| /* |
| * 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 "src/gpu/gradients/GrGradientShader.h" |
| |
| #include "src/gpu/gradients/generated/GrClampedGradientEffect.h" |
| #include "src/gpu/gradients/generated/GrTiledGradientEffect.h" |
| |
| #include "src/gpu/gradients/generated/GrLinearGradientLayout.h" |
| #include "src/gpu/gradients/generated/GrRadialGradientLayout.h" |
| #include "src/gpu/gradients/generated/GrSweepGradientLayout.h" |
| #include "src/gpu/gradients/generated/GrTwoPointConicalGradientLayout.h" |
| |
| #include "src/gpu/gradients/GrGradientBitmapCache.h" |
| #include "src/gpu/gradients/generated/GrDualIntervalGradientColorizer.h" |
| #include "src/gpu/gradients/generated/GrSingleIntervalGradientColorizer.h" |
| #include "src/gpu/gradients/generated/GrTextureGradientColorizer.h" |
| #include "src/gpu/gradients/generated/GrUnrolledBinaryGradientColorizer.h" |
| |
| #include "include/private/GrRecordingContext.h" |
| #include "src/gpu/GrCaps.h" |
| #include "src/gpu/GrColor.h" |
| #include "src/gpu/GrColorInfo.h" |
| #include "src/gpu/GrRecordingContextPriv.h" |
| #include "src/gpu/SkGr.h" |
| |
| // Intervals smaller than this (that aren't hard stops) on low-precision-only devices force us to |
| // use the textured gradient |
| static const SkScalar kLowPrecisionIntervalLimit = 0.01f; |
| |
| // Each cache entry costs 1K or 2K of RAM. Each bitmap will be 1x256 at either 32bpp or 64bpp. |
| static const int kMaxNumCachedGradientBitmaps = 32; |
| static const int kGradientTextureSize = 256; |
| |
| // NOTE: signature takes raw pointers to the color/pos arrays and a count to make it easy for |
| // MakeColorizer to transparently take care of hard stops at the end points of the gradient. |
| static std::unique_ptr<GrFragmentProcessor> make_textured_colorizer(const SkPMColor4f* colors, |
| const SkScalar* positions, int count, bool premul, const GrFPArgs& args) { |
| static GrGradientBitmapCache gCache(kMaxNumCachedGradientBitmaps, kGradientTextureSize); |
| |
| // Use 8888 or F16, depending on the destination config. |
| // TODO: Use 1010102 for opaque gradients, at least if destination is 1010102? |
| SkColorType colorType = kRGBA_8888_SkColorType; |
| if (GrColorTypeIsWiderThan(args.fDstColorInfo->colorType(), 8)) { |
| auto f16Format = args.fContext->priv().caps()->getDefaultBackendFormat( |
| GrColorType::kRGBA_F16, GrRenderable::kNo); |
| if (f16Format.isValid()) { |
| colorType = kRGBA_F16_SkColorType; |
| } |
| } |
| SkAlphaType alphaType = premul ? kPremul_SkAlphaType : kUnpremul_SkAlphaType; |
| |
| SkBitmap bitmap; |
| gCache.getGradient(colors, positions, count, colorType, alphaType, &bitmap); |
| SkASSERT(1 == bitmap.height() && SkIsPow2(bitmap.width())); |
| SkASSERT(bitmap.isImmutable()); |
| |
| sk_sp<GrTextureProxy> proxy = GrMakeCachedBitmapProxy(args.fContext, bitmap); |
| if (proxy == nullptr) { |
| SkDebugf("Gradient won't draw. Could not create texture."); |
| return nullptr; |
| } |
| |
| return GrTextureGradientColorizer::Make(std::move(proxy)); |
| } |
| |
| // Analyze the shader's color stops and positions and chooses an appropriate colorizer to represent |
| // the gradient. |
| static std::unique_ptr<GrFragmentProcessor> make_colorizer(const SkPMColor4f* colors, |
| const SkScalar* positions, int count, bool premul, const GrFPArgs& args) { |
| // If there are hard stops at the beginning or end, the first and/or last color should be |
| // ignored by the colorizer since it should only be used in a clamped border color. By detecting |
| // and removing these stops at the beginning, it makes optimizing the remaining color stops |
| // simpler. |
| |
| // SkGradientShaderBase guarantees that pos[0] == 0 by adding a dummy |
| bool bottomHardStop = SkScalarNearlyEqual(positions[0], positions[1]); |
| // The same is true for pos[end] == 1 |
| bool topHardStop = SkScalarNearlyEqual(positions[count - 2], positions[count - 1]); |
| |
| int offset = 0; |
| if (bottomHardStop) { |
| offset += 1; |
| count--; |
| } |
| if (topHardStop) { |
| count--; |
| } |
| |
| // Two remaining colors means a single interval from 0 to 1 |
| // (but it may have originally been a 3 or 4 color gradient with 1-2 hard stops at the ends) |
| if (count == 2) { |
| return GrSingleIntervalGradientColorizer::Make(colors[offset], colors[offset + 1]); |
| } |
| |
| // Do an early test for the texture fallback to skip all of the other tests for specific |
| // analytic support of the gradient (and compatibility with the hardware), when it's definitely |
| // impossible to use an analytic solution. |
| bool tryAnalyticColorizer = count <= GrUnrolledBinaryGradientColorizer::kMaxColorCount; |
| |
| // The remaining analytic colorizers use scale*t+bias, and the scale/bias values can become |
| // quite large when thresholds are close (but still outside the hardstop limit). If float isn't |
| // 32-bit, output can be incorrect if the thresholds are too close together. However, the |
| // analytic shaders are higher quality, so they can be used with lower precision hardware when |
| // the thresholds are not ill-conditioned. |
| const GrShaderCaps* caps = args.fContext->priv().caps()->shaderCaps(); |
| if (!caps->floatIs32Bits() && tryAnalyticColorizer) { |
| // Could run into problems, check if thresholds are close together (with a limit of .01, so |
| // that scales will be less than 100, which leaves 4 decimals of precision on 16-bit). |
| for (int i = offset; i < count - 1; i++) { |
| SkScalar dt = SkScalarAbs(positions[i] - positions[i + 1]); |
| if (dt <= kLowPrecisionIntervalLimit && dt > SK_ScalarNearlyZero) { |
| tryAnalyticColorizer = false; |
| break; |
| } |
| } |
| } |
| |
| if (tryAnalyticColorizer) { |
| if (count == 3) { |
| // Must be a dual interval gradient, where the middle point is at offset+1 and the two |
| // intervals share the middle color stop. |
| return GrDualIntervalGradientColorizer::Make(colors[offset], colors[offset + 1], |
| colors[offset + 1], colors[offset + 2], |
| positions[offset + 1]); |
| } else if (count == 4 && SkScalarNearlyEqual(positions[offset + 1], |
| positions[offset + 2])) { |
| // Two separate intervals that join at the same threshold position |
| return GrDualIntervalGradientColorizer::Make(colors[offset], colors[offset + 1], |
| colors[offset + 2], colors[offset + 3], |
| positions[offset + 1]); |
| } |
| |
| // The single and dual intervals are a specialized case of the unrolled binary search |
| // colorizer which can analytically render gradients of up to 8 intervals (up to 9 or 16 |
| // colors depending on how many hard stops are inserted). |
| std::unique_ptr<GrFragmentProcessor> unrolled = GrUnrolledBinaryGradientColorizer::Make( |
| colors + offset, positions + offset, count); |
| if (unrolled) { |
| return unrolled; |
| } |
| } |
| |
| // Otherwise fall back to a rasterized gradient sampled by a texture, which can handle |
| // arbitrary gradients (the only downside being sampling resolution). |
| return make_textured_colorizer(colors + offset, positions + offset, count, premul, args); |
| } |
| |
| // Combines the colorizer and layout with an appropriately configured master effect based on the |
| // gradient's tile mode |
| static std::unique_ptr<GrFragmentProcessor> make_gradient(const SkGradientShaderBase& shader, |
| const GrFPArgs& args, std::unique_ptr<GrFragmentProcessor> layout) { |
| // No shader is possible if a layout couldn't be created, e.g. a layout-specific Make() returned |
| // null. |
| if (layout == nullptr) { |
| return nullptr; |
| } |
| |
| // Convert all colors into destination space and into SkPMColor4fs, and handle |
| // premul issues depending on the interpolation mode |
| bool inputPremul = shader.getGradFlags() & SkGradientShader::kInterpolateColorsInPremul_Flag; |
| bool allOpaque = true; |
| SkAutoSTMalloc<4, SkPMColor4f> colors(shader.fColorCount); |
| SkColor4fXformer xformedColors(shader.fOrigColors4f, shader.fColorCount, |
| shader.fColorSpace.get(), args.fDstColorInfo->colorSpace()); |
| for (int i = 0; i < shader.fColorCount; i++) { |
| const SkColor4f& upmColor = xformedColors.fColors[i]; |
| colors[i] = inputPremul ? upmColor.premul() |
| : SkPMColor4f{ upmColor.fR, upmColor.fG, upmColor.fB, upmColor.fA }; |
| if (allOpaque && !SkScalarNearlyEqual(colors[i].fA, 1.0)) { |
| allOpaque = false; |
| } |
| } |
| |
| // SkGradientShader stores positions implicitly when they are evenly spaced, but the getPos() |
| // implementation performs a branch for every position index. Since the shader conversion |
| // requires lots of position tests, calculate all of the positions up front if needed. |
| SkTArray<SkScalar, true> implicitPos; |
| SkScalar* positions; |
| if (shader.fOrigPos) { |
| positions = shader.fOrigPos; |
| } else { |
| implicitPos.reserve(shader.fColorCount); |
| SkScalar posScale = SK_Scalar1 / (shader.fColorCount - 1); |
| for (int i = 0 ; i < shader.fColorCount; i++) { |
| implicitPos.push_back(SkIntToScalar(i) * posScale); |
| } |
| positions = implicitPos.begin(); |
| } |
| |
| // All gradients are colorized the same way, regardless of layout |
| std::unique_ptr<GrFragmentProcessor> colorizer = make_colorizer( |
| colors.get(), positions, shader.fColorCount, inputPremul, args); |
| if (colorizer == nullptr) { |
| return nullptr; |
| } |
| |
| // The master effect has to export premul colors, but under certain conditions it doesn't need |
| // to do anything to achieve that: i.e. its interpolating already premul colors (inputPremul) |
| // or all the colors have a = 1, in which case premul is a no op. Note that this allOpaque |
| // check is more permissive than SkGradientShaderBase's isOpaque(), since we can optimize away |
| // the make-premul op for two point conical gradients (which report false for isOpaque). |
| bool makePremul = !inputPremul && !allOpaque; |
| |
| // All tile modes are supported (unless something was added to SkShader) |
| std::unique_ptr<GrFragmentProcessor> master; |
| switch(shader.getTileMode()) { |
| case SkTileMode::kRepeat: |
| master = GrTiledGradientEffect::Make(std::move(colorizer), std::move(layout), |
| /* mirror */ false, makePremul, allOpaque); |
| break; |
| case SkTileMode::kMirror: |
| master = GrTiledGradientEffect::Make(std::move(colorizer), std::move(layout), |
| /* mirror */ true, makePremul, allOpaque); |
| break; |
| case SkTileMode::kClamp: |
| // For the clamped mode, the border colors are the first and last colors, corresponding |
| // to t=0 and t=1, because SkGradientShaderBase enforces that by adding color stops as |
| // appropriate. If there is a hard stop, this grabs the expected outer colors for the |
| // border. |
| master = GrClampedGradientEffect::Make(std::move(colorizer), std::move(layout), |
| colors[0], colors[shader.fColorCount - 1], makePremul, allOpaque); |
| break; |
| case SkTileMode::kDecal: |
| // Even if the gradient colors are opaque, the decal borders are transparent so |
| // disable that optimization |
| master = GrClampedGradientEffect::Make(std::move(colorizer), std::move(layout), |
| SK_PMColor4fTRANSPARENT, SK_PMColor4fTRANSPARENT, |
| makePremul, /* colorsAreOpaque */ false); |
| break; |
| } |
| |
| if (master == nullptr) { |
| // Unexpected tile mode |
| return nullptr; |
| } |
| if (args.fInputColorIsOpaque) { |
| return GrFragmentProcessor::OverrideInput(std::move(master), SK_PMColor4fWHITE, false); |
| } |
| return GrFragmentProcessor::MulChildByInputAlpha(std::move(master)); |
| } |
| |
| namespace GrGradientShader { |
| |
| std::unique_ptr<GrFragmentProcessor> MakeLinear(const SkLinearGradient& shader, |
| const GrFPArgs& args) { |
| return make_gradient(shader, args, GrLinearGradientLayout::Make(shader, args)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> MakeRadial(const SkRadialGradient& shader, |
| const GrFPArgs& args) { |
| return make_gradient(shader,args, GrRadialGradientLayout::Make(shader, args)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> MakeSweep(const SkSweepGradient& shader, |
| const GrFPArgs& args) { |
| return make_gradient(shader,args, GrSweepGradientLayout::Make(shader, args)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> MakeConical(const SkTwoPointConicalGradient& shader, |
| const GrFPArgs& args) { |
| return make_gradient(shader, args, GrTwoPointConicalGradientLayout::Make(shader, args)); |
| } |
| |
| #if GR_TEST_UTILS |
| RandomParams::RandomParams(SkRandom* random) { |
| // Set color count to min of 2 so that we don't trigger the const color optimization and make |
| // a non-gradient processor. |
| fColorCount = random->nextRangeU(2, kMaxRandomGradientColors); |
| fUseColors4f = random->nextBool(); |
| |
| // if one color, omit stops, otherwise randomly decide whether or not to |
| if (fColorCount == 1 || (fColorCount >= 2 && random->nextBool())) { |
| fStops = nullptr; |
| } else { |
| fStops = fStopStorage; |
| } |
| |
| // if using SkColor4f, attach a random (possibly null) color space (with linear gamma) |
| if (fUseColors4f) { |
| fColorSpace = GrTest::TestColorSpace(random); |
| } |
| |
| SkScalar stop = 0.f; |
| for (int i = 0; i < fColorCount; ++i) { |
| if (fUseColors4f) { |
| fColors4f[i].fR = random->nextUScalar1(); |
| fColors4f[i].fG = random->nextUScalar1(); |
| fColors4f[i].fB = random->nextUScalar1(); |
| fColors4f[i].fA = random->nextUScalar1(); |
| } else { |
| fColors[i] = random->nextU(); |
| } |
| if (fStops) { |
| fStops[i] = stop; |
| stop = i < fColorCount - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f; |
| } |
| } |
| fTileMode = static_cast<SkTileMode>(random->nextULessThan(kSkTileModeCount)); |
| } |
| #endif |
| |
| } |