X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=dither_effect.frag;h=f12530dbdd7cd904b8ae820928c66cf471259f20;hp=3b6b892d7606937867b4ab0c2b749926034d9f29;hb=27496ee4620a3b5380f9d5f2a827d6c599bc1a39;hpb=28bc5f37437fa8eaca523a209c558b807ced2db3

diff --git a/dither_effect.frag b/dither_effect.frag
index 3b6b892..f12530d 100644
--- a/dither_effect.frag
+++ b/dither_effect.frag
@@ -1,15 +1,43 @@
-uniform sampler2D PREFIX(dither_tex);
-uniform vec2 PREFIX(tc_scale);
-uniform float PREFIX(round_fac), PREFIX(inv_round_fac);
+// Implicit uniforms:
+// uniform sampler2D PREFIX(dither_tex);
+// uniform vec2 PREFIX(tc_scale);
+// uniform float PREFIX(round_fac), PREFIX(inv_round_fac);
+
+// See footer.frag for details about this if statement.
+#ifndef YCBCR_ALSO_OUTPUT_RGBA
+#define YCBCR_ALSO_OUTPUT_RGBA 0
+#endif
+
+#if YCBCR_ALSO_OUTPUT_RGBA
+
+// There are two values to dither; otherwise, exactly the same as the algorithm below
+// (so comments are not duplicated).
+
+vec4[2] FUNCNAME(vec2 tc) {
+	vec4[2] result = INPUT(tc);
+	float d = tex2D(PREFIX(dither_tex), tc * PREFIX(tc_scale)).x;
+	result[0].rgb += vec3(d);
+	result[1].rgb += vec3(d);
+
+#if NEED_EXPLICIT_ROUND
+	result[0] = round(result[0] * vec4(PREFIX(round_fac))) * vec4(PREFIX(inv_round_fac));
+	result[1] = round(result[1] * vec4(PREFIX(round_fac))) * vec4(PREFIX(inv_round_fac));
+#endif
+
+	return result;
+}
+
+#else
 
 vec4 FUNCNAME(vec2 tc) {
 	vec4 result = INPUT(tc);
+	float d = tex2D(PREFIX(dither_tex), tc * PREFIX(tc_scale)).x;
 
 	// Don't dither alpha; the case of alpha=255 (1.0) is very important to us,
 	// and if there's any inaccuracy earlier in the chain so that it becomes e.g.
 	// 254.8, it's better to just get it rounded off than to dither and have it
 	// possibly get down to 254. This is not the case for the color components.
-	result.rgb += tex2D(PREFIX(dither_tex), tc * PREFIX(tc_scale)).xxx;
+	result.rgb += vec3(d);
 
 	// NEED_EXPLICIT_ROUND will be #defined to 1 if the GPU has inaccurate
 	// fp32 -> int8 framebuffer rounding, and 0 otherwise.
@@ -19,3 +47,5 @@ vec4 FUNCNAME(vec2 tc) {
 
 	return result;
 }
+
+#endif