[BUG] Default clouds glitchy (flickering)

[faizul726]

Describe the bug
Clouds are flickering on Windows for someone with a Nvidia RTX 4060.

• Person is not using any other resource pack. Newb X Dawn (.130 build) is also affected by same issue according to them.
• They have used Matject to apply the shader and material-updater is off for them so shader is not getting modified.
• Affected commit: Likely 4012a77 as the affected person is saying that they are using "latest legacy release"
• Game version: v1.21.132

Screen record
https://drive.google.com/file/d/1tL0xt7PGCK0ocppuIPBhpvTbylVuCfo8/view
(file too large to include, file may get deleted later)

Sourced from: https://discord.com/channels/844591537430069279/1271123311300055051/1459174136050880594

[devendrn]

Do they face any issue while using rounded clouds or box clouds?

[faizul726]

Box no issue, round yes issue, source amg

(he also has rtx gpu)

[devendrn]

What about realistic clouds type?

[faizul726]

for realistic clouds i assume it needs to be built from source as I am not aware of any new subpack i will let you know later

[faizul726]

sorry for being late

Minecraft_for_Windows_2026-01-15_18-59-38-convert.mp4

realistic clouds look like this for "them" (the first person to report the issue)

as for rounded clouds i didn't get proper response from them

[faizul726]

i accidentally closed the issue

[devendrn]

Possible for someone to test with this change? I'm suspecting issue with uniform

--- a/src/materials/Clouds/fragment.sc
+++ b/src/materials/Clouds/fragment.sc
@@ -17,7 +17,7 @@ void main() {
   #if NL_CLOUD_TYPE >= 2
     vec3 vDir = normalize(v_color0.xyz);
     vec3 cloudPos = v_color0.xyz;
-    cloudPos.xz += CameraPosition.xz;
+    // cloudPos.xz += CameraPosition.xz;
 
     #if NL_CLOUD_TYPE == 2
       color = renderCloudsRounded(vDir, cloudPos, v_color1.w, v_color2.w, v_color2.rgb, v_color1.rgb, NL_CLOUD_PARAMS(_));
@@ -39,7 +39,7 @@ void main() {
       vDir.xz *= 0.3 + v_color0.w; // height parallax
 
       vec2 p = (vDir.xz)/(0.015 + 0.035*abs(vDir.y));
-      p += 0.035*CameraPosition.xz;
+      // p += 0.035*CameraPosition.xz;
 
       vec4 clouds = renderClouds(p, v_color2.w, v_color1.w, v_color2.rgb, v_color1.rgb, NL_CLOUD3_SCALE, NL_CLOUD3_SPEED, NL_CLOUD3_SHADOW);
       color = clouds;

[faizul726]

1 am here right now. Tomorrow I will implement the fix and send file to the person who reported.

Good night

[faizul726]

while the original reporter hasn't tested yet, from my testing realistic clouds seem to work fine

i have uhd 600 igpu

bandicam.2026-01-17.21-23-53-818.mp4

[faizul726]

The original reporter sent these videos

Unbenanntes_Video_Mit_Clipchamp_erstellt.1.mp4

Unbenanntes_Video_Mit_Clipchamp_erstellt_1.2.mp4

Unbenanntes_Video_Mit_Clipchamp_erstellt_3.1.mp4

[devendrn]

Is anyone with this issue available actively to debug this issue with cloud?

[faizul726]

From what I know Amg has this issue. Maybe I can ask him or the original reporter.