我是新手打开GL，我只想在屏幕上随机移动一个圆圈，当用户触摸圆圈时，我需要知道击中和未命中。 这是我通过在线课程可以实现的目标。
render class:
public class HelloOpenGLES10Renderer implements Renderer {
private int points = 250;
private float vertices[] = { 0.0f, 0.0f, 0.0f };
private FloatBuffer vertBuff;
public float x = 0.0f, y = 0.0f;
public boolean color = false;
boolean first = true;
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glTranslatef(x, y, 0);
gl.glColor4f(1.0f, 1.0f, 1.0f, 0f);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertBuff);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, points);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
Log.i("TAG", "change" + width + ":" + height);
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glFrustumf(-ratio, ratio, -1, 1, 3, 7);
GLU.gluLookAt(gl, 0f, 0f, -5f, 0.0f, 0.0f, 0f, 0.0f, 1.0f, 0.0f);
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
Log.i("TAG", "CREATE");
gl.glClearColor(0.1f, 0.1f, 0.0f, 1.0f);
initShapes();
}
private void initShapes() {
vertices = new float[(points + 1) * 3];
for (int i = 3; i < (points + 1) * 3; i += 3) {
double rad = (i * 360 / points * 3) * (3.14 / 180);
vertices[i] = (float) Math.cos(rad) * 0.10f;
vertices[i + 1] = (float) Math.sin(rad) * 0.10f;
vertices[i + 2] = 0;
}
ByteBuffer bBuff = ByteBuffer.allocateDirect(vertices.length * 4);
bBuff.order(ByteOrder.nativeOrder());
vertBuff = bBuff.asFloatBuffer();
vertBuff.put(vertices);
vertBuff.position(0);
}
}
Activity:
package com.example.opengltrail;
import java.util.Random;
import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class MainActivity extends Activity implements OnTouchListener {
private GLSurfaceView mGLView;
float oldx = 0, oldy = 0;
private HelloOpenGLES10Renderer m;
ProgressDialogThread p;
ProgressDialogThread123 t;
boolean stop = true;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mGLView = new GLSurfaceView(this);
m = new HelloOpenGLES10Renderer();
mGLView.setRenderer(m);
mGLView.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
setContentView(mGLView);
mGLView.setOnTouchListener(this);
p = new ProgressDialogThread();
}
@Override
protected void onPause() {
super.onPause();
mGLView.onPause();
p.stop();
stop = false;
}
@Override
protected void onResume() {
super.onResume();
mGLView.onResume();
t = new ProgressDialogThread123();
t.start();
p.start();
}
/**
* gets u the random number btw 0.0 to 1.0
*/
public float getmearandom() {
Random rng = new Random();
float next = rng.nextFloat();
Integer i = rng.nextInt();
if (i % 2 == 0)
next = next * (-1);
return next;
}
class ProgressDialogThread123 extends Thread {
@Override
public void run() {
// TODO Auto-generated method stub
super.run();
for (; stop;) {
p.run();
}
}
}
class ProgressDialogThread extends Thread {
@Override
public void run() {
super.run();
if (stop) {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
m.x = getmearandom();
m.y = getmearandom();
Log.i("m.x=" + m.x + ":", "m.y=" + m.y);
mGLView.requestRender();
}
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
float x = event.getX();
float y = event.getY();
float x1 = ((x * 2) / 480);
float y1 = ((y * 2) / 724);
x1 = -1 + x1;
y1 = -1 + y1;
if (y < 362) {
if (y1 > 0)
y1 = -y1;
} else if (y > 362) {
if (y1 < 0)
y1 = -y1;
} else {
y1 = 0;
}
if (x > 240) {
if (x1 < 0)
x1 = -x1;
} else if (x < 240) {
if (x1 > 0)
x1 = -x1;
} else {
x1 = 0;
}
Log.i("x1=" + x1, "y1=" + y1);
float d = (((m.x - x1) * (m.x - x1)) + ((m.y - y1) * (m.y - y1)));
float dd = FloatMath.sqrt(d);
if (dd <= 0.10f) {
m.color = true;
// mGLView.requestRender();
Log.i("Tag", "Circle");
}
// m.x += 0.10f;
return true;
}
}
Please anyone help me !! thanks in advance
答案 0 :(得分：1)
如果你只是画了2d我建议你松开“视锥体”和“lookAt”并用坐标为ortho(viewOrigin.x, viewOrigin.x + viewSize.width, viewOrigin.y + viewSize.height, viewOrigin.y, -1.0f, 1.0f)的“ortho”替换它们。这将使您的GL坐标系与视图坐标相同。至于圆顶点，而是创建半径为1.0f的圆顶。现在绘制圆形，在绘制调用之前你只需要“推”矩阵，转换为屏幕坐标（X，Y，.0f），缩放到半径R，以像素为单位（R，R，1.0f）和“pop”通话后的矩阵..现在检查圈子是否被击中：
`bool didHit = ((touch.x-cicrcleCenter.x)*(touch.x-cicrcleCenter.x) +
(touch.y-cicrcleCenter.y)*(touch.y-cicrcleCenter.y))
< R*R`;
请注意，“ortho”中的“viewOrigin”取决于您捕捉触摸的位置：如果您在同一视图中捕获它们，无论视图位于何处，它都可能位于（0,0）。当您在视图的左上角和右下角按下时，这些坐标应与您在触摸事件中收到的坐标相对应。
如果你真的需要用3d画画并且你必须使用视锥，你将需要得到你的投影矩阵的反转以从你的触摸创建三维光线，然后检查命中，就像你对子弹一样等。