Different results between CPU and GPU with new Nishita Sky Texture
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	soulfire (vejn)
	Jun 26 2020, 7:31 PM

Description

System Information
Operating system: Windows-10
Graphics card: GeForce GT 1030/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 446.14

Broken: version: 2.90.0 Alpha, branch: master, commit date: 2020-06-25 21:53, hash: rB62aa103d485f
2020-06-26 17:24, hash: rBb7b57e7155ee

Short description of error
Rendering with sky texture give wrong output

Exact steps for others to reproduce the error
Based on the default startup cube with sky texture
GPU CUDA compute gt 1030

CPU compute

test.blend780 KBDownload

Revisions and Commits

rC Cycles
	rC3a16a5a50baa Fix T78324: Different Sky Texture results between CPU and GPU
rB Blender
	rB7fcb6bc59c85 Fix T78324: Different Sky Texture results between CPU and GPU

Related Objects

Mentioned In: D8091: Sky Texture fixes

Event Timeline

soulfire (vejn) renamed this task from Sky texture glitched to Sky texture glitched/Cycles.Jun 26 2020, 7:31 PM

soulfire (vejn) created this task.

soulfire (vejn) updated the task description. (Show Details)Jun 27 2020, 12:27 AM

soulfire (vejn) updated the task description. (Show Details)Jun 27 2020, 12:30 AM

Can't reproduce the issue, try to update the Nvidia drivers, do you get any issues with CPU rendering?

I updated the drivers. It's the same. CUDA is giving glitched output.

In todays build CPU rendering is OK. Only render with CUDA is glitched.

If I render with SKY LIGHT without Sky texture, rendering is fine.

Does it happen with other scenes too? i mean, try without the sky, if the issue persists then the problem could be related to GPU rathen than the sky.

In T78324#969285, @Marco (nacioss) wrote:

Does it happen with other scenes too? i mean, try without the sky, if the issue persists then the problem could be related to GPU rathen than the sky.

I updated previous. With sky light without sky texture, CUDA rendering is fine.

Only sky texture with CUDA rendering is giving issues in every scene.

Ok, i can reproduce it now, it does only with CUDA + CPU, will dig in the code soon, thank you a lot for the report ;) .
Meanwhile, avoid using such low Sun Size values.
EDIT: Using values from 0.4 to above works well

In T78324#969304, @Marco (nacioss) wrote:

Using values from 0.2 to above works well.

It's the same glitch only harder to detect. Zoom in and you'll see.

Sun size 0.2:

Marco (nacioss) mentioned this in D8091: Sky Texture fixes.Jul 2 2020, 9:41 AM

Lukas Stockner (lukasstockner97) renamed this task from Sky texture glitched/Cycles to Different results between CPU and GPU with new Nishita Sky Texture.Jul 8 2020, 2:11 AM

Lukas Stockner (lukasstockner97) closed this task as Resolved by committing rB7fcb6bc59c85: Fix T78324: Different Sky Texture results between CPU and GPU.Jul 8 2020, 2:55 AM

Lukas Stockner (lukasstockner97) claimed this task.

Lukas Stockner (lukasstockner97) added a commit: rB7fcb6bc59c85: Fix T78324: Different Sky Texture results between CPU and GPU.

In case anyone is curious about the difference the fix makes, here's a 0.1° sun at very high focal length:

CPU before: