Math Lib: rotate matrix cleanup

- Remove 'rotate_m2', unlike 'rotate_m4' it created a new matrix
  duplicating 'angle_to_mat2' - now used instead.
  (better avoid matching functions having different behavior).

- Add 'axis_angle_to_mat4_single',
  convenience wrapper for 'axis_angle_to_mat3_single'.

- Replace 'unit_m4(), rotate_m4()' with a single call to 'axis_angle_to_mat4_single'.

source/blender/alembic/intern/abc_transform.cc

@@ -92,8 +92,7 @@ void AbcTransformWriter::do_write()
 	/* Only apply rotation to root camera, parenting will propagate it. */
 	if (m_object->type == OB_CAMERA && !has_parent_camera(m_object)) {
 		float rot_mat[4][4];
-		unit_m4(rot_mat);
+		axis_angle_to_mat4_single(rot_mat, 'X', -M_PI_2);
-		rotate_m4(rot_mat, 'X', -M_PI_2);
 		mul_m4_m4m4(mat, mat, rot_mat);
 	}
 

source/blender/alembic/intern/abc_util.cc

@@ -221,8 +221,7 @@ void convert_matrix(const Imath::M44d &xform, Object *ob,
 
 	if (ob->type == OB_CAMERA) {
 		float cam_to_yup[4][4];
-		unit_m4(cam_to_yup);
+		axis_angle_to_mat4_single(cam_to_yup, 'X', M_PI_2);
-		rotate_m4(cam_to_yup, 'X', M_PI_2);
 		mul_m4_m4m4(r_mat, r_mat, cam_to_yup);
 	}
 

source/blender/blenkernel/intern/object_dupli.c

@@ -642,8 +642,7 @@ static void make_duplis_font(const DupliContext *ctx)
 				float rmat[4][4];
 
 				zero_v3(obmat[3]);
-				unit_m4(rmat);
+				axis_angle_to_mat4_single(rmat, 'Z', -ct->rot);
-				rotate_m4(rmat, 'Z', -ct->rot);
 				mul_m4_m4m4(obmat, obmat, rmat);
 			}
 

source/blender/blenkernel/intern/tracking_stabilize.c

@@ -587,7 +587,7 @@ static void compensate_rotation_center(const int size, float aspect,
 
 	copy_v2_v2(intended_pivot, pivot);
 	copy_v2_v2(rotated_pivot, pivot);
-	rotate_m2(rotation_mat, +angle);
+	angle_to_mat2(rotation_mat, +angle);
 	sub_v2_v2(rotated_pivot, origin);
 	mul_m2v2(rotation_mat, rotated_pivot);
 	mul_v2_fl(rotated_pivot, scale);
@@ -967,7 +967,7 @@ static void initialize_track_for_stabilization(StabContext *ctx,
 
 	pos[0] *= aspect;
 	angle = average_angle - atan2f(pos[1],pos[0]);
-	rotate_m2(local_data->stabilization_rotation_base, angle);
+	angle_to_mat2(local_data->stabilization_rotation_base, angle);
 
 	/* Per track baseline value for zoom. */
 	len = len_v2(pos) + SCALE_ERROR_LIMIT_BIAS;

source/blender/blenlib/BLI_math_matrix.h

@@ -219,7 +219,6 @@ void mat4_to_size(float r[3], float M[4][4]);
 
 void translate_m4(float mat[4][4], float tx, float ty, float tz);
 void rotate_m4(float mat[4][4], const char axis, const float angle);
-void rotate_m2(float mat[2][2], const float angle);
 void transform_pivot_set_m4(float mat[4][4], const float pivot[3]);
 
 void mat3_to_rot_size(float rot[3][3], float size[3], float mat3[3][3]);

source/blender/blenlib/BLI_math_rotation.h

@@ -122,8 +122,9 @@ void mat3_to_axis_angle(float axis[3], float *angle, float M[3][3]);
 void mat4_to_axis_angle(float axis[3], float *angle, float M[4][4]);
 void quat_to_axis_angle(float axis[3], float *angle, const float q[4]);
 
-void axis_angle_to_mat3_single(float R[3][3], const char axis, const float angle);
 void      angle_to_mat2(float R[2][2], const float angle);
+void axis_angle_to_mat3_single(float R[3][3], const char axis, const float angle);
+void axis_angle_to_mat4_single(float R[4][4], const char axis, const float angle);
 
 void axis_angle_to_quat_single(float q[4], const char axis, const float angle);
 

source/blender/blenlib/intern/math_geom.c

@@ -3917,10 +3917,9 @@ void lookat_m4(float mat[4][4], float vx, float vy, float vz, float px, float py
 	float sine, cosine, hyp, hyp1, dx, dy, dz;
 	float mat1[4][4];
 
-	unit_m4(mat);
 	unit_m4(mat1);
 
-	rotate_m4(mat, 'Z', -twist);
+	axis_angle_to_mat3_single(mat, 'Z', -twist);
 
 	dx = px - vx;
 	dy = py - vy;

source/blender/blenlib/intern/math_matrix.c

@@ -1625,6 +1625,13 @@ void translate_m4(float mat[4][4], float Tx, float Ty, float Tz)
 	mat[3][2] += (Tx * mat[0][2] + Ty * mat[1][2] + Tz * mat[2][2]);
 }
 
+/**
+ * Rotate a matrix in-place.
+ *
+ * \note To create a new rotation matrix see:
+ * #axis_angle_to_mat4_single, #axis_angle_to_mat3_single, #angle_to_mat2
+ * (axis & angle args are compatible).
+ */
 void rotate_m4(float mat[4][4], const char axis, const float angle)
 {
 	int col;
@@ -1665,13 +1672,6 @@ void rotate_m4(float mat[4][4], const char axis, const float angle)
 	}
 }
 
-void rotate_m2(float mat[2][2], const float angle)
-{
-	mat[0][0] = mat[1][1] = cosf(angle);
-	mat[0][1] = sinf(angle);
-	mat[1][0] = -mat[0][1];
-}
-
 /**
  * Scale or rotate around a pivot point,
  * a convenience function to avoid having to do inline.

source/blender/blenlib/intern/math_rotation.c

@@ -1009,6 +1009,13 @@ void mat4_to_axis_angle(float axis[3], float *angle, float mat[4][4])
 	quat_to_axis_angle(axis, angle, q);
 }
 
+void axis_angle_to_mat4_single(float mat[4][4], const char axis, const float angle)
+{
+	float mat3[3][3];
+	axis_angle_to_mat3_single(mat3, axis, angle);
+	copy_m4_m3(mat, mat3);
+}
+
 /* rotation matrix from a single axis */
 void axis_angle_to_mat3_single(float mat[3][3], const char axis, const float angle)
 {

source/blender/collada/collada_internal.cpp

@@ -33,11 +33,8 @@
 
 UnitConverter::UnitConverter() : unit(), up_axis(COLLADAFW::FileInfo::Z_UP)
 {
-	unit_m4(x_up_mat4);
+	axis_angle_to_mat4_single(x_up_mat4, 'Y', -0.5 * M_PI);
-	rotate_m4(x_up_mat4, 'Y', -0.5 * M_PI);
+	axis_angle_to_mat4_single(y_up_mat4, 'X', 0.5 * M_PI);
-
-	unit_m4(y_up_mat4);
-	rotate_m4(y_up_mat4, 'X', 0.5 * M_PI);
 
 	unit_m4(z_up_mat4);
 	unit_m4(scale_mat4);

source/blender/editors/mesh/editmesh_knife.c

@@ -2140,7 +2140,7 @@ static float snap_v2_angle(float r[2], const float v[2], const float v_ref[2], f
 	normalize_v2_v2(v_unit, v);
 	angle = angle_signed_v2v2(v_unit, v_ref);
 	angle_delta = (roundf(angle / angle_snap) * angle_snap) - angle;
-	rotate_m2(m2, angle_delta);
+	angle_to_mat2(m2, angle_delta);
 
 	mul_v2_m2v2(r, m2, v);
 	return angle + angle_delta;

source/blender/editors/object/object_warp.c

@@ -53,8 +53,7 @@ static void object_warp_calc_view_matrix(float r_mat_view[4][4], float r_center_
 	float viewmat_roll[4][4];
 
 	/* apply the rotation offset by rolling the view */
-	unit_m4(mat_offset);
+	axis_angle_to_mat4_single(mat_offset, 'Z', offset_angle);
-	rotate_m4(mat_offset, 'Z', offset_angle);
 	mul_m4_m4m4(viewmat_roll, mat_offset, viewmat);
 
 	/* apply the view and the object matrix */

source/blender/editors/sculpt_paint/sculpt.c

@@ -821,10 +821,9 @@ static float calc_overlap(StrokeCache *cache, const char symm, const char axis,
 	flip_v3_v3(mirror, cache->true_location, symm);
 
 	if (axis != 0) {
-		float mat[4][4];
+		float mat[3][3];
-		unit_m4(mat);
+		axis_angle_to_mat3_single(mat, axis, angle);
-		rotate_m4(mat, axis, angle);
+		mul_m3_v3(mat, mirror);
-		mul_m4_v3(mat, mirror);
 	}
 
 	/* distsq = len_squared_v3v3(mirror, cache->traced_location); */

source/blender/editors/uvedit/uvedit_smart_stitch.c

@@ -459,7 +459,7 @@ static void stitch_calculate_island_snapping(
 				            island_stitch_data[i].num_rot_elements_neg) / totelem;
 			}
 
-			rotate_m2(rotation_mat, rotation);
+			angle_to_mat2(rotation_mat, rotation);
 			numOfIslandUVs = getNumOfIslandUvs(state->element_map, i);
 			element = &state->element_map->buf[state->element_map->islandIndices[i]];
 			for (j = 0; j < numOfIslandUVs; j++, element++) {

source/blender/modifiers/intern/MOD_screw.c

@@ -798,13 +798,11 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 		if (ltmd->ob_axis) {
 			axis_angle_normalized_to_mat3(mat3, axis_vec, step_angle);
-			copy_m4_m3(mat, mat3);
 		}
 		else {
-			unit_m4(mat);
+			axis_angle_to_mat3_single(mat3, axis_char, step_angle);
-			rotate_m4(mat, axis_char, step_angle);
-			copy_m3_m4(mat3, mat);
 		}
+		copy_m4_m3(mat, mat3);
 
 		if (screw_ofs)
 			madd_v3_v3fl(mat[3], axis_vec, screw_ofs * ((float)step / (float)(step_tot - 1)));