How to shape this shader more like a triangle than a circle ?

Unity Engine
1

Hi,

I’m working on a third person game, and I’m trying to make a sight vision triangle (or cone-shaped).

I followed a tutorial to make a shader of fog of war which is what I want actually, but it shapes a circle. Is there a possibility to draw a cone-shaped ?

Video of tutorial with the script of the shader :

Screenshot of my current prototype :

What I want :

Thanks for help, if you need some more information, just ask.

2

We discussed this in private but I’m assuming posting about it could help people.
My approach would be to keep the same principle, passing more information to the shader: the “forward” vector (where the direction of the vision cone) and the angle of the cone (or this can be hardcoded in the shader).

In the tutorial, a comment says “return 0 if pos - nearvertex > fogRadius”, thats is “keep black every point outside the radius”, you need to implement it such as it ALSO return 0 if the angle between the forward vector and the vector defined by (pos - player position) is superior to a predefined angle.
I haven’t really messed with Unity shaders for a while so I won’t risk a bad implementation but you get the idea.

3

Yup,

So it seems like the first thing to do is to get the transform.forward of my character, and to send it into the shader script.

To do so i tried to add this in my c# script :

void Update ()
    {
        Vector3 char_forward = _c.transform.forward ;
        GetComponent<Renderer>().material.SetVector("Player1_Forward", char_forward) ;
    }

and to declare it in the shader :

And I get this when I try to read the result :

What i miss ??

This is the full shader script :

Shader "Custom/FogOfWar" {
Properties {
    _Color ("Main Color", Color) = (1,1,1,1)
    _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
    _FogRadius ("FogRadius", Float) = 1.0
    _FogMaxRadius ("FogMaxRadius", Float) = 1.0
    _Player1_Pos ("Player1_Pos", Vector) = (0,0,0,1)
    _Player1_Forward ("Player1_Forward", Vector) = (0,0,0,1)
}

SubShader {
    Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
    LOD 200
    Blend SrcAlpha OneMinusSrcAlpha
    Cull Off

    CGPROGRAM
    #pragma surface surf Lambert vertex:vert

    sampler2D _MainTex;
    fixed4 _Color;
    float _FogRadius;
    float _FogMaxRadius;
    float4 _Player1_Forward;
    float4 _Player1_Pos;

    struct Input {
        float2 uv_MainTex;
        float2 location;
        float4 _Player1_Forward;
    };

    float powerForPos(float4 pos, float2 nearVertex);

    void vert(inout appdata_full vertexData, out Input outData) {
        float4 pos = mul(UNITY_MATRIX_MVP, vertexData.vertex);
        float4 posWorld = mul(_Object2World, vertexData.vertex);
        outData.uv_MainTex = vertexData.texcoord;
        outData.location = posWorld.xz;
    }

    void surf (Input IN, inout SurfaceOutput o) {
        fixed4 baseColor = tex2D(_MainTex, IN.uv_MainTex) * _Color;
       
        float alpha = (1.0 - (baseColor.a + powerForPos (_Player1_Pos, IN.location)));
        o.Albedo = baseColor.rgb;
        o.Alpha = alpha;
    }
   
    // return 0 if (pos - nearVertex) > _FogRadius
    float powerForPos(float4 pos, float2 nearVertex) {

        float atten = clamp(_FogRadius - length(pos.xz - nearVertex.xy), 0.0, _FogRadius);
       
        return (1.0/_FogMaxRadius)*atten/_FogRadius;
    }
    ENDCG
}

Fallback "Transparent/VertexLit"
}