Start replays

racing.h

@@ -1,5 +1,22 @@
 /**
-  racing module: implements the racing physics and logic.
+  Racing module: implements the racing physics and logic as well as replays and
+  other related things.
+
+  Some comments:
+  - Replays are internally stored as follows: the replay consists of 16 bit
+    words representing changes in input at specific frame. In lowest 4 bits the
+    new input state is recorded, the remaining 12 bits record physics frame
+    offset against the previous input change. If the 12 bits don't suffice
+    because the offset is too big (input didn't change for more than 2^12
+    frames), there must simply be inserted an extra word that just copies the
+    current input state.
+  - Replay text format: first there is hexadeciaml hash of the map (exactly 8
+    characters), then the name of the map follows immediately, then the
+    character ';', then the replay data, i.e. the sries of 16 bit words in
+    hexadecimal. The blocks (but nothing else) may be preceeded or followed by
+    blank characters. All hexadecimal letters must be lowercase. The word
+    00000000 may optinally be used to terminate the replay, the rest of the
+    string will be ignored.
 */
 
 #ifndef _LCR_RACING_H
@@ -86,6 +103,12 @@ struct
   uint8_t carNotOKCount;
 } LCR_racing;
 
+struct
+{
+  uint16_t eventCount;
+  uint16_t events[LCR_SETTING_REPLAY_MAX_SIZE]; 
+} LCR_currentReplay;
+
 /**
   Gets times of the run in milliseconds.
 */