visgl / luma.gl / 14540553142

// luma.gl

// SPDX-License-Identifier: MIT

// Copyright (c) vis.gl contributors

import type {VertexFormat} from '../../shadertypes/vertex-arrays/vertex-formats';

/**

 * Provides specific details about the memory layout of the actual buffers

 * that will be provided to a `RenderPipeline`.

 *

 * BufferLayout lets the application describe whether

 * - A single buffer can be used for multiple attributes (using interleaving or offsets),

 * - The data format of the memory being supplied to a specific shader attribute.

 *

 * `BufferLayout` complements the "static" attribute declarations in a ShaderLayout

 * with information about the "dynamic" memory layout of each buffer that will be bound

 * to the render pipeline.

 */

/** 

 * Specify memory layout for one buffer, describing how it is used by one or more attribute

 * @note Specifies format, stride, offset and step mode

 * @note The buffer can be set using the buffer name:`.setAttributes({[bufferName]: buffer})`.

 * @note Needs to match type/components of the ShaderLayout ('f32', 'i32', 's32')

 *

 * A buffer layout is used to specify "non-standard" buffer layouts (buffers with offsets, interleaved buffers etc)

 *

 * @example

 * ```

  device.createRenderPipeline({

    ...

    shaderLayout,

    bufferLayout: [

      {name: 'positions', stepMode: 'vertex', format: 'float32x3'},

      // interleaved bindings, auto offset

      {name: 'particles', stepMode: 'instance', byteStride: 32, attributes: [

        {name: 'instancePositions', format: 'float32x4', byteOffset: 0},

        {name: 'instanceVelocities', format: 'float32x4', byteOffset: 16}

      ]},

    ]

  ];

  ```

  */

export type BufferLayout = {

  /** Name of buffer */

  name: string;

  /** Is the attribute is instanced. Default: auto-deduced from shader name. */

  stepMode?: 'vertex' | 'instance';

  /** bytes between successive elements. If omitted, stride is set to reflect a "packed" buffer */

  byteStride?: number;

  /** Option 1: interleaved attributes that read from this buffer */

  attributes?: BufferAttributeLayout[];

  /** Option 2: Single attribute with same name as buffer. */

  format?: VertexFormat;

};

/** Specifies how the GPU should read one specific attribute from a buffer.  */

export type BufferAttributeLayout = {

  /** Name of attribute that maps to a "view" of this buffer */

  attribute: string;

  /** Data format of the memory in the buffer that is mapped to this attribute */

  format: VertexFormat;

  /** Sum up any the "global" offset (or 0) and the offset each stride (for interleaved data). */

  byteOffset: number;

};