Add a dedicated Op for analytic round rects
Adds a GrAAFillRRectOp class that can draw any round rect, including
complex. The Op makes use of instanced rendering and fwidth().
Bug: chromium:860021
Change-Id: I3d8818a003899b56c33d35babe22cd15d3f8e110
Reviewed-on: https://skia-review.googlesource.com/c/170729
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/ops/GrAAFillRRectOp.cpp b/src/gpu/ops/GrAAFillRRectOp.cpp
new file mode 100644
index 0000000..3c98570
--- /dev/null
+++ b/src/gpu/ops/GrAAFillRRectOp.cpp
@@ -0,0 +1,544 @@
+/*
+ * 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 "GrAAFillRRectOp.h"
+
+#include "GrCaps.h"
+#include "GrContextPriv.h"
+#include "GrGpuCommandBuffer.h"
+#include "GrMemoryPool.h"
+#include "SkRRectPriv.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "glsl/GrGLSLGeometryProcessor.h"
+#include "glsl/GrGLSLVarying.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
+
+// Hardware derivatives are not always accurate enough for highly elliptical corners. This method
+// checks to make sure the corners will still all look good if we use HW derivatives.
+static bool can_use_hw_derivatives(const GrShaderCaps&, const SkMatrix&, const SkRRect&);
+
+std::unique_ptr<GrAAFillRRectOp> GrAAFillRRectOp::Make(
+ GrContext* ctx, const SkMatrix& viewMatrix, const SkRRect& rrect, const GrCaps& caps,
+ GrPaint&& paint) {
+ if (!caps.instanceAttribSupport()) {
+ return nullptr;
+ }
+
+ // TODO: Support perspective in a follow-on CL. This shouldn't be difficult, since we already
+ // use HW derivatives. The only trick will be adjusting the AA outset to account for
+ // perspective. (i.e., outset = 0.5 * z.)
+ if (viewMatrix.hasPerspective()) {
+ return nullptr;
+ }
+
+ GrOpMemoryPool* pool = ctx->contextPriv().opMemoryPool();
+ return pool->allocate<GrAAFillRRectOp>(*caps.shaderCaps(), viewMatrix, rrect, std::move(paint));
+}
+
+GrAAFillRRectOp::GrAAFillRRectOp(const GrShaderCaps& shaderCaps, const SkMatrix& viewMatrix,
+ const SkRRect& rrect, GrPaint&& paint)
+ : GrDrawOp(ClassID())
+ , fOriginalColor(paint.getColor4f())
+ , fLocalRect(rrect.rect())
+ , fProcessors(std::move(paint)) {
+ if (can_use_hw_derivatives(shaderCaps, viewMatrix, rrect)) {
+ fFlags |= Flags::kUseHWDerivatives;
+ }
+
+ // Produce a matrix that draws the round rect from normalized [-1, -1, +1, +1] space.
+ float l = rrect.rect().left(), r = rrect.rect().right(),
+ t = rrect.rect().top(), b = rrect.rect().bottom();
+ SkMatrix m;
+ // Unmap the normalized rect [-1, -1, +1, +1] back to [l, t, r, b].
+ m.setScaleTranslate((r - l)/2, (b - t)/2, (l + r)/2, (t + b)/2);
+ // Map to device space.
+ m.postConcat(viewMatrix);
+
+ // Since m is an affine matrix that maps the rect [-1, -1, +1, +1] into the shape's
+ // device-space quad, it's quite simple to find the bounding rectangle:
+ SkASSERT(!m.hasPerspective());
+ SkRect bounds = SkRect::MakeXYWH(m.getTranslateX(), m.getTranslateY(), 0, 0);
+ bounds.outset(SkScalarAbs(m.getScaleX()) + SkScalarAbs(m.getSkewX()),
+ SkScalarAbs(m.getSkewY()) + SkScalarAbs(m.getScaleY()));
+ this->setBounds(bounds, GrOp::HasAABloat::kYes, GrOp::IsZeroArea::kNo);
+
+ // Write the matrix attribs.
+ this->writeInstanceData(m.getScaleX(), m.getSkewX(), m.getSkewY(), m.getScaleY());
+ this->writeInstanceData(m.getTranslateX(), m.getTranslateY());
+
+ // Convert the radii to [-1, -1, +1, +1] space and write their attribs.
+ Sk4f radiiX, radiiY;
+ Sk4f::Load2(SkRRectPriv::GetRadiiArray(rrect), &radiiX, &radiiY);
+ (radiiX * (2/(r - l))).store(this->appendInstanceData<float>(4));
+ (radiiY * (2/(b - t))).store(this->appendInstanceData<float>(4));
+
+ // We will write the color and local rect attribs during finalize().
+}
+
+GrDrawOp::RequiresDstTexture GrAAFillRRectOp::finalize(const GrCaps& caps,
+ const GrAppliedClip* clip) {
+ SkASSERT(1 == fInstanceCount);
+
+ SkPMColor4f overrideColor;
+ const GrProcessorSet::Analysis& analysis = fProcessors.finalize(
+ fOriginalColor, GrProcessorAnalysisCoverage::kSingleChannel, clip, false, caps,
+ &overrideColor);
+
+ // Finish writing the instance attribs.
+ this->writeInstanceData(
+ (analysis.inputColorIsOverridden() ? overrideColor : fOriginalColor).toBytes_RGBA());
+ if (analysis.usesLocalCoords()) {
+ this->writeInstanceData(fLocalRect);
+ fFlags |= Flags::kHasLocalCoords;
+ }
+ fInstanceStride = fInstanceData.count();
+
+ return RequiresDstTexture(analysis.requiresDstTexture());
+}
+
+GrDrawOp::CombineResult GrAAFillRRectOp::onCombineIfPossible(GrOp* op, const GrCaps&) {
+ const auto& that = *op->cast<GrAAFillRRectOp>();
+ if (fFlags != that.fFlags || fProcessors != that.fProcessors ||
+ fInstanceData.count() > std::numeric_limits<int>::max() - that.fInstanceData.count()) {
+ return CombineResult::kCannotCombine;
+ }
+
+ fInstanceData.push_back_n(that.fInstanceData.count(), that.fInstanceData.begin());
+ fInstanceCount += that.fInstanceCount;
+ SkASSERT(fInstanceStride == that.fInstanceStride);
+ return CombineResult::kMerged;
+}
+
+void GrAAFillRRectOp::onPrepare(GrOpFlushState* flushState) {
+ if (void* instanceData = flushState->makeVertexSpace(fInstanceStride, fInstanceCount,
+ &fInstanceBuffer, &fBaseInstance)) {
+ SkASSERT(fInstanceStride * fInstanceCount == fInstanceData.count());
+ memcpy(instanceData, fInstanceData.begin(), fInstanceData.count());
+ }
+}
+
+namespace {
+
+// Our round rect geometry consists of an inset octagon with solid coverage, surrounded by linear
+// coverage ramps on the horizontal and vertical edges, and "arc coverage" pieces on the diagonal
+// edges. The Vertex struct tells the shader where to place its vertex within a normalized
+// ([l, t, r, b] = [-1, -1, +1, +1]) space, and how to calculate coverage. See onEmitCode.
+struct Vertex {
+ std::array<float, 4> fRadiiSelector;
+ std::array<float, 2> fCorner;
+ std::array<float, 2> fRadiusOutset;
+ std::array<float, 2> fAABloatDirection;
+ float fCoverage;
+ float fIsLinearCoverage;
+ std::array<float, 4> fArcCoordMatrix;
+};
+
+// This is the offset (when multiplied by radii) from the corners of a bounding box to the vertices
+// of its inscribed octagon. We draw the outside portion of arcs with quarter-octagons rather than
+// rectangles.
+static constexpr float kOctoOffset = 1/(1 + SK_ScalarRoot2Over2);
+
+// This matrix is used to calculate normalized arc coordinates.
+// (i.e., arccoord.x^2 + arccoord.y^2 == 1). The formula to find the arc coord is:
+//
+// arccoord = arc_coord_matrix.xz * aa_bloatradius/radii + arc_coord_matrix.yw;
+//
+// See kVertexData and onEmitCode.
+static constexpr std::array<float, 4> kArcMatrices[] = {
+ {{+1, 1, 0, 0}},
+ {{-1, 1, 0, 0}},
+ {{ 0, 0, -1, 1}},
+ {{ 0, 0, +1, 1}},
+ {{+1, 1-kOctoOffset, +1, 1}},
+ {{+1, 1, +1, 1-kOctoOffset}}};
+
+static constexpr Vertex kVertexData[] = {
+ // Left inset edge.
+ {{{0,0,0,1}}, {{-1,+1}}, {{0,-1}}, {{+1,0}}, 1, 1, {{0,0,0,0}}},
+ {{{1,0,0,0}}, {{-1,-1}}, {{0,+1}}, {{+1,0}}, 1, 1, {{0,0,0,0}}},
+
+ // Top inset edge.
+ {{{1,0,0,0}}, {{-1,-1}}, {{+1,0}}, {{0,+1}}, 1, 1, {{0,0,0,0}}},
+ {{{0,1,0,0}}, {{+1,-1}}, {{-1,0}}, {{0,+1}}, 1, 1, {{0,0,0,0}}},
+
+ // Right inset edge.
+ {{{0,1,0,0}}, {{+1,-1}}, {{0,+1}}, {{-1,0}}, 1, 1, {{0,0,0,0}}},
+ {{{0,0,1,0}}, {{+1,+1}}, {{0,-1}}, {{-1,0}}, 1, 1, {{0,0,0,0}}},
+
+ // Bottom inset edge.
+ {{{0,0,1,0}}, {{+1,+1}}, {{-1,0}}, {{0,-1}}, 1, 1, {{0,0,0,0}}},
+ {{{0,0,0,1}}, {{-1,+1}}, {{+1,0}}, {{0,-1}}, 1, 1, {{0,0,0,0}}},
+
+
+ // Left outset edge.
+ {{{0,0,0,1}}, {{-1,+1}}, {{0,-1}}, {{-1,0}}, 0, 1, {{0,0,0,0}}},
+ {{{1,0,0,0}}, {{-1,-1}}, {{0,+1}}, {{-1,0}}, 0, 1, {{0,0,0,0}}},
+
+ // Top outset edge.
+ {{{1,0,0,0}}, {{-1,-1}}, {{+1,0}}, {{0,-1}}, 0, 1, {{0,0,0,0}}},
+ {{{0,1,0,0}}, {{+1,-1}}, {{-1,0}}, {{0,-1}}, 0, 1, {{0,0,0,0}}},
+
+ // Right outset edge.
+ {{{0,1,0,0}}, {{+1,-1}}, {{0,+1}}, {{+1,0}}, 0, 1, {{0,0,0,0}}},
+ {{{0,0,1,0}}, {{+1,+1}}, {{0,-1}}, {{+1,0}}, 0, 1, {{0,0,0,0}}},
+
+ // Bottom outset edge.
+ {{{0,0,1,0}}, {{+1,+1}}, {{-1,0}}, {{0,+1}}, 0, 1, {{0,0,0,0}}},
+ {{{0,0,0,1}}, {{-1,+1}}, {{+1,0}}, {{0,+1}}, 0, 1, {{0,0,0,0}}},
+
+
+ // Top-left corner.
+ {{{1,0,0,0}}, {{-1,-1}}, {{ 0,+1}}, {{-1, 0}}, 0, 0, kArcMatrices[0]},
+ {{{1,0,0,0}}, {{-1,-1}}, {{ 0,+1}}, {{+1, 0}}, 1, 0, kArcMatrices[1]},
+ {{{1,0,0,0}}, {{-1,-1}}, {{+1, 0}}, {{ 0,+1}}, 1, 0, kArcMatrices[2]},
+ {{{1,0,0,0}}, {{-1,-1}}, {{+1, 0}}, {{ 0,-1}}, 0, 0, kArcMatrices[3]},
+ {{{1,0,0,0}}, {{-1,-1}}, {{+kOctoOffset,0}}, {{-1,-1}}, 0, 0, kArcMatrices[4]},
+ {{{1,0,0,0}}, {{-1,-1}}, {{0,+kOctoOffset}}, {{-1,-1}}, 0, 0, kArcMatrices[5]},
+
+ // Top-right corner.
+ {{{0,1,0,0}}, {{+1,-1}}, {{-1, 0}}, {{ 0,-1}}, 0, 0, kArcMatrices[3]},
+ {{{0,1,0,0}}, {{+1,-1}}, {{-1, 0}}, {{ 0,+1}}, 1, 0, kArcMatrices[2]},
+ {{{0,1,0,0}}, {{+1,-1}}, {{ 0,+1}}, {{-1, 0}}, 1, 0, kArcMatrices[1]},
+ {{{0,1,0,0}}, {{+1,-1}}, {{ 0,+1}}, {{+1, 0}}, 0, 0, kArcMatrices[0]},
+ {{{0,1,0,0}}, {{+1,-1}}, {{0,+kOctoOffset}}, {{+1,-1}}, 0, 0, kArcMatrices[5]},
+ {{{0,1,0,0}}, {{+1,-1}}, {{-kOctoOffset,0}}, {{+1,-1}}, 0, 0, kArcMatrices[4]},
+
+ // Bottom-right corner.
+ {{{0,0,1,0}}, {{+1,+1}}, {{ 0,-1}}, {{+1, 0}}, 0, 0, kArcMatrices[0]},
+ {{{0,0,1,0}}, {{+1,+1}}, {{ 0,-1}}, {{-1, 0}}, 1, 0, kArcMatrices[1]},
+ {{{0,0,1,0}}, {{+1,+1}}, {{-1, 0}}, {{ 0,-1}}, 1, 0, kArcMatrices[2]},
+ {{{0,0,1,0}}, {{+1,+1}}, {{-1, 0}}, {{ 0,+1}}, 0, 0, kArcMatrices[3]},
+ {{{0,0,1,0}}, {{+1,+1}}, {{-kOctoOffset,0}}, {{+1,+1}}, 0, 0, kArcMatrices[4]},
+ {{{0,0,1,0}}, {{+1,+1}}, {{0,-kOctoOffset}}, {{+1,+1}}, 0, 0, kArcMatrices[5]},
+
+ // Bottom-left corner.
+ {{{0,0,0,1}}, {{-1,+1}}, {{+1, 0}}, {{ 0,+1}}, 0, 0, kArcMatrices[3]},
+ {{{0,0,0,1}}, {{-1,+1}}, {{+1, 0}}, {{ 0,-1}}, 1, 0, kArcMatrices[2]},
+ {{{0,0,0,1}}, {{-1,+1}}, {{ 0,-1}}, {{+1, 0}}, 1, 0, kArcMatrices[1]},
+ {{{0,0,0,1}}, {{-1,+1}}, {{ 0,-1}}, {{-1, 0}}, 0, 0, kArcMatrices[0]},
+ {{{0,0,0,1}}, {{-1,+1}}, {{0,-kOctoOffset}}, {{-1, 0}}, 0, 0, kArcMatrices[5]},
+ {{{0,0,0,1}}, {{-1,+1}}, {{+kOctoOffset,0}}, {{-1,+1}}, 0, 0, kArcMatrices[4]}};
+
+GR_DECLARE_STATIC_UNIQUE_KEY(gVertexBufferKey);
+
+static constexpr uint16_t kIndexData[] = {
+ // Inset octagon (solid coverage).
+ 0, 1, 7,
+ 1, 2, 7,
+ 7, 2, 6,
+ 2, 3, 6,
+ 6, 3, 5,
+ 3, 4, 5,
+
+ // AA borders (linear coverage).
+ 0, 1, 8, 1, 9, 8,
+ 2, 3, 10, 3, 11, 10,
+ 4, 5, 12, 5, 13, 12,
+ 6, 7, 14, 7, 15, 14,
+
+ // Top-left arc.
+ 16, 17, 21,
+ 17, 21, 18,
+ 21, 18, 20,
+ 18, 20, 19,
+
+ // Top-right arc.
+ 22, 23, 27,
+ 23, 27, 24,
+ 27, 24, 26,
+ 24, 26, 25,
+
+ // Bottom-right arc.
+ 28, 29, 33,
+ 29, 33, 30,
+ 33, 30, 32,
+ 30, 32, 31,
+
+ // Bottom-left arc.
+ 34, 35, 39,
+ 35, 39, 36,
+ 39, 36, 38,
+ 36, 38, 37};
+
+GR_DECLARE_STATIC_UNIQUE_KEY(gIndexBufferKey);
+
+}
+
+class GrAAFillRRectOp::Processor : public GrGeometryProcessor {
+public:
+ Processor(Flags flags)
+ : GrGeometryProcessor(kGrAAFillRRectOp_Processor_ClassID)
+ , fFlags(flags) {
+ this->setVertexAttributes(kVertexAttribs, 4);
+ this->setInstanceAttributes(kInstanceAttribs, (flags & Flags::kHasLocalCoords) ? 6 : 5);
+ SkASSERT(this->vertexStride() == sizeof(Vertex));
+ }
+
+ const char* name() const override { return "GrAAFillRRectOp::Processor"; }
+
+ void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override {
+ b->add32(static_cast<uint32_t>(fFlags));
+ }
+
+ GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override;
+
+private:
+ static constexpr Attribute kVertexAttribs[] = {
+ {"radii_selector", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"corner_and_radius_outsets", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"aa_bloat_and_coverage", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"arc_coord_matrix", kFloat4_GrVertexAttribType, kFloat4_GrSLType}};
+
+ static constexpr Attribute kInstanceAttribs[] = {
+ {"skew", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"translate", kFloat2_GrVertexAttribType, kFloat2_GrSLType},
+ {"radii_x", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"radii_y", kFloat4_GrVertexAttribType, kFloat4_GrSLType},
+ {"color", kUByte4_norm_GrVertexAttribType, kHalf4_GrSLType},
+ {"local_rect", kFloat4_GrVertexAttribType, kFloat4_GrSLType}}; // Conditional.
+
+ static constexpr int kColorAttribIdx = 4;
+
+ const Flags fFlags;
+
+ class Impl;
+};
+
+constexpr GrPrimitiveProcessor::Attribute GrAAFillRRectOp::Processor::kVertexAttribs[];
+constexpr GrPrimitiveProcessor::Attribute GrAAFillRRectOp::Processor::kInstanceAttribs[];
+
+class GrAAFillRRectOp::Processor::Impl : public GrGLSLGeometryProcessor {
+public:
+ void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override {
+ const auto& proc = args.fGP.cast<Processor>();
+ bool useHWDerivatives = (proc.fFlags & Flags::kUseHWDerivatives);
+
+ GrGLSLVaryingHandler* varyings = args.fVaryingHandler;
+ varyings->emitAttributes(proc);
+ varyings->addPassThroughAttribute(proc.kInstanceAttribs[kColorAttribIdx], args.fOutputColor,
+ GrGLSLVaryingHandler::Interpolation::kCanBeFlat);
+
+ // Emit the vertex shader.
+ GrGLSLVertexBuilder* v = args.fVertBuilder;
+
+ // Unpack vertex attribs.
+ v->codeAppend("float2 corner = corner_and_radius_outsets.xy;");
+ v->codeAppend("float2 radius_outset = corner_and_radius_outsets.zw;");
+ v->codeAppend("float2 aa_bloat_direction = aa_bloat_and_coverage.xy;");
+ v->codeAppend("float coverage = aa_bloat_and_coverage.z;");
+ v->codeAppend("float is_linear_coverage = aa_bloat_and_coverage.w;");
+
+ // Find the amount to bloat each edge for AA (in source space).
+ v->codeAppend("float2 pixellength = inversesqrt("
+ "float2(dot(skew.xz, skew.xz), dot(skew.yw, skew.yw)));");
+ v->codeAppend("float4 normalized_axis_dirs = skew * pixellength.xyxy;");
+ v->codeAppend("float2 axiswidths = (abs(normalized_axis_dirs.xy) + "
+ "abs(normalized_axis_dirs.zw));");
+ v->codeAppend("float2 aa_bloatradius = axiswidths * pixellength * .5;");
+
+ // Identify our radii.
+ v->codeAppend("float2 radii = float2(dot(radii_selector, radii_x), "
+ "dot(radii_selector, radii_y));");
+
+ v->codeAppend("if (any(greaterThan(aa_bloatradius, float2(1)))) {");
+ // The rrect is more narrow than an AA coverage ramp. We can't draw as-is
+ // or else opposite AA borders will overlap. Instead, fudge the size up to
+ // the width of a coverage ramp, and then reduce total coverage to make
+ // the rect appear more thin.
+ v->codeAppend( "corner = max(abs(corner), aa_bloatradius) * sign(corner);");
+ v->codeAppend( "coverage /= max(aa_bloatradius.x, 1) * max(aa_bloatradius.y, 1);");
+ // Set radii to zero to ensure we take the "linear coverage" codepath.
+ // (The "coverage" variable only has effect in the linear codepath.)
+ v->codeAppend( "radii = float2(0);");
+ v->codeAppend("}");
+
+ v->codeAppend("if (any(lessThan(radii, aa_bloatradius * 1.25))) {");
+ // The radii are very small. Demote this arc to a sharp 90 degree corner.
+ v->codeAppend( "radii = aa_bloatradius;");
+ // Snap octagon vertices to the corner of the bounding box.
+ v->codeAppend( "radius_outset = floor(abs(radius_outset)) * radius_outset;");
+ v->codeAppend( "is_linear_coverage = 1;");
+ v->codeAppend("} else {");
+ // Don't let actual arc radii get smaller than a pixel.
+ v->codeAppend( "radii = clamp(radii, pixellength, 2 - pixellength);");
+ v->codeAppend("}");
+ // Bias radii slightly inward to avoid accidental overlap of geometries from fp rounding.
+ v->codeAppend("radii -= aa_bloatradius * 1e-3;");
+
+ // Find our vertex position, adjusted for radii and bloated for AA. Our rect is drawn in
+ // normalized [-1,-1,+1,+1] space.
+ v->codeAppend("float2 vertexpos = corner"
+ "+ radius_outset * radii"
+ "+ aa_bloat_direction.xy * aa_bloatradius;");
+
+ // Emit transforms.
+ GrShaderVar localCoord("", kFloat2_GrSLType);
+ if (proc.fFlags & Flags::kHasLocalCoords) {
+ v->codeAppend("float2 localcoord = (local_rect.xy * (1 - vertexpos) + "
+ "local_rect.zw * (1 + vertexpos)) * .5;");
+ localCoord.set(kFloat2_GrSLType, "localcoord");
+ }
+ this->emitTransforms(v, varyings, args.fUniformHandler, localCoord,
+ args.fFPCoordTransformHandler);
+
+ // Transform to device space.
+ v->codeAppend("float2x2 skewmatrix = float2x2(skew.xy, skew.zw);");
+ v->codeAppend("float2 devcoord = vertexpos * skewmatrix + translate;");
+ gpArgs->fPositionVar.set(kFloat2_GrSLType, "devcoord");
+
+ // Setup interpolants for coverage.
+ GrGLSLVarying arcCoord(useHWDerivatives ? kFloat2_GrSLType : kFloat4_GrSLType);
+ varyings->addVarying("arccoord", &arcCoord);
+ v->codeAppend("if (0 != is_linear_coverage) {");
+ // We are a non-corner piece: Set x=0 to indicate built-in coverage, and
+ // interpolate linear coverage across y.
+ v->codeAppendf( "%s.xy = float2(0, coverage);", arcCoord.vsOut());
+ v->codeAppend("} else {");
+ v->codeAppend( "float2 arccoord = "
+ "arc_coord_matrix.xz * aa_bloatradius/radii + arc_coord_matrix.yw;");
+ // We are a corner piece: Interpolate the arc coordinates for coverage.
+ // Emit x+1 to ensure no pixel in the arc has a x value of 0 (since x=0
+ // instructs the fragment shader to use linear coverage).
+ v->codeAppendf( "%s.xy = float2(arccoord.x+1, arccoord.y);", arcCoord.vsOut());
+ if (!useHWDerivatives) {
+ // The gradient is order-1: Interpolate it across arccoord.zw.
+ v->codeAppendf("float2x2 derivatives = inverse(skewmatrix);");
+ v->codeAppendf("%s.zw = derivatives * (arccoord/radii * 2);", arcCoord.vsOut());
+ }
+ v->codeAppend("}");
+
+ // Emit the fragment shader.
+ GrGLSLFPFragmentBuilder* f = args.fFragBuilder;
+
+ f->codeAppendf("float x_plus_1=%s.x, y=%s.y;", arcCoord.fsIn(), arcCoord.fsIn());
+ f->codeAppendf("half coverage;");
+ f->codeAppendf("if (0 == x_plus_1) {");
+ f->codeAppendf( "coverage = y;"); // We are a non-arc pixel (i.e., linear coverage).
+ f->codeAppendf("} else {");
+ f->codeAppendf( "float fn = x_plus_1 * (x_plus_1 - 2);"); // fn = (x+1)*(x-1) = x^2-1
+ f->codeAppendf( "fn = fma(y,y, fn);"); // fn = x^2 + y^2 - 1
+ if (useHWDerivatives) {
+ f->codeAppendf("float fnwidth = fwidth(fn);");
+ } else {
+ // The gradient is interpolated across arccoord.zw.
+ f->codeAppendf("float gx=%s.z, gy=%s.w;", arcCoord.fsIn(), arcCoord.fsIn());
+ f->codeAppendf("float fnwidth = abs(gx) + abs(gy);");
+ }
+ f->codeAppendf( "half d = fn/fnwidth;");
+ f->codeAppendf( "coverage = clamp(.5 - d, 0, 1);");
+ f->codeAppendf("}");
+ f->codeAppendf("%s = half4(coverage);", args.fOutputCoverage);
+ }
+
+ void setData(const GrGLSLProgramDataManager& pdman, const GrPrimitiveProcessor&,
+ FPCoordTransformIter&& transformIter) override {
+ this->setTransformDataHelper(SkMatrix::I(), pdman, &transformIter);
+ }
+};
+
+GrGLSLPrimitiveProcessor* GrAAFillRRectOp::Processor::createGLSLInstance(
+ const GrShaderCaps&) const {
+ return new Impl();
+}
+
+void GrAAFillRRectOp::onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) {
+ if (!fInstanceBuffer) {
+ return; // Setup failed.
+ }
+
+ GR_DEFINE_STATIC_UNIQUE_KEY(gIndexBufferKey);
+
+ sk_sp<const GrBuffer> indexBuffer =
+ flushState->resourceProvider()->findOrMakeStaticBuffer(
+ kIndex_GrBufferType, sizeof(kIndexData), kIndexData, gIndexBufferKey);
+ if (!indexBuffer) {
+ return;
+ }
+
+ GR_DEFINE_STATIC_UNIQUE_KEY(gVertexBufferKey);
+
+ sk_sp<const GrBuffer> vertexBuffer =
+ flushState->resourceProvider()->findOrMakeStaticBuffer(
+ kVertex_GrBufferType, sizeof(kVertexData), kVertexData, gVertexBufferKey);
+ if (!vertexBuffer) {
+ return;
+ }
+
+ Processor proc(fFlags);
+ SkASSERT(proc.instanceStride() == (size_t)fInstanceStride);
+
+ GrPipeline::InitArgs initArgs;
+ initArgs.fProxy = flushState->drawOpArgs().fProxy;
+ initArgs.fCaps = &flushState->caps();
+ initArgs.fResourceProvider = flushState->resourceProvider();
+ initArgs.fDstProxy = flushState->drawOpArgs().fDstProxy;
+ GrPipeline pipeline(initArgs, std::move(fProcessors), flushState->detachAppliedClip());
+
+ GrMesh mesh(GrPrimitiveType::kTriangles);
+ mesh.setIndexedInstanced(indexBuffer.get(), SK_ARRAY_COUNT(kIndexData), fInstanceBuffer,
+ fInstanceCount, fBaseInstance, GrPrimitiveRestart::kNo);
+ mesh.setVertexData(vertexBuffer.get());
+ flushState->rtCommandBuffer()->draw(proc, pipeline, nullptr, nullptr, &mesh, 1, this->bounds());
+}
+
+// Will the given corner look good if we use HW derivatives?
+static bool can_use_hw_derivatives(const Sk2f& devScale, const Sk2f& cornerRadii) {
+ Sk2f devRadii = devScale * cornerRadii;
+ if (devRadii[1] < devRadii[0]) {
+ devRadii = SkNx_shuffle<1,0>(devRadii);
+ }
+ float minDevRadius = SkTMax(devRadii[0], 1.f); // Shader clamps radius at a minimum of 1.
+ // Is the gradient smooth enough for this corner look ok if we use hardware derivatives?
+ // This threshold was arrived at subjevtively on an NVIDIA chip.
+ return minDevRadius * minDevRadius * 5 > devRadii[1];
+}
+
+static bool can_use_hw_derivatives(const Sk2f& devScale, const SkVector& cornerRadii) {
+ return can_use_hw_derivatives(devScale, Sk2f::Load(&cornerRadii));
+}
+
+// Will the given round rect look good if we use HW derivatives?
+static bool can_use_hw_derivatives(const GrShaderCaps& shaderCaps, const SkMatrix& viewMatrix,
+ const SkRRect& rrect) {
+ if (!shaderCaps.shaderDerivativeSupport()) {
+ return false;
+ }
+
+ Sk2f x = Sk2f(viewMatrix.getScaleX(), viewMatrix.getSkewX());
+ Sk2f y = Sk2f(viewMatrix.getSkewY(), viewMatrix.getScaleY());
+ Sk2f devScale = (x*x + y*y).sqrt();
+ switch (rrect.getType()) {
+ case SkRRect::kEmpty_Type:
+ case SkRRect::kRect_Type:
+ return true;
+
+ case SkRRect::kOval_Type:
+ case SkRRect::kSimple_Type:
+ return can_use_hw_derivatives(devScale, rrect.getSimpleRadii());
+
+ case SkRRect::kNinePatch_Type: {
+ Sk2f r0 = Sk2f::Load(SkRRectPriv::GetRadiiArray(rrect));
+ Sk2f r1 = Sk2f::Load(SkRRectPriv::GetRadiiArray(rrect) + 2);
+ Sk2f minRadii = Sk2f::Min(r0, r1);
+ Sk2f maxRadii = Sk2f::Max(r0, r1);
+ return can_use_hw_derivatives(devScale, Sk2f(minRadii[0], maxRadii[1])) &&
+ can_use_hw_derivatives(devScale, Sk2f(maxRadii[0], minRadii[1]));
+ }
+
+ case SkRRect::kComplex_Type: {
+ for (int i = 0; i < 4; ++i) {
+ auto corner = static_cast<SkRRect::Corner>(i);
+ if (!can_use_hw_derivatives(devScale, rrect.radii(corner))) {
+ return false;
+ }
+ }
+ return true;
+ }
+ }
+ SK_ABORT("Unreachable code.");
+ return false; // Add this return to keep GCC happy.
+}