From 472037e3ca557f30c8a7f3258f3b00c748e27ef5 Mon Sep 17 00:00:00 2001
From: Pabloader <pabloader@pabloader.ru>
Date: Mon, 22 Dec 2025 07:28:50 +0000
Subject: [PATCH] vec2 reflect

---
 build/assets/include/vec2.h | 10 ++++++----
 build/assets/lib/vec2.c     | 24 ++++++++++++++++--------
 src/common/physics/engine.c |  5 +----
 3 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/build/assets/include/vec2.h b/build/assets/include/vec2.h
index 6deca26..2175773 100644
--- a/build/assets/include/vec2.h
+++ b/build/assets/include/vec2.h
@@ -8,9 +8,11 @@ typedef struct vec2_t {
 vec2 vec2_add(vec2 a, vec2 b);
 vec2 vec2_sub(vec2 a, vec2 b);
 float vec2_dot(vec2 a, vec2 b);
-vec2 vec2_mul(vec2 x, float f);
-vec2 vec2_div(vec2 x, float f);
-float vec2_mag(vec2 x);
-vec2 vec2_normalize(vec2 x);
+vec2 vec2_mul(vec2 v, float f);
+vec2 vec2_div(vec2 v, float f);
+float vec2_mag(vec2 v);
+vec2 vec2_normalize(vec2 v);
+vec2 vec2_lerp(vec2 a, vec2 b, float t);
+vec2 vec2_reflect(vec2 v, vec2 n);
 
 #endif
diff --git a/build/assets/lib/vec2.c b/build/assets/lib/vec2.c
index 78b0324..5a47edb 100644
--- a/build/assets/lib/vec2.c
+++ b/build/assets/lib/vec2.c
@@ -19,25 +19,33 @@ float vec2_dot(vec2 a, vec2 b) {
     return a.x * b.x + a.y * b.y;
 }
 
-vec2 vec2_mul(vec2 x, float f) {
+vec2 vec2_mul(vec2 v, float f) {
     return (vec2){
-        .x = x.x * f,
-        .y = x.y * f,
+        .x = v.x * f,
+        .y = v.y * f,
     };
 }
 
-vec2 vec2_div(vec2 x, float f) {
+vec2 vec2_div(vec2 v, float f) {
     return (vec2){
-        .x = x.x / f,
-        .y = x.y / f,
+        .x = v.x / f,
+        .y = v.y / f,
     };
 }
 
-float vec2_mag(vec2 x) {
-    return sqrtf(x.x * x.x + x.y * x.y);
+float vec2_mag(vec2 v) {
+    return sqrtf(v.x * v.x + v.y * v.y);
 }
 
 vec2 vec2_normalize(vec2 x) {
     float len = vec2_mag(x);
     return vec2_div(x, len);
 }
+
+vec2 vec2_lerp(vec2 a, vec2 b, float t) {
+    return vec2_add(a, vec2_mul(vec2_sub(b, a), t));
+}
+
+vec2 vec2_reflect(vec2 x, vec2 n) {
+    return vec2_sub(x, vec2_mul(vec2_mul(n, vec2_dot(x, n)), 2));
+}
diff --git a/src/common/physics/engine.c b/src/common/physics/engine.c
index 9c14ca6..d7088ad 100644
--- a/src/common/physics/engine.c
+++ b/src/common/physics/engine.c
@@ -224,10 +224,7 @@ void rigid_body_handle_collision(rigid_body_index idx1, rigid_body_index idx2) {
         vec2 n_overlap = vec2_mul(n, overlap);
 
         rb2->pos = vec2_add(rb2->pos, n_overlap);
-
-        float vn = vec2_dot(rb2->vel, n);
-        vec2 vt = vec2_sub(rb2->vel, vec2_mul(n, vn));
-        rb2->vel = vec2_add(vt, vec2_mul(n, -vn));
+        rb2->vel = vec2_reflect(rb2->vel, n);
     } else if (rb1->type == TYPE_CIRCLE && rb2->type == TYPE_PLANE) {
         rigid_body_handle_collision(idx2, idx1);
     }