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61 lines
1.4 KiB
61 lines
1.4 KiB
/**
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* Central Gravity Solver
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*/
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class CentralGravitySolver {
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/**
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* @param {Object} body
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* @param {{physicsNodeIndices: Array, physicsEdgeIndices: Array, forces: {}, velocities: {}}} physicsBody
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* @param {Object} options
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*/
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constructor(body, physicsBody, options) {
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this.body = body;
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this.physicsBody = physicsBody;
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this.setOptions(options);
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}
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/**
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*
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* @param {Object} options
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*/
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setOptions(options) {
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this.options = options;
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}
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/**
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* Calculates forces for each node
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*/
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solve() {
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let dx, dy, distance, node;
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let nodes = this.body.nodes;
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let nodeIndices = this.physicsBody.physicsNodeIndices;
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let forces = this.physicsBody.forces;
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for (let i = 0; i < nodeIndices.length; i++) {
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let nodeId = nodeIndices[i];
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node = nodes[nodeId];
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dx = -node.x;
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dy = -node.y;
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distance = Math.sqrt(dx * dx + dy * dy);
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this._calculateForces(distance, dx, dy, forces, node);
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}
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}
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/**
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* Calculate the forces based on the distance.
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* @param {number} distance
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* @param {number} dx
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* @param {number} dy
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* @param {Object<Node.id, vis.Node>} forces
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* @param {Node} node
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* @private
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*/
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_calculateForces(distance, dx, dy, forces, node) {
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let gravityForce = (distance === 0) ? 0 : (this.options.centralGravity / distance);
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forces[node.id].x = dx * gravityForce;
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forces[node.id].y = dy * gravityForce;
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}
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}
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export default CentralGravitySolver;
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