add vecn.mix

res/modules/internal/maths_inline.lua

@@ -110,6 +110,21 @@ function vec3.dot(a, b)
     return a[1] * b[1] + a[2] * b[2] + a[3] * b[3]
 end
 
+function vec3.mix(a, b, t, dest)
+    if dest then
+        dest[1] = a[1] * (1.0 - t) + b[1] * t
+        dest[2] = a[2] * (1.0 - t) + b[2] * t
+        dest[3] = a[3] * (1.0 - t) + b[3] * t
+        return dest
+    else
+        return {
+            a[1] * (1.0 - t) + b[1] * t,
+            a[2] * (1.0 - t) + b[2] * t,
+            a[3] * (1.0 - t) + b[3] * t,
+        }
+    end
+end
+
 -- =================================================== --
 -- ====================== vec2 ======================= --
 -- =================================================== --
@@ -210,3 +225,16 @@ end
 function vec2.dot(a, b)
     return a[1] * b[1] + a[2] * b[2]
 end
+
+function vec2.mix(a, b, t, dest)
+    if dest then
+        dest[1] = a[1] * (1.0 - t) + b[1] * t
+        dest[2] = a[2] * (1.0 - t) + b[2] * t
+        return dest
+    else
+        return {
+            a[1] * (1.0 - t) + b[1] * t,
+            a[2] * (1.0 - t) + b[2] * t,
+        }
+    end
+end

src/logic/scripting/lua/libs/libvecn.cpp

@@ -15,6 +15,20 @@ inline T angle(glm::vec<2, T> vec) {
     return val;
 }
 
+template <int n>
+static int l_mix(lua::State* L) {
+    uint argc = lua::check_argc(L, 3, 4);
+    auto a = lua::tovec<n, number_t>(L, 1);
+    auto b = lua::tovec<n, number_t>(L, 2);
+    auto t = lua::tonumber(L, 3);
+
+    if (argc == 3) {
+        return lua::pushvec(L, a * (1.0 - t) + b * t);
+    } else {
+        return lua::setvec(L, 4, a * (1.0 - t) + b * t);
+    }
+}
+
 template <int n, template <class> class Op>
 static int l_binop(lua::State* L) {
     uint argc = lua::check_argc(L, 2, 3);
@@ -200,6 +214,7 @@ const luaL_Reg vec2lib[] = {
     {"pow", lua::wrap<l_pow<2>>},
     {"dot", lua::wrap<l_dot<2>>},
     {"angle", lua::wrap<l_vec2_angle>},
+    {"mix", lua::wrap<l_mix<2>>},
     {NULL, NULL}};
 
 const luaL_Reg vec3lib[] = {
@@ -217,6 +232,7 @@ const luaL_Reg vec3lib[] = {
     {"pow", lua::wrap<l_pow<3>>},
     {"dot", lua::wrap<l_dot<3>>},
     {"spherical_rand", lua::wrap<l_spherical_rand>},
+    {"mix", lua::wrap<l_mix<3>>},
     {NULL, NULL}};
 
 const luaL_Reg vec4lib[] = {
@@ -233,4 +249,5 @@ const luaL_Reg vec4lib[] = {
     {"inverse", lua::wrap<l_inverse<4>>},
     {"pow", lua::wrap<l_pow<4>>},
     {"dot", lua::wrap<l_dot<4>>},
+    {"mix", lua::wrap<l_mix<4>>},
     {NULL, NULL}};

src/logic/scripting/lua/lua_util.hpp

@@ -48,8 +48,8 @@ namespace lua {
         return true;
     }
 
-    template <int n>
-    inline int pushvec(lua::State* L, const glm::vec<n, float>& vec) {
+    template <int n, typename T = float>
+    inline int pushvec(lua::State* L, const glm::vec<n, T>& vec) {
         createtable(L, n, 0);
         for (int i = 0; i < n; i++) {
             pushnumber(L, vec[i]);
@@ -161,8 +161,8 @@ namespace lua {
         }
         return 1;
     }
-    template <int n>
-    inline int setvec(lua::State* L, int idx, glm::vec<n, float> vec) {
+    template <int n, typename T = float>
+    inline int setvec(lua::State* L, int idx, glm::vec<n, T> vec) {
         pushvalue(L, idx);
         for (int i = 0; i < n; i++) {
             pushnumber(L, vec[i]);
@@ -305,15 +305,15 @@ namespace lua {
         setglobal(L, name);
     }
 
-    template <int n>
-    inline glm::vec<n, float> tovec(lua::State* L, int idx) {
+    template <int n, typename T = float>
+    inline glm::vec<n, T> tovec(lua::State* L, int idx) {
         pushvalue(L, idx);
         if (!istable(L, idx) || objlen(L, idx) < n) {
             throw std::runtime_error(
                 "value must be an array of " + std::to_string(n) + " numbers"
             );
         }
-        glm::vec<n, float> vec;
+        glm::vec<n, T> vec;
         for (int i = 0; i < n; i++) {
             rawgeti(L, i + 1);
             vec[i] = tonumber(L, -1);