From 10fe37129236872705093ba4eb4f2e83f5b34c12 Mon Sep 17 00:00:00 2001
From: TSnake41 <TSnake@Outlook.fr>
Date: Fri, 8 May 2020 17:07:34 +0200
Subject: [PATCH] Operator overloading.

---
 makefile       |   4 +-
 src/compat.lua | 114 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+), 3 deletions(-)
 create mode 100644 src/compat.lua

diff --git a/makefile b/makefile
index c0fa370..100d4f1 100644
--- a/makefile
+++ b/makefile
@@ -17,8 +17,6 @@ else
 	LDFLAGS += -ldl -lX11 -lpthread
 endif
 
-BOOT_FILES := src/raylib.lua src/raylua.lua
-
 all: raylua_s raylua_e
 
 %.o: %.c
@@ -51,7 +49,7 @@ src/raylua.o: luajit raylib src/autogen/boot.c src/autogen/bind.c
 
 src/raylua_builder.o: src/autogen/builder.c
 
-src/autogen/boot.c: src/raylib.lua src/raylua.lua
+src/autogen/boot.c: src/raylib.lua src/compat.lua src/raylua.lua
 	$(LUA) tools/lua2str.lua $@ raylua_boot_lua $^
 
 src/autogen/bind.c:
diff --git a/src/compat.lua b/src/compat.lua
new file mode 100644
index 0000000..e56f3c2
--- /dev/null
+++ b/src/compat.lua
@@ -0,0 +1,114 @@
+--[[
+  Copyright (C) 2020 Astie Teddy
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+  OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+  CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+]]
+
+-- math metamethods
+local new = ffi.new
+
+ffi.metatype("Vector2", {
+  __add = function (a, b)
+    if ffi.istype("Vector2", b) then
+      return new("Vector2", a.x + b.x, a.y + b.y)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __sub = function (a, b)
+    if ffi.istype("Vector2", b) then
+      return new("Vector2", a.x - b.x, a.y - b.y)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __unm = function (a)
+    return new("Vector2", -a.x, -a.y)
+  end,
+  __len = function (a)
+    return math.sqrt(a.x * a.x + a.y * a.y)
+  end,
+  __mul = function (a, b)
+    if type(a) == "number" then
+      -- swap if a is a number (a * vector)
+      a, b = b, a
+    end
+
+    if ffi.istype("Vector2", b) then -- dot product
+      return a.x * b.x + a.y * b.y
+    elseif type(b) == "number" then
+      return new("Vector2", a.x * b, a.y * b)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __div = function (a, b)
+    if type(b) == "number" then
+      return new("Vector2", a.x / b, a.y / b)
+    else
+      error "Invalid operation"
+    end
+  end,
+  __tostring = function (a)
+    return string.format("Vector2: (%g %g)", a.x, a.y)
+  end
+})
+
+ffi.metatype("Vector3", {
+  __add = function (a, b)
+    if ffi.istype("Vector3", b) then
+      return new("Vector3", a.x + b.x, a.y + b.y, a.z + b.z)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __sub = function (a, b)
+    if ffi.istype("Vector3", b) then
+      return new("Vector2", a.x - b.x, a.y - b.y, a.z - b.z)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __unm = function (a)
+    return new("Vector2", -a.x, -a.y, -a.z)
+  end,
+  __len = function (a)
+    return math.sqrt(a.x * a.x + a.y * a.y + a.z * a.z)
+  end,
+  __mul = function (a, b)
+    if type(a) == "number" then
+      -- swap if a is a number (a * vector)
+      a, b = b, a
+    end
+
+    if ffi.istype("Vector2", b) then -- dot product
+      return a.x * b.x + a.y * b.y + a.z * b.z
+    elseif type(b) == "number" then
+      return new("Vector2", a.x * b, a.y * b, a.z * b)
+    else
+      error "Invalid operation."
+    end
+  end,
+  __div = function (a, b)
+    if type(b) == "number" then
+      return new("Vector3", a.x / b, a.y / b, a.z / b)
+    else
+      error "Invalid operation"
+    end
+  end,
+  __tostring = function (a)
+    return string.format("Vector3: (%g %g %g)", a.x, a.y, a.z)
+  end
+})
+
+-- TODO: Matrix and Quaternion