Add text drawing support for framebuffer

1 files changed, 34 insertions, 0 deletions

diff --git a/src/renderer.h b/src/renderer.h
new file mode 100644
index 0000000..8bc2069
--- /dev/null
+++ b/src/renderer.h
@@ -0,0 +1,34 @@
+#ifndef RENDERER_H
+#define RENDERER_H
+
+#include "gba/gba.h"
+
+// The frontbuffer is located at the beginning of the VRAM, and requires 20KB of
+// video memory for 32 * 20 tiles at 4bpp.
+#define FRONTBUF ((u32*)(MEM_VRAM))
+
+// Adjust both of these if the location of the map changes. Each screnblock
+// requires less than 2KB.
+#define FRONTBUF_TILEMAP ((u16*)(MEM_VRAM + KB(20)))
+#define FRONTBUF_SB      10
+
+// The backbuffer is located at the end of the VRAM. This can allow us to use
+// more backgrounds but eats into the available memory for sprites. This should
+// be fine for non sprite intensive applications. If more sprite memory is
+// needed, the backbuffer can be located at the end of the background memory
+// instead (64KB - 20KB).
+#define BACKBUF  ((u32*)(MEM_VRAM + KB(96) - KB(20)))
+
+// The font data is located at the end of the frontbuffer memory, after the tile
+// map and requires 8KB for 256 8x8 characters at 4bpp. This, along with the
+// tilemap information allow us to store the frontbuffer and font for a text
+// background in the first 2 charblocks (32KB).
+#define FONT_DATA    ((u32*)(MEM_VRAM + KB(22)))
+#define FONT_TILEMAP ((u16*)(MEM_VRAM + KB(30)))
+#define FONT_SB      15
+#define FONT_OFFSET  192
+
+void draw_pixel(u16 x, u16 y, u8 color);
+void draw_tile(u16 x, u16 y, Tile *tile, bool merge);
+
+#endif // RENDERER__H