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Wireframe.shader
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Wireframe.shader
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///
/// Basic wireframe shader that can be used for rendering spatial mapping meshes.
///
Shader "HoloToolkit/Wireframe"
{
Properties
{
_BaseColor("Base color", Color) = (0.0, 0.0, 0.0, 1.0)
_WireColor("Wire color", Color) = (1.0, 1.0, 1.0, 1.0)
_WireThickness("Wire thickness", Range(0, 800)) = 100
}
SubShader
{
Tags { "RenderType" = "Opaque" }
Pass
{
Offset 50, 100
CGPROGRAM
#pragma vertex vert
#pragma geometry geom
#pragma fragment frag
// We only target the HoloLens (and the Unity editor), so take advantage of shader model 5.
#pragma target 5.0
#pragma only_renderers d3d11
#include "UnityCG.cginc"
float4 _BaseColor;
float4 _WireColor;
float _WireThickness;
// Based on approach described in Shader-Based Wireframe Drawing (2008)
// http://orbit.dtu.dk/en/publications/id(13e2122d-bec7-48de-beca-03ce6ea1c3f1).html
struct v2g
{
float4 viewPos : SV_POSITION;
UNITY_VERTEX_OUTPUT_STEREO
};
v2g vert(appdata_base v)
{
UNITY_SETUP_INSTANCE_ID(v);
v2g o;
o.viewPos = mul(UNITY_MATRIX_MVP, v.vertex);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
return o;
}
// inverseW is to counteract the effect of perspective-correct interpolation so that the lines
// look the same thickness regardless of their depth in the scene.
struct g2f
{
float4 viewPos : SV_POSITION;
float inverseW : TEXCOORD0;
float3 dist : TEXCOORD1;
UNITY_VERTEX_OUTPUT_STEREO
};
[maxvertexcount(3)]
void geom(triangle v2g i[3], inout TriangleStream<g2f> triStream)
{
// Calculate the vectors that define the triangle from the input points.
float2 point0 = i[0].viewPos.xy / i[0].viewPos.w;
float2 point1 = i[1].viewPos.xy / i[1].viewPos.w;
float2 point2 = i[2].viewPos.xy / i[2].viewPos.w;
// Calculate the area of the triangle.
float2 vector0 = point2 - point1;
float2 vector1 = point2 - point0;
float2 vector2 = point1 - point0;
float area = abs(vector1.x * vector2.y - vector1.y * vector2.x);
float3 distScale[3];
distScale[0] = float3(area / length(vector0), 0, 0);
distScale[1] = float3(0, area / length(vector1), 0);
distScale[2] = float3(0, 0, area / length(vector2));
float wireScale = 800 - _WireThickness;
// Output each original vertex with its distance to the opposing line defined
// by the other two vertices.
g2f o;
[unroll]
for (uint idx = 0; idx < 3; ++idx)
{
o.viewPos = i[idx].viewPos;
o.inverseW = 1.0 / o.viewPos.w;
o.dist = distScale[idx] * o.viewPos.w * wireScale;
UNITY_TRANSFER_VERTEX_OUTPUT_STEREO(i[idx], o);
triStream.Append(o);
}
}
float4 frag(g2f i) : COLOR
{
// Calculate minimum distance to one of the triangle lines, making sure to correct
// for perspective-correct interpolation.
float dist = min(i.dist[0], min(i.dist[1], i.dist[2])) * i.inverseW;
// Make the intensity of the line very bright along the triangle edges but fall-off very
// quickly.
float I = exp2(-2 * dist * dist);
// Fade out the alpha but not the color so we don't get any weird halo effects from
// a fade to a different color.
float4 color = I * _WireColor + (1 - I) * _BaseColor;
color.a = I;
return color;
}
ENDCG
}
}
FallBack "Diffuse"
}