From dc926ce4df4d0c27f18eb77bd31c6f59565b299a Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Thu, 11 Jul 2024 03:31:48 +0300
Subject: [PATCH] add mat4.look_at(...)

---
 doc/en/scripting/builtins/libmat4.md |  9 +++++++++
 doc/ru/scripting/builtins/libmat4.md |  9 +++++++++
 src/logic/scripting/lua/libmat4.cpp  | 17 +++++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/doc/en/scripting/builtins/libmat4.md b/doc/en/scripting/builtins/libmat4.md
index a2f8b75a..7133b985 100644
--- a/doc/en/scripting/builtins/libmat4.md
+++ b/doc/en/scripting/builtins/libmat4.md
@@ -115,6 +115,15 @@ mat4.decompose(m: matrix)
 }
 ```
 
+## Look at point - *mat4.look_at(...)*
+
+```lua
+-- creates a view matrix from the 'eye' point to the 'center' point with up vector specified
+mat4.look_at(eye: vec3, center: vec3, up: vec3)
+-- writes the view matrix to dst
+mat4.look_at(eye: vec3, center: vec3, up: vec3, dst: matrix)
+```
+
 ## Casting to string - *mat4.tostring(...)*
 
 ```lua
diff --git a/doc/ru/scripting/builtins/libmat4.md b/doc/ru/scripting/builtins/libmat4.md
index 2a5b4534..585c0374 100644
--- a/doc/ru/scripting/builtins/libmat4.md
+++ b/doc/ru/scripting/builtins/libmat4.md
@@ -115,6 +115,15 @@ mat4.decompose(m: matrix)
 }
 ```
 
+## Отслеживание точки *mat4.look_at(...)*
+
+```lua
+-- cоздает матрицу вида с точки 'eye' на точку 'center', где вектор 'up' определяет верх.
+mat4.look_at(eye: vec3, center: vec3, up: vec3)
+-- записывает матрицу вида в dst
+mat4.look_at(eye: vec3, center: vec3, up: vec3, dst: matrix)
+```
+
 ## Перевод в строку - *mat4.tostring(...)*
 
 ```lua
diff --git a/src/logic/scripting/lua/libmat4.cpp b/src/logic/scripting/lua/libmat4.cpp
index 17ab752b..74b2ce7f 100644
--- a/src/logic/scripting/lua/libmat4.cpp
+++ b/src/logic/scripting/lua/libmat4.cpp
@@ -211,6 +211,22 @@ static int l_decompose(lua::State* L) {
     return 1;
 }
 
+static int l_look_at(lua::State* L) {
+    int argc = lua::gettop(L);
+    if (argc != 3 && argc != 4) {
+        throw std::runtime_error("invalid arguments number (3 or 4 expected)");
+    }
+    auto eye = lua::tovec<3>(L, 1);
+    auto center = lua::tovec<3>(L, 2);
+    auto up = lua::tovec<3>(L, 3);
+
+    if (argc == 3) {
+        return lua::pushmat4(L, glm::lookAt(eye, center, up));
+    } else {
+        return lua::setmat4(L, 4, glm::lookAt(eye, center, up));
+    }
+}
+
 static int l_tostring(lua::State* L) {
     auto matrix = lua::tomat4(L, 1);
     bool multiline = lua::toboolean(L, 2);
@@ -249,6 +265,7 @@ const luaL_Reg mat4lib [] = {
     {"transpose", lua::wrap<l_transpose>},
     {"determinant", lua::wrap<l_determinant>},
     {"decompose", lua::wrap<l_decompose>},
+    {"look_at", lua::wrap<l_look_at>},
     {"tostring", lua::wrap<l_tostring>},
     {NULL, NULL}
 };