Efficient Entities

Efficient Entities speeds up Minecraft by reducing the CPU overhead of rendering mobs. Instead of drawing every body part separately, it collects each model’s geometry into a persistent GPU buffer and submits it in a single draw call.

Requirements:

• MixinBooter or Cleanroom Relauncher

Detailed Explanation:

Minecraft renders entity models one body part at a time. For every part of every mob, every frame, it issues OpenGL matrix pushes, translations, rotations and a display list call. With many mobs on screen this adds up to thousands of small GL calls per frame, which makes entity rendering a significant CPU bottleneck.

This mod works at two levels. When the game loads, an ASM transformer finds the runs of consecutive body-part renders in each model class and marks each run as one batch. While rendering, a Mixin takes over each body part: its bone transforms (rotation points, angles and offsets) are accumulated in a Java matrix stack instead of through OpenGL’s matrix calls, its vertices are written straight into a persistently mapped GPU buffer, and the whole batch is drawn with one call. The geometry is read from the model’s own quads, so mobs look exactly as they do in vanilla, including mirrored limbs and armour layers.

Compatibility:

• OptiFine: when installed, the mod steps aside so shaders and custom entity models keep working.
• Mod Entities: body parts with their own render code are drawn by vanilla, in the correct position.
• Forge and Cleanroom alike: only OpenGL calls that both LWJGL 2 (Forge) and LWJGL 3 (Cleanroom) provide are used, so the mod doesn’t depend on Cleanroom’s LWJGL compatibility layer and keeps working across Cleanroom updates.

Configuration (config/efficiententities.cfg, also editable from the in-game mod list):

• enabled (default true): turn off to compare against vanilla rendering without restarting.
• statisticsLogPeriod (default 0): write a summary line to the log every N frames. 0 turns it off.

With statistics turned on, each summary line looks like this:

[EfficientEntities] Last 200 frames: D draws, B boxes, S single-part batches, V vanilla parts.

What each number means:

• Draws – GPU draw calls the mod issued that period.

• Boxes – model cubes written into the GPU buffer.

• Single-part batches – body parts drawn on their own rather than as part of a batched model.

• Vanilla parts – body parts handed back to vanilla rendering.

Special thanks to seeedl1ng for contributing to the Cleanroom integration features.