@woosh/meep-engine/src/engine/graphics/particles/node-based/simulation/EmitterAttributeData.js

Pure JavaScript game engine. Fully featured and production ready.

export class EmitterAttributeData {
    constructor() {
        /**
         *
         * @type {ParticleSpecification}
         */
        this.spec = null;

        /**
         *
         * @type {GLDataBuffer}
         */
        this.data = null;

        /**
         * Number of particles
         * @type {number}
         */
        this.count = 0;
    }

    /**
     *
     * @param {number} attribute_index
     * @param {number} index
     * @param {number} x
     * @param {number} y
     * @param {number} z
     */
    writeAttributeVector3(attribute_index, index, x, y, z) {
        const spec = this.spec;

        const component_offset = spec.getAttributeOffset(attribute_index);

        const address = index * spec.getTotalAttributeComponentCount() + component_offset;

        const source = this.data.data_f32;
        source[address] = x;
        source[address + 1] = y;
        source[address + 2] = z;
    }

    /**
     *
     * @param {number} attribute_index
     * @param {number} index
     * @returns {number}
     */
    readAttributeFloat(attribute_index, index) {
        const spec = this.spec;

        const component_offset = spec.getAttributeOffset(attribute_index);

        const address = index * spec.getTotalAttributeComponentCount() + component_offset;

        const source = this.data.data_f32;

        return source[address];
    }

    /**
     *
     * @param {number} attribute_index
     * @param {number} index
     * @param {number} destination
     * @param {number} destination_offset
     */
    readAttributeVector3(attribute_index, index, destination, destination_offset) {
        const spec = this.spec;

        const component_offset = spec.getAttributeOffset(attribute_index);

        const address = index * spec.getTotalAttributeComponentCount() + component_offset;

        const source = this.data.data_f32;
        const x = source[address];
        const y = source[address + 1];
        const z = source[address + 2];

        destination[destination_offset] = x;
        destination[destination_offset + 1] = y;
        destination[destination_offset + 2] = z;
    }

    /**
     *
     * @param {ParticleSpecification} spec
     * @param {GLDataBuffer} data
     * @param {number} count
     * @returns {EmitterAttributeData}
     */
    static from(spec, data, count) {
        const r = new EmitterAttributeData();

        r.data = data;
        r.spec = spec;
        r.count = count;

        return r;
    }
}

/**
 * @readonly
 * @type {boolean}
 */
EmitterAttributeData.prototype.isEmitterAttributeData = true;