OS Waves (3014738359) - Rendering Issues Investigation

Investigation of rendering differences between linux-wallpaperengine and the native Windows Wallpaper Engine for the OS Waves wallpaper (workshop ID 3014738359).

Wallpaper Structure

The wallpaper consists of 8 scene objects rendered in this order:

Object ID	Name	Type	Effects	Status
85	Solid1	Image (solid)	None	Renders correctly
173	Windowslogo-_2021.svg	Image	Pulse (audio)	Renders, audio response may differ
57	1024px-Archlinux-icon-crystal-64.svg	Image	Pulse (audio)	Renders, audio response may differ
61	ubuntu-icon-logo-png-transparent	Image	Pulse (audio)	Renders, audio response may differ
140	Clock	Text	N/A	Not rendered (text unsupported)
45	cust	Image (passthrough)	None	Possibly skipped (passthrough w/o effects)
71	13	Image	Water waves	Renders via shader
36	14	Image	Water waves	Renders via shader

Bloom is applied as a post-processing pass (via wpenginelinux.json).

Issues Found

1. Script-based UserSettings not executed (CRITICAL)

Files: src/WallpaperEngine/Data/Parsers/UserSettingParser.cpp:21-24

The wallpaper defines 4 user settings with embedded JavaScript that dynamically control object position (Y and Z axes) via slider properties. The engine currently logs a warning and falls back to the default value, meaning objects are placed at their raw default positions instead of the script-computed ones.

Example script from the wallpaper:

export function update(value) {
    value.y = scriptProperties.posY;  // slider 0-100
    return value;
}

Impact: Object positioning differs from Windows. Sliders for position adjustments are non-functional.

2. Text objects not supported (MEDIUM)

Files: src/WallpaperEngine/Data/Parsers/ObjectParser.cpp:55-56

Object 140 ("Clock") is a text object and is silently skipped. On Windows this would render as a visible clock element.

Impact: Missing UI element in the wallpaper.

3. Orthogonal camera auto-size not implemented (MEDIUM)

Files: src/WallpaperEngine/Render/Wallpapers/CScene.cpp:37-39

When the scene camera uses isAuto=true for orthogonal projection, the engine has a TODO to calculate the projection based on content size. Currently falls through without adjusting.

Impact: If enabled, overall scale and positioning of all objects could be wrong.

4. Passthrough images without effects are skipped (LOW-MEDIUM)

Files: src/WallpaperEngine/Render/Objects/CImage.cpp:226-230

Object 45 ("cust") uses passthrough mode. The engine explicitly skips passthrough images that have no effects attached:

if (this->m_image.model->passthrough && this->m_image.effects.empty()) {
    return;
}

Impact: If this object is meant to composite content from behind, it won't appear.

5. Audio spectrum processing may differ (MEDIUM)

Files: src/WallpaperEngine/Render/Objects/Effects/CPass.cpp:625-630

The pulse effect on the OS logos uses:

AUDIOPROCESSING=3
audioamount=1.0, audiobounds=0.5-1.0, audioexponent=0.35

The DSP algorithm for audio spectrum analysis may produce different results than the Windows implementation.

Impact: Logo pulse animations may respond differently to audio.

6. Fullscreen/autosize behavior incomplete (LOW)

Files: src/WallpaperEngine/Render/Objects/CImage.cpp:66

There is a TODO asking what autosize should do. Fullscreen layers force size to scene dimensions, but autosize behavior is undefined.

Impact: Minor sizing differences for affected layers.

Fix Applied: parallaxDepth UserSetting Support

Commit: fix: support UserSetting objects for parallaxDepth

The original crash was caused by parallaxDepth being declared as glm::vec2 while the wallpaper's scene.json uses it as a UserSetting object:

{"user": "parallaxstrength", "value": "0.19000 0.19000"}

Changes made:

src/WallpaperEngine/Data/Model/Object.h: Changed parallaxDepth from glm::vec2 to UserSettingUniquePtr in both ImageData and ParticleData
src/WallpaperEngine/Data/Parsers/ObjectParser.cpp: Changed 3 parse sites from it.optional() to it.user() to handle both plain values and UserSetting objects
src/WallpaperEngine/Render/Objects/CImage.cpp: Updated access to dereference through the UserSetting wrapper (->value->getVec2())

This follows the same pattern already used by origin, scale, angles, visible, alpha, and color.

Reproduction

linux-wallpaperengine \
  --assets-dir ~/.local/share/Steam/steamapps/common/wallpaper_engine/assets \
  --screen-root DP-2 --screen-root HDMI-A-1 \
  --fps 60 --silent \
  ~/.local/share/Steam/steamapps/workshop/content/431960/3014738359

OS-Waves-rendering-issues.md 4.8 KB Istoric Crud