diff options
| -rw-r--r-- | libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp | 53 |
1 files changed, 30 insertions, 23 deletions
diff --git a/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp b/libs/renderengine/skia/filters/KawaseBlurDualFilter.cpp index db0b133a26..da47aae15b 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, 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 @@ sk_sp<SkImage> KawaseBlurDualFilter::generate(SkiaGpuContext* context, const uin // 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}; - - // 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}; + 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 <= 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 @@ sk_sp<SkImage> KawaseBlurDualFilter::generate(SkiaGpuContext* context, const uin } // 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(); |