@woosh/meep-engine/src/engine/graphics/texture/sampler/sampler2d_channel_compute_min_indices.js

Pure JavaScript game engine. Fully featured and production ready.

import { assert } from "../../../../core/assert.js";

/**
 *
 * @param {number[]|Float32Array|Uint8Array|Uint32Array} result
 * @param {number} result_offset
 * @param {Sampler2D} sampler
 * @param {number} [channel]
 * @return {number}
 */
export function sampler2d_channel_compute_min_indices(
    result, result_offset,
    sampler, channel = 0
) {
    assert.defined(sampler, 'sampler');
    assert.isNonNegativeInteger(result_offset, 'result_offset');

    const itemSize = sampler.itemSize;

    assert.isNumber(channel, "channel");
    assert.isNonNegativeInteger(channel, 'channel');
    assert.ok(channel >= 0, `channel must be >= 0, was ${channel}`);
    assert.ok(channel < itemSize, `channel must be less than itemSize(=${itemSize}), was ${channel}`);

    assert.isArrayLike(result, "result");

    const data = sampler.data;

    const l = data.length;

    if (l === 0) {
        //no data
        return 0;
    }

    let bestValue = data[channel];

    result[result_offset] = 0;

    let result_count = 1;

    for (let i = channel + itemSize; i < l; i += itemSize) {
        const value = data[i];

        if (bestValue > value) {
            bestValue = value;
            //drop result
            result_count = 1;

            result[result_offset] = i;
        } else if (value === bestValue) {
            result[result_offset + result_count] = i;

            result_count++;
        }

    }

    return result_count;
}