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I'm trying to learn OpenGL ES. I've reached a point where I rotate an object by touching the screen. It looks nice but when I rotate the cube up or down 90+ degrees it inverts the rotating. I know why it's happening and all, and I've tried to fix it but I never get it 100%.
ModelViewer.java:
Using java Syntax Highlighting
- package com.test.modelviewer;
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.Window;
- import android.view.WindowManager;
- public class ModelViewer extends Activity {
- private GLControlView glControlView;
- @Override
- public void onCreate( Bundle savedInstanceState ) {
- super.onCreate( savedInstanceState );
- this.requestWindowFeature( Window.FEATURE_NO_TITLE );
- getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN );
- glControlView = new GLControlView( this );
- setContentView( glControlView );
- }
- @Override
- protected void onResume() {
- super.onResume();
- glControlView.onResume();
- }
- @Override
- protected void onPause() {
- super.onPause();
- glControlView.onPause();
- }
- }
Parsed in 0.032 seconds, using GeSHi 1.0.8.4
GLControlView.java:
Using java Syntax Highlighting
- package com.test.modelviewer;
- import javax.microedition.khronos.egl.EGLConfig;
- import javax.microedition.khronos.opengles.GL10;
- import android.content.Context;
- import android.opengl.GLSurfaceView;
- import android.opengl.GLU;
- import android.opengl.GLSurfaceView.Renderer;
- import android.view.MotionEvent;
- public class GLControlView extends GLSurfaceView implements Renderer {
- private float xPrevious, yPrevious;
- private float xRotation = 0.0f, yRotation = 0.0f;
- private SimpleCubeObject cubeObject;
- public GLControlView( Context context ) {
- super( context );
- this.setRenderer( this );
- this.requestFocus();
- this.setFocusableInTouchMode( true );
- cubeObject = new SimpleCubeObject();
- }
- public void onSurfaceCreated( GL10 gl, EGLConfig config ) {
- gl.glClearColor( 0.0f, 0.0f, 0.0f, 0.5f );
- gl.glShadeModel( GL10.GL_SMOOTH );
- gl.glClearDepthf( 1.0f );
- gl.glEnable( GL10.GL_DEPTH_TEST );
- gl.glDepthFunc( GL10.GL_LEQUAL );
- gl.glHint( GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST );
- }
- public void onDrawFrame( GL10 gl ) {
- gl.glClear( GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT );
- gl.glLoadIdentity();
- gl.glTranslatef( 0.0f, 0.0f, -10.0f );
- gl.glPushMatrix();
- gl.glRotatef( xRotation, 1.0f, 0.0f, 0.0f );
- gl.glRotatef( yRotation, 0.0f, 1.0f, 0.0f );
- gl.glPushMatrix();
- cubeObject.draw( gl );
- gl.glPopMatrix();
- gl.glPopMatrix();
- }
- public void onSurfaceChanged( GL10 gl, int width, int height ) {
- gl.glViewport( 0, 0, width, height );
- gl.glMatrixMode( GL10.GL_PROJECTION );
- gl.glLoadIdentity();
- GLU.gluPerspective( gl, 45.0f, ( ( float )width / ( float )height ), 0.1f, 100.0f );
- gl.glMatrixMode( GL10.GL_MODELVIEW );
- gl.glLoadIdentity();
- }
- @Override
- public boolean onTouchEvent( MotionEvent event ) {
- float xEvent = event.getX();
- float yEvent = event.getY();
- switch( event.getAction() ) {
- case MotionEvent.ACTION_DOWN: {
- xPrevious = xEvent;
- yPrevious = yEvent;
- return true;
- }
- case MotionEvent.ACTION_MOVE: {
- float xDelta = xEvent - xPrevious;
- float yDelta = yEvent - yPrevious;
- xRotation += ( yDelta * 0.5f );
- yRotation += ( xDelta * 0.5f );
- xPrevious = xEvent;
- yPrevious = yEvent;
- return true;
- }
- default: return super.onTouchEvent( event );
- }
- }
- }
Parsed in 0.039 seconds, using GeSHi 1.0.8.4
SimpleCubeObject.java:
Using java Syntax Highlighting
- package com.test.modelviewer;
- import java.nio.ByteBuffer;
- import java.nio.ByteOrder;
- import java.nio.FloatBuffer;
- import java.nio.ShortBuffer;
- import javax.microedition.khronos.opengles.GL10;
- public class SimpleCubeObject {
- private float colors[] = {
- 0.0f, 0.0f, 0.0f, 1.0f,
- 1.0f, 0.0f, 0.0f, 1.0f,
- 0.0f, 1.0f, 0.0f, 1.0f,
- 0.0f, 0.0f, 1.0f, 1.0f,
- 1.0f, 0.0f, 1.0f, 1.0f,
- 0.0f, 1.0f, 1.0f, 1.0f,
- 1.0f, 1.0f, 0.0f, 1.0f,
- 1.0f, 1.0f, 1.0f, 1.0f
- };
- private short indices[] = {
- 0, 1, 2, 0, 2, 3,
- 1, 5, 6, 1, 6, 2,
- 2, 6, 7, 2, 7, 3,
- 3, 7, 4, 3, 4, 0,
- 0, 4, 5, 0, 5, 1,
- 7, 6, 5, 7, 5, 4
- };
- private 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
- };
- private FloatBuffer colorBuffer;
- private ShortBuffer indexBuffer;
- private FloatBuffer vertexBuffer;
- public SimpleCubeObject() {
- ByteBuffer cbb = ByteBuffer.allocateDirect( colors.length * 4 );
- cbb.order( ByteOrder.nativeOrder() );
- colorBuffer = cbb.asFloatBuffer();
- colorBuffer.put( colors );
- colorBuffer.position( 0 );
- ByteBuffer ibb = ByteBuffer.allocateDirect( indices.length * 2 );
- ibb.order( ByteOrder.nativeOrder() );
- indexBuffer = ibb.asShortBuffer();
- indexBuffer.put( indices );
- indexBuffer.position( 0 );
- ByteBuffer vbb = ByteBuffer.allocateDirect( vertices.length * 4 );
- vbb.order( ByteOrder.nativeOrder() );
- vertexBuffer = vbb.asFloatBuffer();
- vertexBuffer.put( vertices );
- vertexBuffer.position( 0 );
- }
- public void draw( GL10 gl ) {
- gl.glFrontFace( GL10.GL_CCW );
- gl.glEnable( GL10.GL_CULL_FACE );
- gl.glCullFace( GL10.GL_BACK );
- gl.glEnableClientState( GL10.GL_COLOR_ARRAY );
- gl.glEnableClientState( GL10.GL_VERTEX_ARRAY );
- gl.glColorPointer( 4, GL10.GL_FLOAT, 0, colorBuffer );
- gl.glVertexPointer( 3, GL10.GL_FLOAT, 0, vertexBuffer );
- gl.glDrawElements( GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_SHORT, indexBuffer );
- gl.glDisableClientState( GL10.GL_VERTEX_ARRAY );
- gl.glDisableClientState( GL10.GL_COLOR_ARRAY );
- gl.glDisable( GL10.GL_CULL_FACE );
- }
- }
Parsed in 0.040 seconds, using GeSHi 1.0.8.4
What do I have to do here to make sure rotating moves as expected and doesn't get inverted? To test it out, move the cube up or down 180 degrees and then try to move it left or right.
, MacGoose
