Cube.java

package cg.bouncycube;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import javax.microedition.khronos.opengles.GL10;
import javax.microedition.khronos.opengles.GL11;

/**
 * Created by P17-17 on 3/6/2018.
 */

public class Cube {

    private final FloatBuffer mFVertexBuffer;
    private final ByteBuffer mColorBuffer, mTFan1, mTFan2;
    private FloatBuffer mNormalBuffer;

    public Cube(){
        float vertices[] = {
                -1.0f, 1.0f, 1.0f,
                1.0f, 1.0f, 1.0f,
                1.0f, -1.0f, 1.0f,
                -1.0f, -1.0f, 1.0f,
                -1.0f, 1.0f, -1.0f,
                1.0f, 1.0f, -1.0f,
                1.0f, -1.0f, -1.0f,
                -1.0f, -1.0f, -1.0f
        };

        byte maxColor=(byte)255;
        byte colors[] =
                {
                        maxColor, 0, 0, maxColor,
                        maxColor, 0, 0, maxColor,
                        maxColor, 0, 0, maxColor,
                        maxColor, 0, 0, maxColor,
                        0, 0, 0, maxColor,
                        0, 0, 0, maxColor,
                        0, 0, 0, maxColor,
                        0, 0, 0, maxColor,
                };

        byte tFan1[] =
                {
                        1,0,3,
                        1,3,2,
                        1,2,6,
                        1,6,5,
                        1,5,4,
                        1,4,0
                };
        byte tFan2[] =
                {
                        7,4,5,
                        7,5,6,
                        7,6,2,
                        7,2,3,
                        7,3,0,
                        7,0,4
                };
        float[] normals =
                {
                        -1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3),
                        1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3),
                        1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3),
                        -1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3),
                        -1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3),
                        1.0f/(float)Math.sqrt(3), 1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3),
                        1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3),
                        -1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3), -1.0f/(float)Math.sqrt(3)
                };

        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
        vbb.order(ByteOrder.nativeOrder());
        mFVertexBuffer = vbb.asFloatBuffer();
        mFVertexBuffer.put(vertices);
        mFVertexBuffer.position(0);
        mColorBuffer = ByteBuffer.allocateDirect(colors.length);
        mColorBuffer.put(colors);
        mColorBuffer.position(0);
        mTFan1 = ByteBuffer.allocateDirect(tFan1.length);
        mTFan1.put(tFan1);
        mTFan1.position(0);
        mTFan2 = ByteBuffer.allocateDirect(tFan2.length);
        mTFan2.put(tFan2);
        mTFan2.position(0);
        ByteBuffer nbb = ByteBuffer.allocateDirect(normals.length * 4);
        nbb.order(ByteOrder.nativeOrder());
        mNormalBuffer = nbb.asFloatBuffer();
        mNormalBuffer.put(normals);
        mNormalBuffer.position(0);
    }

    public void draw(GL10 gl){
        gl.glVertexPointer(3, GL11.GL_FLOAT, 0, mFVertexBuffer);
        gl.glColorPointer(4, GL11.GL_UNSIGNED_BYTE, 0, mColorBuffer);
        gl.glDrawElements( gl.GL_TRIANGLE_FAN, 6 * 3, gl.GL_UNSIGNED_BYTE, mTFan1);
        gl.glDrawElements( gl.GL_TRIANGLE_FAN, 6 * 3, gl.GL_UNSIGNED_BYTE, mTFan2);
        gl.glNormalPointer(GL10.GL_FLOAT, 0, mNormalBuffer);
        gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
    }
}