public void onSurfaceChanged(GL10 gl, int width, int height) {

                this.m_width = width;
                this.m_height = height;

                if(buffer == null) {

                        Util.LOGD("make framebuffer");
                        world = new World();
                        m_cam = world.getCamera();

                        // light mass
                        world.setAmbientLight(0xff, 0xff, 0xff);

                        // making background plane
                        float[] coordinates = { // position of vertices
                                0.0f, 0.0f, 0.0f,
                                m_width, 0.0f, 0.0f,
                                0.0f, m_height, 0.0f,
                                m_width, m_height, 0.0f
                        };

                        float[] uvs = { // how uv mapped?
                                0.0f, 0.0f,
                                1.0f, 0.0f,
                                0.0f, 1.0f,
                                1.0f, 1.0f
                        };

                        int[] indices = { // index of each coordinate
                                0, 2, 1,
                                1, 2, 3
                        };

                        // make plane
                        Object3D plane = new Object3D(coordinates, uvs, indices, RMObject2D.getTextureIDByColor(Color.white));
                        plane.build();
                        Util.LOGD("center: " + plane.getTransformedCenter());
                        world.addObject(plane);

                        // FOV settings
                        m_cam.setFOVLimits(0.1f, 2.0f);
                        m_cam.setFOV(0.1f);

                        // set up camera
                        // z = (width/2) / tan(fov/2)
                        m_cam.setPosition(m_width/2, m_height/2, (float) -(m_width/2/Math.tan(m_cam.getFOV()/2.0f)));
                        m_cam.lookAt(plane.getTransformedCenter());
                        fixCubePosition();

                        // configuration to view far object
                        Config.farPlane = Math.abs(m_cam.getPosition().z) + 1000f;
                }

                // make framebuffer
                if(buffer != null)
                        buffer.dispose();
                buffer = new FrameBuffer(m_width, m_height, FrameBuffer.SAMPLINGMODE_NORMAL);
        }

package cau.rpg.maker.object;

import java.awt.Color;

import javax.vecmath.Vector2f;

import com.threed.jpct.Object3D;

public class RMFillBox extends RMObject2D {

        public RMFillBox(float x1, float y1, float x2, float y2, Color color)
        {
                init(x1, y1, x2, y2, color);
        }

        public RMFillBox(Vector2f vStart, Vector2f vEnd, Color color)
        {
                init(vStart.x, vStart.y, vEnd.x, vEnd.y, color);
        }

        private void init(float x1, float y1, float x2, float y2, Color color)
        {
                if(x1 >= x2 || y1 >= y2)
                        return;

                float z = -10f;

                float[] coords = {
                        x1, y1, z,              // up left
                        x1, y2, z,              // bottom left
                        x2, y1, z,              // up right
                        x2, y2, z               // bottom right corner
                };

                float[] uvs = {
                        0f, 0f,
                        0f, 1f,
                        1f, 0f,
                        1f, 1f
                };

                int[] indices = {
                        0, 1, 2,
                        2, 1, 3
                };

                m_polygon = new Object3D(coords, uvs, indices, getTextureIDByColor(color));
        }
}

package cau.rpg.maker.object;

import java.awt.Color;

import javax.vecmath.Vector2f;
import javax.vecmath.Vector3f;

import com.threed.jpct.Object3D;

public class RMLine extends RMObject2D {

        private static final Vector3f vectorZ = new Vector3f(0, 0, -1);

        public RMLine(Vector2f vStart, Vector2f vEnd, float width, Color color)
        {
                float z = -10f;
                Vector3f v3Start = new Vector3f(vStart.x, vStart.y, z);
                Vector3f v3End = new Vector3f(vEnd.x, vEnd.y, z);

                // line vector
                Vector3f lineVector = new Vector3f();
                lineVector.sub(v3End, v3Start);

                // calc normal vector of line
                Vector3f normal = new Vector3f();
                normal.cross(lineVector, vectorZ);
                normal.normalize();
                normal.scale(width/2.0f);

                float[] coords = {
                        (vStart.x + normal.x), (vStart.y + normal.y), z,
                        (vStart.x - normal.x), (vStart.y - normal.y), z,
                        (vEnd.x + normal.x), (vEnd.y + normal.y), z,
                        (vEnd.x - normal.x), (vEnd.y - normal.y), z
                };

                float[] uvs = {
                        0f, 0f,
                        0f, 1f,
                        1f, 0f,
                        1f, 1f
                };

                int[] indices = {
                        0, 2, 1,
                        1, 2, 3
                };

                m_polygon = new Object3D(coords, uvs, indices, getTextureIDByColor(color));
        }

}

        public void setDepth(float depth)
        {
                float delta = depth - this.depth;

                // move object
                SimpleVector curPosition = m_polygon.getTransformedCenter();
                SimpleVector toCam = MainRenderer.getCamera().getPosition().calcSub(curPosition);
                float a = MainRenderer.getCamera().getPosition().z - this.depth;
                toCam.scalarMul(delta/a);
                m_polygon.translate(toCam);
                Util.LOGD("translate to " + toCam);

                // scale
                m_polygon.scale((a-delta)/a);

                this.depth = depth;
        }