src/gpu/ganesh/GrFragmentProcessors.cpp

/*
 * Copyright 2023 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "src/gpu/ganesh/GrFragmentProcessors.h"

#include "include/core/SkAlphaType.h"
#include "include/core/SkBlendMode.h"
#include "include/core/SkColor.h"
#include "include/core/SkColorSpace.h"
#include "include/core/SkData.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkRefCnt.h"
#include "include/effects/SkRuntimeEffect.h"
#include "include/gpu/GrRecordingContext.h"
#include "include/private/SkColorData.h"
#include "include/private/base/SkAssert.h"
#include "include/private/base/SkDebug.h"
#include "include/private/base/SkTArray.h"
#include "src/core/SkBlendModeBlender.h"
#include "src/core/SkBlendModeColorFilter.h"
#include "src/core/SkBlenderBase.h"
#include "src/core/SkColorFilterBase.h"
#include "src/core/SkColorSpacePriv.h"
#include "src/core/SkColorSpaceXformColorFilter.h"
#include "src/core/SkColorSpaceXformSteps.h"
#include "src/core/SkComposeColorFilter.h"
#include "src/core/SkMaskFilterBase.h"
#include "src/core/SkMatrixColorFilter.h"
#include "src/core/SkRuntimeBlender.h"
#include "src/core/SkRuntimeColorFilter.h"
#include "src/core/SkRuntimeEffectPriv.h"
#include "src/core/SkWorkingFormatColorFilter.h"
#include "src/effects/SkShaderMaskFilterImpl.h"
#include "src/effects/SkTableColorFilter.h"
#include "src/gpu/ganesh/GrCaps.h"
#include "src/gpu/ganesh/GrColorInfo.h"
#include "src/gpu/ganesh/GrColorSpaceXform.h"
#include "src/gpu/ganesh/GrFPArgs.h"
#include "src/gpu/ganesh/GrFragmentProcessor.h"
#include "src/gpu/ganesh/GrRecordingContextPriv.h"
#include "src/gpu/ganesh/effects/GrBlendFragmentProcessor.h"
#include "src/gpu/ganesh/effects/GrColorTableEffect.h"
#include "src/gpu/ganesh/effects/GrSkSLFP.h"
#include "src/shaders/SkShaderBase.h"
#include "src/utils/SkGaussianColorFilter.h"

#include <memory>
#include <optional>
#include <utility>
#include <vector>

namespace GrFragmentProcessors {
static std::unique_ptr<GrFragmentProcessor>
        make_fp_from_shader_mask_filter(const SkMaskFilterBase* maskfilter,
                                        const GrFPArgs& args,
                                        const SkMatrix& ctm) {
    SkASSERT(maskfilter);
    auto shaderMF = static_cast<const SkShaderMaskFilterImpl*>(maskfilter);
    auto fp = as_SB(shaderMF->shader())->asFragmentProcessor(args, SkShaderBase::MatrixRec(ctm));
    return GrFragmentProcessor::MulInputByChildAlpha(std::move(fp));
}

std::unique_ptr<GrFragmentProcessor> Make(const SkMaskFilter* maskfilter,
                                          const GrFPArgs& args,
                                          const SkMatrix& ctm) {
    if (!maskfilter) {
        return nullptr;
    }
    auto mfb = as_MFB(maskfilter);
    switch (mfb->type()) {
        case SkMaskFilterBase::Type::kShader:
            return make_fp_from_shader_mask_filter(mfb, args, ctm);
        case SkMaskFilterBase::Type::kBlur:
        case SkMaskFilterBase::Type::kEmboss:
        case SkMaskFilterBase::Type::kSDF:
        case SkMaskFilterBase::Type::kTable:
            return nullptr;
    }
    SkUNREACHABLE;
}

using ChildType = SkRuntimeEffect::ChildType;

GrFPResult make_effect_fp(sk_sp<SkRuntimeEffect> effect,
                          const char* name,
                          sk_sp<const SkData> uniforms,
                          std::unique_ptr<GrFragmentProcessor> inputFP,
                          std::unique_ptr<GrFragmentProcessor> destColorFP,
                          SkSpan<const SkRuntimeEffect::ChildPtr> children,
                          const GrFPArgs& childArgs) {
    skia_private::STArray<8, std::unique_ptr<GrFragmentProcessor>> childFPs;
    for (const auto& child : children) {
        std::optional<ChildType> type = child.type();
        if (type == ChildType::kShader) {
            // Convert a SkShader into a child FP.
            SkShaderBase::MatrixRec mRec(SkMatrix::I());
            mRec.markTotalMatrixInvalid();
            auto childFP = as_SB(child.shader())->asFragmentProcessor(childArgs, mRec);
            if (!childFP) {
                return GrFPFailure(std::move(inputFP));
            }
            childFPs.push_back(std::move(childFP));
        } else if (type == ChildType::kColorFilter) {
            // Convert a SkColorFilter into a child FP.
            auto [success, childFP] = Make(childArgs.fContext,
                                           child.colorFilter(),
                                           /*inputFP=*/nullptr,
                                           *childArgs.fDstColorInfo,
                                           childArgs.fSurfaceProps);
            if (!success) {
                return GrFPFailure(std::move(inputFP));
            }
            childFPs.push_back(std::move(childFP));
        } else if (type == ChildType::kBlender) {
            // Convert a SkBlender into a child FP.
            auto childFP = GrFragmentProcessors::Make(as_BB(child.blender()),
                                                      /*srcFP=*/nullptr,
                                                      GrFragmentProcessor::DestColor(),
                                                      childArgs);
            if (!childFP) {
                return GrFPFailure(std::move(inputFP));
            }
            childFPs.push_back(std::move(childFP));
        } else {
            // We have a null child effect.
            childFPs.push_back(nullptr);
        }
    }
    auto fp = GrSkSLFP::MakeWithData(std::move(effect),
                                     name,
                                     childArgs.fDstColorInfo->refColorSpace(),
                                     std::move(inputFP),
                                     std::move(destColorFP),
                                     std::move(uniforms),
                                     SkSpan(childFPs));
    SkASSERT(fp);
    return GrFPSuccess(std::move(fp));
}

static std::unique_ptr<GrFragmentProcessor> make_blender_fp(
        const SkRuntimeBlender* rtb,
        std::unique_ptr<GrFragmentProcessor> srcFP,
        std::unique_ptr<GrFragmentProcessor> dstFP,
        const GrFPArgs& fpArgs) {
    SkASSERT(rtb);
    if (!SkRuntimeEffectPriv::CanDraw(fpArgs.fContext->priv().caps(), rtb->effect().get())) {
        return nullptr;
    }

    sk_sp<const SkData> uniforms = SkRuntimeEffectPriv::TransformUniforms(
            rtb->effect()->uniforms(),
            rtb->uniforms(),
            fpArgs.fDstColorInfo->colorSpace());
    SkASSERT(uniforms);
    auto children = rtb->children();
    auto [success, fp] = make_effect_fp(rtb->effect(),
                                        "runtime_blender",
                                        std::move(uniforms),
                                        std::move(srcFP),
                                        std::move(dstFP),
                                        SkSpan(children),
                                        fpArgs);

    return success ? std::move(fp) : nullptr;
}

static std::unique_ptr<GrFragmentProcessor> make_blender_fp(
        const SkBlendModeBlender* blender,
        std::unique_ptr<GrFragmentProcessor> srcFP,
        std::unique_ptr<GrFragmentProcessor> dstFP,
        const GrFPArgs& fpArgs) {
    SkASSERT(blender);
    return GrBlendFragmentProcessor::Make(std::move(srcFP), std::move(dstFP), blender->mode());
}

std::unique_ptr<GrFragmentProcessor> Make(const SkBlenderBase* blender,
                                          std::unique_ptr<GrFragmentProcessor> srcFP,
                                          std::unique_ptr<GrFragmentProcessor> dstFP,
                                          const GrFPArgs& fpArgs) {
    if (!blender) {
        return nullptr;
    }
    switch (blender->type()) {
#define M(type)                                                                \
    case SkBlenderBase::BlenderType::k##type:                                  \
        return make_blender_fp(static_cast<const Sk##type##Blender*>(blender), \
                               std::move(srcFP),                               \
                               std::move(dstFP),                               \
                               fpArgs);
        SK_ALL_BLENDERS(M)
#undef M
    }
    SkUNREACHABLE;
}

static SkPMColor4f map_color(const SkColor4f& c, SkColorSpace* src, SkColorSpace* dst) {
    SkPMColor4f color = {c.fR, c.fG, c.fB, c.fA};
    SkColorSpaceXformSteps(src, kUnpremul_SkAlphaType, dst, kPremul_SkAlphaType).apply(color.vec());
    return color;
}
static GrFPResult make_colorfilter_fp(GrRecordingContext*,
                                      const SkBlendModeColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo& dstColorInfo,
                                      const SkSurfaceProps& props) {
    if (filter->mode() == SkBlendMode::kDst) {
        // If the blend mode is "dest," the blend color won't factor into it at all.
        // We can return the input FP as-is.
        return GrFPSuccess(std::move(inputFP));
    }

    SkDEBUGCODE(const bool fpHasConstIO = !inputFP || inputFP->hasConstantOutputForConstantInput();)

    SkPMColor4f color = map_color(filter->color(), sk_srgb_singleton(), dstColorInfo.colorSpace());

    auto colorFP = GrFragmentProcessor::MakeColor(color);
    auto xferFP =
            GrBlendFragmentProcessor::Make(std::move(colorFP), std::move(inputFP), filter->mode());

    if (xferFP == nullptr) {
        // This is only expected to happen if the blend mode is "dest" and the input FP is null.
        // Since we already did an early-out in the "dest" blend mode case, we shouldn't get here.
        SkDEBUGFAIL("GrBlendFragmentProcessor::Make returned null unexpectedly");
        return GrFPFailure(nullptr);
    }

    // With a solid color input this should always be able to compute the blended color
    // (at least for coeff modes).
    // Occasionally, we even do better than we started; specifically, in "src" blend mode, we end up
    // ditching the input FP entirely, which turns a non-constant operation into a constant one.
    SkASSERT(filter->mode() > SkBlendMode::kLastCoeffMode ||
             xferFP->hasConstantOutputForConstantInput() >= fpHasConstIO);

    return GrFPSuccess(std::move(xferFP));
}

static GrFPResult make_colorfilter_fp(GrRecordingContext* context,
                                      const SkComposeColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo& dstColorInfo,
                                      const SkSurfaceProps& props) {
    // Unfortunately, we need to clone the input before we know we need it. This lets us return
    // the original FP if either internal color filter fails.
    auto inputClone = inputFP ? inputFP->clone() : nullptr;

    auto [innerSuccess, innerFP] =
            Make(context, filter->inner().get(), std::move(inputFP), dstColorInfo, props);
    if (!innerSuccess) {
        return GrFPFailure(std::move(inputClone));
    }

    auto [outerSuccess, outerFP] =
            Make(context, filter->outer().get(), std::move(innerFP), dstColorInfo, props);
    if (!outerSuccess) {
        return GrFPFailure(std::move(inputClone));
    }

    return GrFPSuccess(std::move(outerFP));
}

static GrFPResult make_colorfilter_fp(GrRecordingContext*,
                                      const SkColorSpaceXformColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo&,
                                      const SkSurfaceProps&) {
    // wish our caller would let us know if our input was opaque...
    constexpr SkAlphaType alphaType = kPremul_SkAlphaType;
    return GrFPSuccess(GrColorSpaceXformEffect::Make(
            std::move(inputFP), filter->src().get(), alphaType, filter->dst().get(), alphaType));
}

static GrFPResult make_colorfilter_fp(GrRecordingContext*,
                                      const SkGaussianColorFilter*,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo&,
                                      const SkSurfaceProps&) {
    static const SkRuntimeEffect* effect =
            SkMakeRuntimeEffect(SkRuntimeEffect::MakeForColorFilter,
                                "half4 main(half4 inColor) {"
                                "half factor = 1 - inColor.a;"
                                "factor = exp(-factor * factor * 4) - 0.018;"
                                "return half4(factor);"
                                "}");
    SkASSERT(SkRuntimeEffectPriv::SupportsConstantOutputForConstantInput(effect));
    return GrFPSuccess(
            GrSkSLFP::Make(effect, "gaussian_fp", std::move(inputFP), GrSkSLFP::OptFlags::kNone));
}

static std::unique_ptr<GrFragmentProcessor> rgb_to_hsl(std::unique_ptr<GrFragmentProcessor> child) {
    static const SkRuntimeEffect* effect =
            SkMakeRuntimeEffect(SkRuntimeEffect::MakeForColorFilter,
                                "half4 main(half4 color) {"
                                "return $rgb_to_hsl(color.rgb, color.a);"
                                "}");
    SkASSERT(SkRuntimeEffectPriv::SupportsConstantOutputForConstantInput(effect));
    return GrSkSLFP::Make(
            effect, "RgbToHsl", std::move(child), GrSkSLFP::OptFlags::kPreservesOpaqueInput);
}

static std::unique_ptr<GrFragmentProcessor> hsl_to_rgb(std::unique_ptr<GrFragmentProcessor> child) {
    static const SkRuntimeEffect* effect =
            SkMakeRuntimeEffect(SkRuntimeEffect::MakeForColorFilter,
                                "half4 main(half4 color) {"
                                "return $hsl_to_rgb(color.rgb, color.a);"
                                "}");
    SkASSERT(SkRuntimeEffectPriv::SupportsConstantOutputForConstantInput(effect));
    return GrSkSLFP::Make(
            effect, "HslToRgb", std::move(child), GrSkSLFP::OptFlags::kPreservesOpaqueInput);
}

static GrFPResult make_colorfilter_fp(GrRecordingContext*,
                                      const SkMatrixColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo&,
                                      const SkSurfaceProps&) {
    switch (filter->domain()) {
        case SkMatrixColorFilter::Domain::kRGBA:
            return GrFPSuccess(GrFragmentProcessor::ColorMatrix(std::move(inputFP),
                                                                filter->matrix(),
                                                                /* unpremulInput = */ true,
                                                                /* clampRGBOutput = */ true,
                                                                /* premulOutput = */ true));

        case SkMatrixColorFilter::Domain::kHSLA: {
            auto fp = rgb_to_hsl(std::move(inputFP));
            fp = GrFragmentProcessor::ColorMatrix(std::move(fp),
                                                  filter->matrix(),
                                                  /* unpremulInput = */ false,
                                                  /* clampRGBOutput = */ false,
                                                  /* premulOutput = */ false);
            return GrFPSuccess(hsl_to_rgb(std::move(fp)));
        }
    }
    SkUNREACHABLE;
}

static GrFPResult make_colorfilter_fp(GrRecordingContext* context,
                                      const SkRuntimeColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo& colorInfo,
                                      const SkSurfaceProps& props) {
    sk_sp<const SkData> uniforms = SkRuntimeEffectPriv::TransformUniforms(
            filter->effect()->uniforms(), filter->uniforms(), colorInfo.colorSpace());
    SkASSERT(uniforms);

    GrFPArgs childArgs(context, &colorInfo, props);
    auto children = filter->children();
    return make_effect_fp(filter->effect(),
                          "runtime_color_filter",
                          std::move(uniforms),
                          std::move(inputFP),
                          /*destColorFP=*/nullptr,
                          SkSpan(children),
                          childArgs);
}

static GrFPResult make_colorfilter_fp(GrRecordingContext* context,
                                      const SkTableColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo&,
                                      const SkSurfaceProps&) {
    auto cte = ColorTableEffect::Make(std::move(inputFP), context, filter->bitmap());
    return cte ? GrFPSuccess(std::move(cte)) : GrFPFailure(nullptr);
}

static GrFPResult make_colorfilter_fp(GrRecordingContext* context,
                                      const SkWorkingFormatColorFilter* filter,
                                      std::unique_ptr<GrFragmentProcessor> inputFP,
                                      const GrColorInfo& dstColorInfo,
                                      const SkSurfaceProps& props) {
    sk_sp<SkColorSpace> dstCS = dstColorInfo.refColorSpace();
    if (!dstCS) {
        dstCS = SkColorSpace::MakeSRGB();
    }

    SkAlphaType workingAT;
    sk_sp<SkColorSpace> workingCS = filter->workingFormat(dstCS, &workingAT);

    GrColorInfo dst = {dstColorInfo.colorType(), dstColorInfo.alphaType(), dstCS},
                working = {dstColorInfo.colorType(), workingAT, workingCS};

    auto [ok, fp] = Make(context,
                         filter->child().get(),
                         GrColorSpaceXformEffect::Make(std::move(inputFP), dst, working),
                         working,
                         props);

    return ok ? GrFPSuccess(GrColorSpaceXformEffect::Make(std::move(fp), working, dst))
              : GrFPFailure(std::move(fp));
}

GrFPResult Make(GrRecordingContext* ctx,
                const SkColorFilter* cf,
                std::unique_ptr<GrFragmentProcessor> inputFP,
                const GrColorInfo& dstColorInfo,
                const SkSurfaceProps& props) {
    if (!cf) {
        return GrFPFailure(nullptr);
    }
    auto cfb = as_CFB(cf);
    switch (cfb->type()) {
        case SkColorFilterBase::Type::kNoop:
            return GrFPFailure(nullptr);
#define M(type)                                                                   \
    case SkColorFilterBase::Type::k##type:                                        \
        return make_colorfilter_fp(ctx,                                           \
                                   static_cast<const Sk##type##ColorFilter*>(cf), \
                                   std::move(inputFP),                            \
                                   dstColorInfo,                                  \
                                   props);
            SK_ALL_COLOR_FILTERS(M)
#undef M
    }
    SkUNREACHABLE;
}

bool IsSupported(const SkMaskFilter* maskfilter) {
    if (!maskfilter) {
        return false;
    }
    auto mfb = as_MFB(maskfilter);
    switch (mfb->type()) {
        case SkMaskFilterBase::Type::kShader:
            return true;
        case SkMaskFilterBase::Type::kBlur:
        case SkMaskFilterBase::Type::kEmboss:
        case SkMaskFilterBase::Type::kSDF:
        case SkMaskFilterBase::Type::kTable:
            return false;
    }
    SkUNREACHABLE;
}
}  // namespace GrFragmentProcessors