static uint8_t* create_profile(float halfWH, float sigma) {
int kernelWH = SkScalarCeilToInt(6.0f*sigma);
kernelWH = (kernelWH + 1) & ~1; // make it the next even number up
SkAutoTArray<float> halfKernel(kernelWH*kernelWH/2);
make_half_kernel(halfKernel.get(), kernelWH, sigma);
float offset;
int numSteps;
compute_profile_offset_and_size(halfWH, sigma, &offset, &numSteps);
uint8_t* weights = new uint8_t[numSteps];
for (int i = 0; i < numSteps; ++i) {
weights[i] = eval_at(offset+i, halfWH, halfKernel.get(), kernelWH);
}
return weights;
}
GrTexture* GrCircleBlurFragmentProcessor::CreateCircleBlurProfileTexture(
GrTextureProvider* textureProvider,
const SkRect& circle,
float sigma,
float* offset) {
float halfWH = circle.width() / 2.0f;
int size;
compute_profile_offset_and_size(halfWH, sigma, offset, &size);
GrSurfaceDesc texDesc;
texDesc.fWidth = size;
texDesc.fHeight = 1;
texDesc.fConfig = kAlpha_8_GrPixelConfig;
static const GrUniqueKey::Domain kDomain = GrUniqueKey::GenerateDomain();
GrUniqueKey key;
GrUniqueKey::Builder builder(&key, kDomain, 2);
// The profile curve varies with both the sigma of the Gaussian and the size of the
// disk. Quantizing to 16.16 should be close enough though.
builder[0] = SkScalarToFixed(sigma);
builder[1] = SkScalarToFixed(halfWH);
builder.finish();
GrTexture *blurProfile = textureProvider->findAndRefTextureByUniqueKey(key);
if (!blurProfile) {
SkAutoTDeleteArray<uint8_t> profile(create_profile(halfWH, sigma));
blurProfile = textureProvider->createTexture(texDesc, SkBudgeted::kYes, profile.get(), 0);
if (blurProfile) {
textureProvider->assignUniqueKeyToTexture(key, blurProfile);
}
}
return blurProfile;
}
