I’m modifying a relatively simple wireframe shader to render an object on Quest in Multiview. Not really sure what’s gone wrong, as it seems like I should be outputting to stereo correctly.
uniform float _WireThickness = 100;
uniform float _WireSmoothness = 3;
uniform float4 _WireColor = float4(0.0, 1.0, 0.0, 1.0);
uniform float4 _BaseColor = float4(0.0, 0.0, 0.0, 0.0);
uniform float _MaxTriSize = 25.0;
struct appdata
{
float4 vertex : POSITION;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
struct v2g
{
float4 projectionSpaceVertex : SV_POSITION;
float4 worldSpacePosition : TEXCOORD1;
UNITY_VERTEX_OUTPUT_STEREO
};
struct g2f
{
float4 projectionSpaceVertex : SV_POSITION;
float4 worldSpacePosition : TEXCOORD0;
float4 dist : TEXCOORD1;
float4 area : TEXCOORD2;
UNITY_VERTEX_OUTPUT_STEREO
};
v2g vert (appdata v)
{
v2g o;
UNITY_SETUP_INSTANCE_ID(v);
UNITY_INITIALIZE_OUTPUT(v2g, o);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
o.projectionSpaceVertex = UnityObjectToClipPos(v.vertex);
o.worldSpacePosition = mul(unity_ObjectToWorld, v.vertex);
return o;
}
[maxvertexcount(3)]
void geom(triangle v2g i[3], inout TriangleStream<g2f> triangleStream)
{
float2 p0 = i[0].projectionSpaceVertex.xy / i[0].projectionSpaceVertex.w;
float2 p1 = i[1].projectionSpaceVertex.xy / i[1].projectionSpaceVertex.w;
float2 p2 = i[2].projectionSpaceVertex.xy / i[2].projectionSpaceVertex.w;
float2 edge0 = p2 - p1;
float2 edge1 = p2 - p0;
float2 edge2 = p1 - p0;
float4 worldEdge0 = i[0].worldSpacePosition - i[1].worldSpacePosition;
float4 worldEdge1 = i[1].worldSpacePosition - i[2].worldSpacePosition;
float4 worldEdge2 = i[0].worldSpacePosition - i[2].worldSpacePosition;
// To find the distance to the opposite edge, we take the
// formula for finding the area of a triangle Area = Base/2 * Height,
// and solve for the Height = (Area * 2)/Base.
// We can get the area of a triangle by taking its cross product
// divided by 2. However we can avoid dividing our area/base by 2
// since our cross product will already be double our area.
float area = abs(edge1.x * edge2.y - edge1.y * edge2.x);
float wireThickness = 800 - _WireThickness;
g2f o;
o.area = float4(0, 0, 0, 0);
o.area.x = max(length(worldEdge0), max(length(worldEdge1), length(worldEdge2)));
o.worldSpacePosition = i[0].worldSpacePosition;
o.projectionSpaceVertex = i[0].projectionSpaceVertex;
o.dist.xyz = float3( (area / length(edge0)), 0.0, 0.0) * o.projectionSpaceVertex.w * wireThickness;
o.dist.w = 1.0 / o.projectionSpaceVertex.w;
UNITY_TRANSFER_VERTEX_OUTPUT_STEREO(i[0], o);
triangleStream.Append(o);
o.worldSpacePosition = i[1].worldSpacePosition;
o.projectionSpaceVertex = i[1].projectionSpaceVertex;
o.dist.xyz = float3(0.0, (area / length(edge1)), 0.0) * o.projectionSpaceVertex.w * wireThickness;
o.dist.w = 1.0 / o.projectionSpaceVertex.w;
UNITY_TRANSFER_VERTEX_OUTPUT_STEREO(i[1], o);
triangleStream.Append(o);
o.worldSpacePosition = i[2].worldSpacePosition;
o.projectionSpaceVertex = i[2].projectionSpaceVertex;
o.dist.xyz = float3(0.0, 0.0, (area / length(edge2))) * o.projectionSpaceVertex.w * wireThickness;
o.dist.w = 1.0 / o.projectionSpaceVertex.w;
UNITY_TRANSFER_VERTEX_OUTPUT_STEREO(i[2], o);
triangleStream.Append(o);
}
fixed4 frag(g2f i) : SV_Target
{
UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);
float minDistanceToEdge = min(i.dist[0], min(i.dist[1], i.dist[2])) * i.dist[3];
// Early out if we know we are not on a line segment.
if(minDistanceToEdge > 0.9 || i.area.x > _MaxTriSize)
{
return fixed4(_BaseColor.rgb,0);
}
// Smooth our line out
float t = exp2(_WireSmoothness * -1.0 * minDistanceToEdge * minDistanceToEdge);
fixed4 finalColor = lerp(_BaseColor, _WireColor, t);
return finalColor;
}