Support optional effects with multiple inputs.

[nageru] / nageru / scene.h

diff --git a/nageru/scene.h b/nageru/scene.h
index bdd5d7c78c924aa561567ff55a74a42492406cc0..83346647236eb0ecda7aa512ec1fead4172940bf 100644 (file)
--- a/nageru/scene.h
+++ b/nageru/scene.h
@@ -13,6 +13,7 @@
 // (directly to screen, RGBA) or live (Y'CbCr output).
 
 #include <stddef.h>
+#include <bitset>
 #include <functional>
 #include <map>
 #include <memory>
@@ -78,7 +79,11 @@ struct Block {
 
        // Find the chosen alternative for this block in a given instance.
        size_t chosen_alternative(size_t chain_idx) const {
-               return (chain_idx / cardinality_base) % alternatives.size();
+               if (chain_idx == size_t(-1)) {
+                       return currently_chosen_alternative;
+               } else {
+                       return (chain_idx / cardinality_base) % alternatives.size();
+               }
        }
 
        std::vector<EffectBlueprint *> alternatives;  // Must all have the same amount of inputs. Pointers to make things easier for Lua.
@@ -133,9 +138,27 @@ private:
        movit::ResourcePool *resource_pool;
 
        movit::Effect *instantiate_effects(const Block *block, size_t chain_idx, Instantiation *instantiation);
-       size_t compute_chain_number_for_block(size_t block_idx) const;
+       size_t compute_chain_number_for_block(size_t block_idx, const std::bitset<256> &disabled) const;
        static void find_inputs_for_block(lua_State *L, Scene *scene, Block *block);
 
+       // Find out which blocks (indexed by position in the “blocks” array),
+       // if any, are disabled in a given instantiation. A disabled block is
+       // one that will not be instantiated at all, because it is a secondary
+       // (ie., not the first) input of some multi-input effect that was replaced
+       // with IdentityEffect in the given instantiation.
+       //
+       // Set chain_idx to size_t(-1) to use whatever is in each block's
+       // currently_chosen_alternative.
+       std::bitset<256> find_disabled_blocks(size_t chain_idx) const;
+       void find_disabled_blocks(size_t chain_idx, size_t block_idx, bool currently_disabled, std::bitset<256> *disabled) const;
+
+       // If a block is disabled, it should always have alternative 0 chosen,
+       // so that we don't instantiate a bunch of irrelevant duplicates that
+       // differ only in disabled blocks. You can check this property with
+       // is_noncanonical_chain() and then avoid instantiating the ones where
+       // it returns true.
+       bool is_noncanonical_chain(size_t chain_idx) const;
+
 public:
        Scene(Theme *theme, float aspect_nom, float aspect_denom);
        size_t compute_chain_number(bool is_main_chain) const;