OpenGL draw Sphere - Java 2D Graphics

Java examples for 2D Graphics:OpenGL

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Description

OpenGL draw Sphere

Demo Code


import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.util.ArrayList;
import java.util.List;
import javax.microedition.khronos.opengles.GL10;

public class Main{
    //from  ww  w .j  a  v  a  2s  .co  m
    public static void drawSphere(GL10 gl, float r, int stack, int slice) {

        float stackStep = (float) (Math.PI / stack);//
        float sliceStep = (float) Math.PI / slice;//
        float r0, r1, y0, y1, x0, x1, z0, z1;
        float alpha0 = 0, alpha1 = 0;
        float beta = 0;
        List<Float> coordsList = new ArrayList<Float>();
        //
        for (int i = 0; i < stack; i++) {
            alpha0 = (float) (-Math.PI / 2 + (i * stackStep));
            alpha1 = (float) (-Math.PI / 2 + ((i + 1) * stackStep));
            y0 = (float) (r * Math.sin(alpha0));
            r0 = (float) (r * Math.cos(alpha0));
            y1 = (float) (r * Math.sin(alpha1));
            r1 = (float) (r * Math.cos(alpha1));
            //?
            for (int j = 0; j <= (slice * 2); j++) {
                beta = j * sliceStep;
                x0 = (float) (r0 * Math.cos(beta));
                z0 = -(float) (r0 * Math.sin(beta));
                x1 = (float) (r1 * Math.cos(beta));
                z1 = -(float) (r1 * Math.sin(beta));
                coordsList.add(x0);
                coordsList.add(y0);
                coordsList.add(z0);
                coordsList.add(x1);
                coordsList.add(y1);
                coordsList.add(z1);
            }
        }

        FloatBuffer fbb = BufferUtil.list2FloatBuffer(coordsList);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, fbb);
        gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, coordsList.size() / 3);
    }
    
    public static FloatBuffer list2FloatBuffer(List<Float> arr) {

        ByteBuffer ibb = ByteBuffer.allocateDirect(arr.size() * 4);
        ibb.order(ByteOrder.nativeOrder());
        FloatBuffer fbb = ibb.asFloatBuffer();
        for (float f : arr) {
            fbb.put(f);
        }
        //
        fbb.position(0);
        return fbb;
    }
}

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