Problems with a Polygon in J2ME (test source valid)
Hello!I'm struggeling with geometry cordinates and texture cordinates.
I trying to create a polygon with 8 corners, just a plane surface. Something like this:
__
/ \
| |
\__/
I try to fill it with a texture but it will not be correct. Below you got a image that shows what I end up with:
http://www.dsv.su.se/~fr-ander/cubes.jpg
Acording to Andrew Davisons report at...
http://fivedots.coe.psu.ac.th/~ad/jg/objm3g/objM3G.pdf
...and the m3g API at TriangleStripArray the triangles will be created like:
"For example, the strip S = (2, 0, 1, 4) defines two triangles: (2, 0, 1) and (0, 1, 4)."
To me that looks like I should be able just to specify each corner of the polygon to be able to create a 8-corner polygon. That will not fill the total polygon but all the sides of it how ever.
At the image below i try to show how I guess this work if you try out my 8-corner polygon. The numbers are the indecies of the cordinates for the corners. The filled areas are the triangles that will be created if the above theory is correct and I have understand that correct.
http://www.dsv.su.se/~fr-ander/cubes.gif
But my code only generates the first image (http://www.dsv.su.se/~fr-ander/cubes.jpg) and I can't understand why?
So if you could help me out here please let me know!
Best regards
Fredrik
Below is the test sorce for this. All you need is a image with the power of 2.
//The polygon
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.lang.*;
import java.io.*;
import java.util.*;
import javax.microedition.m3g.*;
public class PolygonSurface extends Group
{
private Image image;
private VertexBuffer vertexBuffer;
private IndexBuffer indexBuffer;
private Material material = new Material();
short[] vert = {-10,-9,0, -10,9,0, -9,10,0, 9,10,0, 10,9,0, 10,-9,0, 9,-10,0, -9,-10,0, -10,-9,0};//, -10,9,0, 10,-9,0, 10,9,0, -10,-9,0};
short[] tex = {0, 18, 0, 2, 2, 0, 18, 0, 20, 2, 20, 18, 18, 20, 2, 20, 0, 18};//, 0, 2, 20, 18, 20, 2, 0,18,};
byte[] norm = {0,0,127, 0,0,127, 0,0,127, 0,0,127, 0,0,127, 0,0,127, 0,0,127, 0,0,127, 0,0,127};//, 0,0,127, 0,0,127, 0,0,127, 0,0,127};
int[] stripLen = {9};
public PolygonSurface()
{
try
{
image = Image.createImage( "/images/up/1.png" );
material.setColor(Material.DIFFUSE, 0xFFFFFFFF);
material.setColor(Material.SPECULAR, 0xFFFFFFFF);
material.setShininess(100.0f);
VertexArray vertArray = new VertexArray(vert.length / 3, 3, 2);
vertArray.set(0, vert.length/3, vert);
VertexArray normArray = new VertexArray(norm.length / 3, 3, 1);
normArray.set(0, norm.length/3, norm);
VertexArray texArray = new VertexArray(tex.length / 2, 2, 2);
texArray.set(0, tex.length/2, tex);
VertexBuffer vertexBuffer = new VertexBuffer();
vertexBuffer.setPositions(vertArray, 0.1f, null);
vertexBuffer.setNormals(normArray);
vertexBuffer.setTexCoords(0, texArray, 0.05f, null);
indexBuffer = new TriangleStripArray( 0, stripLen );
Image2D image2D = new Image2D( Image2D.RGB, image );
Texture2D texture = new Texture2D( image2D );
texture.setFiltering(Texture2D.FILTER_NEAREST, Texture2D.FILTER_NEAREST);
texture.setWrapping(Texture2D.WRAP_CLAMP, Texture2D.WRAP_CLAMP);
texture.setBlending(Texture2D.FUNC_MODULATE);
Appearance appearance = new Appearance();
appearance.setTexture(0, texture);
appearance.setMaterial(material);
Mesh mesh = new Mesh(vertexBuffer, indexBuffer, appearance);
addChild(mesh);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
//The Canvas
import javax.microedition.lcdui.*;
import javax.microedition.m3g.*;
import java.util.*;
import javax.microedition.midlet.*;
public class TestCanvas3D extends Canvas
{
private Graphics3D graphics3D = Graphics3D.getInstance();
private Camera camera = new Camera();
private World world = new World();
private Background background = new Background();
private Light light = new Light();
private PolygonSurface polygonSurface = new PolygonSurface();
private Transform cameraTransform = new Transform();
private Transform worldTransform = new Transform();
private Transform lightTransform = new Transform();
public TestCanvas3D()
{
Transform transform4 = new Transform();
transform4.postTranslate(0.0f, 0.0f, 0.0f);
//transform4.postRotate(300f, 0.0f, 1.0f, 0.0f);
polygonSurface.setTransform(transform4);
world.addChild(polygonSurface);
world.setActiveCamera(camera);
worldTransform.postTranslate(0.0f, 0.0f, 0.0f);
lightTransform.postTranslate(0.0f, 0.0f, 10.0f);
graphics3D.resetLights();
graphics3D.addLight(light, lightTransform);
float aspect = (float) getWidth() / (float) getHeight();
camera.setPerspective(60.0f, aspect, 1.0f, 1000.0f);
cameraTransform.postTranslate(0.0f, 0.0f, 3.0f);
graphics3D.setCamera(camera, cameraTransform);
}
protected void paint(Graphics g)
{
graphics3D.bindTarget(g);
try
{
graphics3D.clear(null);
graphics3D.render(world, worldTransform);
}
finally
{
graphics3D.releaseTarget();
}
}
}
//The Midlet
import javax.microedition.lcdui.*;
import javax.microedition.m3g.*;
import java.util.*;
import javax.microedition.midlet.*;
public class TestMIDlet extends MIDlet implements CommandListener
{
private Display display = null;
private TestCanvas3D testCanvas3D = new TestCanvas3D();
private Command exitCommand = new Command("Exit", Command.ITEM, 1);
public TestMIDlet()
{
display = Display.getDisplay(this);
testCanvas3D.setCommandListener(this);
testCanvas3D.addCommand(exitCommand);
}
public void startApp() throws MIDletStateChangeException
{
try
{
testCanvas3D.setTitle("TestMIDlet");
display.setCurrent(testCanvas3D);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public void pauseApp()
{
}
public void destroyApp(boolean unconditional) throws MIDletStateChangeException
{
}
public void commandAction(Command command, Displayable displayable)
{
if (command == exitCommand)
{
try
{
destroyApp(false);
notifyDestroyed();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
}
