我正在通過閱讀教程和應用我已經知道的,學習適用於Android的Java和OpenGL ES。當談到旋轉物體時,我已經撞到了一堵磚牆。OpenGL旋轉問題
通過觸摸屏幕來旋轉立方體是沒有問題的。但是,如果我將立方體向上或向下旋轉180度,那麼當我現在嘗試向左或向右旋轉立方體時,它會倒轉。我知道這是爲什麼發生,但我找不到解決方案。
的代碼如下如果有的想測試一下:
文件 「Rotating.java」:
package com.test.opengl;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
public class Rotating 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);
}
}
文件 「GLControlView.java」:
package com.test.opengl;
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 Context context;
private float xPrevious, yPrevious;
private float xRotation = 0.0f, yRotation = 0.0f;
private SimpleCubeObject cubeObject;
public GLControlView(Context context) {
super(context);
this.context = 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);
}
}
}
文件「SimpleCubeObject .java「:
package com.test.opengl;
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 int[] textures = new int[ 1 ];
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.glBindTexture(GL10.GL_TEXTURE_2D, textures[ 0 ]);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_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);
}
}
我當然希望有人能幫助我。我相信,一如既往,解決方案簡單易行 - 只是我現在看不到它。
Thanx!這似乎是一個不可能完成的任務,但是四元數是我需要的。 – Espen 2010-10-24 20:04:05