我在 Android OpenGL-ES 2.0 上,在它附带的所有限制之后,我不知道如何将 2D 屏幕触摸到我拥有的 3D 点。我无法得到正确的结果。
我正在尝试将光线射入点云,然后我可以比较我的点与光线的距离,找到最近的点。
public class OpenGLRenderer extends Activity implements GLSurfaceView.Renderer {
public PointCloud ptCloud;
MatrixGrabber mg = new MatrixGrabber();
...
public void onDrawFrame(GL10 gl) {
gl.glDisable(GL10.GL_COLOR_MATERIAL);
gl.glDisable(GL10.GL_BLEND);
gl.glDisable(GL10.GL_LIGHTING);
//Background drawing
if(customBackground)
gl.glClearColor(backgroundRed, backgroundGreen, backgroundBlue, 1.0f);
else
gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
if (PointCloud.doneParsing == true) {
if (envDone == false)
setupEnvironment();
// Clears the screen and depth buffer.
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl, 55.0f, (float) screenWidth / (float) screenHeight, 10.0f ,10000.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
GLU.gluLookAt(gl, eyeX, eyeY, eyeZ,
centerX, centerY, centerZ,
upX, upY, upZ);
if(pickPointTrigger)
pickPoint(gl);
gl.glPushMatrix();
gl.glTranslatef(_xTranslate, _yTranslate, _zTranslate);
gl.glTranslatef(centerX, centerY, centerZ);
gl.glRotatef(_xAngle, 1f, 0f, 0f);
gl.glRotatef(_yAngle, 0f, 1f, 0f);
gl.glRotatef(_zAngle, 0f, 0f, 1f);
gl.glTranslatef(-centerX, -centerY, -centerZ);
ptCloud.draw(gl);
gl.glPopMatrix();
}
}
}
这是我的采摘功能。出于调试目的,我将位置设置为屏幕中间:
public void pickPoint(GL10 gl){
mg.getCurrentState(gl);
double mvmatrix[] = new double[16];
double projmatrix[] = new double[16];
int viewport[] = {0,0,screenWidth, screenHeight};
for(int i=0 ; i<16; i++){
mvmatrix[i] = mg.mModelView[i];
projmatrix[i] = mg.mProjection[i];
}
mg.getCurrentState(gl);
float realY = ((float) (screenHeight) - pickY);
float nearCoords[] = { 0.0f, 0.0f, 0.0f, 0.0f };
float farCoords[] = { 0.0f, 0.0f, 0.0f, 0.0f };
GLU.gluUnProject(screenWidth/2, screenHeight/2, 0.0f, mg.mModelView, 0, mg.mProjection, 0,
viewport, 0, nearCoords, 0);
GLU.gluUnProject(screenWidth/2, screenHeight/2, 1.0f, mg.mModelView, 0, mg.mProjection, 0,
viewport, 0, farCoords, 0);
System.out.println("Near: " + nearCoords[0] + "," + nearCoords[1] + "," + nearCoords[2]);
System.out.println("Far: " + farCoords[0] + "," + farCoords[1] + "," + farCoords[2]);
//Plot the points in the scene
nearMarker.set(nearCoords);
farMarker.set(farCoords);
markerOn = true;
double diffX = nearCoords[0] - farCoords[0];
double diffY = nearCoords[1] - farCoords[1];
double diffZ = nearCoords[2] - farCoords[2];
double rayLength = Math.sqrt(Math.pow(diffX, 2) + Math.pow(diffY, 2) + Math.pow(diffZ, 2));
System.out.println("rayLength: " + rayLength);
pickPointTrigger = false;
}
改变透视zNear和Far都没有预期的效果,1.0-1000.0透视的远点怎么可能是11个单位呢?
GLU.gluPerspective(gl, 55.0f, (float) screenWidth / (float) screenHeight, 1.0f ,100.0f);
.....
07-18 11:23:50.430: INFO/System.out(31795): Near: 57.574852,-88.60514,37.272636
07-18 11:23:50.430: INFO/System.out(31795): Far: 0.57574844,0.098602295,0.2700405
07-18 11:23:50.430: INFO/System.out(31795): rayLength: 111.74275719790872
GLU.gluPerspective(gl, 55.0f, (float) width / (float) height, 10.0f , 1000.0f);
...
07-18 11:25:12.420: INFO/System.out(31847): Near: 5.7575016,-7.965394,3.6339219
07-18 11:25:12.420: INFO/System.out(31847): Far: 0.057574987,0.90500546,-0.06634784
07-18 11:25:12.420: INFO/System.out(31847): rayLength: 11.174307289026638
寻找您在我的代码中看到的任何建议或错误。非常感激。我尽我所能(这一直是个问题)。