Add custom text animation code

build.ps1

@@ -18,7 +18,8 @@ $input_c_files =
     "src/c/fileselect.c",
     "src/c/status.c",
     "src/c/battle.c",
-    "src/c/psi.c"
+    "src/c/psi.c",
+    "src/c/title.c"
 
 $base_c_address    = 0x83755B8;
 $scripttool_cmd    = "bin/ScriptTool/ScriptTool.dll"

src/c/title.c

@@ -0,0 +1,36 @@
+#include "title.h"
+
+void title_text_sequence(
+    TITLE_CONTROL *control,
+    TITLE_EXTENDED *ext,
+    TITLE_COORD_TABLE *coords)
+{
+    int duration = 140; // approximate length of EB's animation,
+                        // from the first frame that H is visible
+                        // until all letters have stopped moving
+    int frame = control->frame;
+
+    if (frame > duration)
+    {
+        control->frame = -1;
+        ext->sequence++;
+        return;
+    }
+
+    for (int i = 0; i < 8; i++)
+    {
+        int x_start = coords->x_start[i];
+        int x_end = coords->x_end[i];
+        int x_delta = x_end - x_start;
+        int x_new = (m2_div((x_delta * frame) << 12, duration) >> 12) + x_start;
+
+        // X coordinate is only 9 bits signed, so clamp the values to a reasonable range
+        if (x_new < -250)
+            x_new = -250;
+        if (x_new > 250)
+            x_new = 250;
+
+        ext->sprites[i].x = x_new;
+        ext->sprites[i].y = coords->y_end[i]; // we're not translating the sprites vertically
+    }
+}

src/c/title.h

@@ -0,0 +1,48 @@
+#ifndef HEADER_TITLE_INCLUDED
+#define HEADER_TITLE_INCLUDED
+
+#include "types.h"
+
+typedef struct TITLE_COORD_TABLE {
+    int unknown_a[3];
+    int y_end[8];
+    int y_start[8];
+    int x_end[8];
+    int x_start[8];
+} TITLE_COORD_TABLE;
+
+typedef struct TITLE_SPRITE {
+    struct TITLE_SPRITE *prev;
+    void *anim_table;
+    void *oam_entry_table;
+    void *unknown_table;
+    int unknown_a[5];
+    int x;
+    int y;
+    int unknown_b[5];
+} TITLE_SPRITE;
+
+typedef struct TITLE_EXTENDED {
+    unsigned short *pal_buffer[5];
+    byte unknown_a[0x70];
+    int sequence;
+    TITLE_SPRITE sprites[8];
+    int unknown[0x16];
+} TITLE_EXTENDED;
+
+typedef struct TITLE_CONTROL {
+    int unknown_a;
+    int frame;
+    int unknown_b[3];
+    TITLE_EXTENDED *ext;
+    int unknown_c[2];
+} TITLE_CONTROL;
+
+void title_text_sequence(
+    TITLE_CONTROL *control,
+    TITLE_EXTENDED *ext,
+    TITLE_COORD_TABLE *coords);
+
+extern int m2_div(int dividend, int divisor);
+
+#endif

src/m2-hack.asm

@@ -1582,6 +1582,7 @@ nop
     // Point to sequence hacks
     .org 0x8011798 :: dw title_sequence_00
     .org 0x801179C :: dw title_sequence_01
+    .org 0x80117A4 :: dw title_sequence_03
     .org 0x80117A8 :: dw title_sequence_04
     .org 0x80117AC :: dw title_sequence_05
     .org 0x80117B4 :: dw title_sequence_07

src/m2-title.asm

@@ -111,6 +111,18 @@ beq     @@unset
 @@end:
 b       title_return
 
+//---------------------------------------------------------
+title_sequence_03:
+
+push    {r0-r3}
+mov     r0,r2           // 0x2028008
+mov     r1,r9           // 0x2028028
+mov     r2,sp
+add     r2,0x10         // coord table on the stack
+bl      title_text_sequence
+pop     {r0-r3}
+b       title_return
+
 //---------------------------------------------------------
 title_sequence_04: