 +114,9 @@
return;
}
+ const float* conicWeights = SkPathPriv::ConicWeightData(path);
int ptsIdx = 0;
+ int conicWeightsIdx = 0;
bool insideContour = false;
for (SkPath::Verb verb : SkPathPriv::Verbs(path)) {
@@ -142,11 +144,16 @@
ptsIdx += 3;
continue;
case SkPath::kConic_Verb:
- SK_ABORT("Conics are not supported.");
+ fGeometry.conicTo(&deviceSpacePts[ptsIdx - 1], conicWeights[conicWeightsIdx]);
+ ptsIdx += 2;
+ ++conicWeightsIdx;
+ continue;
default:
SK_ABORT("Unexpected path verb.");
}
}
+ SkASSERT(ptsIdx == path.countPoints());
+ SkASSERT(conicWeightsIdx == SkPathPriv::ConicWeightCnt(path));
this->endContourIfNeeded(insideContour);
}
@@ -196,6 +203,7 @@
continue;
case GrCCGeometry::Verb::kMonotonicQuadraticTo:
+ case GrCCGeometry::Verb::kMonotonicConicTo:
fan.lineTo(pts[ptsIdx + 1]);
ptsIdx += 2;
continue;
@@ -377,7 +385,9 @@
fBaseInstances[0].fCubics = fBaseInstances[1].fWeightedTriangles +
fTotalPrimitiveCounts[1].fWeightedTriangles;
fBaseInstances[1].fCubics = fBaseInstances[0].fCubics + fTotalPrimitiveCounts[0].fCubics;
- int quadEndIdx = fBaseInstances[1].fCubics + fTotalPrimitiveCounts[1].fCubics;
+ fBaseInstances[0].fConics = fBaseInstances[1].fCubics + fTotalPrimitiveCounts[1].fCubics;
+ fBaseInstances[1].fConics = fBaseInstances[0].fConics + fTotalPrimitiveCounts[0].fConics;
+ int quadEndIdx = fBaseInstances[1].fConics + fTotalPrimitiveCounts[1].fConics;
fInstanceBuffer = onFlushRP->makeBuffer(kVertex_GrBufferType,
quadEndIdx * sizeof(QuadPointInstance));
@@ -400,6 +410,7 @@
const SkTArray<SkPoint, true>& pts = fGeometry.points();
int ptsIdx = -1;
+ int nextConicWeightIdx = 0;
// Expand the ccpr verbs into GPU instance buffers.
for (GrCCGeometry::Verb verb : fGeometry.verbs()) {
@@ -454,6 +465,17 @@
}
continue;
+ case GrCCGeometry::Verb::kMonotonicConicTo:
+ quadPointInstanceData[currIndices->fConics++].setW(
+ &pts[ptsIdx], atlasOffset, fGeometry.getConicWeight(nextConicWeightIdx));
+ ptsIdx += 2;
+ ++nextConicWeightIdx;
+ if (!currFanIsTessellated) {
+ SkASSERT(!currFan.empty());
+ currFan.push_back(ptsIdx);
+ }
+ continue;
+
case GrCCGeometry::Verb::kEndClosedContour: // endPt == startPt.
if (!currFanIsTessellated) {
SkASSERT(!currFan.empty());
@@ -489,7 +511,9 @@
SkASSERT(instanceIndices[0].fWeightedTriangles == fBaseInstances[1].fWeightedTriangles);
SkASSERT(instanceIndices[1].fWeightedTriangles == fBaseInstances[0].fCubics);
SkASSERT(instanceIndices[0].fCubics == fBaseInstances[1].fCubics);
- SkASSERT(instanceIndices[1].fCubics == quadEndIdx);
+ SkASSERT(instanceIndices[1].fCubics == fBaseInstances[0].fConics);
+ SkASSERT(instanceIndices[0].fConics == fBaseInstances[1].fConics);
+ SkASSERT(instanceIndices[1].fConics == quadEndIdx);
fMeshesScratchBuffer.reserve(fMaxMeshesPerDraw);
fDynamicStatesScratchBuffer.reserve(fMaxMeshesPerDraw);
@@ -527,6 +551,11 @@
this->drawPrimitives(flushState, pipeline, batchID, PrimitiveType::kCubics,
&PrimitiveTallies::fCubics, drawBounds);
}
+
+ if (batchTotalCounts.fConics) {
+ this->drawPrimitives(flushState, pipeline, batchID, PrimitiveType::kConics,
+ &PrimitiveTallies::fConics, drawBounds);
+ }
}
void GrCCPathParser::drawPrimitives(GrOpFlushState* flushState, const GrPipeline& pipeline,
diff --git a/src/gpu/ccpr/GrCoverageCountingPathRenderer.cpp b/src/gpu/ccpr/GrCoverageCountingPathRenderer.cpp
index 90d89de..b6f5770 100644
--- a/src/gpu/ccpr/GrCoverageCountingPathRenderer.cpp
+++ b/src/gpu/ccpr/GrCoverageCountingPathRenderer.cpp
@@ -65,10 +65,6 @@
SkPath path;
args.fShape->asPath(&path);
- if (SkPathPriv::ConicWeightCnt(path)) {
- return CanDrawPath::kNo;
- }
-
SkRect devBounds;
SkIRect devIBounds;
args.fViewMatrix->mapRect(&devBounds, path.getBounds());
@@ -193,11 +189,6 @@
if (!fDrawCachablePaths && !deviceSpacePath.isVolatile()) {
return false;
}
-
- if (SkPathPriv::ConicWeightCnt(deviceSpacePath)) {
- return false;
- }
-
return true;
}