SL-18095 WIP -- Add Mikktspace tangent generation for PBR materials and switch to per-pixel binormal generation. Still bugged with some test content.

4 files changed, 46 insertions, 33 deletions

diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index cd33690075..9508c1dc2d 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -10558,6 +10558,17 @@
     <key>Value</key>
     <integer>0</integer>
   </map>
+  <key>RenderUseMikktSpace</key>
+  <map>
+    <key>Comment</key>
+    <string>Use Mikkt Space tangents on GLTF materials.</string>
+    <key>Persist</key>
+    <integer>1</integer>
+    <key>Type</key>
+    <string>Boolean</string>
+    <key>Value</key>
+    <integer>1</integer>
+  </map>
   <key>RenderUseTriStrips</key>
   <map>
     <key>Comment</key>
diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbropaqueF.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbropaqueF.glsl
index f5b5698305..69019667de 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbropaqueF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbropaqueF.glsl
@@ -42,6 +42,8 @@ uniform vec3 emissiveColor;
 
 #ifdef HAS_NORMAL_MAP
     uniform sampler2D bumpMap;
+    VARYING vec3 vary_tangent;
+    flat in float vary_sign;
 #endif
 
 #ifdef HAS_EMISSIVE_MAP
@@ -66,9 +68,6 @@ VARYING vec4 vertex_color;
 VARYING vec2 vary_texcoord0;
 #ifdef HAS_NORMAL_MAP
 VARYING vec3 vary_normal;
-VARYING vec3 vary_mat0;
-VARYING vec3 vary_mat1;
-VARYING vec3 vary_mat2;
 VARYING vec2 vary_texcoord1;
 #endif
 
@@ -94,21 +93,14 @@ void main()
 
     vec3 col = vertex_color.rgb * albedo.rgb;
 
-#ifdef HAS_NORMAL_MAP
-    vec4 norm = texture2D(bumpMap, vary_texcoord1.xy);
-    norm.xyz = normalize(norm.xyz * 2 - 1);
-
-    vec3 tnorm = vec3(dot(norm.xyz,vary_mat0),
-                      dot(norm.xyz,vary_mat1),
-                      dot(norm.xyz,vary_mat2));
-#else
-    vec4 norm = vec4(0,0,0,1.0);
-//    vec3 tnorm = vary_normal;
-    vec3 tnorm = vec3(0,0,1);
-#endif
+    // from mikktspace.com
+    vec4 vNt = texture2D(bumpMap, vary_texcoord1.xy)*2.0-1.0;
+    float sign = vary_sign;
+    vec3 vN = vary_normal;
+    vec3 vT = vary_tangent.xyz;
 
-    tnorm = normalize(tnorm.xyz);
-    norm.xyz = tnorm.xyz;
+    vec3 vB = sign * cross(vN, vT);
+    vec3 tnorm = normalize( vNt.x * vT + vNt.y * vB + vNt.z * vN );
 
     // RGB = Occlusion, Roughness, Metal
     // default values, see LLViewerTexture::sDefaultPBRORMImagep
@@ -155,6 +147,9 @@ void main()
 
     tnorm *= gl_FrontFacing ? 1.0 : -1.0;
 
+    //col = vec3(0,0,0);
+    //emissive = vary_tangent.xyz*0.5+0.5;
+    //emissive = vec3(vary_sign*0.5+0.5);
     // See: C++: addDeferredAttachments(), GLSL: softenLightF
     frag_data[0] = vec4(col, 0.0);                                                   // Diffuse
     frag_data[1] = vec4(emissive, vertex_color.a);                                   // PBR sRGB Emissive
diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbropaqueV.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbropaqueV.glsl
index a2606ed771..e17d91af38 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbropaqueV.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbropaqueV.glsl
@@ -59,13 +59,7 @@ ATTRIBUTE vec2 texcoord0;
 ATTRIBUTE vec4 tangent;
 ATTRIBUTE vec2 texcoord1;
 
-VARYING vec3 vary_mat0;
-VARYING vec3 vary_mat1;
-VARYING vec3 vary_mat2;
-
 VARYING vec2 vary_texcoord1;
-#else
-VARYING vec3 vary_normal;
 #endif
 
 #ifdef HAS_SPECULAR_MAP
@@ -75,6 +69,10 @@ VARYING vec2 vary_texcoord2;
  
 VARYING vec4 vertex_color;
 VARYING vec2 vary_texcoord0;
+VARYING vec3 vary_tangent;
+flat out float vary_sign;
+
+VARYING vec3 vary_normal;
 
 void main()
 {
@@ -113,9 +111,9 @@ void main()
 	vec3 t = normalize((mat*vec4(tangent.xyz+position.xyz,1.0)).xyz-pos.xyz);
 	vec3 b = cross(n, t)*tangent.w;
 	
-	vary_mat0 = vec3(t.x, b.x, n.x);
-	vary_mat1 = vec3(t.y, b.y, n.y);
-	vary_mat2 = vec3(t.z, b.z, n.z);
+	//vary_mat0 = vec3(t.x, b.x, n.x);
+	//vary_mat1 = vec3(t.y, b.y, n.y);
+	//vary_mat2 = vec3(t.z, b.z, n.z);
 #else //HAS_NORMAL_MAP
 vary_normal  = n;
 #endif //HAS_NORMAL_MAP
@@ -123,12 +121,16 @@ vary_normal  = n;
 	vec3 n = normalize(normal_matrix * normal);
 #ifdef HAS_NORMAL_MAP
 	vec3 t = normalize(normal_matrix * tangent.xyz);
-	vec3 b = cross(n,t)*tangent.w;
+    vary_tangent = t;
+    vary_sign = tangent.w;
+    vary_normal = n;
+
+	//vec3 b = cross(n,t)*tangent.w;
 	//vec3 t = cross(b,n) * binormal.w;
 	
-	vary_mat0 = vec3(t.x, b.x, n.x);
-	vary_mat1 = vec3(t.y, b.y, n.y);
-	vary_mat2 = vec3(t.z, b.z, n.z);
+	//vary_mat0 = vec3(t.x, b.x, n.x);
+	//vary_mat1 = vec3(t.y, b.y, n.y);
+	//vary_mat2 = vec3(t.z, b.z, n.z);
 #else //HAS_NORMAL_MAP
 	vary_normal = n;
 #endif //HAS_NORMAL_MAP
diff --git a/indra/newview/llface.cpp b/indra/newview/llface.cpp
index 52aacb607c..f35b4b6d91 100644
--- a/indra/newview/llface.cpp
+++ b/indra/newview/llface.cpp
@@ -2166,14 +2166,19 @@ BOOL LLFace::getGeometryVolume(const LLVolume& volume,
 			mVertexBuffer->getTangentStrider(tangent, mGeomIndex, mGeomCount, map_range);
 			F32* tangents = (F32*) tangent.get();
 			
-			mVObjp->getVolume()->genTangents(f);
+            LLGLTFMaterial* gltf_mat = tep->getGLTFMaterial();
+            static LLCachedControl<bool> use_mikktspace(gSavedSettings, "RenderUseMikktSpace");
+            bool mikktspace = use_mikktspace && gltf_mat != nullptr;
+
+			mVObjp->getVolume()->genTangents(f, mikktspace);
 			
 			LLVector4Logical mask;
 			mask.clear();
 			mask.setElement<3>();
 
-			LLVector4a* src = vf.mTangents;
-			LLVector4a* end = vf.mTangents+num_vertices;
+            LLVector4a* tbuff = mikktspace ? vf.mMikktSpaceTangents : vf.mTangents;
+			LLVector4a* src = tbuff;
+			LLVector4a* end = tbuff+num_vertices;
 
 			while (src < end)
 			{