1 files changed, 19 insertions, 4 deletions

diff --git a/src/common.h b/src/common.h
index 35b4619..6047e5f 100644
--- a/src/common.h
+++ b/src/common.h
@@ -76,6 +76,20 @@
 #define BG_V_SCROLL_2 *((vu16*)(0x04000012 + 0x0004 * 2))
 #define BG_V_SCROLL_3 *((vu16*)(0x04000012 + 0x0004 * 3))
 
+// Screenblocks for BGs.
+typedef u16 ScreenBlock[1024];
+#define SCREENBLOCK_MEM ((ScreenBlock*)MEM_VRAM)
+
+// Screenblock entry bits.
+#define SCREENBLOCK_ENTRY_H_FLIP (1 << 0xA)
+#define SCREENBLOCK_ENTRY_V_FLIP (1 << 0xB)
+#define SCREENBLOCK_ENTRY_PAL(N) ((N) << 0xC)
+
+size_t se_index(size_t tile_x, size_t tile_y, size_t map_width) {
+    size_t sbb = ((tile_x >> 5) + (tile_y >> 5) * (map_width >> 5));
+    return sbb * 1024 + ((tile_x & 31) + (tile_y & 31) * 32);
+}
+
 // Screen settings.
 #define SCREEN_WIDTH 240
 #define SCREEN_HEIGHT 160
@@ -84,6 +98,9 @@
 // (RGB) have a 0--31 range. For example, pure red would be rgb15(31, 0, 0).
 typedef u16 Color;
 
+// A palette is composed of 16 colors, with color at index 0 being transparent.
+typedef Color Palette[16];
+
 //
 // Tile memory access.
 //
@@ -96,9 +113,6 @@ typedef struct Tile {
 typedef Tile TileBlock[512];
 #define TILE_MEM ((TileBlock*) MEM_VRAM)
 
-typedef u16 ScreenBlock[1024];
-#define SCREENBLOCK_MEM ((ScreenBlock*)MEM_VRAM)
-
 // We can treat the screen as a HxW matrix. With the following macro we can
 // write a pixel to the screen at the (x, y) position using:
 //
@@ -109,6 +123,8 @@ typedef Color Scanline[SCREEN_WIDTH];
 #define SCREEN_BUFFER      ((u16*) MEM_VRAM)
 #define PAL_BUFFER_BG      ((u16*) MEM_PAL)
 #define PAL_BUFFER_SPRITES ((u16*) 0x05000200)
+#define PAL_BANK_BG        ((Palette*) MEM_PAL)
+#define PAL_BANK_SPRITES   ((Palette*) 0x05000200)
 
 //
 // Colors.
@@ -277,5 +293,4 @@ key_hold(u32 key) {
 // Check if the given key/button is currently pressed.
 #define KEY_PRESSED(key) (~(KEY_INPUTS) & key)
 
-
 #endif // GBAEXP_COMMON_H