MeshReader

package org.destr.jogl.mesh;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.media.opengl.GL2;

public class MeshReader extends DataInputStream {

    public static int glTypeToSize(int glType) {
        switch(glType) {

            case GL2.GL_BYTE:   return  1;
            case GL2.GL_SHORT:  return  2;
            case GL2.GL_INT:    return  4;
            case GL2.GL_DOUBLE: return  8;

            case GL2.GL_FLOAT:  return  4;

            default: return -1;
        }
    }

    public MeshReader(InputStream is) {
        super(is);
    }

    public BufferedMeshData readMesh() throws IOException {
        BufferedMeshData mesh = new BufferedMeshData();

        String version = readUTF();

        if(!version.equals("JMESH1.0")) {
            throw new IOException(String.format(
                "Invalis header \"%s\"", version
            ));
        }

        String format = readUTF().toUpperCase();

        if(format.equals("VNC")) {

            mesh.count  = readInt();

            mesh.vGLType    = readInt();
            mesh.vSize  = readInt();
            mesh.vStride    = readInt();
            mesh.vOffset    = readLong();

            mesh.nUsed  = true;
            mesh.nGLType    = readInt();
            mesh.nStride    = readInt();
            mesh.nOffset    = readLong();

            mesh.tUsed  = true;
            mesh.tGLType    = readInt();
            mesh.tSize  = readInt();
            mesh.tStride    = readInt();
            mesh.tOffset    = readLong();

            int vBytes = mesh.vSize * glTypeToSize(mesh.vGLType);
            if(vBytes < 0) {
                throw new IOException(String.format(
                    "Can not read vertex glType %d", mesh.vGLType
                ));
            }

            int nBytes = 3 * glTypeToSize(mesh.nGLType);
            if(nBytes < 0) {
                throw new IOException(String.format(
                    "Can not read normal glType %d", mesh.nGLType
                ));
            }

            int tBytes = mesh.tSize * glTypeToSize(mesh.tGLType);
            if(tBytes < 0) {
                throw new IOException(String.format(
                    "Can not read texture coord glType %d", mesh.tGLType
                ));
            }

            mesh.data = new byte[mesh.count * (vBytes + nBytes + tBytes)];
            read(mesh.data);

        } else {
            throw new IOException(String.format(
                "Invalid format \"%s\"", format
            ));
        }

        return mesh;
    }

}