Decouple spatial 3D source resolution from 2D display cap

The 3D resolution limit was being silently clamped by the 2D
maxImageResolution setting, so picking "Off" for the 3D cap still
inherited whatever 2D was set to. The two caps govern different
pipelines (MTLTexture vs Spatial3DImage source) and should be
fully independent.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: illixion

SpatialStash/SpatialStash/Model/AppModel.swift

@@ -546,10 +546,10 @@ class AppModel {
         ("Off", 0),
     ]
 
-    /// Maximum resolution passed to RealityKit's `Spatial3DImage`. Independent
-    /// of `maxImageResolution` so the 2D path can stay full-res while the 3D
-    /// depth/parallax mesh uses a smaller source. Capped at min(this, maxImageResolution)
-    /// when the latter is non-zero. 0 = no extra cap (defer to maxImageResolution).
+    /// Maximum resolution passed to RealityKit's `Spatial3DImage`. Fully
+    /// independent of `maxImageResolution` — the 2D cap governs the on-screen
+    /// MTLTexture, this one governs the source fed into the depth/parallax
+    /// mesh. 0 = no cap (use native resolution).
     var spatial3DMaxResolution: Int {
         didSet {
             if spatial3DMaxResolution != oldValue {

SpatialStash/SpatialStash/Model/PhotoWindowModel+Spatial3D.swift

@@ -158,20 +158,11 @@ extension PhotoWindowModel {
                 sourceURL = imageURL
             }
 
-            // Respect the max image resolution setting by downsampling the source
-            // image before passing it to RealityKit's Spatial3DImage. The dedicated
-            // spatial3DMaxResolution can clamp lower than the global cap so the 2D
-            // path keeps its full resolution while the depth/parallax mesh works
-            // off a smaller source.
-            let globalRes = effectiveMaxResolution
-            let s3dRes = effectiveSpatial3DMaxResolution
-            let effectiveRes: Int
-            switch (globalRes, s3dRes) {
-            case (0, 0): effectiveRes = 0
-            case (0, let s): effectiveRes = s
-            case (let g, 0): effectiveRes = g
-            case (let g, let s): effectiveRes = min(g, s)
-            }
+            // The spatial 3D source resolution is independent of the 2D display
+            // resolution: the 2D cap governs the on-screen MTLTexture, while
+            // this cap governs the source fed into RealityKit's Spatial3DImage.
+            // 0 = no cap (use native resolution).
+            let effectiveRes = effectiveSpatial3DMaxResolution
             if effectiveRes > 0,
                let downsampledData = Self.createDownsampledImageData(from: sourceURL, maxDimension: CGFloat(effectiveRes)),
                let downsampledSource = CGImageSourceCreateWithData(downsampledData as CFData, nil) {

SpatialStash/SpatialStash/Model/PhotoWindowModel.swift

@@ -468,7 +468,7 @@ class PhotoWindowModel {
     }
 
     /// The effective spatial 3D source resolution, considering per-window override.
-    /// 0 means "no extra cap beyond `effectiveMaxResolution`".
+    /// 0 means "no cap" (use native resolution).
     var effectiveSpatial3DMaxResolution: Int {
         spatial3DResolutionOverride ?? appModel.spatial3DMaxResolution
     }