diff options
Diffstat (limited to 'source/blender/blenlib/intern/math_geom.c')
| -rw-r--r-- | source/blender/blenlib/intern/math_geom.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c index 7cdac6b1497..b4a96ff316a 100644 --- a/source/blender/blenlib/intern/math_geom.c +++ b/source/blender/blenlib/intern/math_geom.c @@ -4481,6 +4481,50 @@ void projmat_dimensions(const float projmat[4][4], } } +/** + * Creates a projection matrix for a small region of the viewport. + * + * \param projmat: Projection Matrix. + * \param win_size: Viewport Size. + * \param x_min, x_max, y_min, y_max: Coordinates of the subregion. + * \return r_projmat: Resulting Projection Matrix. + */ +void projmat_from_subregion(const float projmat[4][4], + const int win_size[2], + const int x_min, + const int x_max, + const int y_min, + const int y_max, + float r_projmat[4][4]) +{ + float rect_width = (float)(x_max - x_min); + float rect_height = (float)(y_max - y_min); + + float x_fac = (float)((x_min + x_max) - win_size[0]) / rect_width; + float y_fac = (float)((y_min + y_max) - win_size[1]) / rect_height; + + copy_m4_m4(r_projmat, projmat); + r_projmat[0][0] *= (float)win_size[0] / rect_width; + r_projmat[1][1] *= (float)win_size[1] / rect_height; + +#if 0 /* TODO: check if this is more efficient. */ + r_projmat[2][0] -= x_fac * r_projmat[2][3]; + r_projmat[2][1] -= y_fac * r_projmat[2][3]; + + r_projmat[3][0] -= x_fac * r_projmat[3][3]; + r_projmat[3][1] -= y_fac * r_projmat[3][3]; +#else + if (projmat[3][3] == 0.0f) { + r_projmat[2][0] += x_fac; + r_projmat[2][1] += y_fac; + } + else { + r_projmat[3][0] -= x_fac; + r_projmat[3][1] -= y_fac; + } +#endif +} + static void i_multmatrix(float icand[4][4], float Vm[4][4]) { int row, col; |