vo_opengl: clamp filters to their size

This gives better results with fancy-downscaling. The issue here is that
fancy-downscalign "extends" the filter radius by some amount, which
requires using a larger filter size and shader. Then most of the filter
is "unused", but some filters still return non-0 coefficients, which
create heavy artifacts. Just clamp them off.

I'm not sure if this is the right solution, but at least it's better
than before.

1 files changed, 2 insertions, 1 deletions

diff --git a/video/out/filter_kernels.c b/video/out/filter_kernels.c
index 217bb25730..26f62ff567 100644
--- a/video/out/filter_kernels.c
+++ b/video/out/filter_kernels.c
@@ -91,7 +91,8 @@ void mp_compute_weights(struct filter_kernel *filter, double f, float *out_w)
     double sum = 0;
     for (int n = 0; n < filter->size; n++) {
         double x = f - (n - filter->size / 2 + 1);
-        double w = filter->weight(filter, fabs(x) / filter->inv_scale);
+        double c = fabs(x) / filter->inv_scale;
+        double w = c <= filter->radius ? filter->weight(filter, c) : 0;
         out_w[n] = w;
         sum += w;
     }