Vulkan: Errors related to gaussian blur when using textureLod(SCREEN_TEXTURE, ...) in a shader

[CsloudX]

Godot version

v4.0.dev.calinou [e6a544c]

System information

windows 10

Issue description

shader in editor use SCREEN_TEXTURE no any effect and, once run the scene, it will report error
Can't use the compute version of the gaussian blur with the mobile renderer.

In 3.3.2, it right:

Steps to reproduce

please run the reproduction project

Minimal reproduction project

ScreenTexTest.zip

[DeeJayLSP]

I would like to confirm this also happens with texture()

[nonunknown]

@Calinou Can confirm this still happens in: v4.0.dev.custom_build [78931aa]

As far I've understood this happens only on canvas_item shaders, yesterday I tried spatial and this doesnt happens!

Here a more detailed log:

log_shader.txt

I just placed this shader in a texture_rect with a texture applied:

shader_type canvas_item;

uniform float scale : hint_range(0.0, 2.0) = 0.5;
uniform vec2 unk = vec2(1);

void fragment(){
	vec2 res = 1.0 / SCREEN_PIXEL_SIZE;
	float s = scale * (res.x / 6e1);
	COLOR = texture(SCREEN_TEXTURE, floor( (unk + .5) / s ) * s / res.xy );
}

[Calinou]

As far I've understood this happens only on canvas_item shaders, yesterday I tried spatial and this doesnt happens!

It seems gaussian mipmap generation isn't correctly reimplemented in master yet: godotengine/godot-proposals#3231

[unfa]

I have the same issue using Screen texture in a 2D Canvas Visual Shader.

[nonunknown]

@Calinou not sure it its only 2d related, because In my use case, I'm using canvas_item to modify the 3d environment!

[Calinou]

@Calinou not sure it its only 2d related, because In my use case, I'm using canvas_item to modify the 3d environment!

It is still related to 2D rendering, as the errors only occur in canvas_item shaders, not spatial shaders.

[jimbeauphloyd]

As far I've understood this happens only on canvas_item shaders, yesterday I tried spatial and this doesnt happens!

It seems gaussian mipmap generation isn't correctly reimplemented in master yet: godotengine/godot-proposals#3231

If I do just a texture lookup on a regular texture (not the screen texture), I don't get errors, but I do get a blurry screen. I guess the blurriness is related to this issue since it has to do with gaussian mipmap generation? Should I open a separate ticket for the blurriness since it isn't getting errors, it just isn't pixel perfect?
Shader code:

shader_type canvas_item;

uniform sampler2D tilemap_texture : hint_albedo;

void fragment() {
	COLOR = texture(tilemap_texture, UV);
}

Image Example: https://imgur.com/a/FNj1JOe

[Calinou]

If I do just a texture lookup on a regular texture (not the screen texture), I don't get errors, but I do get a blurry screen. I guess the blurriness is related to this issue since it has to do with gaussian mipmap generation? Should I open a separate ticket for the blurriness since it isn't getting errors, it just isn't pixel perfect?

Indeed, please open a separate issue for this (then I'll close godotengine/godot-proposals#3231).

[jimbeauphloyd]

If I do just a texture lookup on a regular texture (not the screen texture), I don't get errors, but I do get a blurry screen. I guess the blurriness is related to this issue since it has to do with gaussian mipmap generation? Should I open a separate ticket for the blurriness since it isn't getting errors, it just isn't pixel perfect?

Indeed, please open a separate issue for this (then I'll close godotengine/godot-proposals#3231).

Thanks, submitted issue: #55755

[saki7]

godot/servers/rendering/renderer_rd/effects_rd.cpp

Lines 448 to 449 in 91b97da

	void EffectsRD::gaussian_blur(RID p_source_rd_texture, RID p_texture, RID p_back_texture, const Rect2i &p_region, bool p_8bit_dst) {
	ERR_FAIL_COND_MSG(!prefer_raster_effects, "Can't use the compute version of the gaussian blur with the mobile renderer.");

In case of non-raster effect implementation, the error condition must be prefer_raster_effects, not !prefer_raster_effects.

Similar codes:

godot/servers/rendering/renderer_rd/effects_rd.cpp

Lines 483 to 484 in 91b97da

	void EffectsRD::gaussian_glow(RID p_source_rd_texture, RID p_back_texture, const Size2i &p_size, float p_strength, bool p_high_quality, bool p_first_pass, float p_luminance_cap, float p_exposure, float p_bloom, float p_hdr_bleed_threshold, float p_hdr_bleed_scale, RID p_auto_exposure, float p_auto_exposure_grey) {
	ERR_FAIL_COND_MSG(prefer_raster_effects, "Can't use the compute version of the gaussian glow with the mobile renderer.");

godot/servers/rendering/renderer_rd/effects_rd.cpp

Lines 519 to 520 in 91b97da

	void EffectsRD::gaussian_glow_raster(RID p_source_rd_texture, RID p_framebuffer_half, RID p_rd_texture_half, RID p_dest_framebuffer, const Vector2 &p_pixel_size, float p_strength, bool p_high_quality, bool p_first_pass, float p_luminance_cap, float p_exposure, float p_bloom, float p_hdr_bleed_threshold, float p_hdr_bleed_scale, RID p_auto_exposure, float p_auto_exposure_grey) {
	ERR_FAIL_COND_MSG(!prefer_raster_effects, "Can't use the raster version of the gaussian glow with the clustered renderer.");

I guess there's nothing wrong with the graphic implementation itself, it should be an error output mistake. The error message is being shown on the inverted condition, so if we could flip the flag, then we could get rid of those false-positives.

For reference, I think it is a copy-and-paste error which was introduced in this commit: 1f69582#diff-cff00d5ca58d233af4e4590bfa182d3f6a10b10e9f9aaecbd6e8907efc259fba

@BastiaanOlij As the commit author, could you confirm that this is the valid solution?

[unfa]

I am having the same problem when using Visual Shader:

Minimal reproduction project:
Test Project.zip

Changing the texture type from Screen will stop the error flood.

Can't use the compute version of the gaussian blur with the mobile renderer.

The project is using the Clustered renderer, and also I am not using gaussian blur anywhere.

[wizcas]

Hey guys 👋 I still encounter this error in build v4.0.beta2.mono.official [f8745f2f7]. Is the merged PR not included in the latest release, or shall I request for reopening this issue?

[akien-mga]

This was fixed in January, it would be better to open a new issue if a new bug with the same symptoms reappeared. The cause and fix are likely different.