Add text drawing support for framebuffer

4 files changed, 63 insertions, 34 deletions

diff --git a/src/main.c b/src/main.c
index 913043a..61547c8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,7 +31,7 @@ WITH REGARD TO THIS SOFTWARE.
 #define PROF_SHOW_Y 0
 #endif
 #define PROF_SHOW() \
-    do { \
+    do {\
         txt_position((PROF_SHOW_X), (PROF_SHOW_Y));\
         txt_printf("EVAL:  %lu    ", eval_cycles);\
         txt_position((PROF_SHOW_X), (PROF_SHOW_Y)+1);\
@@ -64,15 +64,11 @@ int main(void) {
     irq_init();
     irs_set(IRQ_VBLANK, irs_stub);
 
-    Tile *tile = FONT_DATA;
-    tile += 'A';
-    draw_tile(0, 0, tile, true);
-    draw_tile(0, 4, tile, true);
-    draw_tile(4, 0, tile, true);
+    txt_drawf("Hello world: %d", 4, 4, 6, 10);
 
     // Main loop.
     PROF_INIT();
-    while(true) {
+    while (true) {
         bios_vblank_wait();
         PROF_SHOW();
         PROF(flip_buffer(), flip_cycles);
diff --git a/src/renderer.c b/src/renderer.c
index 500cc78..f950a4d 100644
--- a/src/renderer.c
+++ b/src/renderer.c
@@ -16,31 +16,7 @@
 //
 
 #include "text.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
+#include "renderer.h"
 
 // Keep track of which tiles need to be copied to the frontbuffer.
 static u32 dirty_tiles[21] = {0};
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
diff --git a/src/text/text.h b/src/text/text.h
index 65003c5..630f04f 100644
--- a/src/text/text.h
+++ b/src/text/text.h
@@ -1,9 +1,10 @@
 #ifndef TEXT_H
 #define TEXT_H
 
-#include "bd-font.c"
-#include "shorthand.h"
 #include "posprintf.h"
+#include "renderer.h"
+
+#include "bd-font.c"
 
 typedef struct TextEngine {
     // Cursor for tiled text mode The X and Y positions correspond to the tile
@@ -103,6 +104,21 @@ txt_position(size_t tile_x, size_t tile_y) {
     text_engine.cursor_y = tile_y;
 }
 
+// Draws a message where the first character's top-left corner begins at the
+// given x and y position. The character spacing can be adjusted, but beware of
+// color merging issues.
+static inline
+void
+txt_draws(char *msg, size_t x, size_t y, size_t spacing) {
+    while (*msg) {
+        char c = *msg++;
+        Tile *tile = FONT_DATA;
+        tile += c;
+        draw_tile(x, y, tile, true);
+        x += spacing;
+    }
+}
+
 // Print text to the screen with formatting.
 #define txt_printf(msg, ...) \
         { \
@@ -111,4 +127,11 @@ txt_position(size_t tile_x, size_t tile_y) {
                 txt_puts(buf); \
         }
 
+#define txt_drawf(msg, x, y, s, ...) \
+        { \
+                char buf[256] = {0}; \
+                posprintf(buf, msg, ##__VA_ARGS__); \
+                txt_draws(buf, x, y, s); \
+        }
+
 #endif // TEXT_H