Tweak Kawase2 to use fewer passes and fewer samples.
Test: atest librenderengine_bench
Bug: 353826438
Flag: EXEMPT behind sysprop flag already
Change-Id: Ifcc4e76aa35eb0793734e085ccaeba7d468e4bce
diff --git a/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp b/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp
index db0b133..da47aae 100644
--- a/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp
+++ b/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp
@@ -96,13 +96,17 @@
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));
+ if (radius == 0) {
+ paint.setShader(std::move(input));
+ paint.setAlphaf(alpha);
+ } else {
+ SkRuntimeShaderBuilder blurBuilder(mBlurEffect);
+ blurBuilder.child("child") = std::move(input);
+ blurBuilder.uniform("in_blurOffset") = radius;
+ blurBuilder.uniform("in_crossFade") = alpha;
+ paint.setShader(blurBuilder.makeShader(nullptr));
+ }
paint.setBlendMode(alpha == 1.0f ? SkBlendMode::kSrc : SkBlendMode::kSrcOver);
drawSurface->getCanvas()->drawPaint(paint);
}
@@ -116,32 +120,35 @@
// 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)));
+ constexpr int kMaxSurfaces = 3;
+ const float filterDepth = std::min(kMaxSurfaces - 1.0f, radius * kInputScale / 2.5f);
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.
+ // Render into surfaces downscaled by 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};
+ filterPasses >= 1 ? makeSurface(context, blurRect, 2 * kInverseInputScale) : nullptr,
+ filterPasses >= 2 ? 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};
+ // These weights for scaling offsets per-pass are handpicked to look good at 1 <= radius <= 250.
+ static const float kWeights[5] = {
+ 1.0f, // 1st downsampling pass
+ 1.0f, // 2nd downsampling pass
+ 1.0f, // 3rd downsampling pass
+ 0.0f, // 1st upscaling pass. Set to zero to upscale without blurring for performance.
+ 1.0f, // 2nd upscaling pass
+ };
// 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);
+ float sumSquaredR = powf(kWeights[0], 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);
+ sumSquaredR += powf(powf(2.0f, i) * alpha * kWeights[1 + i] / kInputScale, 2.0f);
+ sumSquaredR += powf(powf(2.0f, i + 1) * alpha * kWeights[4 - i] / kInputScale, 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));
+ // Solve for R = sqrt(sum(r_i^2)).
+ const float step = radius * sqrt(1.0f / sumSquaredR);
// Start by downscaling and doing the first blur pass.
{
@@ -162,7 +169,7 @@
}
// 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,
+ blurInto(surfaces[i], surfaces[i + 1]->makeImageSnapshot(), kWeights[4 - i] * step,
std::min(1.0f, filterDepth - i));
}
return surfaces[0]->makeImageSnapshot();