Problem with Camera - Object collision

[indigo]

Hi,
First to introduce myself: I'm new here. Wowzah.

I did install JPCT-AE today and downloaded the basic example code, and I was able to compile and run it in the emulator. I then wanted to build a bit more around that barebone. I intended to make the camera moveable and colliding with objects.

I added/changed the following parts of the main class (just toying around):
onKeyDown (in HelloWorld)

Code Select Expand

public boolean onKeyDown(int kc, KeyEvent e) {

if (kc == KeyEvent.KEYCODE_DPAD_UP) {
if (world.checkCameraCollision(Camera.CAMERA_MOVEIN, 2.f)) {
AlertDialog alertDialog;
alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle("Collision");
alertDialog.setMessage("Happens.");
alertDialog.show();
}

} else if (kc == KeyEvent.KEYCODE_DPAD_DOWN) {
        world.checkCameraCollision(Camera.CAMERA_MOVEOUT, 2.f);
} else {
                        return false;
                }

return true;

}
in onSurfaceChanged (in MyRenderer)

Code Select Expand

cube = Primitives.getSphere(10); //ik...
cube.calcTextureWrapSpherical();
cube.setTexture("texture");
cube.setCollisionMode(Object3D.COLLISION_CHECK_OTHERS);
cube.strip();
cube.build();
Of course I also did the necessary import for the AlertDialog.

Yet it doesn't work: I get neither an AlertDialog nor does the camera stop when it hits the sphere.

Is my code wrong and can you help me correct it or am I going entirely the wrong way?

Thanks!

[EgonOlsen]

Adding your changes to the original HelloWorld-example, the collision happens as it should. Here's my version of it:

Code Select Expand


package com.threed.jpct.example;

import java.lang.reflect.Field;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.opengles.GL10;

import android.app.Activity;
import android.app.AlertDialog;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.MotionEvent;

import com.threed.jpct.Camera;
import com.threed.jpct.FrameBuffer;
import com.threed.jpct.Light;
import com.threed.jpct.Logger;
import com.threed.jpct.Object3D;
import com.threed.jpct.Primitives;
import com.threed.jpct.RGBColor;
import com.threed.jpct.SimpleVector;
import com.threed.jpct.Texture;
import com.threed.jpct.TextureManager;
import com.threed.jpct.World;
import com.threed.jpct.util.BitmapHelper;
import com.threed.jpct.util.MemoryHelper;

/**
* A simple demo. This shows more how to use jPCT-AE than it shows how to write
* a proper application for Android. It includes basic activity management to
* handle pause and resume...
*
* @author EgonOlsen
*
*/
public class HelloWorld extends Activity {

// Used to handle pause and resume...
private static HelloWorld master = null;

private GLSurfaceView mGLView;
private MyRenderer renderer = null;
private FrameBuffer fb = null;
private World world = null;
private RGBColor back = new RGBColor(50, 50, 100);

private float touchTurn = 0;
private float touchTurnUp = 0;

private float xpos = -1;
private float ypos = -1;

private Object3D cube = null;
private int fps = 0;

private Light sun = null;

protected void onCreate(Bundle savedInstanceState) {

Logger.log("onCreate");

if (master != null) {
copy(master);
}

super.onCreate(savedInstanceState);
mGLView = new GLSurfaceView(getApplication());

mGLView.setEGLConfigChooser(new GLSurfaceView.EGLConfigChooser() {
public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
// Ensure that we get a 16bit framebuffer. Otherwise, we'll fall
// back to Pixelflinger on some device (read: Samsung I7500)
int[] attributes = new int[] { EGL10.EGL_DEPTH_SIZE, 16, EGL10.EGL_NONE };
EGLConfig[] configs = new EGLConfig[1];
int[] result = new int[1];
egl.eglChooseConfig(display, attributes, configs, 1, result);
return configs[0];
}
});

renderer = new MyRenderer();
mGLView.setRenderer(renderer);
setContentView(mGLView);
}

@Override
protected void onPause() {
super.onPause();
mGLView.onPause();
}

@Override
protected void onResume() {
super.onResume();
mGLView.onResume();
}

@Override
protected void onStop() {
super.onStop();
}

private void copy(Object src) {
try {
Logger.log("Copying data from master Activity!");
Field[] fs = src.getClass().getDeclaredFields();
for (Field f : fs) {
f.setAccessible(true);
f.set(this, f.get(src));
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}

public boolean onTouchEvent(MotionEvent me) {

if (me.getAction() == MotionEvent.ACTION_DOWN) {
xpos = me.getX();
ypos = me.getY();
return true;
}

if (me.getAction() == MotionEvent.ACTION_UP) {
xpos = -1;
ypos = -1;
touchTurn = 0;
touchTurnUp = 0;
return true;
}

if (me.getAction() == MotionEvent.ACTION_MOVE) {
float xd = me.getX() - xpos;
float yd = me.getY() - ypos;

xpos = me.getX();
ypos = me.getY();

touchTurn = xd / -100f;
touchTurnUp = yd / -100f;
return true;
}

try {
Thread.sleep(15);
} catch (Exception e) {
// No need for this...
}

return super.onTouchEvent(me);
}

@Override
public boolean onKeyDown(int kc, KeyEvent e) {

if (kc == KeyEvent.KEYCODE_DPAD_UP) {
if (world.checkCameraCollision(Camera.CAMERA_MOVEIN, 2.f)) {
AlertDialog alertDialog;
alertDialog = new AlertDialog.Builder(this).create();
alertDialog.setTitle("Collision");
alertDialog.setMessage("Happens.");
alertDialog.show();
}

} else if (kc == KeyEvent.KEYCODE_DPAD_DOWN) {
world.checkCameraCollision(Camera.CAMERA_MOVEOUT, 2.f);
} else {
return false;
}

return true;

}

protected boolean isFullscreenOpaque() {
return true;
}

class MyRenderer implements GLSurfaceView.Renderer {

private long time = System.currentTimeMillis();

public MyRenderer() {
}

public void onSurfaceChanged(GL10 gl, int w, int h) {
if (fb != null) {
fb.dispose();
}
fb = new FrameBuffer(gl, w, h);

if (master == null) {

world = new World();
world.setAmbientLight(20, 20, 20);

sun = new Light(world);
sun.setIntensity(250, 250, 250);

// Create a texture out of the icon...:-)
Texture texture = new Texture(BitmapHelper.rescale(BitmapHelper.convert(getResources().getDrawable(R.drawable.icon)), 64, 64));
TextureManager.getInstance().addTexture("texture", texture);

cube = Primitives.getSphere(10); // ik...
cube.calcTextureWrapSpherical();
cube.setTexture("texture");
cube.setCollisionMode(Object3D.COLLISION_CHECK_OTHERS);
cube.strip();
cube.build();

world.addObject(cube);

Camera cam = world.getCamera();
cam.moveCamera(Camera.CAMERA_MOVEOUT, 50);
cam.lookAt(cube.getTransformedCenter());

SimpleVector sv = new SimpleVector();
sv.set(cube.getTransformedCenter());
sv.y -= 100;
sv.z -= 100;
sun.setPosition(sv);
MemoryHelper.compact();

if (master == null) {
Logger.log("Saving master Activity!");
master = HelloWorld.this;
}
}
}

public void onSurfaceCreated(GL10 gl, EGLConfig config) {
}

public void onDrawFrame(GL10 gl) {
if (touchTurn != 0) {
cube.rotateY(touchTurn);
touchTurn = 0;
}

if (touchTurnUp != 0) {
cube.rotateX(touchTurnUp);
touchTurnUp = 0;
}

fb.clear(back);
world.renderScene(fb);
world.draw(fb);
fb.display();

if (System.currentTimeMillis() - time >= 1000) {
Logger.log(fps + "fps");
fps = 0;
time = System.currentTimeMillis();
}
fps++;
}
}
}


[indigo]

Erm, sorry. Ostensibly I ran an old build or something (it worked now after I restarted the emulator).

Thanks for your time though!

[EgonOlsen]

No problem. Just keep in mind that the ellipsoid collision detection is better suited for most kinds of camera collisions than the ray/polygon-approach is that you are currently using.