Buffers and Uniforms

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Buffers and Uniforms can be distinguished by their pin visual. Uniform pins have standard round pins, whereas Buffer pins are represented by a square pin.

Buffers can only be used as an input for Buffer pins specifically. Uniforms can be used as an input for both Buffer and Uniform pins.

A single-length Buffer is functionally identical to a Uniform, and using one will not have any impact on performance. Performance considerations only change if the Buffer contains multiple values.

The most straight-forward rule of thumb for whether a given value should be a Bufferor a uniform is this:

• If a value changes based on position, it is almost always a Buffer.

• If a value is the same for every position, it is almost always a Uniform.

On a technical level, a Buffer is simply a stack of data: a single Buffer pin represents the data for every point within a chunk at the same time, rather than just being a single value. Having this data in a stack allows it to be operated on in bulk, i.e. by calculating many values at once using ISPC on the CPU, or GPU compute.

Uniform values are constant throughout all of a chunk's positions. If needed, a Uniform value can change from once chunk to the next. For example, the Get LOD node returns a uniform. It reports the current LOD, which varies from one chunk to the next. Because the LOD value will never change within a chunk, however, it can still be a uniform.