Chasm: Fix achievement popups on low-memory devices.

[ThalesC]

Summary

This PR restores achievement popups on low-memory devices by fixing the underlying texture atlas unloading issue.

Previously, achievement rendering was disabled entirely to avoid crashes:

// Don't draw achievements...
return false;

Instead of suppressing achievement popups, this patch reloads the drmfree texture atlas after texture bank switches, allowing achievements to render normally.

Root cause

Achievement icons are stored in the drmfree texture atlas.

On low-memory devices, Database.LoadTextureKey() unloads texture atlases that are no longer needed. After switching texture banks, the drmfree atlas can be unloaded while achievement popups may still need to reference textures from it.

When an achievement is displayed, this results in a crash while drawing the popup.

Reloading drmfree after texture bank switches ensures the achievement atlas remains available whenever achievement popups are rendered.

Memory impact

I inspected the atlas used for achievement icons:

• 1 atlas (atlas_drmfree_0)
• 256 × 256 pixels
• SurfaceFormat.Color
• LevelCount = 1

This corresponds to approximately 256 KiB of GPU texture memory, making the tradeoff very small while restoring the intended game behavior.

The previous workaround disabled achievement rendering to avoid the crash. This patch restores the original functionality while keeping the additional memory usage limited to a single 256 KiB texture atlas.

Testing

Tested on:

• RG35XX H
• Knulli

Verified that achievement popups:

• render their icons correctly,
• no longer crash the game,
• and continue to work after multiple texture bank switches.

The screenshot below shows the Warrior achievement popup rendered correctly after the patch.

The screenshot below shows two achievement popups rendered correctly after the patch.

[JohnnyonFlame]

Thank you for the contribution! I have some more changes to do in regards to fixing issues due to SDL3 support being added to FNA3D which caused some linking woes. When I find myself going back I'll review, merge and credit you.