Add a whole font and some real text, wahoo

Makefile

@@ -3,6 +3,7 @@ BUILD := build
 RGBASM := rgbasm
 RGBLINK := rgblink
 RGBFIX := rgbfix
+PYTHON := python
 
 NAME := anise-cheezball-rising
 TARGET := $(BUILD)/$(NAME).gbc
@@ -17,7 +18,17 @@ DEPS := $(foreach src,$(SOURCES),$(patsubst $(SRC)/%,$(BUILD)/%.deps,$(src)))
 
 all: $(TARGET)
 
-$(BUILD)/%.rgbasm.o: $(SRC)/%.rgbasm
+# Special intermediate targets
+
+$(BUILD)/font.inc: util/font-to-tiles.py data/font.png
+	$(PYTHON) util/font-to-tiles.py data/font.png > $(BUILD)/font.inc
+
+# The regular expected stuff
+# TODO: i've manually listed font.inc here because otherwise, on first build,
+# rgbasm will balk that it doesn't exist, so it'll never create the deps file,
+# so make will never know it needs to be built first.  this enforces build
+# order without supplying the explicit dependency.  is there a better fix?
+$(BUILD)/%.rgbasm.o: $(SRC)/%.rgbasm | $(BUILD)/font.inc
 	$(RGBASM) -i $(SRC)/ -i $(BUILD)/ -M $(BUILD)/$*.rgbasm.deps -o $@ $<
 
 $(TARGET): $(OBJECTS)
@@ -32,4 +43,6 @@ clean:
 	rm -f $(SYMFILE)
 
 # Include generated dependency files
+# TODO: if i remove a dep, make will be unable to recreate it, but these
+# lingering files will still say it's necessary.  is that fixable?
 -include $(DEPS)

src/main.rgbasm

@@ -527,47 +527,10 @@ include "tilesets/testmap.rgbasm"
 include "tilesets/testanise.rgbasm"
 
 SECTION "Font", ROMX
-; FONT
-font:
-; A
-    db 6
-    dw `00000000
-    dw `00000000
-    dw `01110000
-    dw `10001000
-    dw `10001000
-    dw `10001000
-    dw `11111000
-    dw `10001000
-    dw `10001000
-    dw `10001000
-    dw `10001000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-; B
-    db 6
-    dw `00000000
-    dw `00000000
-    dw `11110000
-    dw `10001000
-    dw `10001000
-    dw `10001000
-    dw `11110000
-    dw `10001000
-    dw `10001000
-    dw `10001000
-    dw `11110000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-    dw `00000000
-
 text:
-    db "ABABAAA", 0
+    db "Hello, world!", 0
+; FONT
+font: include "font.inc"
 
 SECTION "Text buffer", WRAM0[$C200]
 text_buffer:
@@ -689,7 +652,7 @@ show_dialogue:
     ; character address in hl and /then/ put it in de.  But I
     ; already pushed de, so I can use that as scratch space.
     push hl
-    sub a, 65   ; TODO temporary
+    sub a, 32   ; TODO temporary...?
     ld hl, font
     ld de, 33                   ; 1 width byte + 16 * 2 tiles
     ; TODO can we speed striding up with long mult?
@@ -784,6 +747,7 @@ show_dialogue:
     ; right?  wait, no, it comes /before/...  well fuck
     ; TODO actually that might make something weird happen due
     ; to the inc b above, maybe...?
+    dec b
     add a, b                    ; a <- new x offset
     ld bc, -32                  ; move the VRAM pointer back...
     add hl, bc                  ; ...to the start of the tile

util/font-to-tiles.py

@@ -0,0 +1,77 @@
+"""Converts a PNG containing a variable-width font into a source
+file for rgbasm.
+
+The image format is similar to the one LÖVE uses: the upper-left
+pixel of the whole image is considered to mark the start of a
+new letter whenever it appears in the top row.  Unlike LÖVE,
+that column is also part of the following letter, and is
+replaced with color zero.  Also, no letter may be wider than 8
+pixels (though the renderer includes a 1px gap after every
+character).
+
+The palette is ignored and indices are used directly, but
+generally color 0 should be the background and color 1 should be
+the primary text color.
+"""
+from pathlib import Path
+import sys
+
+import PIL.Image
+
+
+TILE_SIZE = 8
+METATILE_SIZE = 16
+
+
+def main(font_image_path):
+    im = PIL.Image.open(font_image_path)
+
+    width, height = im.size
+    if height != 16:
+        # TODO well, not necessarily!  in fact i'd like to cut
+        # it down to 12.  but for now, yes
+        raise RuntimeError("Font image must be exactly 16 pixels tall")
+
+    pixels = im.load()
+    indicator = pixels[0, 0]  # this color starts a new glyph
+    glyph_starts = []  # x-offsets of where glyphs begin
+    glyphs = []  # lists of rows of pixels
+
+    # Deal with the first row first, so we know where the
+    # divisions are
+    for x in range(width):
+        pixel = pixels[x, 0]
+        if pixel == indicator:
+            glyph_starts.append(x)
+            glyphs.append([[]])
+            pixel = 0
+        glyphs[-1][0].append(pixel)
+        # TODO enforce no more than 8 pixels
+
+    # Continue with subsequent rows
+    for y in range(1, height):
+        g = -1
+        for x in range(width):
+            if g + 1 < len(glyph_starts) and x == glyph_starts[g + 1]:
+                g += 1
+                glyphs[g].append([])
+            pixel = pixels[x, y]
+            glyphs[g][-1].append(pixel)
+
+    # Write it out
+    for g, glyph in enumerate(glyphs):
+        if g + 1 < len(glyphs):
+            glyph_width = glyph_starts[g + 1] - glyph_starts[g]
+        else:
+            glyph_width = width - glyph_starts[g]
+
+        print(f"; {chr(g + 32)}")
+        print(f"    db {glyph_width}")
+
+        for row in glyph:
+            row = (row + [0] * 8)[:8]
+            print('    dw `' + ''.join(map(str, row)))
+
+
+if __name__ == '__main__':
+    main(*sys.argv[1:])