From ff683a7127d299694a8fece5772f3656d9214edc Mon Sep 17 00:00:00 2001
From: Dave Houlton <euclid@lindenlab.com>
Date: Wed, 18 Mar 2020 16:30:20 -0600
Subject: [PATCH] SL-12865, add bias to alpha mask values to avoid 8-bit acne
---
.../app_settings/shaders/class1/deferred/materialF.glsl | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
index f1b13c88254..4198053c99e 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
@@ -230,7 +230,10 @@ void main()
vec4 diffuse_linear = vec4(srgb_to_linear(diffuse_srgb.rgb), diffuse_srgb.a);
#if (DIFFUSE_ALPHA_MODE == DIFFUSE_ALPHA_MODE_MASK)
- if (diffuse_linear.a < minimum_alpha)
+
+ // Comparing floats cast from 8-bit values, produces acne right at the 8-bit transition points
+ float bias = 0.001953125; // 1/512, or half an 8-bit quantization
+ if (diffuse_linear.a < minimum_alpha-bias)
{
discard;
}
--
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