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嘿,我试图在我的程序中实现3D拾取,并且如果我不从原点移动,它会很好地工作。这是完全准确的。但是如果我将模型矩阵从原点移开(视图矩阵仍然在0,0,0),拾取矢量仍然从原始位置绘制。它应该仍然从视图矩阵眼(0,0,0)绘制,但事实并非如此。这里是我的一些代码,看看你是否可以找出原因..3D模型矩阵翻译之后挑选OpenGL ES 2.0
Vector3d near = unProject(x, y, 0, mMVPMatrix, this.width, this.height);
Vector3d far = unProject(x, y, 1, mMVPMatrix, this.width, this.height);
Vector3d pickingRay = far.subtract(near);
//pickingRay.z *= -1;
Vector3d normal = new Vector3d(0,0,1);
if (normal.dot(pickingRay) != 0 && pickingRay.z < 0)
{
float t = (-5f-normal.dot(mCamera.eye))/(normal.dot(pickingRay));
pickingRay = mCamera.eye.add(pickingRay.scale(t));
addObject(pickingRay.x, pickingRay.y, pickingRay.z+.5f, Shape.BOX);
//a line for the picking vector for debugging
PrimProperties a = new PrimProperties(); //new prim properties for size and center
Prim result = null;
result = new Line(a, mCamera.eye, far);//new line object for seeing look at vector
result.createVertices();
objects.add(result);
}
public static Vector3d unProject(
float winx, float winy, float winz,
float[] resultantMatrix,
float width, float height)
{
winy = height-winy;
float[] m = new float[16],
in = new float[4],
out = new float[4];
Matrix.invertM(m, 0, resultantMatrix, 0);
in[0] = (winx/width) * 2 - 1;
in[1] = (winy/height) * 2 - 1;
in[2] = 2 * winz - 1;
in[3] = 1;
Matrix.multiplyMV(out, 0, m, 0, in, 0);
if (out[3]==0)
return null;
out[3] = 1/out[3];
return new Vector3d(out[0] * out[3], out[1] * out[3], out[2] * out[3]);
}
Matrix.translateM(mModelMatrix, 0, this.diffX, this.diffY, 0); //i use this to move the model matrix based on pinch zooming stuff.
任何帮助将不胜感激!谢谢。
我其实已经想通了。这只是投射射线并检查与设置平面的交叉点。后来我实现了检查物体中心与光线的距离有多近,如果足够接近,它会选择该物体。不过谢谢。 – scssquatch