src/gsData.js

/*
Copyright (c) 2025 Very 360 VR. DBA Hyper Interactive

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

class cGSData {
    static ROW_LENGTH_IN_BITES = 32; // Bytes per splat
    static FLOAT_SIZE = 4; // Bytes per float
    static ROW_LENGTH_IN_FLOATS = cGSData.ROW_LENGTH_IN_BITES / cGSData.FLOAT_SIZE;

    static POSITION = 0;
    static SCALE = 1;
    static QUATERNION = 2;
    static COLOR = 3;
    static MASTER_BUFFER = 4;

    constructor(splatData){       
        
        this.uBuffer = new Uint8Array(splatData);
        this.fBuffer = new Float32Array(this.uBuffer.buffer);

        if(!this.uBuffer){
            console.error("invalid splatData")
        }
    }

    getBuffer(typeData) {
        switch(typeData){
            case cGSData.POSITION:
            case cGSData.SCALE:
                return this.fBuffer;
            case cGSData.QUATERNION:
            case cGSData.COLOR:
            case cGSData.MASTER_BUFFER:
                return this.uBuffer;
        }
        console.log(typeData, " returning NULL");
        return null;
    }

    getBufferInd(typeData, splatInd){
        switch(typeData){
            case cGSData.POSITION:
                return cGSData.ROW_LENGTH_IN_FLOATS * splatInd;
            case cGSData.SCALE:
                return cGSData.ROW_LENGTH_IN_FLOATS * splatInd + 3;
            case cGSData.QUATERNION:
                return cGSData.ROW_LENGTH_IN_BITES * splatInd + 28;
            case cGSData.COLOR:
                return cGSData.ROW_LENGTH_IN_BITES * splatInd + 24;
        }
        return -1;
    }


    print(ind) {
        const pBuffer  = this.getBuffer(cGSData.POSITION)
        const sBuffer  = this.getBuffer(cGSData.SCALE)
        const qBuffer  = this.getBuffer(cGSData.QUATERNION)
        const cBuffer  = this.getBuffer(cGSData.COLOR)
    
         let bufferInd = this.getBufferInd(cGSData.POSITION, ind);
         console.log("pos ", pBuffer[bufferInd], pBuffer[bufferInd+1],pBuffer[bufferInd+2])

         bufferInd = this.getBufferInd(cGSData.SCALE, ind);
         console.log("scl ", sBuffer[bufferInd], sBuffer[bufferInd+1], sBuffer[bufferInd+2])

         bufferInd = this.getBufferInd(cGSData.QUATERNION, ind);
         let quat = [];
         for(let i=0; i<4; i++) {
            quat[i] = (qBuffer[bufferInd + i] - 128) / 128;
         }
         console.log("quat ", quat[0], quat[1], quat[2], quat[3])
    }

    getNumberOfSplats() {
        return this.fBuffer.length / cGSData.ROW_LENGTH_IN_FLOATS;
    }

    getPositionBounds() {
        
        let min = [100000, 100000, 100000];
        let max = [-100000, -100000, -100000];

        for(let i=0; i<this.getNumberOfSplats(); i++){
            let bufferInd = this.getBufferInd(cGSData.POSITION, i);
            for(let j=0; j<3; j++){
                if(i===0 || this.fBuffer[bufferInd + j] < min[j]){
                    min[j] = this.fBuffer[bufferInd + j];
                }
                if(i===0 || this.fBuffer[bufferInd + j] > max[j]){
                    max[j] = this.fBuffer[bufferInd + j];
                }
            }
        }

        let eps = 0.0001;
        return ensureDifference(min, max, eps);
    }

    getScaleBounds() {
        let min = [100000, 100000, 100000];
        let max = [-100000, -100000, -100000];

        for(let i=0; i<this.getNumberOfSplats(); i++){
            let bufferInd = this.getBufferInd(cGSData.SCALE, i);
            for(let j=0; j<3; j++){
                if(i===0 || this.fBuffer[bufferInd + j] < min[j]){
                    min[j] = this.fBuffer[bufferInd + j];
                }
                if(i===0 || this.fBuffer[bufferInd + j] > max[j]){
                    max[j] = this.fBuffer[bufferInd + j];
                }
            }
        }

        let eps = 0.0001;
        return ensureDifference(min, max, eps);
    }

    async getUniqueColors(colorTolerance, maxIndexCount, updateCB) {
        let n = this.getNumberOfSplats();
        let cBuffer = this.getBuffer(cGSData.COLOR);
        let splatIndToCInd = new Array(n).fill(-1);        
        let uniqueColors = [];
        for(let i=0; i<n; i++){

            if (i % 1000 === 0) {
                await new Promise(resolve => {
                  requestAnimationFrame(() => {
                    
                    if(updateCB){
                        updateCB((i + 1.0) / n);
                    }
                    let progress = Math.floor((i + 1) / n * 100);
                    console.log("progress", progress);

                    resolve();
                  });
                });
            } // end if

            let bufferInd = this.getBufferInd(cGSData.COLOR, i);
            // check if the color is already in the set
            let isUnique = true;
            let uniqueInd = 0;
            for(let uniqueColor of uniqueColors){
                let sumSq = 0;
                // compare uniqueColor with the i-th color 
                for(let j=0; j<4; j++){
                    sumSq += Math.pow(uniqueColor[j] - cBuffer[bufferInd+j], 2);
                }
                if(sumSq < colorTolerance){
                    isUnique = false;
                    splatIndToCInd[i] = uniqueInd;
                    break;
                }
                uniqueInd++;

                if(uniqueInd > maxIndexCount){
                    console.error("Too many unique colors. Max number allowed is ", maxIndexCount);
                    return null;
                }                
            }

            if(isUnique){

                splatIndToCInd[i] = uniqueColors.length;

                let color = [cBuffer[bufferInd], cBuffer[bufferInd+1], cBuffer[bufferInd+2], cBuffer[bufferInd+3]];                
                uniqueColors.push(color);
            }
        }

        return [splatIndToCInd, uniqueColors];
    }
}

function ensureDifference(min, max, eps) {
    if(Math.abs(min[0] - max[0]) < eps){
        min[0] -= eps;
        max[0] += eps;
    }
    if(Math.abs(min[1] - max[1]) < eps){
        min[1] -= eps;
        max[1] += eps;
    }
    if(Math.abs(min[2] - max[2]) < eps){
        min[2] -= eps;
        max[2] += eps;
    }
    return [min[0], max[0], min[1], max[1], min[2], max[2]];
}