Allow giving class names to Block.choose_alternative.

[nageru] / nageru / scene.cpp

diff --git a/nageru/scene.cpp b/nageru/scene.cpp
index 6eb86ac91e6f85e1cf45120cc82910aceb3a0374..a3d3c6a20f172496f58b1509b82c59eccb0050e8 100644 (file)
--- a/nageru/scene.cpp
+++ b/nageru/scene.cpp
@@ -495,7 +495,22 @@ int Block_choose_alternative(lua_State* L)
 {
        assert(lua_gettop(L) == 2);
        Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
-       int alternative_idx = luaL_checknumber(L, 2);
+       int alternative_idx = -1;
+       if (lua_isnumber(L, 2)) {
+               alternative_idx = luaL_checknumber(L, 2);
+       } else if (lua_istable(L, 2)) {
+               // See if it's an Effect metatable (e.g. foo:choose_alternative(ResampleEffect))
+               lua_getfield(L, 2, "__effect_type_id");
+               if (lua_isnumber(L, -1)) {
+                       EffectType effect_type = EffectType(luaL_checknumber(L, -1));
+                       alternative_idx = find_index_of(block, effect_type);
+               }
+               lua_pop(L, 1);
+       }
+
+       if (alternative_idx == -1) {
+               luaL_error(L, "choose_alternative() called with something that was not an index or an effect type (e.g. ResampleEffect) that was part of the alternatives");
+       }
 
        assert(alternative_idx >= 0);
        assert(size_t(alternative_idx) < block->alternatives.size());