CRT shader issues

[Decypher]

Finally I decided to give FS-UAE shaders a go but encountered a weird problem with CRT shader.

I have tested several shaders, from Curvature to TestBloom to HQ2x, all are working flawlessly. But when I choose crt shader (or the newer crt-geom-interlaced-curved shader) FS-UAE is giving me "[SHADERS] Failed to compile fragment shader, [SHADERS] No shader passes loaded" error.

I checked log file and in both shader errors are the same:

[SHADERS] Initialize
[SHADERS] Checking shader shaders\\crt-geom-interlaced-curved.shader
WARNING: 0:23: warning(#437) Extension GL_ARB_shading_language_420pack or version 4.20 is requried''.

[SHADERS] Compiled vertex shader successfully
Fragment shader failed to compile with the following errors:
WARNING: 0:6: warning(#437) Extension GL_ARB_shading_language_420pack or version 4.20 is requried''.
WARNING: 0:9: warning(#437) Extension GL_ARB_shading_language_420pack or version 4.20 is requried''.
ERROR: 0:157: error(#133) Reserved word: filter
ERROR: 0:157: error(#132) Syntax error: "filter" parse error
ERROR: error(#273) 2 compilation errors. No code generated

I'm using ATI R9 380x graphics card and this is the first time I had problems with any shaders (no problem at all with MAME HLSL shaders).

Is there any way to fix this problem, or does that mean I won't be able to use these two crt shaders?

[FrodeSolheim]

I think it seems quite obvious from the warnings that your OpenGL drivers do not meet the minimum requirements of that shader. According to the messages, you need shader version 4.20. This (usually) corresponds to the OpenGL driver supporting OpenGL 4.2+.

[Decypher]

At first I thought the same thing and I installed OpenGL Extensions Viewer to confirm I don't have an old driver.

According to this program I have OpenGL 4.4 installed.



I reinstalled my graphics card drivers just to be sure, but nothing is changed. I don't know if I need to try an older version of gfx driver (or OpenGL drivers), but it seems weird to me.

[FrodeSolheim]

Probably not much I can do about it anyway, but you can attach fs-uae.log.txt here, so we can validate what kind of OpenGL information FS-UAE queries from the actual OpenGL driver it uses.

[FrodeSolheim]

Hmm, actually, it is possible the only real problem is the name of a variable ("filter") in the shader - if the shader version warnings themselves "are harmless". Please upload fs-uae.log.txt, and I may provide a tweaked crt.shader file for you test.

[Decypher]

My fs-uae.log is attached, I hope that 'filter' thing is the culprit

[Decypher]

You were totally right Frode! I changed the word 'filter' to 'filterz' and it worked. Seems like they reserved the 'filter' word in newer OpenGL extensions.

Thank you very much for your spot-on solution

[FrodeSolheim]

Log confirms that the OpenGL driver in use supports OpenGL version 4.5.

I'm now guessing - based on looking at the shader (which I have not written) - that the warning is because the shader requires version 4.20, but the shader fails to declare minimum version in the shader source.

Attached is a modified shader with the "filter" variable renamed to "filter_".

Extract crt.shader to somewhere, and in advanced settings in FS-UAE Launcher, add something like (with correct path, of course):

shader = c:\shaders\crt.shader

EDIT: Didn't notice that you had tested the fix yourself in the meantime

EDIT2: Bundled shader updated for next development release.

[Decypher]

I just tested the unmodified shader files on my laptop (which is using a Nvidia gfx card and OpenGL 4.4) and shaders working there.

So this problem may be specific to ATI cards, maybe they broke something in new drivers. In any case I hope this thread will help others if they face the same problem.