Method set

src/webgpu/p5.RendererWebGPU.js:314–358

* Updates a single element in the buffer at a given index. Use this * when only a small number of elements need to change. If you need to * replace all the data at once, use * `update()` instead. * * ```js * let buf; * *

(index, value)

     *   struct buffers.
     */
    set(index, value) {
      const device = this._renderer.device;

      if (this._schema !== null) {
        // buffer was created with an array of structs
        if (typeof value !== 'object' || value === null || Array.isArray(value)) {
          throw new Error(
            'set() expects a plain object matching the original struct format for this buffer'
          );
        }

        const { stride } = this._schema;
        const byteOffset = index * stride;

        if (byteOffset + stride > this.size) {
          throw new Error(
            `set() index ${index} is out of bounds for this buffer ` +
            `(buffer holds ${Math.floor(this.size / stride)} elements)`
          );
        }

        // pack just this one element using the same logic as update()
        const packed = this._renderer._packStructArray([value], this._schema);
        // use packed.buffer (ArrayBuffer) so the size arg is always in bytes
        device.queue.writeBuffer(this.buffer, byteOffset, packed.buffer, 0, stride);
      } else {
        // buffer was created with a float array
        if (typeof value !== 'number') {
          throw new Error(
            'set() expects a number for this float buffer'
          );
        }

        const byteOffset = index * 4;

        if (byteOffset + 4 > this.size) {
          throw new Error(
            `set() index ${index} is out of bounds for this buffer ` +
            `(buffer holds ${Math.floor(this.size / 4)} floats)`
          );
        }

        device.queue.writeBuffer(this.buffer, byteOffset, new Float32Array([value]));
      }
    }
  }

  /**