Inline dests in mat4.lookAt
Opened this issue · 3 comments
GoogleCodeExporter commented
Something like this (didn't test it)?
mat4.lookAt = function(eye, center, up, dest) {
var eyex = eye[0],
eyey = eye[1],
eyez = eye[2],
upx = up[0],
upy = up[1],
upz = up[2],
centerx = center[0],
centery = center[1],
centerz = center[2];
if (eyex == centerx && eyey == centery && eyez == centerz) {
return mat4.identity();
}
var z0,z1,z2,x0,x1,x2,y0,y1,y2,len;
//vec3.direction(eye, center, z);
z0 = eyex - center[0];
z1 = eyey - center[1];
z2 = eyez - center[2];
// normalize (no check needed for 0 becuase of early return)
len = Math.sqrt(z0 * z0 + z1 * z1 + z2 * z2);
z0 = z0/len;
z1 = z1/len;
z2 = z2/len;
//vec3.normalize(vec3.cross(up, z, x));
x0 = upy * z2 - upz * z1;
x1 = upz * z0 - upx * z2;
x2 = upx * z1 - upy * z0;
len = Math.sqrt(x0 * x0 + x1 * x1 + x2 * x2);
if (!len) {
dest[0] = 0;
dest[4] = 0;
dest[8] = 0;
dest[12] = 0;
} else {
x0 = x0/len;
x1 = x1/len;
x2 = x2/len;
dest[0] = x0;
dest[4] = x1;
dest[8] = x2;
dest[12] = -(x0 * eyex + x1 * eyey + x2 * eyez);
};
//vec3.normalize(vec3.cross(z, x, y));
y0 = z1 * x2 - z2 * x1;
y1 = z2 * x0 - z0 * x2;
y2 = z0 * x1 - z1 * x0;
len = Math.sqrt(y0 * y0 + y1 * y1 + y2 * y2);
if (!len) {
dest[1] = 0;
dest[5] = 0;
dest[9] = 0;
dest[13] = 0;
} else {
y0 = y0/len;
y1 = y1/len;
y2 = y2/len;
dest[1] = y0;
dest[5] = y1;
dest[9] = y2;
dest[13] = -(y0 * eyex + y1 * eyey + y2 * eyez);
}
dest[2] = z0;
dest[3] = 0;
dest[6] = z1;
dest[7] = 0;
dest[10] = z2;
dest[11] = 0;
dest[14] = -(z0 * eyex + z1 * eyey + z2 * eyez);
dest[15] = 1;
return dest;
};
Original issue reported on code.google.com by danielhe...@gmail.com
on 14 Jun 2010 at 6:09
GoogleCodeExporter commented
Original comment by Tojiro@gmail.com
on 1 Jul 2010 at 9:36
- Added labels: Type-Optimization
- Removed labels: Type-Defect
GoogleCodeExporter commented
[deleted comment]
GoogleCodeExporter commented
z0 = eyex - center[0];
z1 = eyey - center[1];
z2 = eyez - center[2];
to
z0 = eyex - centerx;
z1 = eyey - centery;
z2 = eyez - centerz;
and maybe also don't calculate the square root in len = Math.sqrt(x0 * x0 + x1
* x1 + x2 * x2), but later and than invert it also and do a multiplication in
the else block.
Original comment by danielhe...@gmail.com
on 28 Feb 2011 at 9:52