/*
* 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().
}
GrProcessorSet::Analysis 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 analysis;
}
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;
};
// 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);
static constexpr Vertex kVertexData[] = {
// Left inset edge.
{{{0,0,0,1}}, {{-1,+1}}, {{0,-1}}, {{+1,0}}, 1, 1},
{{{1,0,0,0}}, {{-1,-1}}, {{0,+1}}, {{+1,0}}, 1, 1},
// Top inset edge.
{{{1,0,0,0}}, {{-1,-1}}, {{+1,0}}, {{0,+1}}, 1, 1},
{{{0,1,0,0}}, {{+1,-1}}, {{-1,0}}, {{0,+1}}, 1, 1},
// Right inset edge.
{{{0,1,0,0}}, {{+1,-1}}, {{0,+1}}, {{-1,0}}, 1, 1},
{{{0,0,1,0}}, {{+1,+1}}, {{0,-1}}, {{-1,0}}, 1, 1},
// Bottom inset edge.
{{{0,0,1,0}}, {{+1,+1}}, {{-1,0}}, {{0,-1}}, 1, 1},
{{{0,0,0,1}}, {{-1,+1}}, {{+1,0}}, {{0,-1}}, 1, 1},
// Left outset edge.
{{{0,0,0,1}}, {{-1,+1}}, {{0,-1}}, {{-1,0}}, 0, 1},
{{{1,0,0,0}}, {{-1,-1}}, {{0,+1}}, {{-1,0}}, 0, 1},
// Top outset edge.
{{{1,0,0,0}}, {{-1,-1}}, {{+1,0}}, {{0,-1}}, 0, 1},
{{{0,1,0,0}}, {{+1,-1}}, {{-1,0}}, {{0,-1}}, 0, 1},
// Right outset edge.
{{{0,1,0,0}}, {{+1,-1}}, {{0,+1}}, {{+1,0}}, 0, 1},
{{{0,0,1,0}}, {{+1,+1}}, {{0,-1}}, {{+1,0}}, 0, 1},
// Bottom outset edge.
{{{0,0,1,0}}, {{+1,+1}}, {{-1,0}}, {{0,+1}}, 0, 1},
{{{0,0,0,1}}, {{-1,+1}}, {{+1,0}}, {{0,+1}}, 0, 1},
// Top-left corner.
{{{1,0,0,0}}, {{-1,-1}}, {{ 0,+1}}, {{-1, 0}}, 0, 0},
{{{1,0,0,0}}, {{-1,-1}}, {{ 0,+1}}, {{+1, 0}}, 1, 0},
{{{1,0,0,0}}, {{-1,-1}}, {{+1, 0}}, {{ 0,+1}}, 1, 0},
{{{1,0,0,0}}, {{-1,-1}}, {{+1, 0}}, {{ 0,-1}}, 0, 0},
{{{1,0,0,0}}, {{-1,-1}}, {{+kOctoOffset,0}}, {{-1,-1}}, 0, 0},
{{{1,0,0,0}}, {{-1,-1}}, {{0,+kOctoOffset}}, {{-1,-1}}, 0, 0},
// Top-right corner.
{{{0,1,0,0}}, {{+1,-1}}, {{-1, 0}}, {{ 0,-1}}, 0, 0},
{{{0,1,0,0}}, {{+1,-1}}, {{-1, 0}}, {{ 0,+1}}, 1, 0},
{{{0,1,0,0}}, {{+1,-1}}, {{ 0,+1}}, {{-1, 0}}, 1, 0},
{{{0,1,0,0}}, {{+1,-1}}, {{ 0,+1}}, {{+1, 0}}, 0, 0},
{{{0,1,0,0}}, {{+1,-1}}, {{0,+kOctoOffset}}, {{+1,-1}}, 0, 0},
{{{0,1,0,0}}, {{+1,-1}}, {{-kOctoOffset,0}}, {{+1,-1}}, 0, 0},
// Bottom-right corner.
{{{0,0,1,0}}, {{+1,+1}}, {{ 0,-1}}, {{+1, 0}}, 0, 0},
{{{0,0,1,0}}, {{+1,+1}}, {{ 0,-1}}, {{-1, 0}}, 1, 0},
{{{0,0,1,0}}, {{+1,+1}}, {{-1, 0}}, {{ 0,-1}}, 1, 0},
{{{0,0,1,0}}, {{+1,+1}}, {{-1, 0}}, {{ 0,+1}}, 0, 0},
{{{0,0,1,0}}, {{+1,+1}}, {{-kOctoOffset,0}}, {{+1,+1}}, 0, 0},
{{{0,0,1,0}}, {{+1,+1}}, {{0,-kOctoOffset}}, {{+1,+1}}, 0, 0},
// Bottom-left corner.
{{{0,0,0,1}}, {{-1,+1}}, {{+1, 0}}, {{ 0,+1}}, 0, 0},
{{{0,0,0,1}}, {{-1,+1}}, {{+1, 0}}, {{ 0,-1}}, 1, 0},
{{{0,0,0,1}}, {{-1,+1}}, {{ 0,-1}}, {{+1, 0}}, 1, 0},
{{{0,0,0,1}}, {{-1,+1}}, {{ 0,-1}}, {{-1, 0}}, 0, 0},
{{{0,0,0,1}}, {{-1,+1}}, {{0,-kOctoOffset}}, {{-1,+1}}, 0, 0},
{{{0,0,0,1}}, {{-1,+1}}, {{+kOctoOffset,0}}, {{-1,+1}}, 0, 0}};
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, 3);
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}};
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("float4 radii_and_neighbors = radii_selector"
"* float4x4(radii_x, radii_y, radii_x.yxwz, radii_y.wzyx);");
v->codeAppend("float2 radii = radii_and_neighbors.xy;");
v->codeAppend("float2 neighbor_radii = radii_and_neighbors.zw;");
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 radii get smaller than a pixel.
v->codeAppend( "radii = clamp(radii, pixellength, 2 - pixellength);");
v->codeAppend( "neighbor_radii = clamp(neighbor_radii, pixellength, 2 - pixellength);");
// Don't let neighboring radii get closer together than 1/16 pixel.
v->codeAppend( "float2 spacing = 2 - radii - neighbor_radii;");
v->codeAppend( "float2 extra_pad = max(pixellength * .0625 - spacing, float2(0));");
v->codeAppend( "radii -= extra_pad * .5;");
v->codeAppend("}");
// 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 aa_outset = aa_bloat_direction.xy * aa_bloatradius;");
v->codeAppend("float2 vertexpos = corner + radius_outset * radii + aa_outset;");
// 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 {");
// Find the normalized arc coordinates for our corner ellipse.
// (i.e., the coordinate system where x^2 + y^2 == 1).
v->codeAppend( "float2 arccoord = 1 - abs(radius_outset) + aa_outset/radii * corner;");
// 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.fCaps = &flushState->caps();
initArgs.fResourceProvider = flushState->resourceProvider();
initArgs.fDstProxy = flushState->drawOpArgs().fDstProxy;
auto clip = flushState->detachAppliedClip();
GrPipeline::FixedDynamicState fixedDynamicState(clip.scissorState().rect());
GrPipeline pipeline(initArgs, std::move(fProcessors), std::move(clip));
GrMesh mesh(GrPrimitiveType::kTriangles);
mesh.setIndexedInstanced(std::move(indexBuffer), SK_ARRAY_COUNT(kIndexData), fInstanceBuffer,
fInstanceCount, fBaseInstance, GrPrimitiveRestart::kNo);
mesh.setVertexData(std::move(vertexBuffer));
flushState->rtCommandBuffer()->draw(proc, pipeline, &fixedDynamicState, 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.
}