From 702bed817365a83051e4856a363fabcd16c8207d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wladislav=20=E3=83=B4=E3=83=A9=E3=83=89=20Artsimovich?=
 <wladislav.artsimovich@dmgmori.com>
Date: Thu, 15 Jun 2023 18:18:52 +0900
Subject: [PATCH] Implement missing Struct API 3D Affine Transforms

---
 include/cglm/struct/affine-mat.h | 90 ++++++++++++++++++++++++++++++++
 include/cglm/struct/affine.h     |  1 +
 2 files changed, 91 insertions(+)
 create mode 100644 include/cglm/struct/affine-mat.h

diff --git a/include/cglm/struct/affine-mat.h b/include/cglm/struct/affine-mat.h
new file mode 100644
index 0000000..78a6a40
--- /dev/null
+++ b/include/cglm/struct/affine-mat.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+/*
+ Functions:
+   CGLM_INLINE mat4s glms_mul(mat4 m1, mat4 m2);
+   CGLM_INLINE mat4s glms_mul_rot(mat4 m1, mat4 m2);
+   CGLM_INLINE mat4s glms_inv_tr();
+ */
+
+#ifndef cglms_affine_mat_h
+#define cglms_affine_mat_h
+
+#include "../common.h"
+#include "../types-struct.h"
+#include "../affine-mat.h"
+#include "vec3.h"
+#include "vec4.h"
+#include "mat4.h"
+
+/*!
+ * @brief this is similar to glms_mat4_mul but specialized to affine transform
+ *
+ * Matrix format should be:
+ *   R  R  R  X
+ *   R  R  R  Y
+ *   R  R  R  Z
+ *   0  0  0  W
+ *
+ * this reduces some multiplications. It should be faster than mat4_mul.
+ * if you are not sure about matrix format then DON'T use this! use mat4_mul
+ *
+ * @param[in]   m1    affine matrix 1
+ * @param[in]   m2    affine matrix 2
+ * @returns         destination matrix
+ */
+CGLM_INLINE
+mat4s
+glms_mul(mat4s m1, mat4s m2){
+  mat4s r;
+  glm_mul(m1.raw, m2.raw, r.raw);
+  return r;
+}
+
+/*!
+ * @brief this is similar to glm_mat4_mul but specialized to affine transform
+ *
+ * Right Matrix format should be:
+ *   R  R  R  0
+ *   R  R  R  0
+ *   R  R  R  0
+ *   0  0  0  1
+ *
+ * this reduces some multiplications. It should be faster than mat4_mul.
+ * if you are not sure about matrix format then DON'T use this! use mat4_mul
+ *
+ * @param[in]   m1    affine matrix 1
+ * @param[in]   m2    affine matrix 2
+ * @returns         destination matrix
+ */
+CGLM_INLINE
+mat4s
+glms_mul_rot(mat4s m1, mat4s m2){
+  mat4s r;
+  glm_mul_rot(m1.raw, m2.raw, r.raw);
+  return r;
+}
+
+/*!
+ * @brief inverse orthonormal rotation + translation matrix (ridig-body)
+ *
+ * @code
+ * X = | R  T |   X' = | R' -R'T |
+ *     | 0  1 |        | 0     1 |
+ * @endcode
+ *
+ * @param[in]  mat  matrix
+ * @returns         destination matrix
+ */
+CGLM_INLINE
+mat4s
+glms_inv_tr(mat4s m){
+  glm_inv_tr(m.raw);
+  return m;
+}
+#endif /* cglms_affine_mat_h */
diff --git a/include/cglm/struct/affine.h b/include/cglm/struct/affine.h
index 64e56d0..bc62846 100644
--- a/include/cglm/struct/affine.h
+++ b/include/cglm/struct/affine.h
@@ -39,6 +39,7 @@
 #include "vec3.h"
 #include "vec4.h"
 #include "mat4.h"
+#include "affine-mat.h"
 
 /*!
  * @brief creates NEW translate transform matrix by v vector