1 files changed, 48 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_matrix.c b/source/blender/blenlib/intern/math_matrix.c
index 54bee803f9c..152b31754bb 100644
--- a/source/blender/blenlib/intern/math_matrix.c
+++ b/source/blender/blenlib/intern/math_matrix.c
@@ -2215,3 +2215,51 @@ void invert_m4_m4_safe(float Ainv[4][4], float A[4][4])
 		}
 	}
 }
+
+/**
+ * SpaceTransform struct encapsulates all needed data to convert between two coordinate spaces
+ * (where conversion can be represented by a matrix multiplication).
+ *
+ * A SpaceTransform is initialized using:
+ *   BLI_SPACE_TRANSFORM_SETUP(&data,  ob1, ob2)
+ *
+ * After that the following calls can be used:
+ *   BLI_space_transform_apply(&data, co);  // converts a coordinate in ob1 space to the corresponding ob2 space
+ *   BLI_space_transform_invert(&data, co);  // converts a coordinate in ob2 space to the corresponding ob1 space
+ *
+ * Same concept as BLI_space_transform_apply and BLI_space_transform_invert, but no is normalized after conversion
+ * (and not translated at all!):
+ *   BLI_space_transform_apply_normal(&data, no);
+ *   BLI_space_transform_invert_normal(&data, no);
+ *
+ */
+
+void BLI_space_transform_from_matrices(SpaceTransform *data, float local[4][4], float target[4][4])
+{
+	float itarget[4][4];
+	invert_m4_m4(itarget, target);
+	mul_m4_m4m4(data->local2target, itarget, local);
+	invert_m4_m4(data->target2local, data->local2target);
+}
+
+void BLI_space_transform_apply(const SpaceTransform *data, float co[3])
+{
+	mul_v3_m4v3(co, ((SpaceTransform *)data)->local2target, co);
+}
+
+void BLI_space_transform_invert(const SpaceTransform *data, float co[3])
+{
+	mul_v3_m4v3(co, ((SpaceTransform *)data)->target2local, co);
+}
+
+void BLI_space_transform_apply_normal(const SpaceTransform *data, float no[3])
+{
+	mul_mat3_m4_v3(((SpaceTransform *)data)->local2target, no);
+	normalize_v3(no);
+}
+
+void BLI_space_transform_invert_normal(const SpaceTransform *data, float no[3])
+{
+	mul_mat3_m4_v3(((SpaceTransform *)data)->target2local, no);
+	normalize_v3(no);
+}