minosoft/doc/rendering/Entities.md

Entity rendering

Entity rendering is a quite hard topic.

Classes

• Player renderer
  • player model
  • feature renderer:
    • armor
    • stuck arrows

Skeletal models

• SkeletalModel (raw data)
• BakedSkeletalModel (baked mesh)
• SkeletalInstance (renders baked mesh, contains transform values)
• Wrapper (indirectly accesses skeletal instance transforms)

Model designing

Entities

Entities are always designed without any rotation (i.e. yaw=0)

Things to consider

• name rendering (without culling and visible through walls) (and scoreboard objective)
• hitbox rendering
• entity model itself
  • player with arms, legs, ...
  • has animations, ...
  • different poses (sneaking, etc)
• yaw vs head yaw
• "features"
  • armor (and armor trims)
  • elytra
  • stuck arrows (and bee stingers)
  • cape
  • shoulder entities (parrots)
  • held item
• light (shade and lightmap)

General

• render layers (opaque -> transparent -> translucent -> ...) (but face culling enabled)
  • sort in layers after distance (or -distance)
  • there are also invisible renderers (like AreaEffectCloud is just emitting particles)
• update all models async (with their visibility, etc)
• queue for unloading and loading meshes before draw (better while async preparing to save time. Maybe port that system to block entities)
• Loop over all visible entity renderers and work on the entity layer as needed
• update visible and not visible
  • entity name is also visible through walls, rest not
  • also with frustum (no need to update renderers that are out of the frustum)
  • -> handle occlusion differently from visibility
• option to turn on/off "features"
• how to register entity models?
  • loop over all entity (and block entity) types and register?
• store entities in octree like structure
  • ways faster collisions with them -> physics
  • way faster getInRadius -> particles, maybe entities in the future

Hitboxes

• Create line mesh with default aabb
  • interpolate
    • aabb (not at all, taken from renderInfo)
    • color: 0.5s
    • velocity (ticks)
    • direction (taken from renderInfo)
    • eye height (taken from renderInfo)
  • they must alight with the matrix handler -> mustn't be a frame too late/early
• Store offset and rotation as uniform
• Make hitbox a default feature of entity renderer
• highest priority (enables cheap gpu clipping)
• dynamic enabling and disabling (hitbox manager, keybinding)

Tests

• hitbox (data, loading, unloading)
• collect visible meshes (with sorting, priority type and distance)