Implemented Vector2 rotation around a pivot point

sparky-game · Nov 28, 2024 · 910b594 · 910b594
1 parent af307fb
commit 910b594
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 0 deletions.
diff --git a/carbon.h b/carbon.h
@@ -338,6 +338,7 @@ CARBON_API f32 carbon_math_vec2_dot(CBN_Vec2 u, CBN_Vec2 v);
 CARBON_API f32 carbon_math_vec3_dot(CBN_Vec3 u, CBN_Vec3 v);
 CARBON_API CBN_Vec3 carbon_math_vec3_cross(CBN_Vec3 u, CBN_Vec3 v);
 CARBON_API CBN_Vec2 carbon_math_vec2_rotate(CBN_Vec2 v, f32 angle);
+CARBON_API CBN_Vec2 carbon_math_vec2_rotate_around_pivot(CBN_Vec2 v, f32 angle, CBN_Vec2 pivot);
 CARBON_API u8 carbon_math_rect_contains_point(CBN_Rect r, CBN_Vec2 p);
 CARBON_API CBN_Matrix carbon_math_mat_create(usz rows, usz cols);
 CARBON_API void carbon_math_mat_destroy(CBN_Matrix *m);

diff --git a/src/carbon_math.c b/src/carbon_math.c
@@ -342,6 +342,11 @@ CBN_Vec2 carbon_math_vec2_rotate(CBN_Vec2 v, f32 angle) {
   };
 }
 
+CBN_Vec2 carbon_math_vec2_rotate_around_pivot(CBN_Vec2 v, f32 angle, CBN_Vec2 pivot) {
+  CBN_Vec2 r = carbon_math_vec2_rotate((CBN_Vec2){{v.x - pivot.x, v.y - pivot.y}}, angle);
+  return (CBN_Vec2) {{r.x + pivot.x, r.y + pivot.y}};
+}
+
 u8 carbon_math_rect_contains_point(CBN_Rect r, CBN_Vec2 p) {
   return (p.x >= r.x && p.x <= r.x + r.w) && (p.y >= r.y && p.y <= r.y + r.h);
 }