1 files changed, 46 insertions, 0 deletions
diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
index 5098de717e..dc43007dca 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
@@ -51,7 +51,12 @@
 #define TERRAIN_PBR_DETAIL_NORMAL -2
 #define TERRAIN_PBR_DETAIL_METALLIC_ROUGHNESS -3
 
+#define TERRAIN_PAINT_TYPE_HEIGHTMAP_WITH_NOISE 0
+#define TERRAIN_PAINT_TYPE_PBR_PAINTMAP 1
+
+#if TERRAIN_PLANAR_TEXTURE_SAMPLE_COUNT == 3
 in vec3 vary_vertex_normal;
+#endif
 
 vec3 srgb_to_linear(vec3 c);
 
@@ -202,6 +207,45 @@ TerrainMix get_terrain_mix_weights(float alpha1, float alpha2, float alphaFinal)
     return tm;
 }
 
+// A paintmap weight applier for 4 swatches. The input saves a channel by not
+// storing swatch 1, and assuming the weights of the 4 swatches add to 1.
+// The components of weight3 should be between 0 and 1
+// The sum of the components of weight3 should be between 0 and 1
+TerrainMix get_terrain_usage_from_weight3(vec3 weight3)
+{
+    // These steps ensure the output weights add to between 0 and 1
+    weight3.xyz = max(vec3(0.0), weight3.xyz);
+    weight3.xyz /= max(1.0, weight3.x + weight3.y + weight3.z);
+
+    TerrainMix tm;
+
+    // Extract the first weight from the other weights
+    tm.weight.x = 1.0 - (weight3.x + weight3.y + weight3.z);
+    tm.weight.yzw = weight3.xyz;
+    ivec4 usage = max(ivec4(0), ivec4(ceil(tm.weight)));
+
+    tm.type = (usage.x * MIX_X) |
+              (usage.y * MIX_Y) |
+              (usage.z * MIX_Z) |
+              (usage.w * MIX_W);
+    return tm;
+}
+
+// Inverse of get_terrain_usage_from_weight3, excluding usage flags
+// The components of weight should be between 0 and 1
+// The sum of the components of weight should be 1
+vec3 get_weight3_from_terrain_weight(vec4 weight)
+{
+    // These steps ensure the input weights add to 1
+    weight = max(vec4(0.0), weight);
+    weight.x += 1.0 - sign(weight.x + weight.y + weight.z + weight.w);
+    weight /= weight.x + weight.y + weight.z + weight.w;
+
+    // Then return the input weights with the first weight truncated
+    return weight.yzw;
+}
+
+#if TERRAIN_PLANAR_TEXTURE_SAMPLE_COUNT == 3
 TerrainTriplanar _t_triplanar()
 {
     float sharpness = TERRAIN_TRIPLANAR_BLEND_FACTOR;
@@ -219,6 +263,8 @@ TerrainTriplanar _t_triplanar()
               ((usage.z) * SAMPLE_Z);
     return tw;
 }
+#endif
+
 
 // Assume weights add to 1
 float terrain_mix(TerrainMix tm, vec4 tms4)