fix: trims off effect layers, makes rendering a bit more sane (#295)

* Adds a wider span for layers without mixup with planes

The existing multiplier is lower then layer values encoraged by byond,
so it breaks easy. Hopefully a larger value will help here.

* let's lower that down to make INF less likely

* fuckoff big number

* offset strategy

internal/app/render/bucket/level/chunk/unit/unit.go

@@ -91,6 +91,21 @@ func countLayer(p *dmmprefab.Prefab) float32 {
 	plane, _ := p.Vars().Float("plane")
 	layer, _ := p.Vars().Float("layer")
 
+	// Layers can have essentially effect values added onto them
+	// We should clip them off to reduce the max possible layer to like 4999 (likely far lower)
+	const BACKGROUND_LAYER = 20_000
+	const TOPDOWN_LAYER = 10_000
+	const EFFECTS_LAYER = 5000
+	if layer > BACKGROUND_LAYER {
+		layer -= BACKGROUND_LAYER
+	}
+	if layer > TOPDOWN_LAYER {
+		layer -= TOPDOWN_LAYER
+	}
+	if layer > EFFECTS_LAYER {
+		layer -= EFFECTS_LAYER
+	}
+
 	layer = plane*10_000 + layer*1000
 
 	// When mobs are on the same Layer with object they are always rendered above them (BYOND specific stuff).