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#ifndef GBAEXP_TILES_H
#define GBAEXP_TILES_H
#include <stdarg.h>
#include <stdio.h>
#include "common.h"
typedef enum {
TXT_MODE_TILED_BG,
TXT_MODE_MODE3,
} TextMode;
typedef struct Font {
// A pointer to an area of memory containing font data.
// TODO: Should we unpack each char everytime or unpack everything into RAM?
// Maybe this should be optional?
u32 *data;
// The char_map stores the index to the character position within the font
// array depending on the ascii number we want to render. This allows
// the usage reduced font sets, for example just uppercase letters and
// numbers.
u8 *char_map;
// Width and height of each font character. Only monospaced fonts are
// currently supported.
u8 char_width;
u8 char_height;
// The color of this font.
Color color;
} Font;
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 memory being used for writing to the screen.
u16 *memory;
// TODO: Support other modes and monospaced fonts should be simple but we
// need to keep track of a couple of other variables, which may not be
// available for all modes. For example, tile modes can't have a font width
// smaller than the tile size, although bigger fonts (For example fonts
// composed of multiple tiles) should still be possible. This may not be
// a good time investment, but can be done in the future if needed.
// The mode controls how the text is rendered and how the memory is managed.
TextMode mode;
// The font used to render the text.
Font font;
} TextEngine;
static TextEngine text_engine = {0};
static u8 default_char_map[256] = {0};
void
txt_putc_tile(char c) {
if (c == '\0') {
return;
}
if (c == '\n') {
text_engine.cursor_x = 0;
text_engine.cursor_y++;
} else {
text_engine.memory[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;
}
}
void
txt_putc_m3(char c) {
if (c == '\0') {
return;
}
if (c == '\n') {
text_engine.cursor_x = 0;
text_engine.cursor_y += text_engine.font.char_height;
} else {
u8 idx = text_engine.font.char_map[c] * 2;
u32 *packed_char = text_engine.font.data;
packed_char += idx;
Tile tile = {0};
unpack_tiles(packed_char, &tile, 1);
int x = text_engine.cursor_x;
int y = text_engine.cursor_y;
for (size_t i = 0; i < text_engine.font.char_height; ++i) {
for (size_t j = 0; j < text_engine.font.char_width; ++j) {
if ((tile.row[i] >> 4 * j) & 0x1) {
FRAMEBUFFER[y + i][x + j] = text_engine.font.color;
}
}
}
text_engine.cursor_x += text_engine.font.char_width;
if (text_engine.cursor_x >= SCREEN_WIDTH) {
text_engine.cursor_x = 0;
text_engine.cursor_y += text_engine.font.char_height;
}
}
if (text_engine.cursor_y >= SCREEN_HEIGHT) {
text_engine.cursor_y = 0;
}
}
void
txt_putc(char c) {
switch (text_engine.mode) {
case TXT_MODE_TILED_BG: {
txt_putc_tile(c);
} break;
case TXT_MODE_MODE3: {
txt_putc_m3(c);
} break;
}
}
static inline void
txt_puts(char *msg) {
while (*msg) {
txt_putc(*msg++);
}
}
void
txt_init_tile(size_t bg, Font font, 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).
text_engine.font = font;
unpack_tiles(font.data, &TILE_MEM[cb_idx], 256);
// Initialize default values.
if (font.color == 0) {
font.color = COLOR_WHITE;
}
// Load palette color.
PAL_BUFFER_BG[1] = font.color;
// Update text_engine variables.
text_engine.memory = SCREENBLOCK_MEM[sb_idx];
}
void
txt_init_bitmap(TextMode mode, Font font) {
// NOTE: Only mode 3 is currently supported
assert(mode == TXT_MODE_MODE3);
// If font_map is NULL, initialize the standard 0-255 character map.
if (font.char_map == NULL) {
for (size_t i = 0; i < 256; ++i) {
default_char_map[i] = i;
}
font.char_map = &default_char_map;
}
// Initialize default values if set to zero.
if (font.char_width == 0) {
font.char_width = 8;
}
if (font.char_height == 0) {
font.char_height = 8;
}
if (font.color == 0) {
font.color = COLOR_WHITE;
}
// Prepare text engine.
text_engine.font = font;
text_engine.mode = mode;
}
// Print text to the screen with formatting.
void
txt_printf(char *msg, ...) {
va_list arg_list;
va_start(arg_list, msg);
char buf[512] = {0};
vsprintf(buf, msg, arg_list);
txt_puts(buf);
}
// TODO: Update for working on bitmap modes.
void
txt_clear_line(void) {
for (size_t i = 0; i < 30; ++i) {
text_engine.memory[i + 32 * text_engine.cursor_y] = ' ';
}
text_engine.cursor_x = 0;
}
// TODO: Update for working on bitmap modes.
void
txt_clear_screen(void) {
for (size_t j = 0; j < 20; ++j) {
for (size_t i = 0; i < 30; ++i) {
text_engine.memory[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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