X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=fft_pass_effect.frag;fp=fft_pass_effect.frag;h=462a6734c9ba87eae62f67aa2d09c5d264066718;hp=0000000000000000000000000000000000000000;hb=c4f0d4e876a8177db5738596f22349e030e0a1dc;hpb=614bef1bce4e94e7774d965b790a1d95b55b81bc

diff --git a/fft_pass_effect.frag b/fft_pass_effect.frag
new file mode 100644
index 0000000..462a673
--- /dev/null
+++ b/fft_pass_effect.frag
@@ -0,0 +1,24 @@
+// DIRECTION_VERTICAL will be #defined to 1 if we are doing a vertical FFT,
+// and 0 otherwise.
+
+uniform float PREFIX(num_repeats);
+uniform sampler1D PREFIX(support_tex);
+
+vec4 FUNCNAME(vec2 tc) {
+#if DIRECTION_VERTICAL
+	vec4 support = texture1D(PREFIX(support_tex), tc.y * PREFIX(num_repeats));
+        vec4 c1 = INPUT(vec2(tc.x, 1.0 - (tc.y + support.x)));
+        vec4 c2 = INPUT(vec2(tc.x, 1.0 - (tc.y + support.y)));
+#else
+	vec4 support = texture1D(PREFIX(support_tex), tc.x * PREFIX(num_repeats));
+        vec4 c1 = INPUT(vec2(tc.x + support.x, tc.y));
+        vec4 c2 = INPUT(vec2(tc.x + support.y, tc.y));
+#endif
+	// Two complex additions and multiplications in parallel; essentially
+	//
+	//   result.xy = c1.xy + twiddle * c2.xy
+	//   result.zw = c1.zw + twiddle * c2.zw
+	//
+	// where * is complex multiplication.
+	return c1 + support.z * c2 + support.w * vec4(-c2.y, c2.x, -c2.w, c2.z);
+}