From a30247cf16445fc99dafaca6328ee65e5502a806 Mon Sep 17 00:00:00 2001
From: Lior Halphon <LIJI32@gmail.com>
Date: Fri, 10 Dec 2021 19:49:52 +0200
Subject: [PATCH] LCD line callback (for #422)

---
 Core/display.c | 10 ++++++++++
 Core/gb.c      |  5 +++++
 Core/gb.h      |  5 ++++-
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Core/display.c b/Core/display.c
index caf517c..f1f474e 100644
--- a/Core/display.c
+++ b/Core/display.c
@@ -456,6 +456,10 @@ void GB_lcd_off(GB_gameboy_t *gb)
     
     gb->accessed_oam_row = -1;
     gb->wy_triggered = false;
+    
+    if (unlikely(gb->lcd_line_callback)) {
+        gb->lcd_line_callback(gb, 0);
+    }
 }
 
 static void add_object_from_index(GB_gameboy_t *gb, unsigned index)
@@ -983,6 +987,9 @@ void GB_display_run(GB_gameboy_t *gb, uint8_t cycles)
         /* Lines 0 - 143 */
         gb->window_y = -1;
         for (; gb->current_line < LINES; gb->current_line++) {
+            if (unlikely(gb->lcd_line_callback)) {
+                gb->lcd_line_callback(gb, gb->current_line);
+            }
             
             gb->oam_write_blocked = GB_is_cgb(gb) && !gb->cgb_double_speed;
             gb->accessed_oam_row = 0;
@@ -1343,6 +1350,9 @@ abort_fetching_object:
         for (; gb->current_line < VIRTUAL_LINES - 1; gb->current_line++) {
             gb->io_registers[GB_IO_LY] = gb->current_line;
             gb->ly_for_comparison = -1;
+            if (unlikely(gb->lcd_line_callback)) {
+                gb->lcd_line_callback(gb, gb->current_line);
+            }
             GB_SLEEP(gb, display, 26, 2);
             if (gb->current_line == LINES && !gb->stat_interrupt_line && (gb->io_registers[GB_IO_STAT] & 0x20)) {
                 gb->io_registers[GB_IO_IF] |= 2;
diff --git a/Core/gb.c b/Core/gb.c
index d177822..cc85c92 100644
--- a/Core/gb.c
+++ b/Core/gb.c
@@ -1211,6 +1211,11 @@ void GB_set_execution_callback(GB_gameboy_t *gb, GB_execution_callback_t callbac
     gb->execution_callback = callback;
 }
 
+void GB_set_lcd_line_callback(GB_gameboy_t *gb, GB_lcd_line_callback_t callback)
+{
+    gb->lcd_line_callback = callback;
+}
+
 const GB_palette_t GB_PALETTE_GREY = {{{0x00, 0x00, 0x00}, {0x55, 0x55, 0x55}, {0xaa, 0xaa, 0xaa}, {0xff, 0xff, 0xff}, {0xff, 0xff, 0xff}}};
 const GB_palette_t GB_PALETTE_DMG  = {{{0x08, 0x18, 0x10}, {0x39, 0x61, 0x39}, {0x84, 0xa5, 0x63}, {0xc6, 0xde, 0x8c}, {0xd2, 0xe6, 0xa6}}};
 const GB_palette_t GB_PALETTE_MGB  = {{{0x07, 0x10, 0x0e}, {0x3a, 0x4c, 0x3a}, {0x81, 0x8d, 0x66}, {0xc2, 0xce, 0x93}, {0xcf, 0xda, 0xac}}};
diff --git a/Core/gb.h b/Core/gb.h
index 872ab19..d5a6471 100644
--- a/Core/gb.h
+++ b/Core/gb.h
@@ -284,6 +284,7 @@ typedef void (*GB_icd_vreset_callback_t)(GB_gameboy_t *gb);
 typedef void (*GB_boot_rom_load_callback_t)(GB_gameboy_t *gb, GB_boot_rom_t type);
 
 typedef void (*GB_execution_callback_t)(GB_gameboy_t *gb, uint16_t address, uint8_t opcode);
+typedef void (*GB_lcd_line_callback_t)(GB_gameboy_t *gb, uint8_t line);
 
 struct GB_breakpoint_s;
 struct GB_watchpoint_s;
@@ -668,6 +669,7 @@ struct GB_gameboy_internal_s {
         GB_workboy_set_time_callback workboy_set_time_callback;
         GB_workboy_get_time_callback workboy_get_time_callback;
         GB_execution_callback_t execution_callback;
+        GB_lcd_line_callback_t lcd_line_callback;
 
         /*** Debugger ***/
         volatile bool debug_stopped, debug_disable;
@@ -843,7 +845,8 @@ void GB_set_update_input_hint_callback(GB_gameboy_t *gb, GB_update_input_hint_ca
 void GB_set_boot_rom_load_callback(GB_gameboy_t *gb, GB_boot_rom_load_callback_t callback);
     
 void GB_set_execution_callback(GB_gameboy_t *gb, GB_execution_callback_t callback);
-    
+void GB_set_lcd_line_callback(GB_gameboy_t *gb, GB_lcd_line_callback_t callback);
+
 void GB_set_palette(GB_gameboy_t *gb, const GB_palette_t *palette);
 
 /* These APIs are used when using internal clock */