Artifacting when blurring a SCREEN_TEXTURE with textureLod on the mobile renderer.

[Felipe-Sena]

Tested versions

• Reproducible in: 4.3.dev6 [89850d5], 4.2.2-stable and 4.2.stable

System information

Godot v4.2.2.stable - Windows 10.0.22631 - Vulkan (Mobile) - dedicated NVIDIA GeForce RTX 4070 (NVIDIA; 31.0.15.5222) - AMD Ryzen 9 7900X 12-Core Processor (24 Threads)

Issue description

Whenever a shader that reads from hint_screen_texture is blurred with a textureLod in the Vulkan Mobile renderer an artifact appears in the upper part of the image. Using SCREEN_UV or UV does not affect the outcome. This does not happen with regular textures blurred with textureLod that use any of the two UV methods described above.

On the mobile renderer you can clearly see the artifact:

This issue disappears once I switch to the Forward+ renderer:

Steps to reproduce

Create a new project with the Mobile renderer and then create a spatial shader that contains the following lines:

shader_type spatial;

uniform sampler2D screen_texture : hint_screen_texture, filter_linear_mipmap;


void fragment() {
	ALBEDO = textureLod(screen_texture, SCREEN_UV, 1).rgb;
}

And then apply it to a ShaderMaterial.

Minimal reproduction project (MRP)

MRP.zip

[clayjohn]

This appears to be a duplicate of #88786.

We like to reduce duplicate bug reports and track the bug in one place. So I am going to close this report in favour of #88786