Increase anisotropic filtering quality in the presets and don't offer x2 anisotropic filtering

supertuxkart / stk-code

The code base of supertuxkart

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Increase anisotropic filtering quality in the presets and don't offer x2 anisotropic filtering #5076

Closed Alayan-stk-2 closed 7 months ago

Alayan-stk-2 commented 7 months ago

Currently, SuperTuxKart has 3 levels of anisotropic filtering supported through presets:

x2 (lowest Image Quality preset, used by graphics presets 1 and 2)
x4 (middle Image Quality preset, used by graphics presets 3 and 4)
x16 (highest Image Quality preset, used by graphics presets 5 and 6)

Generally speaking:

x2 looks like trash. When I used to play in Graphics 2, I strongly believed that STK was suffering from some serious bug.
x4 is visibly subpar, but much more tolerable
x16 looks fine

Visual demonstration of x2: BLUR

The performance cost of anisotropic filtering has been really small on any hardware that has come out for many years, whereas the visual impact is massive.

I intend to:

Allow x4 on the lowest preset and have it used by graphics preset 1
Use x16 on all other graphics presets.

Here is a comparison of performance for different settings on my iGPU:

Anisotropic

Alayan-stk-2 commented 7 months ago

Based on PocketMarty's tests, the VRAM impact of the anisotropic filtering setting is negligible, as I expected. It consumes some bandwidth, but that's already accounted for in FPS figures.

qwertychouskie commented 7 months ago

Can we look into using anisotropic filtering on GLES as well? Last I saw, aniso was force-disabled for GLES.

Alayan-stk-2 commented 7 months ago

Can we look into using anisotropic filtering on GLES as well? Last I saw, aniso was force-disabled for GLES.

I don't know about this, but if it's disabled, it would indeed be very worth it to get it enabled.

@deveee @Benau Was this done only for performance reasons or were there compatibility issues?

deveee commented 7 months ago

I don't remember, maybe it wasn't available in gles.

Alayan-stk-2 commented 7 months ago

As far as I can tell:

The code checks for the support of GL_EXT_texture_filter_anisotropic
This exists for GL ES https://registry.khronos.org/OpenGL/extensions/EXT/EXT_texture_filter_anisotropic.txt
I haven't found code testing for GL ES in relation to anisotropic filtering

So I would think it should work.

However, the people I asked to test don't have it working on their device, but this might be because their devices don't support it.

Alayan-stk-2 commented 7 months ago

Image quality settings now work like this from lowest to highest :

Anisotropic x4, low resolution textures
Anisotropic x16, low resolution textures
Anisotropic x16, HD textures
Anisotropic x16, HD textures, HQ mipmap