anim: add state interpolation function (unused now)

diff --git a/src/game/g_animations.pas b/src/game/g_animations.pas
index 9c6dd4cb2aa53ab0a9086994dbf64ac00093d420..efa32ec8e2c5d94ca8886abf344e8a0881a40328 100644 (file)
--- a/src/game/g_animations.pas
+++ b/src/game/g_animations.pas
@@ -22,7 +22,7 @@ interface
   type
     TAnimState = record
       private
-        mCounter: Byte;         // delay counter (normally [0..mSpeed])
+        mCounter: Byte;         // delay counter (normally [0..mSpeed - 1])
         mSpeed: Byte;           // delay between frames
         mCurrentFrame: Integer; // current frame (normally [0..mLength - 1])
         mLoop: Boolean;         // looped animation
@@ -78,6 +78,7 @@ interface
   procedure g_Anim_GetState (const anim: TAnimInfo; time: LongWord; out state: TAnimState);
 
   procedure g_Anim_GetFrameFromState (const s: TAnimState; backanim: Boolean; out frame: LongInt);
+  procedure g_Anim_GetInterplatedFrameFromState (const s: TAnimState; newlength: LongInt; out frame: LongInt);
 
 implementation
 
@@ -303,4 +304,23 @@ implementation
     end;
   end;
 
+  procedure g_Anim_GetInterplatedFrameFromState (const s: TAnimState; newlength: LongInt; out frame: LongInt);
+    var delay, curframe, curcount, fulltime, curtime, newtime: LongInt;
+  begin
+    ASSERT(s.length > 0);
+    ASSERT(newlength > 0);
+    (* 1. normalize state values *)
+    delay := MAX(1, s.speed);
+    curframe := MIN(MAX(s.CurrentFrame, 0), s.length - 1);
+    curcount := MIN(MAX(s.CurrentCounter, 0), delay - 1);
+    (* 2. calc current time (normalized) *)
+    fulltime := s.length * delay;
+    curtime := MIN(curframe * delay + curcount, fulltime);
+    (* 3. calc interpolated frame *)
+    newtime := curtime * newlength div s.length;
+    frame := newtime div delay;
+    ASSERT(frame >= 0);
+    ASSERT(frame < newlength);
+  end;
+
 end.