From bcbec562ac8cfb1a2fccaf27eb818adf4d1a2abf Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Wed, 19 Jun 2024 14:38:50 +0300
Subject: [PATCH] add mat4.determinant(...)

---
 doc/en/scripting/builtins/libmat4.md | 7 +++++++
 doc/ru/scripting/builtins/libmat4.md | 7 +++++++
 src/logic/scripting/lua/libmat4.cpp  | 9 +++++++++
 3 files changed, 23 insertions(+)

diff --git a/doc/en/scripting/builtins/libmat4.md b/doc/en/scripting/builtins/libmat4.md
index 3d0bb1d1..6216dff2 100644
--- a/doc/en/scripting/builtins/libmat4.md
+++ b/doc/en/scripting/builtins/libmat4.md
@@ -25,6 +25,13 @@ mat4.idt()
 mat4.idt(dst: matrix)
 ```
 
+## Matrix determinant - *mat4.determinant(...)*
+
+```lua
+-- calculates the determinant of the matrix
+mat4.determinant(m: matrix)
+```
+
 ## Matrix multiplication - *mat4.mul(...)*
 
 ```lua
diff --git a/doc/ru/scripting/builtins/libmat4.md b/doc/ru/scripting/builtins/libmat4.md
index a451ad3f..30d02784 100644
--- a/doc/ru/scripting/builtins/libmat4.md
+++ b/doc/ru/scripting/builtins/libmat4.md
@@ -25,6 +25,13 @@ mat4.idt()
 mat4.idt(dst: matrix)
 ```
 
+## Определитель матрицы - *mat4.determinant(...)*
+
+```lua
+-- вычисляет определитель матрицы
+mat4.determinant(m: matrix)
+```
+
 ## Умножение матриц - *mat4.mul(...)*
 
 ```lua
diff --git a/src/logic/scripting/lua/libmat4.cpp b/src/logic/scripting/lua/libmat4.cpp
index 97e9ae82..00dd2e96 100644
--- a/src/logic/scripting/lua/libmat4.cpp
+++ b/src/logic/scripting/lua/libmat4.cpp
@@ -22,6 +22,14 @@ static int l_idt(lua::State* L) {
     return 0;
 }
 
+/// mat4.determinant(matrix: float[16]) - calculates matrix determinant
+static int l_determinant(lua::State* L) {
+    if (lua::gettop(L) != 1) {
+        throw std::runtime_error("invalid arguments number (1 expected)");
+    }
+    return lua::pushnumber(L, glm::determinant(lua::tomat4(L, 1)));
+}
+
 /// Overloads:
 /// mat4.mul(m1: float[16], m2: float[16]) -> float[16] - creates matrix of m1 and m2 multiplication result
 /// mat4.mul(m1: float[16], m2: float[16], dst: float[16]) -> float[16] - updates dst matrix with m1 and m2 multiplication result
@@ -193,6 +201,7 @@ const luaL_Reg mat4lib [] = {
     {"translate", lua::wrap<l_transform_func<glm::translate>>},
     {"inverse", lua::wrap<l_inverse>},
     {"transpose", lua::wrap<l_transpose>},
+    {"determinant", lua::wrap<l_determinant>},
     {"tostring", lua::wrap<l_tostring>},
     {NULL, NULL}
 };