add mat4.determinant(...)

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

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

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}
 };