Add test for AABB collision functions

Internal Changelog:
- Fix some off-by-one errors

run_tests.sh

@@ -0,0 +1 @@
+ctest --rerun-failed --output-on-failure --test-dir build/tests

scenes/engine/AABB.c

@@ -14,7 +14,7 @@ uint8_t find_1D_overlap(Vector2 l1, Vector2 l2, float* overlap)
     }
     //Partial overlap
     // x is p1, y is p2
-    *overlap =  (l2.y >= l1.y)? l2.x - l1.y : l2.y - l1.x;
+    *overlap =  (l2.y >= l1.y)? l2.x - l1.y - 1 : l2.y - l1.x + 1;
     return 1;
 }
 
@@ -25,15 +25,15 @@ uint8_t find_AABB_overlap(const Vector2 tl1, const Vector2 sz1, const Vector2 tl
     Vector2 l1, l2;
     uint8_t overlap_x, overlap_y;
     l1.x = tl1.x;
-    l1.y = tl1.x + sz1.x;
+    l1.y = tl1.x + sz1.x - 1;
     l2.x = tl2.x;
-    l2.y = tl2.x + sz2.x;
+    l2.y = tl2.x + sz2.x - 1;
 
     overlap_x = find_1D_overlap(l1, l2, &overlap->x);
     l1.x = tl1.y;
-    l1.y = tl1.y + sz1.y;
+    l1.y = tl1.y + sz1.y - 1;
     l2.x = tl2.y;
-    l2.y = tl2.y + sz2.y;
+    l2.y = tl2.y + sz2.y - 1;
     overlap_y = find_1D_overlap(l1, l2, &overlap->y);
 
     if (overlap_x == 2 && overlap_y == 2) return 2;
@@ -43,8 +43,8 @@ uint8_t find_AABB_overlap(const Vector2 tl1, const Vector2 sz1, const Vector2 tl
 bool point_in_AABB(Vector2 point, Rectangle box)
 {
     return (
-        point.x > box.x
+        point.x >= box.x
-        && point.y > box.y
+        && point.y >= box.y
         && point.x < box.x + box.width
         && point.y < box.y + box.height
     );

tests/test_AABB.c

@@ -6,19 +6,86 @@
 #include <setjmp.h>
 #include <cmocka.h>
 
-static void test_no_overlap(void **state)
+static void test_point_AABB(void **state)
+{
+    (void) state;
+
+    Rectangle box = {0, 0, 20, 20};
+    Vector2 p = {-5, -5};
+    assert_false(point_in_AABB(p, box));
+
+    p.x = 10;
+    p.y = 10;
+    assert_true(point_in_AABB(p, box));
+
+    p.x = 0;
+    p.y = 0;
+    assert_true(point_in_AABB(p, box));
+
+    p.x = 20;
+    p.y = 20;
+    assert_false(point_in_AABB(p, box));
+
+}
+
+static void test_AABB_overlap(void **state)
+{
+    (void) state;
+    Vector2 p1 = {10, 10};
+    Vector2 sz1 = {10, 10};
+    Vector2 p2 = {25, 25};
+    Vector2 sz2 = {20, 20};
+
+    Vector2 overlap = {0};
+    assert_int_equal(find_AABB_overlap(p1, sz1, p2, sz2, &overlap), 0);
+    assert_int_equal(find_AABB_overlap(p2, sz2, p1, sz1, &overlap), 0);
+
+    p2.x = 10;
+    p2.y = 10;
+    assert_int_equal(find_AABB_overlap(p1, sz1, p2, sz2, &overlap), 2); // Smaller one is complete overlap
+    assert_int_equal(find_AABB_overlap(p2, sz2, p1, sz1, &overlap), 1); // Bigger on is not
+
+    p2.x = 15;
+    p2.y = 15;
+    assert_int_equal(find_AABB_overlap(p1, sz1, p2, sz2, &overlap), 1);
+    assert_float_equal(overlap.x, -5, 1e-5);
+    assert_float_equal(overlap.y, -5, 1e-5);
+    assert_int_equal(find_AABB_overlap(p2, sz2, p1, sz1, &overlap), 1);
+    assert_float_equal(overlap.x, 5, 1e-5);
+    assert_float_equal(overlap.y, 5, 1e-5);
+}
+
+static void test_1D_overlap(void **state)
 {
     (void) state;
     Vector2 a = {0, 5};
     Vector2 b = {6, 9};
     float overlap = 0;
     assert_int_equal(find_1D_overlap(a, b, &overlap), 0);
+
+    a.y = 6;
+    assert_int_equal(find_1D_overlap(a, b, &overlap), 1);
+    assert_float_equal(overlap, -1, 1e-5);
+    assert_int_equal(find_1D_overlap(b, a, &overlap), 1);
+    assert_float_equal(overlap, 1, 1e-5);
+
+    a.y = 7;
+    assert_int_equal(find_1D_overlap(a, b, &overlap), 1);
+    assert_float_equal(overlap, -2, 1e-5);
+    assert_int_equal(find_1D_overlap(b, a, &overlap), 1);
+    assert_float_equal(overlap, 2, 1e-5);
+    
+    a.x = 7;
+    a.y = 9;
+    assert_int_equal(find_1D_overlap(a, b, &overlap), 2);
 }
 
 int main(void)
 {
     const struct CMUnitTest tests[] = {
-        cmocka_unit_test(test_no_overlap),
+        cmocka_unit_test(test_1D_overlap),
+        cmocka_unit_test(test_AABB_overlap),
+        cmocka_unit_test(test_point_AABB),
     };
 
     return cmocka_run_group_tests(tests, NULL, NULL);