New BLI Function: projmat_from_window_region

Creates a projection matrix for a small region of the viewport.

Reviewers: campbellbarton, brecht

Differential Revision: https://developer.blender.org/D5412

1 files changed, 8 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index d5485765844..5ac4ce8be0b 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -635,6 +635,14 @@ void projmat_dimensions(const float projmat[4][4],
                         float *r_near,
                         float *r_far);
 
+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]);
+
 int box_clip_bounds_m4(float boundbox[2][3], const float bounds[4], float winmat[4][4]);
 void box_minmax_bounds_m4(float min[3], float max[3], float boundbox[2][3], float mat[4][4]);