From 75565ecf2d0d5cf3c257b8376c45ef3e5675000f Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 27 Aug 2025 23:17:56 +0300
Subject: [PATCH] Adds left- and right-handed ortho matrices.

Adds functions to generate left- and right-handed orthographic projection matrices.
This provides more flexibility when defining a projection for rendering.
---
 include/omath/mat.hpp | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/include/omath/mat.hpp b/include/omath/mat.hpp
index 0ad81f1..1f1f086 100644
--- a/include/omath/mat.hpp
+++ b/include/omath/mat.hpp
@@ -479,6 +479,35 @@ namespace omath
                 {0.f, 0.f, -(far + near) / (far - near), -(2.f * near * far) / (far - near)},
                 {0.f, 0.f, -1.f, 0.f}};
     }
+    template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR>
+    [[nodiscard]]
+    Mat<4, 4, Type, St> mat_ortho_left_handed(const Type left, const Type right,
+                                              const Type bottom, const Type top,
+                                              const Type near, const Type far) noexcept
+    {
+        return
+        {
+            { static_cast<Type>(2) / (right - left), 0.f,       0.f,    -(right + left) / (right - left)},
+            { 0.f,      static_cast<Type>(2) / (top - bottom),  0.f,    -(top + bottom) / (top - bottom)},
+            { 0.f,      0.f,       static_cast<Type>(2) / (far - near), -(far + near) / (far - near)    },
+            { 0.f,      0.f,       0.f,                                 1.f                             }
+        };
+    }
+    template<class Type = float, MatStoreType St = MatStoreType::ROW_MAJOR>
+    [[nodiscard]]
+    Mat<4, 4, Type, St> mat_ortho_right_handed(const Type left, const Type right,
+                                              const Type bottom, const Type top,
+                                              const Type near, const Type far) noexcept
+    {
+        return
+        {
+                { static_cast<Type>(2) / (right - left), 0.f,       0.f,     -(right + left) / (right - left)},
+                { 0.f,      static_cast<Type>(2) / (top - bottom),  0.f,     -(top + bottom) / (top - bottom)},
+                { 0.f,      0.f,       -static_cast<Type>(2) / (far - near), -(far + near) / (far - near)    },
+                { 0.f,      0.f,       0.f,                                  1.f                             }
+        };
+    }
+
 } // namespace omath
 
 template<size_t Rows, size_t Columns, class Type, omath::MatStoreType StoreType>