From dc66182afb7448c6a9188ca809fdeea7c7e14f63 Mon Sep 17 00:00:00 2001
From: Miloslav Ciz <drummyfish@disroot.org>
Date: Wed, 22 Jan 2025 15:35:58 +0100
Subject: [PATCH] Continue ghost

---
 TODO.txt |   1 +
 data     |   2 +
 game.h   | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 111 insertions(+), 10 deletions(-)
 create mode 100644 data

diff --git a/TODO.txt b/TODO.txt
index c2a15bd..24de835 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,5 +1,6 @@
 =========== GENERAL ==============
 
+- test if the replay stretching works
 - replay validation
 - ghosts: if the replay for the ghost is too long (too many samples for the
   preallocated array), we can subdivide the sample resolution (i.e. "stretch"
diff --git a/data b/data
new file mode 100644
index 0000000..f3324aa
--- /dev/null
+++ b/data
@@ -0,0 +1,2 @@
+#Mmap2;4321 1 :*H1k0J :,s0s0 :fd190
+#Rrep2;testmap;482f70f9 00000843:0173:0081:0029:0111:0039:0071:00a3:0061:0169:0051:00b3:0041:0073:0081:0033:0041:0033:0231:0030:0098:0029:0011:0163:00f1:0053:0081:0033:0051:0023:0031:00f0:0032:0023:0131:00b9:0081:0023:00a1:0119:00e1:00c9:0071:0039:00a1:00d3:0021:01f9:0091:0079:0091:0039:0051:0049:0021:0083:0031:0083:0031:0083:0061:0089:0121:00a0:0058:002c:0048:0061:0013:0150:0052:00c0:00a1:0053:0041:0043:0031:0020:0092:0063:0181:0010:00a2:0013:0071:00e0:0028:00e9:0078:00a9:0043:0032:0123:0042:0080:0038:004c:01a8:0050:0032:0033:0101
diff --git a/game.h b/game.h
index ae3791f..dd3c8b9 100644
--- a/game.h
+++ b/game.h
@@ -278,7 +278,7 @@ struct
   {
     uint8_t active;
     uint8_t samples[LCR_SETTING_GHOST_MAX_SAMPLES * LCR_GHOST_SAMPLE_SIZE];
-                      /**< Samples, each 5 bytes: 9 bits for X and Z, 10 for Z,
+                      /**< Samples, each 5 bytes: 9 bits for X and Z, 10 for Y,
                            4 for each rotation component. */
     uint8_t stretch;  /**< Stretch of the base sample step, as a bit shift
                            (i.e. 1 means the step will be 2x as long etc.). This
@@ -350,19 +350,90 @@ void LCR_gameResetRun(uint8_t replay, uint8_t ghost)
   LCR_game.runTimeMS = 0;
 }
 
+void _LCR_gameGetNthGhostSample(unsigned int n,
+  LCR_GameUnit position[3], LCR_GameUnit rotation[3])
+{
+  n *= LCR_GHOST_SAMPLE_SIZE;
+
+position[0] = LCR_game.ghost.samples[n];
+n++;
+
+position[0] |= 
+ ((LCR_GameUnit) (LCR_game.ghost.samples[n] & 0x01)) << 8;
+position[1] = LCR_game.ghost.samples[n] >> 1;
+
+n++;
+
+position[1] |= 
+((LCR_GameUnit) (LCR_game.ghost.samples[n] & 0x07)) << 7;
+position[2] = LCR_game.ghost.samples[n] >> 3;
+
+n++;
+
+position[2] |= 
+ ((LCR_GameUnit) (LCR_game.ghost.samples[n] & 0x0f)) << 5;
+
+rotation[0] = LCR_game.ghost.samples[n] >> 4;
+
+n++;
+
+rotation[1] = LCR_game.ghost.samples[n] & 0x0f;
+rotation[2] = LCR_game.ghost.samples[n] >> 4;
+
+for (int i = 0; i < 3; ++i)
+{
+  if (i != 2)
+    position[i] <<= 1;
+
+  position[i] = (position[i] * LCR_GAME_UNIT) / 16;
+
+  position[i] -=
+    (LCR_MAP_SIZE_BLOCKS / 2) *
+    (i == 1 ? LCR_GAME_UNIT / 2 : LCR_GAME_UNIT);
+
+  rotation[i] = (rotation[i] * LCR_GAME_UNIT) / 16;
+}
+
+}
+
 void LCR_gameGhostGetTransform(uint32_t frame,
   LCR_GameUnit position[3], LCR_GameUnit rotation[3])
 {
- 
-LCR_racingGetCarTransform(position,rotation,0);
+  unsigned int n = ((frame >> LCR_game.ghost.stretch) / LCR_SETTING_GHOST_STEP); 
+
+_LCR_gameGetNthGhostSample(n % 64,position,rotation);
+
+
+if (n < LCR_SETTING_GHOST_MAX_SAMPLES - 1)
+{
+  LCR_GameUnit carTransform[6];
+
+  // interpolate
+
+  _LCR_gameGetNthGhostSample((n % 64) + 1,carTransform,carTransform + 3);
+
+  n = (frame >> LCR_game.ghost.stretch) % LCR_SETTING_GHOST_STEP;
+
+  for (int i = 0; i < 3; ++i)
+  {
+    position[i] = position[i] +      
+      ((carTransform[i] - position[i]) * n) /
+        LCR_SETTING_GHOST_STEP;
+  }
+
+
+}
+
+
   
 }
 
+
 void _LCR_gamePrepareGhost(void)
 {
   LCR_GameUnit carTransform[6];
   LCR_LOG1("preparing ghost");
-      
+ 
   LCR_gameResetRun(1,0);
   
   uint8_t *currentSample = LCR_game.ghost.samples;
@@ -384,18 +455,36 @@ void _LCR_gamePrepareGhost(void)
     {
       LCR_racingGetCarTransform(carTransform,carTransform + 3,0);
 
-      currentSample[0] = carTransform[0];
+
+for (int i = 0; i < 3; ++i)
+{
+  // convert positions to unsigned 10 bit values
+
+carTransform[i] += // make non-negative
+  (LCR_MAP_SIZE_BLOCKS / 2) * (i == 1 ? LCR_GAME_UNIT / 2 : LCR_GAME_UNIT);
+
+// convert to 10 bit value
+carTransform[i] = (carTransform[i] * 16) / LCR_GAME_UNIT;
+
+// conv. rots to 4 bits, we rely on them being non-negative!
+carTransform[3 + i] =
+  (carTransform[3 + i] * 16) / LCR_GAME_UNIT;
+}
+
+      // format: XXXXXXXX YYYYYYYX ZZZZZYYY AAAAZZZZ CCCCBBBB
+
+      currentSample[0] = carTransform[0] >> 1;
       currentSample[1] =
-        ((carTransform[0] >> 8) & 0x01) |
+        ((carTransform[0] >> 9) & 0x01) |
         (carTransform[1] << 1);
       currentSample[2] =
-        ((carTransform[1] >> 7) & 0x03) |
-        (carTransform[2] << 2);
+        ((carTransform[1] >> 7) & 0x07) |
+        ((carTransform[2] << 2) & 0xf8);
       currentSample[3] =
-        ((carTransform[2] >> 6) & 0x0f) |
+        ((carTransform[2] >> 5) & 0x0f) |
           (carTransform[3] << 4);
       currentSample[4] =
-        (carTransform[4] >> 4) |
+        (carTransform[4] & 0x0f) |
         (carTransform[5] << 4);
 
       currentSample += LCR_GHOST_SAMPLE_SIZE;
@@ -403,6 +492,15 @@ void _LCR_gamePrepareGhost(void)
 
     LCR_racingStep(0);
   }
+
+  while ( // fill the rest with the last sample
+    currentSample >= LCR_game.ghost.samples + LCR_GHOST_SAMPLE_SIZE &&
+    currentSample < LCR_game.ghost.samples +
+      LCR_SETTING_GHOST_MAX_SAMPLES * LCR_GHOST_SAMPLE_SIZE)
+  {
+    *currentSample = *(currentSample - LCR_GHOST_SAMPLE_SIZE);
+    currentSample++;
+  }
 }
 
 LCR_GameUnit LCR_carSpeedKMH(void)