From 7f7d0668542162dc71d256a6908ab7d7d743cffc Mon Sep 17 00:00:00 2001
From: David Guillen Fandos <david@davidgf.net>
Date: Sun, 15 Aug 2021 23:27:04 +0200
Subject: [PATCH] Remove video vars serialization

This is not needed at all, since the variables are not updated between
reload and end-of-frame (where we take our savestates). Added a reload
call during gba_load_state() to initialize it from the I/O regs.
---
 gba_memory.c |  5 +++--
 main.c       |  9 +--------
 video.c      | 13 +++++++++++++
 video.h      |  3 +--
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/gba_memory.c b/gba_memory.c
index 0925a14..cb28486 100644
--- a/gba_memory.c
+++ b/gba_memory.c
@@ -3122,8 +3122,7 @@ void memory_term(void)
   input_##type##_savestate();   \
   main_##type##_savestate();    \
   memory_##type##_savestate();  \
-  sound_##type##_savestate();   \
-  video_##type##_savestate()
+  sound_##type##_savestate();
 
 
 const u8 *state_mem_read_ptr;
@@ -3152,6 +3151,8 @@ void gba_load_state(const void* src)
        convert_palette(current_color);
    }
 
+   video_reload_counters();
+
    // Oops, these contain raw pointers
    for(i = 0; i < 4; i++)
       gbc_sound_channel[i].sample_table_idx = 2;
diff --git a/main.c b/main.c
index e1508fd..370399f 100644
--- a/main.c
+++ b/main.c
@@ -195,14 +195,7 @@ u32 update_gba(void)
             irq_raised |= IRQ_VBLANK;
           }
 
-          affine_reference_x[0] =
-           (s32)(readaddress32(io_registers, 0x28) << 4) >> 4;
-          affine_reference_y[0] =
-           (s32)(readaddress32(io_registers, 0x2C) << 4) >> 4;
-          affine_reference_x[1] =
-           (s32)(readaddress32(io_registers, 0x38) << 4) >> 4;
-          affine_reference_y[1] =
-           (s32)(readaddress32(io_registers, 0x3C) << 4) >> 4;
+          video_reload_counters();
 
           for(i = 0; i < 4; i++)
           {
diff --git a/video.c b/video.c
index 4dec8bf..8f1e213 100644
--- a/video.c
+++ b/video.c
@@ -2336,6 +2336,19 @@ static void render_scanline_text_transparent_alpha(u32 layer,
 s32 affine_reference_x[2];
 s32 affine_reference_y[2];
 
+void video_reload_counters()
+{
+  /* This happens every Vblank */
+  affine_reference_x[0] = (s32)(read_ioreg(REG_BG2X_L) |
+     ((read_ioreg(REG_BG2X_H) & 0xFFF) << 16));
+  affine_reference_y[0] = (s32)(read_ioreg(REG_BG2Y_L) |
+     ((read_ioreg(REG_BG2Y_H) & 0xFFF) << 16));
+  affine_reference_x[1] = (s32)(read_ioreg(REG_BG3X_L) |
+     ((read_ioreg(REG_BG3X_H) & 0xFFF) << 16));
+  affine_reference_y[1] = (s32)(read_ioreg(REG_BG3Y_L) |
+     ((read_ioreg(REG_BG3Y_H) & 0xFFF) << 16));
+}
+
 #define affine_render_bg_pixel_normal()                                       \
   current_pixel = palette_ram_converted[0]                                    \
 
diff --git a/video.h b/video.h
index 0f21d19..35dc0f4 100644
--- a/video.h
+++ b/video.h
@@ -21,8 +21,7 @@
 #define VIDEO_H
 
 void update_scanline(void);
-void video_write_savestate(void);
-void video_read_savestate(void);
+void video_reload_counters(void);
 
 extern s32 affine_reference_x[2];
 extern s32 affine_reference_y[2];