| 66 | #define dist_2d(x, y) sqrt((x) * (x) + (y) * (y)) |
| 67 | |
| 68 | void GetMouseRotation(int idx, int idy, matrix *RotMat) { |
| 69 | float dr, cos_theta, sin_theta, denom, cos_theta1; |
| 70 | float Radius = 100.0; |
| 71 | float dx, dy; |
| 72 | float dxdr, dydr; |
| 73 | |
| 74 | idy *= -1; |
| 75 | |
| 76 | dx = idx; |
| 77 | dy = idy; |
| 78 | |
| 79 | dr = dist_2d(dx, dy); |
| 80 | |
| 81 | denom = dist_2d(Radius, dr); |
| 82 | |
| 83 | cos_theta = Radius / denom; |
| 84 | sin_theta = dr / denom; |
| 85 | |
| 86 | cos_theta1 = 1.0 - cos_theta; |
| 87 | |
| 88 | dxdr = dx / dr; |
| 89 | dydr = dy / dr; |
| 90 | |
| 91 | RotMat->rvec.x = cos_theta + ((dydr * dydr) * cos_theta1); |
| 92 | RotMat->uvec.x = -((dxdr * dydr) * cos_theta1); |
| 93 | RotMat->fvec.x = (dxdr * sin_theta); |
| 94 | |
| 95 | RotMat->rvec.y = RotMat->uvec.x; |
| 96 | RotMat->uvec.y = cos_theta + ((dxdr * dxdr) * cos_theta1); |
| 97 | RotMat->fvec.y = (dydr * sin_theta); |
| 98 | |
| 99 | RotMat->rvec.z = -RotMat->fvec.x; |
| 100 | RotMat->uvec.z = -RotMat->fvec.y; |
| 101 | RotMat->fvec.z = cos_theta; |
| 102 | } |
| 103 | |
| 104 | // Variables for current view position and orientation |
| 105 | #define DEFAULT_VIEW_DIST 500 |