From 3bdd70261a5b77609f31cc2262e2fa511370dd8d Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sun, 7 Jul 2024 14:48:23 -0700
Subject: AABB empty.

---
 include/math/aabb2.h | 9 +++++++++
 include/math/aabb3.h | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/math/aabb2.h b/include/math/aabb2.h
index edb6cb6..916b1ba 100644
--- a/include/math/aabb2.h
+++ b/include/math/aabb2.h
@@ -9,6 +9,12 @@ typedef struct aabb2 {
   vec2 max;
 } aabb2;
 
+/// Construct an empty AABB.
+static inline aabb2 aabb2_make_empty() {
+  return (aabb2){
+      .min = vec2_from_scalar(R_MAX), .max = vec2_from_scalar(R_MIN)};
+}
+
 /// Construct an AABB from min and max bounds.
 static inline aabb2 aabb2_make(vec2 min, vec2 max) {
   return (aabb2){.min = min, .max = max};
@@ -33,3 +39,6 @@ static inline aabb2 aabb2_add(aabb2 box, vec2 p) {
 static inline aabb2 aabb2_sum(aabb2 a, aabb2 b) {
   return (aabb2){.min = vec2_min(a.min, b.min), .max = vec2_max(a.max, b.max)};
 }
+
+/// Return true if the AABB is empty.
+static inline bool aabb2_is_empty(aabb2 a) { return (a.min.x > a.max.x); }
diff --git a/include/math/aabb3.h b/include/math/aabb3.h
index 0b0005c..f4c9338 100644
--- a/include/math/aabb3.h
+++ b/include/math/aabb3.h
@@ -9,6 +9,12 @@ typedef struct aabb3 {
   vec3 max;
 } aabb3;
 
+/// Construct an empty AABB.
+static inline aabb3 aabb3_make_empty() {
+  return (aabb3){
+      .min = vec3_from_scalar(R_MAX), .max = vec3_from_scalar(R_MIN)};
+}
+
 /// Construct an AABB from min and max bounds.
 static inline aabb3 aabb3_make(vec3 min, vec3 max) {
   return (aabb3){.min = min, .max = max};
@@ -33,3 +39,6 @@ static inline aabb3 aabb3_add(aabb3 box, vec3 p) {
 static inline aabb3 aabb3_sum(aabb3 a, aabb3 b) {
   return (aabb3){.min = vec3_min(a.min, b.min), .max = vec3_max(a.max, b.max)};
 }
+
+/// Return true if the AABB is empty.
+static inline bool aabb3_is_empty(aabb3 a) { return (a.min.x > a.max.x); }
-- 
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