Efficient Entities

Efficient Entities speeds up Minecraft by reducing the CPU overhead of rendering mobs, collecting each entity's geometry into a persistent GPU buffer and submitting it in one draw call instead of dozens of small ones.

Requirements: MixinBooter or Cleanroom Relauncher

Detailed Explanation:

Minecraft renders entity models using OpenGL display lists one per body part, per mob, per frame. Each part triggers its own GL draw call along with matrix pushes, pops and state changes. With many mobs on screen this adds up to thousands of individual GPU submissions every frame, which becomes a significant CPU bottleneck.

This mod solves this by intercepting the rendering pipeline at two levels before the world loads. An ASM transformer scans entity model classes at load time and injects batch markers around their render calls. A Mixin then redirects geometry output away from the display list path and into a persistent buffer mapped directly inside GPU memory, so the CPU can write vertex data without any overhead. When a mob renders, each body part's bone transforms rotation points, angles, offsets are accumulated in a Java matrix stack rather than going through OpenGL's matrix calls

Every 200 rendered frames the mod writes one summary line:

In an empty world with just your hand visible:

[EfficientEntities] Last 200 frames: 12 batches, 84 cubes, 200 auto-wrapped.

Near a group of mobs:

[EfficientEntities] Last 200 frames: 840 batches, 6120 cubes, 0 auto-wrapped.

Near armoured entities:

[EfficientEntities] Last 200 frames: 15000 batches, 90000 cubes, 400 auto-wrapped.

What each number means:

• Batches - number of entity model render calls processed through the VBO path that period.

• Cubes - total geometry processed.

• Auto-wrapped - render calls caught by the fallback path (hand, held items, armour pieces).