X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=nageru%2Fscene.h;h=83346647236eb0ecda7aa512ec1fead4172940bf;hb=87509c3d91b3726ba3186cb92c44db2e8fb50a40;hp=bdd5d7c78c924aa561567ff55a74a42492406cc0;hpb=83b3d508575124fb83c823ca2439f728d43c7647;p=nageru

diff --git a/nageru/scene.h b/nageru/scene.h
index bdd5d7c..8334664 100644
--- 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;