Implemented Vector3's cross product

sparky-game · Nov 6, 2024 · 173c488 · 173c488
1 parent f2c5d6f
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diff --git a/carbon.h b/carbon.h
@@ -247,6 +247,7 @@ CARBON_API CBN_Vec2 carbon_math_vec2_sub(CBN_Vec2 u, CBN_Vec2 v);
 CARBON_API CBN_Vec3 carbon_math_vec3_sub(CBN_Vec3 u, CBN_Vec3 v);
 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);
 
 #ifdef __cplusplus

diff --git a/src/carbon_math.c b/src/carbon_math.c
@@ -108,6 +108,14 @@ f32 carbon_math_vec3_dot(CBN_Vec3 u, CBN_Vec3 v) {
   return (u.x * v.x) + (u.y * v.y) + (u.z * v.z);
 }
 
+CBN_Vec3 carbon_math_vec3_cross(CBN_Vec3 u, CBN_Vec3 v) {
+  return (CBN_Vec3) {
+    .x = (u.y * v.z) - (u.z * v.y),
+    .y = (u.z * v.x) - (u.x * v.z),
+    .z = (u.x * v.y) - (u.y * v.x)
+  };
+}
+
 CBN_Vec2 carbon_math_vec2_rotate(CBN_Vec2 v, f32 angle) {
   f32 rads = angle * (CARBON_PI / 180);
   f32 c = cosf(rads), s = sinf(rads);

diff --git a/test/carbon_math_test.c b/test/carbon_math_test.c
@@ -102,3 +102,13 @@ CARBON_TEST(carbon_math, vec3_dot) {
   carbon_should_be_f(32, carbon_math_vec3_dot(u, v));
   return CARBON_OK;
 }
+
+CARBON_TEST(carbon_math, vec3_cross) {
+  CBN_Vec3 u = {{3, -3, 1}};
+  CBN_Vec3 v = {{4, 9, 2}};
+  CBN_Vec3 r = carbon_math_vec3_cross(u, v);
+  carbon_should_be_f(-15, r.x);
+  carbon_should_be_f(-2, r.y);
+  carbon_should_be_f(39, r.z);
+  return CARBON_OK;
+}