- // See the comments on changes_output_size() in the .h file to see
- // why this is legal. It is _needed_ because it counteracts the
- // precision issues we get because we sample the input texture with
- // normalized coordinates (especially when the repeat count along
- // the axis is not a power of two); we very rapidly end up in narrowly
- // missing a texel center, which causes precision loss to propagate
- // throughout the FFT.
- assert(*sampler_num == 1);
- glActiveTexture(GL_TEXTURE0);
+ // This is needed because it counteracts the precision issues we get
+ // because we sample the input texture with normalized coordinates
+ // (especially when the repeat count along the axis is not a power of
+ // two); we very rapidly end up in narrowly missing a texel center,
+ // which causes precision loss to propagate throughout the FFT.
+ Node *self = chain->find_node_for_effect(this);
+ glActiveTexture(chain->get_input_sampler(self, 0));