IconRenderer

Pure-Java software rasterizer that generates 64x64 inventory icons from Java 3D item models. Replaces the legacy "UV-atlas as icon" placeholder in the generic Bedrock pipeline.

Algorithm summary:

1. Parse elements[] from the merged Java model JSON.
2. Read display.gui (rotation/translation/scale), defaulting to Mojang's GUI camera (rotation = [30, 225, 0], no translation, scale = [1, 1, 1]). The vanilla default scale 0.625 only applies to item/generated-rooted (flat) models; cuboid models authored without an explicit display.gui look correct at scale 1.
3. For each element, build the 8 cube corners in Java's 16-unit space centred at (8, 8, 8). Apply the per-element rotation (around its own origin), then the display.gui pivot rotation around (8,8,8), then display.gui scale and translation.
4. For each of the 6 faces, back-face cull against -Z and compute the 2D destination quad on the 64x64 canvas (orthographic, 4 px per model unit).
5. Paint visible faces back-to-front via painter's algorithm using a Java2D AffineTransform that maps the source-texture UV rect to the destination parallelogram. Nearest-neighbour interpolation keeps the pixel-art aesthetic.

UV defaults (when faces.<name>.uv is absent), per-face UV rotation, and the up/down-face flip convention all follow vanilla FaceBakery semantics — the same rules already implemented in defaultFaceUV are mirrored here (the helper itself is private, but the algorithm is straightforward enough to inline).