| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| in half4x4 gradientMatrix; |
| |
| layout(tracked) in uniform half bias; |
| layout(tracked) in uniform half scale; |
| |
| @coordTransform { |
| gradientMatrix |
| } |
| |
| void main() { |
| // On some devices they incorrectly implement atan2(y,x) as atan(y/x). In actuality it is |
| // atan2(y,x) = 2 * atan(y / (sqrt(x^2 + y^2) + x)). So to work around this we pass in (sqrt(x^2 |
| // + y^2) + x) as the second parameter to atan2 in these cases. We let the device handle the |
| // undefined behavior of the second paramenter being 0 instead of doing the divide ourselves and |
| // using atan instead. |
| half angle; |
| if (sk_Caps.atan2ImplementedAsAtanYOverX) { |
| angle = half(2 * atan(-sk_TransformedCoords2D[0].y, |
| length(sk_TransformedCoords2D[0]) - sk_TransformedCoords2D[0].x)); |
| } else { |
| angle = half(atan(-sk_TransformedCoords2D[0].y, -sk_TransformedCoords2D[0].x)); |
| } |
| |
| // 0.1591549430918 is 1/(2*pi), used since atan returns values [-pi, pi] |
| half t = (angle * 0.1591549430918 + 0.5 + bias) * scale; |
| sk_OutColor = half4(t, 1, 0, 0); // y = 1 for always valid |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| @header { |
| #include "SkSweepGradient.h" |
| #include "GrGradientShader.h" |
| } |
| |
| // The sweep gradient never rejects a pixel so it doesn't change opacity |
| @optimizationFlags { |
| kPreservesOpaqueInput_OptimizationFlag |
| } |
| |
| @make { |
| static std::unique_ptr<GrFragmentProcessor> Make(const SkSweepGradient& gradient, |
| const GrFPArgs& args); |
| } |
| |
| @cppEnd { |
| std::unique_ptr<GrFragmentProcessor> GrSweepGradientLayout::Make( |
| const SkSweepGradient& grad, const GrFPArgs& args) { |
| SkMatrix matrix; |
| if (!grad.totalLocalMatrix(args.fPreLocalMatrix, args.fPostLocalMatrix)->invert(&matrix)) { |
| return nullptr; |
| } |
| matrix.postConcat(grad.getGradientMatrix()); |
| return std::unique_ptr<GrFragmentProcessor>(new GrSweepGradientLayout( |
| matrix, grad.getTBias(), grad.getTScale())); |
| } |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| @test(d) { |
| SkScalar scale = GrGradientShader::RandomParams::kGradientScale; |
| SkPoint center = {d->fRandom->nextRangeScalar(0.0f, scale), |
| d->fRandom->nextRangeScalar(0.0f, scale)}; |
| |
| GrGradientShader::RandomParams params(d->fRandom); |
| auto shader = params.fUseColors4f ? |
| SkGradientShader::MakeSweep(center.fX, center.fY, params.fColors4f, params.fColorSpace, |
| params.fStops, params.fColorCount) : |
| SkGradientShader::MakeSweep(center.fX, center.fY, params.fColors, |
| params.fStops, params.fColorCount); |
| GrTest::TestAsFPArgs asFPArgs(d); |
| std::unique_ptr<GrFragmentProcessor> fp = as_SB(shader)->asFragmentProcessor(asFPArgs.args()); |
| GrAlwaysAssert(fp); |
| return fp; |
| } |