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Weird shader error X5204 - read of uninitialized components
1) In Camera.OnRenderImage(..) I'm using camera's depth buffer to determine if certain areas of the image should be drawn. I ran into weird problem where I get shader error when IF statement is used to check the depth value. Can anyone explain what am I doing wrong?
I attached a unity package with scene, script and shader so that anybody can try to run it. (sorry for cross-posting here and in the forum) When the IF statement in the fragment shader below is uncommented I get following error in the console:
Shader error in 'Depth test': D3D shader assembly failed with: (11): error X5204: Read of uninitialized components(*) in r1: *r/x/0 *g/y/1 *b/z/2 *a/w/3
Shader Assembly: ps_2_0
; 8 ALU, 1 TEX
dcl_2d s0
def c0, -1.00000000, 1.00000000, 0.00000000, 0.50000000
dcl t0.xy
texld r3, t0, s0
add r0.x, r3, c0
mov r2.yz, c0.w
mov r2.x, c0.z
mov r2.w, c0.y
cmp_pp r1, r0.x, r1, r2
cmp_pp r0.x, r0, c0.y, c0.z
cmp_pp r0, -r0.x, r1, r3
mov_pp oC0, r0
2) Another mystery for me is why I don't get depth rendered on the screen (get black screen) when I first output depth to texDepth RenderTexture and only then to the screen (target). I'd be grateful if anybody could explain what is wrong in these scripts. I
Here's C# script
using UnityEngine;
[RequireComponent(typeof(Camera))]
public class Test : ImageEffectBase
{
public RenderTexture texDepth;
void Awake()
{
Camera.main.depthTextureMode = DepthTextureMode.Depth;
texDepth = new RenderTexture(Screen.width, Screen.height, 24, RenderTextureFormat.Depth);
}
public void OnRenderImage(RenderTexture source, RenderTexture target)
{
// source ignored, material's shader outputs depth to target (screen)
Graphics.Blit(source, target, material);
// texDepth is completely black in Inspector
//Graphics.Blit(source, texDepth, material);
//Graphics.Blit(texDepth, target);
}
}
Here's image effect shader which is outputing just depth:
Shader "Depth test" {
SubShader {
Pass {
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata_t {
float4 vertex : POSITION;
float2 texcoord : TEXCOORD0;
};
struct v2f {
float4 pos : POSITION;
float2 texcoord : TEXCOORD0;
};
v2f vert (appdata_t v)
{
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.texcoord = v.texcoord;
return o;
}
sampler2D _MainTex;
uniform sampler2D _CameraDepthTexture;
half4 frag (v2f i) : COLOR
{
float sceneZ = tex2D(_CameraDepthTexture, i.texcoord).x;
// if uncommented getting error
// "D3D shader assembly failed with: (11): error X5204: Read of uninitialized components(*) in r1: *r/x/0 *g/y/1 *b/z/2 *a/w/3"
//if (sceneZ < 1f)
// return half4(0,0.5,0.5,1);
return tex2D(_CameraDepthTexture, i.texcoord);
}
ENDCG
}
}
Fallback off
}
Here is how the scene looks when value from depth buffer is sent directly to the screen:
Another thing puzzling me is that very similar fragment shader to the one above actually works fine in one different case:
half4 frag (v2f i) : COLOR
{
half4 col = tex2D(_MainTex, i.texcoord);
float compositZ = tex2D(_CompositTex, i.texcoord).r;
float sceneZ = tex2D(_CameraDepthTexture, i.texcoord).r;
if (sceneZ < compositZ && col.a > 0f)
return half4(col.rgb, 0);
else
return col;
}
Answer by Joshua 3 · Jan 16, 2012 at 11:02 PM
I had the same error message and if it is the same problem to fix it you have to change
if (sceneZ < 1f)
return half4(0,0.5,0.5,1);
return tex2D(_CameraDepthTexture, i.texcoord);
to
if (sceneZ < 1f)
return half4(0,0.5,0.5,1);
else
return tex2D(_CameraDepthTexture, i.texcoord);
I don't know why this is. Maybe some strange compiler optimization bug.
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