DRTVWR-592: Clean up

2 files changed, 30 insertions, 407 deletions

diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainF.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainF.glsl
index 0a7c58451d..18f8c4aa73 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainF.glsl
@@ -36,18 +36,11 @@
 #define MIX_Z    1 << 5
 #define MIX_W    1 << 6
 
-#if 0 // TODO: Remove debug
-#define TERRAIN_DEBUG 1
-#endif
-
 // TODO: Decide if this struct needs to be declared
 struct TerrainMix
 {
     vec4 weight;
     int type;
-#if TERRAIN_DEBUG
-    ivec4 usage;
-#endif
 };
 
 TerrainMix get_terrain_mix_weights(float alpha1, float alpha2, float alphaFinal);
@@ -127,12 +120,7 @@ in vec4 vary_texcoord1;
 
 vec2 encode_normal(vec3 n);
 
-float terrain_mix(vec4 samples, float alpha1, float alpha2, float alphaFinal);
-// TODO: Clean these up
-vec3 sample_and_mix_color3(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec3[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3);
-vec4 sample_and_mix_color4(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec4[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3);
-vec3 sample_and_mix_vector3(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec3[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3);
-vec3 sample_and_mix_normal(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3);
+float terrain_mix(TerrainMix tm, vec4 tms4);
 
 void main()
 {
@@ -170,14 +158,14 @@ void main()
             , detail_0_base_color
             , detail_0_metallic_roughness
             , detail_0_normal
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , detail_0_emissive
-        #endif
+#endif
             , baseColorFactors[0]
             , orm_factors[0]
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , emissiveColors[0]
-        #endif
+#endif
         );
         mix = mix_pbr(mix, mix2, tm.weight.x);
         break;
@@ -192,14 +180,14 @@ void main()
             , detail_1_base_color
             , detail_1_metallic_roughness
             , detail_1_normal
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , detail_1_emissive
-        #endif
+#endif
             , baseColorFactors[1]
             , orm_factors[1]
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , emissiveColors[1]
-        #endif
+#endif
         );
         mix = mix_pbr(mix, mix2, tm.weight.y);
         break;
@@ -214,14 +202,14 @@ void main()
             , detail_2_base_color
             , detail_2_metallic_roughness
             , detail_2_normal
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , detail_2_emissive
-        #endif
+#endif
             , baseColorFactors[2]
             , orm_factors[2]
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , emissiveColors[2]
-        #endif
+#endif
         );
         mix = mix_pbr(mix, mix2, tm.weight.z);
         break;
@@ -236,14 +224,14 @@ void main()
             , detail_3_base_color
             , detail_3_metallic_roughness
             , detail_3_normal
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , detail_3_emissive
-        #endif
+#endif
             , baseColorFactors[3]
             , orm_factors[3]
-        #if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
+#if (TERRAIN_PBR_DETAIL >= TERRAIN_PBR_DETAIL_EMISSIVE)
             , emissiveColors[3]
-        #endif
+#endif
         );
         mix = mix_pbr(mix, mix2, tm.weight.w);
         break;
@@ -251,12 +239,12 @@ void main()
         break;
     }
 
-    float minimum_alpha = terrain_mix(minimum_alphas, alpha1, alpha2, alphaFinal);
+    float minimum_alpha = terrain_mix(tm, minimum_alphas);
     if (mix.col.a < minimum_alpha)
     {
         discard;
     }
-    float base_color_factor_alpha = terrain_mix(vec4(baseColorFactors[0].z, baseColorFactors[1].z, baseColorFactors[2].z, baseColorFactors[3].z), alpha1, alpha2, alphaFinal);
+    float base_color_factor_alpha = terrain_mix(tm, vec4(baseColorFactors[0].z, baseColorFactors[1].z, baseColorFactors[2].z, baseColorFactors[3].z));
 
     // from mikktspace.com
     vec3 vNt = mix.vNt;
diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
index 078c753a35..c18cf832f8 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbrterrainUtilF.glsl
@@ -138,16 +138,10 @@ struct TerrainTriplanar
     int type;
 };
 
-#if 0 // TODO: Remove debug
-#define TERRAIN_DEBUG 1
-#endif
 struct TerrainMix
 {
     vec4 weight;
     int type;
-#if TERRAIN_DEBUG
-    ivec4 usage;
-#endif
 };
 
 #define TerrainMixSample vec4[4]
@@ -172,9 +166,6 @@ TerrainMix get_terrain_mix_weights(float alpha1, float alpha2, float alphaFinal)
               (usage.y * MIX_Y) |
               (usage.z * MIX_Z) |
               (usage.w * MIX_W);
-#if TERRAIN_DEBUG // TODO: Remove debug
-    tm.usage = usage;
-#endif
     return tm;
 }
 
@@ -196,32 +187,13 @@ TerrainTriplanar _t_triplanar()
     return tw;
 }
 
-float terrain_mix(vec4 samples, float alpha1, float alpha2, float alphaFinal)
-{
-    TerrainMix tm = get_terrain_mix_weights(alpha1, alpha2, alphaFinal);
-    // Assume weights add to 1
-    return tm.weight.x * samples.x +
-           tm.weight.y * samples.y +
-           tm.weight.z * samples.z +
-           tm.weight.w * samples.w;
-}
-
-vec4 terrain_mix(TerrainMix tm, TerrainMixSample tms)
-{
-    // Assume weights add to 1
-    return tm.weight.x * tms[0] +
-           tm.weight.y * tms[1] +
-           tm.weight.z * tms[2] +
-           tm.weight.w * tms[3];
-}
-
-vec3 terrain_mix(TerrainMix tm, TerrainMixSample3 tms3)
+// Assume weights add to 1
+float terrain_mix(TerrainMix tm, vec4 tms4)
 {
-    // Assume weights add to 1
-    return tm.weight.x * tms3[0] +
-           tm.weight.y * tms3[1] +
-           tm.weight.z * tms3[2] +
-           tm.weight.w * tms3[3];
+    return (tm.weight.x * tms4[0]) +
+           (tm.weight.y * tms4[1]) +
+           (tm.weight.z * tms4[2]) +
+           (tm.weight.w * tms4[3]);
 }
 
 #if TERRAIN_PLANAR_TEXTURE_SAMPLE_COUNT == 3
@@ -230,17 +202,6 @@ vec3 terrain_mix(TerrainMix tm, TerrainMixSample3 tms3)
 // Pre-transformed texture coordinates for each axial uv slice (Packing: xy, yz, (-x)z, unused)
 #define TerrainCoord vec4[2]
 
-vec4 _t_texture(sampler2D tex, vec2 uv_unflipped, float sign_or_zero)
-{
-    // Handle case where sign is 0
-    float sign = (2.0*sign_or_zero) + 1.0;
-    sign /= abs(sign);
-    // If the vertex normal is negative, flip the texture back
-    // right-side up.
-    vec2 uv = uv_unflipped * vec2(sign, 1);
-    return texture(tex, uv);
-}
-
 vec2 _t_uv(vec2 uv_unflipped, float sign_or_zero)
 {
     // Handle case where sign is 0
@@ -287,132 +248,6 @@ vec3 _t_normal_post_z(vec3 vNt0)
     return vNt_z;
 }
 
-struct TerrainSample
-{
-    vec4 x;
-    vec4 y;
-    vec4 z;
-};
-
-TerrainSample _t_sample(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
-{
-    TerrainSample ts;
-
-    // The switch..case is broken up into three parts deliberately.  A single
-    // switch..case caused unexplained, "ant trail" seams in terrain. (as seen
-    // on Nvidia/Windows 10).  The extra two branches are not free, but it's
-    // still a performance win compared to sampling along all three axes for
-    // every terrain fragment.
-    #define do_sample_x() _t_texture(tex, terrain_coord[0].zw, sign(vary_vertex_normal.x))
-    #define do_sample_y() _t_texture(tex, terrain_coord[1].xy, sign(vary_vertex_normal.y))
-    #define do_sample_z() _t_texture(tex, terrain_coord[0].xy, sign(vary_vertex_normal.z))
-    switch (tw.type & SAMPLE_X)
-    {
-        case SAMPLE_X:
-            ts.x = do_sample_x();
-        break;
-        default:
-            ts.x = vec4(1.0, 0.0, 1.0, 1.0);
-        break;
-    }
-    switch (tw.type & SAMPLE_Y)
-    {
-        case SAMPLE_Y:
-            ts.y = do_sample_y();
-        break;
-        default:
-            ts.y = vec4(1.0, 0.0, 1.0, 1.0);
-        break;
-    }
-    switch (tw.type & SAMPLE_Z)
-    {
-        case SAMPLE_Z:
-            ts.z = do_sample_z();
-        break;
-        default:
-            ts.z = vec4(1.0, 0.0, 1.0, 1.0);
-        break;
-    }
-
-    return ts;
-}
-
-struct TerrainSampleNormal
-{
-    vec3 x;
-    vec3 y;
-    vec3 z;
-};
-
-TerrainSampleNormal _t_sample_n(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
-{
-    TerrainSample ts = _t_sample(tex, terrain_coord, tw);
-    TerrainSampleNormal tsn;
-    // Unpack normals
-    tsn.x = ts.x.xyz*2.0-1.0;
-    tsn.y = ts.y.xyz*2.0-1.0;
-    tsn.z = ts.z.xyz*2.0-1.0;
-    // Get sign
-    vec3 ns = sign(vary_vertex_normal);
-    // Handle case where sign is 0
-    ns = (2.0*ns) + 1.0;
-    ns /= abs(ns);
-    // If the sign is negative, rotate normal by 180 degrees
-    tsn.x.xy = (min(0, ns.x) * tsn.x.xy) + (min(0, -ns.x) * -tsn.x.xy);
-    tsn.y.xy = (min(0, ns.y) * tsn.y.xy) + (min(0, -ns.y) * -tsn.y.xy);
-    tsn.z.xy = (min(0, ns.z) * tsn.z.xy) + (min(0, -ns.z) * -tsn.z.xy);
-    // *HACK: Transform normals according to orientation of the UVs
-    tsn.x.xy = vec2(-tsn.x.y, tsn.x.x);
-    tsn.y.xy = -tsn.y.xy;
-    return tsn;
-}
-
-TerrainSample _t_sample_c(sampler2D tex, TerrainCoord terrain_coord, TerrainTriplanar tw)
-{
-    TerrainSample ts = _t_sample(tex, terrain_coord, tw);
-    ts.x.xyz = srgb_to_linear(ts.x.xyz);
-    ts.y.xyz = srgb_to_linear(ts.y.xyz);
-    ts.z.xyz = srgb_to_linear(ts.z.xyz);
-    return ts;
-}
-
-// Triplanar sampling of things that are neither colors nor normals (i.e. orm)
-vec4 terrain_texture(sampler2D tex, TerrainCoord terrain_coord)
-{
-    TerrainTriplanar tw = _t_triplanar();
-
-    TerrainSample ts = _t_sample(tex, terrain_coord, tw);
-
-    return ((ts.x * tw.weight.x) + (ts.y * tw.weight.y) + (ts.z * tw.weight.z)) / (tw.weight.x + tw.weight.y + tw.weight.z);
-}
-
-// Specialized triplanar normal texture sampling implementation, taking into
-// account how the rotation of the texture affects the lighting and trying to
-// negate that.
-// *TODO: Decide if we want this. It may be better to just calculate the
-// tangents on-the-fly here rather than messing with the normals, due to the
-// subtleties of the effects of triplanar mapping on UVs. These sampled normals
-// are only valid on the faces of a cube.
-// *NOTE: Bottom face has not been tested
-vec3 terrain_texture_normal(sampler2D tex, TerrainCoord terrain_coord)
-{
-    TerrainTriplanar tw = _t_triplanar();
-
-    TerrainSampleNormal ts = _t_sample_n(tex, terrain_coord, tw);
-
-    return ((ts.x * tw.weight.x) + (ts.y * tw.weight.y) + (ts.z * tw.weight.z)) / (tw.weight.x + tw.weight.y + tw.weight.z);
-}
-
-// Triplanar sampling of colors. Colors are converted to linear space before blending.
-vec4 terrain_texture_color(sampler2D tex, TerrainCoord terrain_coord)
-{
-    TerrainTriplanar tw = _t_triplanar();
-
-    TerrainSample ts = _t_sample_c(tex, terrain_coord, tw);
-
-    return ((ts.x * tw.weight.x) + (ts.y * tw.weight.y) + (ts.z * tw.weight.z)) / (tw.weight.x + tw.weight.y + tw.weight.z);
-}
-
 PBRMix terrain_sample_pbr(
     TerrainCoord terrain_coord
     , TerrainTriplanar tw
@@ -426,9 +261,9 @@ PBRMix terrain_sample_pbr(
 {
     PBRMix mix = init_pbr_mix();
 
-    #define get_uv_x() _t_uv(terrain_coord[0].zw, sign(vary_vertex_normal.x))
-    #define get_uv_y() _t_uv(terrain_coord[1].xy, sign(vary_vertex_normal.y))
-    #define get_uv_z() _t_uv(terrain_coord[0].xy, sign(vary_vertex_normal.z))
+#define get_uv_x() _t_uv(terrain_coord[0].zw, sign(vary_vertex_normal.x))
+#define get_uv_y() _t_uv(terrain_coord[1].xy, sign(vary_vertex_normal.y))
+#define get_uv_z() _t_uv(terrain_coord[0].xy, sign(vary_vertex_normal.z))
     switch (tw.type & SAMPLE_X)
     {
     case SAMPLE_X:
@@ -482,6 +317,7 @@ PBRMix terrain_sample_pbr(
 #endif
             );
         // Triplanar-specific normal texture fix
+        // *NOTE: Bottom face has not been tested
         mix_z.vNt = _t_normal_post_z(mix_z.vNt);
         mix = mix_pbr(mix, mix_z, tw.weight.z);
         break;
@@ -493,214 +329,13 @@ PBRMix terrain_sample_pbr(
 }
 
 #elif TERRAIN_PLANAR_TEXTURE_SAMPLE_COUNT == 1
-#define TerrainCoord vec2
-vec4 terrain_texture(sampler2D tex, TerrainCoord terrain_coord)
-{
-    return texture(tex, terrain_coord);
-}
-
-vec3 terrain_texture_normal(sampler2D tex, TerrainCoord terrain_coord)
-{
-    return texture(tex, terrain_coord).xyz*2.0-1.0;
-}
 
-vec4 terrain_texture_color(sampler2D tex, TerrainCoord terrain_coord)
-{
-    vec4 col = texture(tex, terrain_coord);
-    col.xyz = srgb_to_linear(col.xyz);
-    return col;
-}
+#define TerrainCoord vec2
 
 #define terrain_sample_pbr sample_pbr
 
 #endif
 
-// The goal of _tmix_sample and related functions is to only sample textures when necessary, ignoring if the weights are low.
-// *TODO: Currently, there is much more switch..case branching than needed. This could be simplified by branching per-material rather than per-texture.
-
-TerrainMixSample _tmix_sample(TerrainMix tm, TerrainCoord texcoord, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMixSample tms;
-
-    switch (tm.type & MIX_X)
-    {
-        case MIX_X:
-            tms[0] = terrain_texture(tex0, texcoord);
-            break;
-        default:
-            tms[0] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Y)
-    {
-        case MIX_Y:
-            tms[1] = terrain_texture(tex1, texcoord);
-            break;
-        default:
-            tms[1] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Z)
-    {
-        case MIX_Z:
-            tms[2] = terrain_texture(tex2, texcoord);
-            break;
-        default:
-            tms[2] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_W)
-    {
-        case MIX_W:
-            tms[3] = terrain_texture(tex3, texcoord);
-            break;
-        default:
-            tms[3] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-
-    return tms;
-}
-
-TerrainMixSample _tmix_sample_color(TerrainMix tm, TerrainCoord texcoord, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMixSample tmix;
-
-    switch (tm.type & MIX_X)
-    {
-        case MIX_X:
-            tmix[0] = terrain_texture_color(tex0, texcoord);
-            break;
-        default:
-            tmix[0] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Y)
-    {
-        case MIX_Y:
-            tmix[1] = terrain_texture_color(tex1, texcoord);
-            break;
-        default:
-            tmix[1] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Z)
-    {
-        case MIX_Z:
-            tmix[2] = terrain_texture_color(tex2, texcoord);
-            break;
-        default:
-            tmix[2] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_W)
-    {
-        case MIX_W:
-            tmix[3] = terrain_texture_color(tex3, texcoord);
-            break;
-        default:
-            tmix[3] = vec4(1.0, 0.0, 1.0, 1.0);
-            break;
-    }
-
-    return tmix;
-}
-
-TerrainMixSample3 _tmix_sample_normal(TerrainMix tm, TerrainCoord texcoord, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMixSample3 tmix3;
-
-    switch (tm.type & MIX_X)
-    {
-        case MIX_X:
-            tmix3[0] = terrain_texture_normal(tex0, texcoord);
-            break;
-        default:
-            tmix3[0] = vec3(1.0, 0.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Y)
-    {
-        case MIX_Y:
-            tmix3[1] = terrain_texture_normal(tex1, texcoord);
-            break;
-        default:
-            tmix3[1] = vec3(1.0, 0.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_Z)
-    {
-        case MIX_Z:
-            tmix3[2] = terrain_texture_normal(tex2, texcoord);
-            break;
-        default:
-            tmix3[2] = vec3(1.0, 0.0, 1.0);
-            break;
-    }
-    switch (tm.type & MIX_W)
-    {
-        case MIX_W:
-            tmix3[3] = terrain_texture_normal(tex3, texcoord);
-            break;
-        default:
-            tmix3[3] = vec3(1.0, 0.0, 1.0);
-            break;
-    }
-
-    return tmix3;
-}
-
-vec3 sample_and_mix_color3(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec3[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMix tm = get_terrain_mix_weights(alpha1, alpha2, alphaFinal);
-    TerrainMixSample tms = _tmix_sample_color(tm, texcoord, tex0, tex1, tex2, tex3);
-    vec3[4] tms3;
-    tms3[0] = tms[0].xyz;
-    tms3[1] = tms[1].xyz;
-    tms3[2] = tms[2].xyz;
-    tms3[3] = tms[3].xyz;
-    tms3[0] *= factors[0];
-    tms3[1] *= factors[1];
-    tms3[2] *= factors[2];
-    tms3[3] *= factors[3];
-    return terrain_mix(tm, tms3);
-}
-
-vec4 sample_and_mix_color4(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec4[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMix tm = get_terrain_mix_weights(alpha1, alpha2, alphaFinal);
-    TerrainMixSample tms = _tmix_sample_color(tm, texcoord, tex0, tex1, tex2, tex3);
-    tms[0] *= factors[0];
-    tms[1] *= factors[1];
-    tms[2] *= factors[2];
-    tms[3] *= factors[3];
-    return terrain_mix(tm, tms);
-}
-
-vec3 sample_and_mix_vector3(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, vec3[4] factors, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMix tm = get_terrain_mix_weights(alpha1, alpha2, alphaFinal);
-    TerrainMixSample tms = _tmix_sample(tm, texcoord, tex0, tex1, tex2, tex3);
-    vec3[4] tms3;
-    tms3[0] = tms[0].xyz;
-    tms3[1] = tms[1].xyz;
-    tms3[2] = tms[2].xyz;
-    tms3[3] = tms[3].xyz;
-    tms3[0] *= factors[0];
-    tms3[1] *= factors[1];
-    tms3[2] *= factors[2];
-    tms3[3] *= factors[3];
-    return terrain_mix(tm, tms3);
-}
-
-// Returns the unpacked normal texture in range [-1, 1]
-vec3 sample_and_mix_normal(float alpha1, float alpha2, float alphaFinal, TerrainCoord texcoord, sampler2D tex0, sampler2D tex1, sampler2D tex2, sampler2D tex3)
-{
-    TerrainMix tm = get_terrain_mix_weights(alpha1, alpha2, alphaFinal);
-    TerrainMixSample3 tms3 = _tmix_sample_normal(tm, texcoord, tex0, tex1, tex2, tex3);
-    return terrain_mix(tm, tms3);
-}
-
 PBRMix multiply_factors_pbr(
     PBRMix mix_in
     , vec4 factor_col