Constant MAX_JOINTS 

pub const MAX_JOINTS: usize = 64; // 64usize

Maximum number of joints in a single skinned-mesh skeleton. Enforced CPU-side as a clamp on each SkinnedDrawObject.joint_count and on the matching skinned_joint_matrices Vec length. The skinned shaders read the joints buffer through a pointer (constant float4x4 *joints) using vertex-encoded joint indices, so the GPU buffer size and joint count are fully dynamic: this constant just caps how many matrices the per-frame upload may carry per object.