Vulkan: Projector textures on SpotLight3D and OmniLight3D needs adjustment to scaling

[pracedru]

Godot version

4.0.dev

System information

PopOS, Vulkan, Nvidia GTX 1060

Issue description

The current build of Godot only show a small section of the center of the texture on spotlight.
Maybe a texture scale feature could be added to the light projector texture.

Steps to reproduce

Make 3D scene.
Add Spotlight.
enable shadows.
Add texture to Projector.
Place a surface on which the light can be seen.

Here a 11x11 tiled texture is added to the projector and only 4-5 partial segments of the texture is shown in the light.

Minimal reproduction project

No response

[jcostello]

Can you show what happens if you move the light away to almost hit the mesh with the edge of the cone? Also can you set up the default attenuation?

[pracedru]

Attenuation, Angle, Angle Atenuation and the position of the light has no impact on the scaling of the texture. The same small subsection is always projected.

[dusakus]

So I hit that problem recently, which prompted me to look into the engine to check how the projector calculates the texture UV, and I found this:

vec2 proj_uv = normal_to_panorama(splane.xyz) * spot_lights.data[idx].projector_rect.zw;
link to this exact line in scene_forward_lights_inc.glsl

Since we are talking about SpotLights, I tried removing the "normal_to_panorama()" part, as I'm pretty sure SpotLights are not supposed to use panoramic textures.
The resulting line is

vec2 proj_uv = splane.xy * spot_lights.data[idx].projector_rect.zw;

And the result?

While I'm sure this isn't a proper fix, it might at least point someone much more knowledgeable to possibly implement one.

Edit to clarify:
I'm running Arch, with GTX 1060 using Nvidia binary driver and Vulkan renderer.
Testing using a fresh build of master branch, with the only difference being the above mentioned line.
With a clean build (without the change mentioned above) I get a "random" tiny piece of the texture instead of the whole thing, as shown in the screenshot below

[akien-mga]

Fixed by #57888.