Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 26315204 authored by Robin Lee's avatar Robin Lee
Browse files

Add Kawase blur with dual filtering 

Blurs are smoother between R=50 to R=200 with similar performance to
the previous version. We use between 1 and 5 passes at progressively
smaller resolutions depending on the blur radius that was requested.

This is currently not enabled in code, but will be enabled by a
follow-up CL.

Test: atest BlurTests
Bug: 185365391
Flag: EXEMPT already behind a non-aconfig flag
Change-Id: I2ad47d83b69b69215fe59a5ecda3b1766177a852
parent a912e4d3

libs/renderengine/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ filegroup { 
        "skia/debug/SkiaMemoryReporter.cpp",

        "skia/filters/BlurFilter.cpp",

        "skia/filters/GaussianBlurFilter.cpp",

        "skia/filters/KawaseBlurDualFilter.cpp",

        "skia/filters/KawaseBlurFilter.cpp",

        "skia/filters/LinearEffect.cpp",

        "skia/filters/MouriMap.cpp",

libs/renderengine/benchmark/RenderEngineBench.cpp

+14 −6
Original line number Diff line number Diff line
@@ -64,14 +64,15 @@ std::pair<uint32_t, uint32_t> getDisplaySize() { 
    return std::pair<uint32_t, uint32_t>(width, height);

}



static std::unique_ptr<RenderEngine> createRenderEngine(RenderEngine::Threaded threaded,

                                                        RenderEngine::GraphicsApi graphicsApi) {

static std::unique_ptr<RenderEngine> createRenderEngine(

        RenderEngine::Threaded threaded, RenderEngine::GraphicsApi graphicsApi,

        RenderEngine::BlurAlgorithm blurAlgorithm = RenderEngine::BlurAlgorithm::KAWASE) {

    auto args = RenderEngineCreationArgs::Builder()

                        .setPixelFormat(static_cast<int>(ui::PixelFormat::RGBA_8888))

                        .setImageCacheSize(1)

                        .setEnableProtectedContext(true)

                        .setPrecacheToneMapperShaderOnly(false)

                        .setBlurAlgorithm(renderengine::RenderEngine::BlurAlgorithm::KAWASE)

                        .setBlurAlgorithm(blurAlgorithm)

                        .setContextPriority(RenderEngine::ContextPriority::REALTIME)

                        .setThreaded(threaded)

                        .setGraphicsApi(graphicsApi)
@@ -180,7 +181,8 @@ template <class... Args> 
void BM_blur(benchmark::State& benchState, Args&&... args) {

    auto args_tuple = std::make_tuple(std::move(args)...);

    auto re = createRenderEngine(static_cast<RenderEngine::Threaded>(std::get<0>(args_tuple)),

                                 static_cast<RenderEngine::GraphicsApi>(std::get<1>(args_tuple)));

                                 static_cast<RenderEngine::GraphicsApi>(std::get<1>(args_tuple)),

                                 static_cast<RenderEngine::BlurAlgorithm>(std::get<2>(args_tuple)));



    // Initially use cpu access so we can decode into it with AImageDecoder.

    auto [width, height] = getDisplaySize();
@@ -224,5 +226,11 @@ void BM_blur(benchmark::State& benchState, Args&&... args) { 
    benchDrawLayers(*re, layers, benchState, "blurred");

}



BENCHMARK_CAPTURE(BM_blur, SkiaGLThreaded, RenderEngine::Threaded::YES,

                  RenderEngine::GraphicsApi::GL);
 
BENCHMARK_CAPTURE(BM_blur, gaussian, RenderEngine::Threaded::YES, RenderEngine::GraphicsApi::GL,

                  RenderEngine::BlurAlgorithm::GAUSSIAN);



BENCHMARK_CAPTURE(BM_blur, kawase, RenderEngine::Threaded::YES, RenderEngine::GraphicsApi::GL,

                  RenderEngine::BlurAlgorithm::KAWASE);



BENCHMARK_CAPTURE(BM_blur, kawase_dual_filter, RenderEngine::Threaded::YES,

                  RenderEngine::GraphicsApi::GL, RenderEngine::BlurAlgorithm::KAWASE_DUAL_FILTER);

libs/renderengine/include/renderengine/RenderEngine.h

+1 −0
Original line number Diff line number Diff line
@@ -131,6 +131,7 @@ public: 
        NONE,

        GAUSSIAN,

        KAWASE,

        KAWASE_DUAL_FILTER,

    };



    static std::unique_ptr<RenderEngine> create(const RenderEngineCreationArgs& args);

libs/renderengine/skia/SkiaRenderEngine.cpp

+6 −0
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ 
#include "compat/SkiaGpuContext.h"

#include "filters/BlurFilter.h"

#include "filters/GaussianBlurFilter.h"

#include "filters/KawaseBlurDualFilter.h"

#include "filters/KawaseBlurFilter.h"

#include "filters/LinearEffect.h"

#include "filters/MouriMap.h"
@@ -285,6 +286,11 @@ SkiaRenderEngine::SkiaRenderEngine(Threaded threaded, PixelFormat pixelFormat, 
            mBlurFilter = new KawaseBlurFilter();

            break;

        }

        case BlurAlgorithm::KAWASE_DUAL_FILTER: {

            ALOGD("Background Blurs Enabled (Kawase dual-filtering algorithm)");

            mBlurFilter = new KawaseBlurDualFilter();

            break;

        }

        default: {

            mBlurFilter = nullptr;

            break;

libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp

0 → 100644
+173 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2024 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */



#define ATRACE_TAG ATRACE_TAG_GRAPHICS



#include "KawaseBlurDualFilter.h"

#include <SkAlphaType.h>

#include <SkBlendMode.h>

#include <SkCanvas.h>

#include <SkData.h>

#include <SkPaint.h>

#include <SkRRect.h>

#include <SkRuntimeEffect.h>

#include <SkShader.h>

#include <SkSize.h>

#include <SkString.h>

#include <SkSurface.h>

#include <SkTileMode.h>

#include <include/gpu/GpuTypes.h>

#include <include/gpu/ganesh/SkSurfaceGanesh.h>

#include <log/log.h>

#include <utils/Trace.h>



namespace android {

namespace renderengine {

namespace skia {



KawaseBlurDualFilter::KawaseBlurDualFilter() : BlurFilter() {

    // A shader to sample each vertex of a unit regular heptagon

    // plus the original fragment coordinate.

    SkString blurString(R"(

        uniform shader child;

        uniform float in_blurOffset;

        uniform float in_crossFade;



        const float2 STEP_0 = float2( 1.0, 0.0);

        const float2 STEP_1 = float2( 0.623489802,  0.781831482);

        const float2 STEP_2 = float2(-0.222520934,  0.974927912);

        const float2 STEP_3 = float2(-0.900968868,  0.433883739);

        const float2 STEP_4 = float2( 0.900968868, -0.433883739);

        const float2 STEP_5 = float2(-0.222520934, -0.974927912);

        const float2 STEP_6 = float2(-0.623489802, -0.781831482);



        half4 main(float2 xy) {

            half3 c = child.eval(xy).rgb;



            c += child.eval(xy + STEP_0 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_1 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_2 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_3 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_4 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_5 * in_blurOffset).rgb;

            c += child.eval(xy + STEP_6 * in_blurOffset).rgb;



            return half4(c * 0.125 * in_crossFade, in_crossFade);

        }

    )");



    auto [blurEffect, error] = SkRuntimeEffect::MakeForShader(blurString);

    LOG_ALWAYS_FATAL_IF(!blurEffect, "RuntimeShader error: %s", error.c_str());

    mBlurEffect = std::move(blurEffect);

}



static sk_sp<SkSurface> makeSurface(SkiaGpuContext* context, const SkRect& origRect, int scale) {

    SkImageInfo scaledInfo =

            SkImageInfo::MakeN32Premul(ceil(static_cast<float>(origRect.width()) / scale),

                                       ceil(static_cast<float>(origRect.height()) / scale));

    return context->createRenderTarget(scaledInfo);

}



void KawaseBlurDualFilter::blurInto(const sk_sp<SkSurface>& drawSurface,

                                    const sk_sp<SkImage>& readImage, const float radius,

                                    const float alpha) const {

    const float scale = static_cast<float>(drawSurface->width()) / readImage->width();

    SkMatrix blurMatrix = SkMatrix::Scale(scale, scale);

    blurInto(drawSurface,

             readImage->makeShader(SkTileMode::kClamp, SkTileMode::kClamp,

                                   SkSamplingOptions(SkFilterMode::kLinear, SkMipmapMode::kNone),

                                   blurMatrix),

             readImage->width() / static_cast<float>(drawSurface->width()), radius, alpha);

}



void KawaseBlurDualFilter::blurInto(const sk_sp<SkSurface>& drawSurface, sk_sp<SkShader> input,

                                    const float inverseScale, const float radius,

                                    const float alpha) const {

    SkRuntimeShaderBuilder blurBuilder(mBlurEffect);

    blurBuilder.child("child") = std::move(input);

    blurBuilder.uniform("in_inverseScale") = inverseScale;

    blurBuilder.uniform("in_blurOffset") = radius;

    blurBuilder.uniform("in_crossFade") = alpha;

    SkPaint paint;

    paint.setShader(blurBuilder.makeShader(nullptr));

    paint.setBlendMode(alpha == 1.0f ? SkBlendMode::kSrc : SkBlendMode::kSrcOver);

    drawSurface->getCanvas()->drawPaint(paint);

}



sk_sp<SkImage> KawaseBlurDualFilter::generate(SkiaGpuContext* context, const uint32_t blurRadius,

                                              const sk_sp<SkImage> input,

                                              const SkRect& blurRect) const {

    // Apply a conversion factor of (1 / sqrt(3)) to match Skia's built-in blur as used by

    // RenderEffect. See the comment in SkBlurMask.cpp for reasoning behind this.

    const float radius = blurRadius * 0.57735f;



    // Use a variable number of blur passes depending on the radius. The non-integer part of this

    // calculation is used to mix the final pass into the second-last with an alpha blend.

    constexpr int kMaxSurfaces = 4;

    const float filterDepth =

            std::min(kMaxSurfaces - 1.0f, 1.0f + std::max(0.0f, log2f(radius * kInputScale)));

    const int filterPasses = std::min(kMaxSurfaces - 1, static_cast<int>(ceil(filterDepth)));



    // Render into surfaces downscaled by 1x, 1x, 2x, and 4x from the initial downscale.

    sk_sp<SkSurface> surfaces[kMaxSurfaces] =

            {filterPasses >= 0 ? makeSurface(context, blurRect, 1 * kInverseInputScale) : nullptr,

             filterPasses >= 1 ? makeSurface(context, blurRect, 1 * kInverseInputScale) : nullptr,

             filterPasses >= 2 ? makeSurface(context, blurRect, 2 * kInverseInputScale) : nullptr,

             filterPasses >= 3 ? makeSurface(context, blurRect, 4 * kInverseInputScale) : nullptr};



    // These weights for scaling offsets per-pass are handpicked to look good at 1 <= radius <= 600.

    static const float kWeights[7] = {1.0f, 2.0f, 3.5f, 1.0f, 2.0f, 2.0f, 2.0f};



    // Kawase is an approximation of Gaussian, but behaves differently because it is made up of many

    // simpler blurs. A transformation is required to approximate the same effect as Gaussian.

    float sumSquaredR = powf(kWeights[0] * powf(2.0f, 1), 2.0f);

    for (int i = 0; i < filterPasses; i++) {

        const float alpha = std::min(1.0f, filterDepth - i);

        sumSquaredR += powf(powf(2.0f, i + 1) * alpha * kWeights[1 + i], 2.0f);

        sumSquaredR += powf(powf(2.0f, i + 1) * alpha * kWeights[6 - i], 2.0f);

    }

    // Solve for R = sqrt(sum(r_i^2)). Divide R by hypot(1,1) to find some (x,y) offsets.

    const float step = M_SQRT1_2 *

            sqrtf(max(0.0f, (powf(radius, 2.0f) - powf(kInverseInputScale, 2.0f)) / sumSquaredR));



    // Start by downscaling and doing the first blur pass.

    {

        // For sampling Skia's API expects the inverse of what logically seems appropriate. In this

        // case one may expect Translate(blurRect.fLeft, blurRect.fTop) * Scale(kInverseInputScale)

        // but instead we must do the inverse.

        SkMatrix blurMatrix = SkMatrix::Translate(-blurRect.fLeft, -blurRect.fTop);

        blurMatrix.postScale(kInputScale, kInputScale);

        const auto sourceShader =

                input->makeShader(SkTileMode::kClamp, SkTileMode::kClamp,

                                  SkSamplingOptions(SkFilterMode::kLinear, SkMipmapMode::kNone),

                                  blurMatrix);

        blurInto(surfaces[0], std::move(sourceShader), kInputScale, kWeights[0] * step, 1.0f);

    }

    // Next the remaining downscale blur passes.

    for (int i = 0; i < filterPasses; i++) {

        blurInto(surfaces[i + 1], surfaces[i]->makeImageSnapshot(), kWeights[1 + i] * step, 1.0f);

    }

    // Finally blur+upscale back to our original size.

    for (int i = filterPasses - 1; i >= 0; i--) {

        blurInto(surfaces[i], surfaces[i + 1]->makeImageSnapshot(), kWeights[6 - i] * step,

                 std::min(1.0f, filterDepth - i));

    }

    return surfaces[0]->makeImageSnapshot();

}



} // namespace skia

} // namespace renderengine

} // namespace android