FWIW, the following unproject code seems to line up properly for me.
Notice that I had to map view coordinates to (-1.25,1.25) instead of
from (-2,2). I got these numbers empirically and have no idea why
this would be so or how close to the correct values I am.
static void fixW(float[] v) {
for(int i = 0; i < 4; i++)
v[i] = v[i] / v[3];
}
public static float[] unProject(float[] win, float[] mod, float[]
proj, int[] view) {
// XXX check for invertability and w=0.0
float[] m = multMM(proj, mod);
float[] im = new float[16];
Matrix.invertM(im, 0, m, 0);
// This should scale by 2f, but 1.25f seems to give
// accurate results.. I dont know why! XXX!
float[] w = new float[] {
1.25f * ((win[0] - view[0]) / view[2] - 0.5f),
1.25f * ((win[1] - view[1]) / view[3] - 0.5f),
2f * win[2] - 1f,
1f };
float[] r = multMV(im, w);
fixW(r);
return r;
}
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