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#ifndef GBAEXP_TILES_H
#define GBAEXP_TILES_H
#include <stdarg.h>
#include "common.h"
#include "bd-font.c"
typedef struct TextEngine {
// Currently working on tiled backgrounds only. The X and Y positions
// correspond to the tile X and Y starting from the top left of the screen.
// For a 240x160 screen, we have 30x20 tiles available.
size_t cursor_x;
size_t cursor_y;
// Pointer to the screenblock being used for writing to the screen.
u16 *screenblock;
} TextEngine;
static TextEngine text_engine = {0};
void
txt_putc(char c) {
if (c == '\0') {
return;
}
if (c == '\n') {
text_engine.cursor_x = 0;
text_engine.cursor_y++;
} else {
text_engine.screenblock[text_engine.cursor_x + 32 * text_engine.cursor_y] = c;
text_engine.cursor_x++;
if (text_engine.cursor_x >= 30) {
text_engine.cursor_x = 0;
text_engine.cursor_y++;
}
}
if (text_engine.cursor_y >= 20) {
text_engine.cursor_y = 0;
}
}
static inline void
txt_puts(char *msg) {
while (*msg) {
txt_putc(*msg++);
}
}
void
txt_init(size_t bg, Color clr, size_t cb_idx) {
// The screenblock for the tile map should start after the tile memory
// (MEM_VRAM + 0x2000 for 256 characters). Since each screenblock is
// composed of 1024 screenblock entries of u16 (2 bytes), we need an
// screenblock index offset of 8192 / (1024 * 2) = 4 screen blocks.
size_t sb_idx = cb_idx * 8 + 4;
// Set the background parameters for the text layer.
BG_CTRL(bg) = BG_CHARBLOCK(cb_idx) | BG_SCREENBLOCK(sb_idx) | BG_PRIORITY(3);
// Load font data in video memory. Each character is unpacked into a tile of
// 8 32bit values (4bpp), meaning that for the full ASCII set of 256
// characters, we need 8192 bytes of VRAM (8 * 4 * 256).
unpack_tiles(&bd_font, &CHARBLOCK_MEM[cb_idx], 256);
// Load palette color.
PAL_BUFFER_BG[1] = clr;
// Update text_engine variables.
text_engine.screenblock = SCREENBLOCK_MEM[sb_idx];
}
// Print text to the screen with formatting.
void
txt_printf(char *msg, ...) {
va_list arg_list;
va_start(arg_list, msg);
char c;
char prev_c;
while ((c = *msg++) != '\0') {
if (c != '%') {
txt_putc(c);
prev_c = c;
continue;
}
c = *msg++;
switch (c) {
case 's': {
txt_puts(va_arg(arg_list, char *));
} break;
case 'd': {
char buf[32] = {0};
int x = va_arg(arg_list, int);
sprintf(buf, "%d", x);
txt_puts(buf);
} break;
case 'u': {
char buf[32] = {0};
unsigned int x = va_arg(arg_list, unsigned int);
sprintf(buf, "%u", x);
txt_puts(buf);
} break;
case 'x': {
char buf[32] = {0};
unsigned int x = va_arg(arg_list, unsigned int);
sprintf(buf, "%x", x);
txt_puts(buf);
} break;
default: {
txt_putc('%');
txt_putc(c);
} break;
}
}
}
void
txt_clear_line(void) {
for (size_t i = 0; i < 30; ++i) {
text_engine.screenblock[i + 32 * text_engine.cursor_y] = ' ';
}
text_engine.cursor_x = 0;
}
void
txt_clear_screen(void) {
for (size_t j = 0; j < 20; ++j) {
for (size_t i = 0; i < 30; ++i) {
text_engine.screenblock[i + 32 * j] = ' ';
}
}
text_engine.cursor_x = 0;
text_engine.cursor_y = 0;
}
void
txt_position(size_t tile_x, size_t tile_y) {
text_engine.cursor_x = tile_x;
text_engine.cursor_y = tile_y;
}
#endif // GBAEXP_TILES_H
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