Line Renderer GPU instancing breaks when setting the PropertyBlock?

Unity Engine
1

I’m on 5.5.0p1. Instancing works fine when I just start the Game, 19 Draw Calls for everything, 2 instance Draws for the Linerenderer.
When I set the property:

foreach (var start in lines){
                var line = start.GetComponent<LineRenderer>();
                line.SetPropertyBlock(probs);
                line.startColor = line.endColor = start.lineColor;
                line.colorGradient = getColor(start);
            }

Code Breaks, 98 Draw Calls, all lines draw dynamic.

The shader:

Shader "Instanced/UnlitInstanced"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_instancing

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            UNITY_INSTANCING_CBUFFER_START(Props)
                UNITY_DEFINE_INSTANCED_PROP(fixed4, _Color)    // Make _Color an instanced property (i.e. an array)
            UNITY_INSTANCING_CBUFFER_END

            sampler2D _MainTex;
            float4 _MainTex_ST;
          
            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }
          
            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv) * UNITY_ACCESS_INSTANCED_PROP(_Color);
                // apply fog
                UNITY_APPLY_FOG(i.fogCoord, col);
                return col;
            }
            ENDCG
        }
    }
}
2

Hey, there is no such thing as gpu instancing for line renderers :slight_smile:

You shouldn’t try to use instancing shaders with them.

2 Likes
3

Oops, thanks for clearing that up. Have to use the particle shaders to get batching to work on LineRenderers :).

4

Do you think line renderers will ever allow GPU instancing? :eyes:

5

No - there is no point. (Caveat - maybe if you want to render many identical lines, it could be useful, but that seems very niché, and could be solved with meshes)