text: import { typedArrayTypes } from './constants.js';
  
  function set1(a) {
      this.array[this.index] = a;
  }
  
  function set2(a, b) {
      this.array[this.index] = a;
      this.array[this.index + 1] = b;
  }
  
  function set3(a, b, c) {
      this.array[this.index] = a;
      this.array[this.index + 1] = b;
      this.array[this.index + 2] = c;
  }
  
  function set4(a, b, c, d) {
      this.array[this.index] = a;
      this.array[this.index + 1] = b;
      this.array[this.index + 2] = c;
      this.array[this.index + 3] = d;
  }
  
  function arraySet1(index, inputArray, inputIndex) {
      this.array[index] = inputArray[inputIndex];
  }
  
  function arraySet2(index, inputArray, inputIndex) {
      this.array[index] = inputArray[inputIndex];
      this.array[index + 1] = inputArray[inputIndex + 1];
  }
  
  function arraySet3(index, inputArray, inputIndex) {
      this.array[index] = inputArray[inputIndex];
      this.array[index + 1] = inputArray[inputIndex + 1];
      this.array[index + 2] = inputArray[inputIndex + 2];
  }
  
  function arraySet4(index, inputArray, inputIndex) {
      this.array[index] = inputArray[inputIndex];
      this.array[index + 1] = inputArray[inputIndex + 1];
      this.array[index + 2] = inputArray[inputIndex + 2];
      this.array[index + 3] = inputArray[inputIndex + 3];
  }
  
  function arrayGet1(offset, outputArray, outputIndex) {
      outputArray[outputIndex] = this.array[offset];
  }
  
  function arrayGet2(offset, outputArray, outputIndex) {
      outputArray[outputIndex] = this.array[offset];
      outputArray[outputIndex + 1] = this.array[offset + 1];
  }
  
  function arrayGet3(offset, outputArray, outputIndex) {
      outputArray[outputIndex] = this.array[offset];
      outputArray[outputIndex + 1] = this.array[offset + 1];
      outputArray[outputIndex + 2] = this.array[offset + 2];
  }
  
  function arrayGet4(offset, outputArray, outputIndex) {
      outputArray[outputIndex] = this.array[offset];
      outputArray[outputIndex + 1] = this.array[offset + 1];
      outputArray[outputIndex + 2] = this.array[offset + 2];
      outputArray[outputIndex + 3] = this.array[offset + 3];
  }
  
  /**
   * @class
   * @name VertexIteratorAccessor
   * @classdesc Helps with accessing a specific vertex attribute.
   * @description Returns a new VertexIteratorAccessor object.
   * @param {ArrayBuffer} buffer - The vertex buffer containing the attribute to be accessed.
   * @param {object} vertexElement - The vertex attribute to be accessed.
   * @param {string} vertexElement.name - The meaning of the vertex element. This is used to link
   * the vertex data to a shader input. Can be:
   *
   * * {@link SEMANTIC_POSITION}
   * * {@link SEMANTIC_NORMAL}
   * * {@link SEMANTIC_TANGENT}
   * * {@link SEMANTIC_BLENDWEIGHT}
   * * {@link SEMANTIC_BLENDINDICES}
   * * {@link SEMANTIC_COLOR}
   * * {@link SEMANTIC_TEXCOORD0}
   * * {@link SEMANTIC_TEXCOORD1}
   * * {@link SEMANTIC_TEXCOORD2}
   * * {@link SEMANTIC_TEXCOORD3}
   * * {@link SEMANTIC_TEXCOORD4}
   * * {@link SEMANTIC_TEXCOORD5}
   * * {@link SEMANTIC_TEXCOORD6}
   * * {@link SEMANTIC_TEXCOORD7}
   *
   * If vertex data has a meaning other that one of those listed above, use the user-defined
   * semantics: {@link SEMANTIC_ATTR0} to {@link SEMANTIC_ATTR15}.
   * @param {number} vertexElement.numComponents - The number of components of the vertex attribute.
   * Can be 1, 2, 3 or 4.
   * @param {number} vertexElement.dataType - The data type of the attribute. Can be:
   *
   * * {@link TYPE_INT8}
   * * {@link TYPE_UINT8}
   * * {@link TYPE_INT16}
   * * {@link TYPE_UINT16}
   * * {@link TYPE_INT32}
   * * {@link TYPE_UINT32}
   * * {@link TYPE_FLOAT32}
   * @param {boolean} vertexElement.normalize - If true, vertex attribute data will be mapped from a
   * 0 to 255 range down to 0 to 1 when fed to a shader. If false, vertex attribute data is left
   * unchanged. If this property is unspecified, false is assumed.
   * @param {number} vertexElement.offset - The number of initial bytes at the start of a vertex that are not relevant to this attribute.
   * @param {number} vertexElement.stride - The number of total bytes that are between the start of one vertex, and the start of the next.
   * @param {ScopeId} vertexElement.scopeId - The shader input variable corresponding to the attribute.
   * @param {number} vertexElement.size - The size of the attribute in bytes.
   * @param {VertexFormat} vertexFormat - A vertex format that defines the layout of vertex data inside the buffer.
   */
  class VertexIteratorAccessor {
      constructor(buffer, vertexElement, vertexFormat) {
          this.index = 0;
          this.numComponents = vertexElement.numComponents;
  
          // create the typed array based on the element data type
          if (vertexFormat.interleaved) {
              this.array = new typedArrayTypes[vertexElement.dataType](buffer, vertexElement.offset);
          } else {
              this.array = new typedArrayTypes[vertexElement.dataType](buffer, vertexElement.offset, vertexFormat.vertexCount * vertexElement.numComponents);
          }
  
          // BYTES_PER_ELEMENT is on the instance and constructor for Chrome, Safari and Firefox, but just the constructor for Opera
          this.stride = vertexElement.stride / this.array.constructor.BYTES_PER_ELEMENT;
  
          // Methods
          switch (vertexElement.numComponents) {
              case 1:
                  this.set = set1;
                  this.getToArray = arrayGet1;
                  this.setFromArray = arraySet1;
                  break;
  
              case 2:
                  this.set = set2;
                  this.getToArray = arrayGet2;
                  this.setFromArray = arraySet2;
                  break;
  
              case 3:
                  this.set = set3;
                  this.getToArray = arrayGet3;
                  this.setFromArray = arraySet3;
                  break;
  
              case 4:
                  this.set = set4;
                  this.getToArray = arrayGet4;
                  this.setFromArray = arraySet4;
                  break;
          }
      }
  
      /**
       * @function
       * @name VertexIteratorAccessor#get
       * @description Get a attribute component at the iterator's current index.
       * @param {number} offset - The component offset. Should be either 0, 1, 2, or 3.
       * @returns {number} The value of a attribute component.
       */
      get(offset) {
          return this.array[this.index + offset];
      }
  
      /**
       * @function
       * @name VertexIteratorAccessor#set
       * @description Set all the attribute components at the iterator's current index.
       * @param {number} a - The first component value.
       * @param {number} [b] - The second component value (if applicable).
       * @param {number} [c] - The third component value (if applicable).
       * @param {number} [d] - The fourth component value (if applicable).
       */
      set(a, b, c, d) {
          // Will be replaced with specialized implementation based on number of components
      }
  
      /**
       * @function
       * @name VertexIteratorAccessor#getToArray
       * @description Read attribute components to an output array.
       * @param {number} offset - The component offset at which to read data from the buffer. Will be used instead of the iterator's current index.
       * @param {number[]|Int8Array|Uint8Array|Uint8ClampedArray|Int16Array|Uint16Array|Int32Array|Uint32Array|Float32Array} outputArray - The output array to write data into.
       * @param {number} outputIndex - The output index at which to write into the output array.
       */
      getToArray(offset, outputArray, outputIndex) {
          // Will be replaced with specialized implementation based on number of components
      }
  
      /**
       * @function
       * @name VertexIteratorAccessor#setFromArray
       * @description Write attribute components from an input array.
       * @param {number} index - The starting index at which to write data into the buffer. Will be used instead of the iterator's current index.
       * @param {number[]|Int8Array|Uint8Array|Uint8ClampedArray|Int16Array|Uint16Array|Int32Array|Uint32Array|Float32Array} inputArray - The input array to read data from.
       * @param {number} inputIndex - The input index at which to read from the input array.
       */
      setFromArray(index, inputArray, inputIndex) {
          // Will be replaced with specialized implementation based on number of components
      }
  }
  
  /**
   * @class
   * @name VertexIterator
   * @classdesc A vertex iterator simplifies the process of writing vertex data to a vertex buffer.
   * @description Returns a new VertexIterator object.
   * @param {VertexBuffer} vertexBuffer - The vertex buffer to be iterated.
   * @property {object<string, VertexIteratorAccessor>} element The vertex buffer elements.
   */
  class VertexIterator {
      constructor(vertexBuffer) {
          // Store the vertex buffer
          this.vertexBuffer = vertexBuffer;
          this.vertexFormatSize = vertexBuffer.getFormat().size;
  
          // Lock the vertex buffer
          this.buffer = this.vertexBuffer.lock();
  
          // Create an empty list
          this.accessors = [];
          this.element = {};
  
          // Add a new 'setter' function for each element
          const vertexFormat = this.vertexBuffer.getFormat();
          for (let i = 0; i < vertexFormat.elements.length; i++) {
              const vertexElement = vertexFormat.elements[i];
              this.accessors[i] = new VertexIteratorAccessor(this.buffer, vertexElement, vertexFormat);
              this.element[vertexElement.name] = this.accessors[i];
          }
      }
  
      /**
       * @function
       * @name VertexIterator#next
       * @description Moves the vertex iterator on to the next vertex.
       * @param {number} [count] - Optional number of steps to move on when calling next. Defaults to 1.
       * @example
       * var iterator = new pc.VertexIterator(vertexBuffer);
       * iterator.element[pc.SEMANTIC_POSTIION].set(-0.9, -0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(255, 0, 0, 255);
       * iterator.next();
       * iterator.element[pc.SEMANTIC_POSTIION].set(0.9, -0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(0, 255, 0, 255);
       * iterator.next();
       * iterator.element[pc.SEMANTIC_POSTIION].set(0.0, 0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(0, 0, 255, 255);
       * iterator.end();
       */
      next(count = 1) {
          let i = 0;
          const accessors = this.accessors;
          const numAccessors = this.accessors.length;
          while (i < numAccessors) {
              const accessor = accessors[i++];
              accessor.index += count * accessor.stride;
          }
      }
  
      /**
       * @function
       * @name VertexIterator#end
       * @description Notifies the vertex buffer being iterated that writes are complete. Internally
       * the vertex buffer is unlocked and vertex data is uploaded to video memory.
       * @example
       * var iterator = new pc.VertexIterator(vertexBuffer);
       * iterator.element[pc.SEMANTIC_POSTIION].set(-0.9, -0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(255, 0, 0, 255);
       * iterator.next();
       * iterator.element[pc.SEMANTIC_POSTIION].set(0.9, -0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(0, 255, 0, 255);
       * iterator.next();
       * iterator.element[pc.SEMANTIC_POSTIION].set(0.0, 0.9, 0.0);
       * iterator.element[pc.SEMANTIC_COLOR].set(0, 0, 255, 255);
       * iterator.end();
       */
      end() {
          // Unlock the vertex buffer
          this.vertexBuffer.unlock();
      }
  
      // Copies data for specified semantic into vertex buffer.
      // Works with both interleaved (slower) and non-interleaved (fast) vertex buffer
      writeData(semantic, data, numVertices) {
          const element = this.element[semantic];
          if (element) {
  
              if (numVertices > this.vertexBuffer.numVertices) {
                  // #if _DEBUG
                  console.error(`NumVertices provided to setData: ${numVertices} is larger than space in VertexBuffer: ${this.vertexBuffer.numVertices}`);
                  // #endif
  
                  // avoid overwrite
                  numVertices = this.vertexBuffer.numVertices;
              }
  
              const numComponents = element.numComponents;
  
              // copy data to interleaved buffer by looping over vertices and copying them manually
              if (this.vertexBuffer.getFormat().interleaved) {
                  let index = 0;
                  for (let i = 0; i < numVertices; i++) {
                      element.setFromArray(index, data, i * numComponents);
                      index += element.stride;
                  }
              } else {    // non-interleaved copy
  
                  // if data contains more  data than needed, copy from its subarray
                  if (data.length > numVertices * numComponents) {
                      const copyCount = numVertices * numComponents;
  
                      // if data is typed array
                      if (ArrayBuffer.isView(data)) {
                          data = data.subarray(0, copyCount);
                          element.array.set(data);
                      } else {
                          // data is array, copy right amount manually
                          for (let i = 0; i < copyCount; i++)
                              element.array[i] = data[i];
                      }
                  } else {
                      // copy whole data
                      element.array.set(data);
                  }
              }
          }
      }
  
      // Function to extract elements of a specified semantic from vertex buffer into flat array (data).
      // Works with both interleaved (slower) and non-interleaved (fast) vertex buffer
      // returns number of verticies
      // Note: when data is typed array and is smaller than needed, only part of data gets copied out (typed arrays ignore read/write out of range)
      readData(semantic, data) {
          const element = this.element[semantic];
          let count = 0;
          if (element) {
              count = this.vertexBuffer.numVertices;
              let i;
              const numComponents = element.numComponents;
  
              if (this.vertexBuffer.getFormat().interleaved) {
  
                  // extract data from interleaved buffer by looping over vertices and copying them manually
                  if (Array.isArray(data))
                      data.length = 0;
  
                  element.index = 0;
                  let offset = 0;
                  for (i = 0; i < count; i++) {
                      element.getToArray(offset, data, i * numComponents);
                      offset += element.stride;
                  }
              } else {
                  if (ArrayBuffer.isView(data)) {
                      // destination data is typed array
                      data.set(element.array);
                  } else {
                      // destination data is array
                      data.length = 0;
                      const copyCount = count * numComponents;
                      for (i = 0; i < copyCount; i++)
                          data[i] = element.array[i];
                  }
              }
          }
  
          return count;
      }
  }
  
  export { VertexIterator, VertexIteratorAccessor };
  