diff options
Diffstat (limited to 'tessellation.cginc')
| -rw-r--r-- | tessellation.cginc | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/tessellation.cginc b/tessellation.cginc index 2725776..30c3c63 100644 --- a/tessellation.cginc +++ b/tessellation.cginc @@ -16,20 +16,54 @@ tess_factors patch_constant(InputPatch<v2f, 3> patch) { tess_factors f; #if defined(_TESSELLATION) #if defined(_TESSELLATION_RANGE_FACTOR) - float d = length(getCenterCamPos() - patch[0].worldPos.xyz); + float3 vec = getCenterCamPos() - patch[0].worldPos.xyz; + float d2 = dot(vec, vec); float factor = lerp( _Tessellation_Range_Factor_Factor_Near, _Tessellation_Range_Factor_Factor_Far, smoothstep( _Tessellation_Range_Factor_Distance_Near, _Tessellation_Range_Factor_Distance_Far, - d)); + d2)); #else float factor = _Tessellation_Factor; #endif + { + // Frustum culling - don't tessellate if the patch is outside the viewport + // (xy) or behind the camera (w). We approximate this by checking the + // un-transformed and maximally transformed locations. Technically we could + // miss an intersection in the middle, but I haven't noticed any visible + // popping with this approach. + float max_displacement = _Tessellation_Heightmap_Scale * 0.5 + _Tessellation_Heightmap_Offset; + float3 p0d = patch[0].objPos.xyz + patch[0].normal.xyz * max_displacement; + float3 p1d = patch[1].objPos.xyz + patch[1].normal.xyz * max_displacement; + float3 p2d = patch[2].objPos.xyz + patch[2].normal.xyz * max_displacement; + float4 p0_clipPos = UnityObjectToClipPos(float4(patch[0].objPos.xyz, 1)); + float4 p1_clipPos = UnityObjectToClipPos(float4(patch[1].objPos.xyz, 1)); + float4 p2_clipPos = UnityObjectToClipPos(float4(patch[2].objPos.xyz, 1)); + float4 p0d_clipPos = UnityObjectToClipPos(float4(p0d, 1)); + float4 p1d_clipPos = UnityObjectToClipPos(float4(p1d, 1)); + float4 p2d_clipPos = UnityObjectToClipPos(float4(p2d, 1)); + float3 p0_ndc = p0_clipPos.xyz / p0_clipPos.w; + float3 p1_ndc = p1_clipPos.xyz / p1_clipPos.w; + float3 p2_ndc = p2_clipPos.xyz / p2_clipPos.w; + float3 p0d_ndc = p0d_clipPos.xyz / p0d_clipPos.w; + float3 p1d_ndc = p1d_clipPos.xyz / p1d_clipPos.w; + float3 p2d_ndc = p2d_clipPos.xyz / p2d_clipPos.w; + + bool on_screen = + (p0_ndc.x > -1 && p0_ndc.x < 1 && p0_ndc.y > -1 && p0_ndc.y < 1 && p0_clipPos.w > 0) || + (p1_ndc.x > -1 && p1_ndc.x < 1 && p1_ndc.y > -1 && p1_ndc.y < 1 && p1_clipPos.w > 0) || + (p2_ndc.x > -1 && p2_ndc.x < 1 && p2_ndc.y > -1 && p2_ndc.y < 1 && p2_clipPos.w > 0) || + (p0d_ndc.x > -1 && p0d_ndc.x < 1 && p0d_ndc.y > -1 && p0d_ndc.y < 1 && p0d_clipPos.w > 0) || + (p1d_ndc.x > -1 && p1d_ndc.x < 1 && p1d_ndc.y > -1 && p1d_ndc.y < 1 && p1d_clipPos.w > 0) || + (p2d_ndc.x > -1 && p2d_ndc.x < 1 && p2d_ndc.y > -1 && p2d_ndc.y < 1 && p2d_clipPos.w > 0); + factor = lerp(0, factor, on_screen); + } #else float factor = 1; #endif + f.edge[0] = factor; f.edge[1] = factor; f.edge[2] = factor; @@ -40,7 +74,7 @@ tess_factors patch_constant(InputPatch<v2f, 3> patch) { [UNITY_domain("tri")] [UNITY_outputcontrolpoints(3)] [UNITY_outputtopology("triangle_cw")] -[UNITY_partitioning("fractional_odd")] +[UNITY_partitioning("integer")] [UNITY_patchconstantfunc("patch_constant")] v2f hull( InputPatch<v2f, 3> patch, @@ -55,7 +89,7 @@ v2f domain( OutputPatch<v2f, 3> patch, float3 baryc : SV_DomainLocation) { - v2f o; + v2f o = (v2f) 0; #define DOMAIN_INTERP(fieldName) \ patch[0].fieldName * baryc.x + \ patch[1].fieldName * baryc.y + \ |