convolutionShaderBuildKernel top-level property
Function
convolutionShaderBuildKernel
getter/setter pair
Implementation
Function convolutionShaderBuildKernel = (sigma) {
// We lop off the sqrt(2 * pi) * sigma term, since we're going to normalize anyway.
gauss(x, sigma) {
return Math.exp(-(x * x) / (2.0 * sigma * sigma));
}
var i, values, sum, halfWidth, kMaxKernelSize = 25;
int kernelSize = (2 * Math.ceil(sigma * 3.0) + 1).toInt();
if (kernelSize > kMaxKernelSize) kernelSize = kMaxKernelSize;
halfWidth = (kernelSize - 1) * 0.5;
values = List<num>.filled(kernelSize, 0.0);
sum = 0.0;
for (i = 0; i < kernelSize; ++i) {
values[i] = gauss(i - halfWidth, sigma);
sum += values[i];
}
// normalize the kernel
for (i = 0; i < kernelSize; ++i) {
values[i] /= sum;
}
return values;
};