Merge pull request #1400 from Santarh/mtoonOutlineFix

Fix migration error in MToon & Modify Screen Coords Outline drawing algorithm.

Assets/VRM10/Runtime/Migration/Materials/MigrationMToonMaterial.cs

@@ -298,7 +298,9 @@ namespace UniVRM10
                         break;
                     case OutlineWidthMode.ScreenCoordinates:
                         dst.OutlineWidthMode = UniGLTF.Extensions.VRMC_materials_mtoon.OutlineWidthMode.screenCoordinates;
-                        dst.OutlineWidthFactor = mtoon.Definition.Outline.OutlineWidthValue * oneHundredth;
+                        // NOTE: 従来は、縦幅の半分を 100% としたときの % の値だった。
+                        //       1.0 では縦幅を 1 としたときの値とするので、 1/200 する。
+                        dst.OutlineWidthFactor = mtoon.Definition.Outline.OutlineWidthValue * oneHundredth * 0.5f;
                         break;
                     default:
                         throw new ArgumentOutOfRangeException($"OutlineWidthMode: {(int)mtoon.Definition.Outline.OutlineWidthMode}");

Assets/VRMShaders/VRM10/MToon10/Resources/VRM10/vrmc_materials_mtoon_define.hlsl

@@ -138,4 +138,14 @@ inline bool MToon_IsOutlineModeDisabled()
 #endif
 }
 
+// Compile-time constant
+inline bool MToon_UseStrictMode()
+{
+ #if defined(_MTOON_USE_STRICT_MODE)
+    return true;
+#else
+    return false;
+#endif
+}
+
 #endif

Assets/VRMShaders/VRM10/MToon10/Resources/VRM10/vrmc_materials_mtoon_geometry_vertex.hlsl

@@ -24,13 +24,33 @@ inline half MToon_GetOutlineVertex_OutlineWidth(const float2 uv)
     }
 }
 
+inline float MToon_GetOutlineVertex_ScreenCoordinatesWidthMultiplier(const float4 positionCS)
+{
+    // NOTE: VRM 1.0 の仕様にはない実装なので、ユーザが任意で機能を外せるようにする.
+    if (MToon_UseStrictMode())
+    {
+        return 1.0f;
+    }
+    else
+    {
+        const float maxViewFrustumPlaneHeight = 2.0f;
+        const float invTangentHalfVerticalFov = unity_CameraProjection[1][1];
+        // NOTE: viewFrustumPlaneHeight = tan(halfFov) * viewDirDistance * 2.0
+        //           -> viewDirDistance = viewFrustumPlaneHeight / (tan(halfFov) * 2.0)
+        const float widthScaledMaxDistance = maxViewFrustumPlaneHeight * invTangentHalfVerticalFov * 0.5f;
+        // NOTE: VR などの高視野角カメラでは、純粋な実装では太くなりすぎる.
+        //       よってある距離での視錐台平面が高さ 2m 以上になったらスケールをやめる.
+        return min(positionCS.w, widthScaledMaxDistance);
+    }
+}
+
 inline VertexPositionInfo MToon_GetOutlineVertex(const float3 positionOS, const half3 normalOS, const float2 uv)
 {
     if (MToon_IsOutlineModeWorldCoordinates())
     {
         const float3 positionWS = mul(unity_ObjectToWorld, float4(positionOS, 1)).xyz;
-        const half outlineWidth = MToon_GetOutlineVertex_OutlineWidth(uv);
         const half3 normalWS = UnityObjectToWorldNormal(normalOS);
+        const half outlineWidth = MToon_GetOutlineVertex_OutlineWidth(uv);
 
         VertexPositionInfo output;
         output.positionWS = float4(positionWS + normalWS * outlineWidth, 1);
@@ -45,17 +65,20 @@ inline VertexPositionInfo MToon_GetOutlineVertex(const float3 positionOS, const
         const float4 nearUpperRight = mul(unity_CameraInvProjection, float4(1, 1, UNITY_NEAR_CLIP_VALUE, _ProjectionParams.y));
         const half aspect = abs(nearUpperRight.y / nearUpperRight.x);
 
-        float4 positionCS = UnityObjectToClipPos(positionOS);
+        const float4 positionCS = UnityObjectToClipPos(positionOS);
         const half3 normalVS = MToon_GetObjectToViewNormal(normalOS);
         const half3 normalCS = TransformViewToProjection(normalVS.xyz);
+
         half2 normalProjectedCS = normalize(normalCS.xy);
-        normalProjectedCS *= positionCS.w;
+        const float clipSpaceHeight = 2.0f;
+        normalProjectedCS *= clipSpaceHeight * outlineWidth * MToon_GetOutlineVertex_ScreenCoordinatesWidthMultiplier(positionCS);
         normalProjectedCS.x *= aspect;
-        positionCS.xy += outlineWidth * normalProjectedCS.xy * saturate(1 - abs(normalVS.z)); // ignore offset when normal toward camera
+        // NOTE: カメラ方向軸を向く法線を持つ頂点が XY 方向にだけずれると困るので、それを抑制する.
+        normalProjectedCS.xy *= saturate(1 - normalVS.z * normalVS.z);
 
         VertexPositionInfo output;
         output.positionWS = float4(positionWS, 1);
-        output.positionCS = positionCS;
+        output.positionCS = float4(positionCS.xy + normalProjectedCS.xy, positionCS.zw);
         return output;
     }
     else

Assets/VRMShaders/VRM10/MToon10/Resources/VRM10/vrmc_materials_mtoon_utility.hlsl

@@ -7,6 +7,11 @@
 static const float PI_2 = 6.28318530718;
 static const float EPS_COL = 0.00001;
 
+inline half mtoon_linearstep(const half start, const half end, const half t)
+{
+    return min(max((t - start) / (end - start), 0.0), 1.0);
+}
+
 inline half3 mtoon_linearstep(const half3 start, const half3 end, const half t)
 {
     return min(max((t - start) / (end - start), 0.0), 1.0);
@@ -17,6 +22,20 @@ inline bool MToon_IsPerspective()
     return unity_OrthoParams.w != 1.0;
 }
 
+inline float3 MToon_GetWorldSpaceViewDir(const float3 positionWS)
+{
+    if (MToon_IsPerspective())
+    {
+        return _WorldSpaceCameraPos.xyz - positionWS;
+    }
+    else
+    {
+        const float3 cameraForwardWS = normalize(UNITY_MATRIX_V[2].xyz);
+        const float3 viewDirWS = _WorldSpaceCameraPos.xyz - positionWS;
+        return cameraForwardWS * dot(cameraForwardWS, viewDirWS);
+    }
+}
+
 inline float3 MToon_GetWorldSpaceNormalizedViewDir(const float3 positionWS)
 {
     if (MToon_IsPerspective())