import getAccessorByteStride from './getAccessorByteStride.js'
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import getComponentReader from './getComponentReader.js'
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import numberOfComponentsForType from './numberOfComponentsForType.js'
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import arrayFill from '../../Core/arrayFill.js'
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import ComponentDatatype from '../../Core/ComponentDatatype.js'
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import defined from '../../Core/defined.js'
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/**
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* Finds the min and max values of the accessor.
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*
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* @param {Object} gltf A javascript object containing a glTF asset.
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* @param {Object} accessor The accessor object from the glTF asset to read.
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* @returns {{min: Array, max: Array}} min holding the array of minimum values and max holding the array of maximum values.
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*
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* @private
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*/
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function findAccessorMinMax(gltf, accessor) {
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var bufferViews = gltf.bufferViews;
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var buffers = gltf.buffers;
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var bufferViewId = accessor.bufferView;
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var numberOfComponents = numberOfComponentsForType(accessor.type);
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// According to the spec, when bufferView is not defined, accessor must be initialized with zeros
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if (!defined(accessor.bufferView)) {
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return {
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min: arrayFill(new Array(numberOfComponents), 0.0),
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max: arrayFill(new Array(numberOfComponents), 0.0)
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};
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}
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var min = arrayFill(new Array(numberOfComponents), Number.POSITIVE_INFINITY);
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var max = arrayFill(new Array(numberOfComponents), Number.NEGATIVE_INFINITY);
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var bufferView = bufferViews[bufferViewId];
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var bufferId = bufferView.buffer;
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var buffer = buffers[bufferId];
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var source = buffer.extras._pipeline.source;
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var count = accessor.count;
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var byteStride = getAccessorByteStride(gltf, accessor);
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var byteOffset = accessor.byteOffset + bufferView.byteOffset + source.byteOffset;
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var componentType = accessor.componentType;
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var componentTypeByteLength = ComponentDatatype.getSizeInBytes(componentType);
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var dataView = new DataView(source.buffer);
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var components = new Array(numberOfComponents);
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var componentReader = getComponentReader(componentType);
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for (var i = 0; i < count; i++) {
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componentReader(dataView, byteOffset, numberOfComponents, componentTypeByteLength, components);
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for (var j = 0; j < numberOfComponents; j++) {
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var value = components[j];
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min[j] = Math.min(min[j], value);
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max[j] = Math.max(max[j], value);
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}
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byteOffset += byteStride;
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}
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return {
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min: min,
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max: max
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};
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}
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export default findAccessorMinMax;
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