script.js

// Room Acoustics Calculator Logic

class RoomAcousticsCalculator {
    constructor() {
        this.speedOfSound = 343; // m/s
        this.roomDimensions = { length: 5, width: 4, height: 3 };
        this.subwooferPosition = { x: 2.5, y: 2, z: 1.5 };
        this.modes = [];
        this.init();
    }

    init() {
        this.calculateModes();
    }

    setRoomDimensions(dimensions) {
        this.roomDimensions = dimensions;
        this.calculateModes();
    }

    setSubwooferPosition(position) {
        this.subwooferPosition = position;
        this.calculatePressureDistribution();
    }

    calculateModes(maxFrequency = 200) {
        const { length, width, height } = this.roomDimensions;
        this.modes = [];
        
        // Maximum mode numbers based on max frequency
        const maxN = Math.ceil((2 * maxFrequency * length) / this.speedOfSound);
        const maxM = Math.ceil((2 * maxFrequency * width) / this.speedOfSound);
        const maxP = Math.ceil((2 * maxFrequency * height) / this.speedOfSound);
        
        for (let n = 0; n <= maxN; n++) {
            for (let m = 0; m <= maxM; m++) {
                for (let p = 0; p <= maxP; p++) {
                    if (n === 0 && m === 0 && p === 0) continue;
                    
                    const frequency = (this.speedOfSound / 2) * 
                        Math.sqrt(
                            Math.pow(n / length, 2) + 
                            Math.pow(m / width, 2) + 
                            Math.pow(p / height, 2)
                        );
                    
                    if (frequency <= maxFrequency) {
                        let modeType = 'oblique';
                        if ((n > 0 && m === 0 && p === 0) || 
                            (n === 0 && m > 0 && p === 0) || 
                            (n === 0 && m === 0 && p > 0)) {
                            modeType = 'axial';
                        } else if ((n > 0 && m > 0 && p === 0) || 
                                   (n > 0 && m === 0 && p > 0) || 
                                   (n === 0 && m > 0 && p > 0)) {
                            modeType = 'tangential';
                        }
                        
                        this.modes.push({
                            n, m, p,
                            frequency: parseFloat(frequency.toFixed(2)),
                            type: modeType
                        });
                    }
                }
            }
        }
        
        // Sort by frequency
        this.modes.sort((a, b) => a.frequency - b.frequency);
        return this.modes;
    }

    calculatePressureAtPosition(x, y, z) {
        const { length, width, height } = this.roomDimensions;
        let pressure = 0;
        
        // Simplified pressure calculation based on mode shapes
        this.modes.forEach(mode => {
            const { n, m, p, frequency } = mode;
            if (frequency >= 20 && frequency <= 200) {
                // Mode shape function
                const modeShape = Math.cos((n * Math.PI * x) / length) *
                                  Math.cos((m * Math.PI * y) / width) *
                                  Math.cos((p * Math.PI * z) / height);
                
                // Pressure contribution (simplified)
                pressure += Math.abs(modeShape) / (frequency * frequency);
            }
        });
        
        return pressure;
    }

    calculatePressureDistribution() {
        // This would normally generate a full 3D pressure map
        // For now we'll just return pressure at subwoofer position
        return this.calculatePressureAtPosition(
            this.subwooferPosition.x,
            this.subwooferPosition.y,
            this.subwooferPosition.z
        );
    }

    getCriticalFrequencies() {
        const { length, width, height } = this.roomDimensions;
        return [
            {
                name: "Length Axial",
                frequency: parseFloat(((this.speedOfSound / 2) / length).toFixed(2)),
                dimension: "length"
            },
            {
                name: "Width Axial",
                frequency: parseFloat(((this.speedOfSound / 2) / width).toFixed(2)),
                dimension: "width"
            },
            {
                name: "Height Axial",
                frequency: parseFloat(((this.speedOfSound / 2) / height).toFixed(2)),
                dimension: "height"
            }
        ];
    }
}

// Global calculator instance
const calculator = new RoomAcousticsCalculator();

// Utility functions
function updateResults() {
    document.dispatchEvent(new CustomEvent('calculatorUpdated', {
        detail: {
            modes: calculator.modes,
            criticalFrequencies: calculator.getCriticalFrequencies(),
            pressure: calculator.calculatePressureDistribution()
        }
    }));
}

// Initialize when DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
    updateResults();
});

// Export for use in components
window.calculator = calculator;
window.updateResults = updateResults;