Add an enable_if() to Block, for convenience.

[nageru] / nageru / scene.cpp

diff --git a/nageru/scene.cpp b/nageru/scene.cpp
index 8df9511276c65c8202e75c3ed84597dc078add7a..ccb3b1bf241c74c7c72ca1a1bcaac4c0f0c927ce 100644 (file)
--- a/nageru/scene.cpp
+++ b/nageru/scene.cpp
@@ -191,8 +191,7 @@ Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::
        }
 
        // Find the chosen alternative for this block in this instance.
-       size_t chosen_alternative = (chain_idx / block->cardinality_base) % block->alternatives.size();
-       EffectType chosen_type = block->alternatives[chosen_alternative]->effect_type;
+       EffectType chosen_type = block->alternatives[block->chosen_alternative(chain_idx)]->effect_type;
 
        Effect *effect;
        switch (chosen_type) {
@@ -225,7 +224,7 @@ Effect *Scene::instantiate_effects(const Block *block, size_t chain_idx, Scene::
                break;
        }
        default:
-               effect = instantiate_effect(instantiation->chain.get(), block->alternatives[chosen_alternative]->effect_type);
+               effect = instantiate_effect(instantiation->chain.get(), chosen_type);
                instantiation->chain->add_effect(effect, inputs);
                break;
        }
@@ -532,6 +531,20 @@ int Block_enable(lua_State *L)
        return 0;
 }
 
+int Block_enable_if(lua_State *L)
+{
+       assert(lua_gettop(L) == 2);
+       Block *block = *(Block **)luaL_checkudata(L, 1, "Block");
+
+       if (block->alternatives.size() != 2 ||
+           block->alternatives[1]->effect_type != IDENTITY_EFFECT) {
+               luaL_error(L, "enable_if() called on something that wasn't added with add_optional_effect()");
+       }
+       bool enabled = checkbool(L, 2);
+       block->currently_chosen_alternative = enabled ? 0 : 1;
+       return 0;
+}
+
 int Block_disable(lua_State *L)
 {
        assert(lua_gettop(L) == 1);