Trying to understand the workflow of using RenderTextures and using Texture2D to visualize results from fragment shader and am running into issues with RenderTexture sizes approaching 2k by 2k.
Results at 2000x2000
Results at 2048x2048
These results are taken from the Play window. I have tried removing logic from the shader by always returning black but it still appears as that slight grey color. I’ve also tested for an upper limit and it happens when the texture hits 2035x2035. 2034x2034 works as expected. I checked maxTextureSize and it returns over 16k.
The script
```csharp
** public void OnEnable()
{
output = new RenderTexture(
mapSize, mapSize, 0,
RenderTextureFormat.ARGB32,
RenderTextureReadWrite.Linear
);
meshMat = GetComponent<MeshRenderer>().materials[0];
debugTexture = new Texture2D(mapSize, mapSize, TextureFormat.ARGB32, -1, true);
debugTexture.filterMode = FilterMode.Point;
debugTexture.wrapMode = TextureWrapMode.Clamp;
}
void Update()
{
// generate new diagram every time space is pressed
if (Input.GetKeyDown("space"))
{
// run at the end of rendering
RenderPipelineManager.endContextRendering += blit;
}
}
private void blit(ScriptableRenderContext c, List<Camera> cams)
{
RenderPipelineManager.endContextRendering -= blit;
// random seeds and associated color for diagram
float[] pos = {
Random.Range(0.0f, 1.0f),Random.Range(0.0f, 1.0f), 1.0f, 0.0f,0.0f,
Random.Range(0.0f, 1.0f),Random.Range(0.0f, 1.0f),1.0f, 1.0f,0.0f,
Random.Range(0.0f, 1.0f),Random.Range(0.0f, 1.0f),1.0f, 1.0f,1.0f,
Random.Range(0.0f, 1.0f),Random.Range(0.0f, 1.0f),0.0f, 1.0f,1.0f,
Random.Range(0.0f, 1.0f),Random.Range(0.0f, 1.0f),0.0f, 0.0f,1.0f,
};
// send to shader
voronoiMaterial.SetFloatArray("pos", pos);
Graphics.Blit(null, output, voronoiMaterial);
updateTexture();
}
private void updateTexture()
{
// output should be active but make sure anyways
RenderTexture.active = output;
// read entire texture
debugTexture.ReadPixels(
new Rect(0, 0, mapSize, mapSize),
0, 0, false
);
debugTexture.Apply(false);
meshMat.SetTexture("_MainTex", debugTexture);
}**
** **The shader:** **csharp
**Shader “Unlit/Voronoi”
{
Properties
{
}
SubShader
{
Tags { “RenderType”=“Opaque” }
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
float pos[25];
struct appdata
{
float4 vertex : POSITION;
float2 texcoord: TEXCOORD0;
};
struct v2f
{
float4 vertex : SV_POSITION;
float2 uv: TEXCOORD0;
};
float uvArrDistSqrd (float2 uv, float x, float y)
{
float dx = uv.x - x;
float dy = uv.y - y;
return dx*dx + dy*dy;
}
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = v.texcoord;
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float2 uv = i.uv;
float currDistance = uvArrDistSqrd(uv, pos[0], pos[1]);
float4 color = float4(pos[2], pos[3], pos[4], 1.0f);
// if (currDistance < 0.00025f) {
// color = float4(0, 0,0,1.0f);
// }
[unroll(4)] for (int i = 1; i < 5; ++i)
{
int offset = i * 5;
float d = uvArrDistSqrd(uv, pos[offset], pos[offset+1]);
// if (d < 0.00025f) {
// return float4(0, 0,0,1.0f);
// }
if (d < currDistance)
{
currDistance = d;
color = float4(pos[offset + 2],pos[offset + 3], pos[offset + 4], 1.0f);
}
}
return color;
}
ENDCG
}
}
}**
```
System:
Unity: 2021.3.11f1 3D HDRP scene
CPU: Ryzen9 5900x
GPU: AMD 6900xt
Mem: 32GB
Question:
I’m curious if there is some limitation I’m not aware of? Or perhaps timing issue? Any help is appreciated.