proc_field_scale (compute shader)

Element-wise scale of an f32 field: dst[i] = src[i] * scale. One GPU thread per element. Reads a storage buffer (src), writes a storage buffer (dst), and multiplies by the scale params uniform.

The gpu.scale op (proc.gpu.eval("scale", { input = f, count = n, scale = 2 })) dispatches it and returns dst as a GPU-backed Field.