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More efficient rotation matrix calc from Norm Vine.

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david 2002-07-18 15:54:21 +00:00
parent f4cfe4c207
commit 4ab343569f
1 changed files with 27 additions and 11 deletions
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38
src/Objects/obj.cxx
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@ -599,20 +599,36 @@ setup_triangle (float * p1, float * p2, float * p3,
* @param lon_deg The longitude in degrees.
* @param lat_deg The latitude in degrees.
*/
static void
void
makeWorldUpRotationMatrix (sgMat4 ROT, double hdg_deg,
double lon_deg, double lat_deg)
{
sgVec3 obj_right, obj_up;
sgSetVec3(obj_right, 0.0, 1.0, 0.0); // Y axis
sgSetVec3(obj_up, 0.0, 0.0, 1.0); // Z axis
sgMat4 ROT_lon, ROT_lat, ROT_hdg;
sgMakeRotMat4(ROT_lon, lon_deg, obj_up);
sgMakeRotMat4(ROT_lat, 90 - lat_deg, obj_right);
sgMakeRotMat4(ROT_hdg, hdg_deg, obj_up);
sgCopyMat4(ROT, ROT_hdg);
sgPostMultMat4(ROT, ROT_lat);
sgPostMultMat4(ROT, ROT_lon);
SGfloat sin_lat = sin( lat_deg * SGD_DEGREES_TO_RADIANS );
SGfloat cos_lat = cos( lat_deg * SGD_DEGREES_TO_RADIANS );
SGfloat sin_lon = sin( lon_deg * SGD_DEGREES_TO_RADIANS );
SGfloat cos_lon = cos( lon_deg * SGD_DEGREES_TO_RADIANS );
SGfloat sin_hdg = sin( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
SGfloat cos_hdg = cos( hdg_deg * SGD_DEGREES_TO_RADIANS ) ;
ROT[0][0] = cos_hdg * sin_lat * cos_lon - sin_hdg * sin_lon;
ROT[0][1] = cos_hdg * sin_lat * sin_lon + sin_hdg * cos_lon;
ROT[0][2] = -cos_hdg * cos_lat;
ROT[0][3] = SG_ZERO;
ROT[1][0] = -sin_hdg * sin_lat * cos_lon - cos_hdg * sin_lon;
ROT[1][1] = -sin_hdg * sin_lat * sin_lon + cos_hdg * cos_lon;
ROT[1][2] = sin_hdg * cos_lat;
ROT[1][3] = SG_ZERO;
ROT[2][0] = cos_lat * cos_lon;
ROT[2][1] = cos_lat * sin_lon;
ROT[2][2] = sin_lat;
ROT[2][3] = SG_ZERO;
ROT[3][0] = SG_ZERO;
ROT[3][1] = SG_ZERO;
ROT[3][2] = SG_ZERO;
ROT[3][3] = SG_ONE ;
}