Expand text engine to allow writing to mode 3

3 files changed, 153 insertions, 61 deletions

diff --git a/src/main.c b/src/main.c
index 05bfa26..33e7ebf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -6,6 +6,7 @@
 #include "sprites.h"
 #include "text.h"
 #include "sequencer.c"
+#include "bd-font.c"
 
 //
 // Main functions.
@@ -14,14 +15,13 @@
 // TODO: Cleanup OBJ/OAM memory copying and access.
 //
 
-
 int main(void) {
     // Configure the display in mode 0 to show OBJs, where tile memory is
     // sequential.
     DISP_CTRL = DISP_ENABLE_SPRITES | DISP_MODE_3 | DISP_BG_2;
 
     // Initialize text engine.
-    // txt_init(0, COLOR_RED, 0);
+    txt_init_bitmap(TXT_MODE_MODE3, (Font){.data = bd_font, .char_width = 6});
 
     // Register interrupts.
     irq_init();
@@ -37,16 +37,6 @@ int main(void) {
         handle_sequencer_input();
         update_sequencer_sprites();
         render_sequencer_sprites();
-
-        // DEBUG: Output
-        // txt_position(1,0);
-        // txt_clear_line();
-        // txt_printf(" BPM: %d\n\n", bpm);
-
-        // txt_clear_line();
-        // txt_printf(" Step: %d\n", step_counter);
-        // txt_clear_line();
-        // txt_printf(" Note: %s\n", note_names[active_note]);
     };
 
     return 0;
diff --git a/src/sequencer.c b/src/sequencer.c
index c83fa5a..6f7dd21 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -537,7 +537,6 @@ typedef struct SeqSprite {
     u16 obj_attr_2;
 } SeqSprite;
 
-
 typedef enum {
     SEQ_SELECT_TRIGGER,
     SEQ_SELECT_CHANNEL,
@@ -1058,12 +1057,30 @@ update_sequencer_sprites(void) {
         int x = SEQ_ENV_POS_X + 8;
         int y = SEQ_ENV_POS_Y;
 
+        draw_fill_rect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, COLOR_BLACK);
+
         // Clear wave A and draw.
-        draw_fill_rect(x, y, x + 64, y + 16, COLOR_BLACK);
+        // draw_fill_rect(x, y, x + 64, y + 16, COLOR_BLACK);
         draw_wave_pattern(wave_a, x, y, COLOR_RED);
 
+        // Write wave text.
+        txt_position(x, y + 20);
+        txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x",
+                wave_a[0], wave_a[1], wave_a[2], wave_a[3],
+                wave_a[4], wave_a[5], wave_a[6], wave_a[7]);
+        txt_position(x, y + 20 + 8);
+        txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x",
+                wave_a[8], wave_a[9], wave_a[10], wave_a[11],
+                wave_a[12], wave_a[13], wave_a[14], wave_a[15]);
+        // txt_position(0,y + 20 + 8);
+        // txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x\n",
+        //         wave_b[0], wave_b[1], wave_b[2], wave_b[3],
+        //         wave_b[4], wave_b[5], wave_b[6], wave_b[7],
+        //         wave_b[8], wave_b[9], wave_b[10], wave_b[11],
+        //         wave_b[12], wave_b[13], wave_b[14], wave_b[15]);
+
         // Clear wave B and draw.
-        draw_fill_rect(x + 64 + 16, y, x + 64 * 2 + 16, y + 16, COLOR_BLACK);
+        // draw_fill_rect(x + 64 + 16, y, x + 64 * 2 + 16, y + 16, COLOR_BLACK);
         draw_wave_pattern(wave_b, x + 64 + 16, y, COLOR_CYAN);
     } else if ((current_selection == SEQ_SELECT_TRIGGER
                 || current_selection == SEQ_SELECT_PARAMETER)
diff --git a/src/text.h b/src/text.h
index f178608..3c0b3a8 100644
--- a/src/text.h
+++ b/src/text.h
@@ -5,7 +5,29 @@
 #include <stdio.h>
 
 #include "common.h"
-#include "bd-font.c"
+
+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
@@ -13,14 +35,26 @@ typedef struct TextEngine {
     // 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;
+    // 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(char c) {
+txt_putc_tile(char c) {
     if (c == '\0') {
         return;
     }
@@ -28,7 +62,7 @@ txt_putc(char c) {
         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.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;
@@ -40,6 +74,52 @@ txt_putc(char c) {
     }
 }
 
+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) {
@@ -48,7 +128,7 @@ txt_puts(char *msg) {
 }
 
 void
-txt_init(size_t bg, Color clr, size_t cb_idx) {
+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
@@ -61,13 +141,48 @@ txt_init(size_t bg, Color clr, size_t cb_idx) {
     // 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, &TILE_MEM[cb_idx], 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] = clr;
+    PAL_BUFFER_BG[1] = font.color;
 
     // Update text_engine variables.
-    text_engine.screenblock = SCREENBLOCK_MEM[sb_idx];
+    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.
@@ -75,56 +190,26 @@ void
 txt_printf(char *msg, ...) {
     va_list arg_list;
     va_start(arg_list, msg);
-    char c;
-    while ((c = *msg++) != '\0') {
-        if (c != '%') {
-            txt_putc(c);
-            continue;
-        }
-        c = *msg++;
-        switch (c) {
-            case 's': {
-                txt_puts(va_arg(arg_list, char *));
-            } break;
-            case 'd': {
-                char buf[12] = {0};
-                int x = va_arg(arg_list, int);
-                sprintf(buf, "%d", x);
-                txt_puts(buf);
-            } break;
-            case 'u': {
-                char buf[12] = {0};
-                unsigned int x = va_arg(arg_list, unsigned int);
-                sprintf(buf, "%u", x);
-                txt_puts(buf);
-            } break;
-            case 'x': {
-                char buf[12] = {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;
-        }
-    }
+    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.screenblock[i + 32 * text_engine.cursor_y] = ' ';
+        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.screenblock[i + 32 * j] = ' ';
+            text_engine.memory[i + 32 * j] = ' ';
         }
     }
     text_engine.cursor_x = 0;