Java get min and max value of several float numbers

Question

I'm trying to creat an axis aligned bounding box (aabb) and would like to get the min and max values of all my vertice coordinates.

I'm reading from an obj file to get the vertex coordinates, the print out would be a list of x,y,z coordinates in float numbers.

float xVertices;
float yVertices;
float zVertices;

private void getObjVertices(String fileName)
{       
    BufferedReader meshReader = null;

    try
    {
        meshReader = new BufferedReader(new FileReader(fileName));
        String line;

        while((line = meshReader.readLine()) != null)
        {
            String[] tokens = line.split(" ");
            tokens = Util.RemoveEmptyStrings(tokens);

            if(tokens.length == 0 || tokens[0].equals("#") || 
                    tokens[0].equals("vt") || tokens[0].equals("vn") || tokens[0].equals("f"))
                continue;
            else if(tokens[0].equals("v"))
            {                                               
                xVertices = Float.parseFloat(tokens[1]);
                yVertices = Float.parseFloat(tokens[2]);
                zVertices =  Float.parseFloat(tokens[3]);

                System.out.println("xVertices:" + xVertices);
                System.out.println("yVertices:" + yVertices);
                System.out.println("zVertices:" + zVertices);

        // get min/max x,y,z values, calculatre width, height, depth
            }
        }           
        meshReader.close();
    }
    catch(Exception e)
    {
        e.printStackTrace();
        System.exit(1);
    }
}

What I would like to achieve is to get all xVertices, yVertices, zVertices and find out which number in each axis is greates and which is smallest.

With this information I would be able to create the collider.. has someone an idea how I can calclate greates and smallest numbers in my code?

Thanks for any help in advance!

Why not just maintain a record of the greatest and smallest number? and keeping updating them as you are reading new vertices? — Bon
– Bon, Commented Oct 18, 2015 at 0:51
oh yea, that's an interesting idea, funny it didn't occur to me.. would you have a concrete suggestion? — DisasterCoder
– DisasterCoder, Commented Oct 18, 2015 at 0:53

Bon · Accepted Answer · 2015-10-18 00:59:52Z

You can maintain records of the greatest and smallest number and updating them as your program is reading the vertices. Below is an example.

float xMin, xMax, yMin, yMax, zMin, zMax;
    xMin = yMin = zMin = Float.MAX_VALUE;
    xMax = yMax = zMax = Float.MIN_VALUE;

    while ((line = meshReader.readLine()) != null) {
        String[] tokens = line.split(" ");
        tokens = Util.RemoveEmptyStrings(tokens);

        if (tokens.length == 0 || tokens[0].equals("#") ||
                tokens[0].equals("vt") || tokens[0].equals("vn") || tokens[0].equals("f"))
            continue;
        else if (tokens[0].equals("v")) {
            xVertices = Float.parseFloat(tokens[1]);
            yVertices = Float.parseFloat(tokens[2]);
            zVertices = Float.parseFloat(tokens[3]);

            if (xMin > xVertices) xMin = xVertices;
            if (yMin > yVertices) yMin = yVertices;
            if (zMin > zVertices) zMin = zVertices;

            if (xMax < xVertices) xMax = xVertices;
            if (yMax < yVertices) yMax = yVertices;
            if (zMax < zVertices) zMax = zVertices;

            System.out.println("xVertices:" + xVertices);
            System.out.println("yVertices:" + yVertices);
            System.out.println("zVertices:" + zVertices);

            // get min/max x,y,z values, calculatre width, height, depth
        }

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