level: structure animated textures

This is an internal change to place animated textures into structures
for improved readability.

src/game/level.c

@@ -720,14 +720,33 @@ static bool Level_LoadBoxes(MYFILE *fp)
 
 static bool Level_LoadAnimatedTextures(MYFILE *fp)
 {
+    int16_t num_ranges;
     File_Read(&m_LevelInfo.anim_texture_range_count, sizeof(int32_t), 1, fp);
-    LOG_INFO("%d animated textures", m_LevelInfo.anim_texture_range_count);
+    File_Read(&num_ranges, sizeof(int16_t), 1, fp);
+    LOG_INFO("%d animated texture ranges", num_ranges);
+    if (!num_ranges) {
+        g_AnimTextureRanges = NULL;
+        return true;
+    }
+
     g_AnimTextureRanges = GameBuf_Alloc(
-        sizeof(int16_t) * m_LevelInfo.anim_texture_range_count,
-        GBUF_ANIMATING_TEXTURE_RANGES);
-    File_Read(
-        g_AnimTextureRanges, sizeof(int16_t),
-        m_LevelInfo.anim_texture_range_count, fp);
+        sizeof(TEXTURE_RANGE) * num_ranges, GBUF_ANIMATING_TEXTURE_RANGES);
+    for (int32_t i = 0; i < num_ranges; i++) {
+        TEXTURE_RANGE *range = &g_AnimTextureRanges[i];
+        range->next_range =
+            i == num_ranges - 1 ? NULL : &g_AnimTextureRanges[i + 1];
+
+        // Level data is tied to the original logic in Output_AnimateTextures
+        // and hence stores one less than the actual count here.
+        File_Read(&range->num_textures, sizeof(int16_t), 1, fp);
+        range->num_textures++;
+
+        range->textures = GameBuf_Alloc(
+            sizeof(int16_t) * range->num_textures,
+            GBUF_ANIMATING_TEXTURE_RANGES);
+        File_Read(range->textures, sizeof(int16_t), range->num_textures, fp);
+    }
+
     return true;
 }
 

src/game/output.c

@@ -928,21 +928,16 @@ void Output_AnimateTextures(void)
         return;
     }
 
-    if (g_AnimTextureRanges) {
-        const int16_t *ptr = g_AnimTextureRanges;
-        int16_t i = *ptr++;
-        while (i > 0) {
-            int16_t j = *ptr++;
-            const PHD_TEXTURE temp = g_PhdTextureInfo[*ptr];
-            while (j > 0) {
-                g_PhdTextureInfo[ptr[0]] = g_PhdTextureInfo[ptr[1]];
-                j--;
-                ptr++;
-            }
-            g_PhdTextureInfo[*ptr] = temp;
-            i--;
-            ptr++;
+    const TEXTURE_RANGE *range = g_AnimTextureRanges;
+    while (range) {
+        int32_t i = 0;
+        const PHD_TEXTURE temp = g_PhdTextureInfo[range->textures[i]];
+        for (; i < range->num_textures - 1; i++) {
+            g_PhdTextureInfo[range->textures[i]] =
+                g_PhdTextureInfo[range->textures[i + 1]];
         }
+        g_PhdTextureInfo[range->textures[i]] = temp;
+        range = range->next_range;
     }
 
     for (int32_t i = 0; i < STATIC_NUMBER_OF; i++) {

src/global/types.h

@@ -1142,6 +1142,12 @@ typedef struct PHD_SPRITE {
     int16_t y2;
 } PHD_SPRITE;
 
+typedef struct TEXTURE_RANGE {
+    int16_t num_textures;
+    int16_t *textures;
+    struct TEXTURE_RANGE *next_range;
+} TEXTURE_RANGE;
+
 typedef struct DOOR_INFO {
     int16_t room_num;
     struct {

src/global/vars.c

@@ -79,7 +79,7 @@ int16_t *g_FlyZone[2] = { NULL };
 ANIM_STRUCT *g_Anims = NULL;
 ANIM_CHANGE_STRUCT *g_AnimChanges = NULL;
 ANIM_RANGE_STRUCT *g_AnimRanges = NULL;
-int16_t *g_AnimTextureRanges = NULL;
+TEXTURE_RANGE *g_AnimTextureRanges = NULL;
 int16_t *g_AnimCommands = NULL;
 int32_t *g_AnimBones = NULL;
 FRAME_INFO *g_AnimFrames = NULL;

src/global/vars.h

@@ -67,7 +67,7 @@ extern int16_t *g_FlyZone[2];
 extern ANIM_STRUCT *g_Anims;
 extern ANIM_CHANGE_STRUCT *g_AnimChanges;
 extern ANIM_RANGE_STRUCT *g_AnimRanges;
-extern int16_t *g_AnimTextureRanges;
+extern TEXTURE_RANGE *g_AnimTextureRanges;
 extern int16_t *g_AnimCommands;
 extern int32_t *g_AnimBones;
 extern FRAME_INFO *g_AnimFrames;