Font engine refactor

String rendering code is now replicated for each font, which makes the code much faster and tighter. This will also immensely simplify switching to left-justified text rendering, which turns out to be important. :-|

.gitignore

@@ -7,3 +7,4 @@
 /fontEngine.lst
 /FONTBANK\#060000
 /Art/Generated
+/fonts.lst

CompileFont.py

@@ -40,6 +40,9 @@ def main(argv):
 	numCharX = (int)(image.size[0]/CHAR_WIDTH)
 	numCharY = (int)(image.size[1]/CHAR_HEIGHT)
 		
+	# Generate wrapper code
+	addWrapperCode(prefix,CHAR_WIDTH,CHAR_FIRST)
+	
 	# Generate jump table for glyphs
 	print ("%scharacterJumpTable:" % prefix)
 	for charY in range(0,numCharY):
@@ -152,7 +155,91 @@ def main(argv):
 				pendingStackMove += nextRowDelta		# Save this stack move for next row, because we can often combine them
 				
 			# Footer for each rendering operation
-			print ("\tjmp renderCharJumpReturn\n")
-			
+			print ("\tjmp renderCharJumpReturn_%s\n" % prefix)
+	return
+
+def addWrapperCode(prefix, charWidth, firstChar):
+	code = """
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderString_{:s}
+;
+; Draws a Pascal string for font "{:s}"
+;
+; PARAML0 = Pointer to string
+; Y = VRAM position of lower right corner of string at which to draw
+;
+; Trashes SCRATCHL,X,Y,A
+;
+renderString_{:s}:
+	sty SCRATCHL	; Cache VRAM position
+
+	plb				; Temporarily revert to caller's DBR to access their pointer
+	BITS8
+	lda (PARAML0)
+	tax
+	BITS16
+	phb
+
+renderStringLoop_{:s}:
+
+	; Fetch and render next character in string
+	txy
+	lda #0
+	plb				; Temporarily revert to caller's DBR to access their pointer
+	BITS8A
+	lda (PARAML0),y
+	BITS16
+	phb
+	ldy SCRATCHL
+	jsr renderChar_{:s}
+
+	dex
+	beq renderStringDone_{:s}
+
+	; Calculate VRAM pointer for position of next character
+	lda SCRATCHL
+	sec
+	sbc #{:d}/2					; Width of one char in bytes
+	sta SCRATCHL
+	bra renderStringLoop_{:s}
+
+renderStringDone_{:s}:
+	jmp renderStringReturn
+
+.export renderString_{:s}
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; renderChar_{:s}
+;
+; Draws a single character
+;
+; A = ASCII code to draw
+; Y = VRAM position of lower right corner at which to draw
+;
+renderChar_{:s}:
+	SAVE_AXY
+
+	sec
+	sbc #{:d}		; ASCII code of first char in font sheet
+	asl
+	tax
+	FASTGRAPHICS
+
+	jmp ({:s}characterJumpTable,x)
+
+renderCharJumpReturn_{:s}:	; Compiled glyphs jump back here. Can't rts because stack is turboborked
+	SLOWGRAPHICS
+
+	RESTORE_AXY
+	rts
+
+""".format(prefix,prefix,prefix,prefix,prefix,prefix,charWidth,prefix,prefix,prefix,prefix,prefix,firstChar,prefix,prefix)
+	print (code)
+	return
+
+
 if __name__ == "__main__":
 	main(sys.argv[1:])
+
+

Makefile

@@ -71,10 +71,10 @@ terrain_e1:
 
 fonts:
 	rm -rf $(FONTBANK)
-	./CompileFont.py 8 8 32 0 "font8" "Art/Assets/Font8x8.gif" > font8x8.s
-	./CompileFont.py 16 16 32 14 "font16" "Art/Assets/Font16x16.gif" > font16x16.s
-	./CompileFont.py 4 5 48 0 "num4" "Art/Assets/TinyNumbers.gif" > tinyNumbers.s
-	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh -C linkerConfig --cpu 65816 --start-addr 0000 -lfonts.lst fontEngine.s -o $(FONTBANK)
+	./CompileFont.py 4 5 48 0 "tinyNum" "Art/Assets/TinyNumbers.gif" > fonts.s
+	./CompileFont.py 8 8 32 0 "font8" "Art/Assets/Font8x8.gif" >> fonts.s
+#	./CompileFont.py 16 16 32 14 "font16" "Art/Assets/Font16x16.gif" > font16x16.s
+	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh -C linkerConfig --cpu 65816 --start-addr 0000 -lfontEngine.lst fontEngine.s -o $(FONTBANK)
 	rm -f fontEngine.o
 
 clean:

equates.s

@@ -44,9 +44,6 @@ RANDOM			= $ce		; 16 bit random number
 RANDOML			= $ce		; Low byte of random number generator
 RANDOMH			= $cf		; High byte of random number generator
 
-; Far entry points
-renderStringFar	= $050000
-
 ; Terrain constants
 TERRAINWIDTH = 640		; In pixels
 MAXTERRAINHEIGHT = 100	; In pixels
@@ -65,6 +62,9 @@ terrainData = $f500
 ;	.endrepeat
 terrainDataEnd = terrainData + (TERRAINWIDTH/2 * 2)
 
+; Far symbols
+renderStringFar = $050000			; Main entry for font rendering engine
+
 ; Stash the size of the sound bank at the end of sound memory so loader can pass it to sound system
 soundBankSize=$04fffe
 

fontEngine.s

@@ -4,113 +4,35 @@
 .org $0000
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; renderString (Far entry point)
+; renderString (Far entry point at $050000)
 ;
-; Draws a Pascal string
+; Draws a Pascal string in any font
 ;
 ; PARAML0 = Pointer to string
-; X = Font index
 ; Y = VRAM position of lower right corner of string at which to draw
+; A = Font index
 ;
-; Trashes SCRATCHL,SCRATCHL2,PARAML1,X, Y, A
+; Trashes SCRATCHL,X,Y,A
 ;
 renderString:
 	NATIVE
 	SAVE_DBR
 
-	sty SCRATCHL	; Cache VRAM position
-
-	txa				; Cache font character tables
 	asl
-	tay
-	lda fontJumpTable,y
-	sta renderCharBounce+1
-
-	lda fontFirstCharTable,y
-	sta SCRATCHL2
-
-	lda fontCharWidthTable,y
-	sta PARAML1
-
-	plb				; Temporarily revert to caller's DBR to access their pointer
-	BITS8
-	lda (PARAML0)
 	tax
-	BITS16
-	phb
+	jmp (fontJumpTable,x)		; Can't JSR here because we need the stack in a particular state (with DBR cached on top)
 
-renderStringLoop:
-
-	; Fetch and render next character in string
-	txy
-	lda #0
-	plb				; Temporarily revert to caller's DBR to access their pointer
-	BITS8A
-	lda (PARAML0),y
-	BITS16
-	phb
-	ldy SCRATCHL
-	jsr renderChar
-
-	dex
-	beq renderStringDone
-
-	; Calculate VRAM pointer for position of next character
-	lda SCRATCHL
-	sec
-	sbc PARAML1
-	sta SCRATCHL
-	bra renderStringLoop
-
-renderStringDone:
+renderStringReturn:
 	RESTORE_DBR
 	rtl
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; renderChar
-;
-; Draws a single character
-;
-; A = ASCII code to draw
-; Y = VRAM position of lower right corner at which to draw
-; SCRATCHL2 = First char in font
-;
-renderChar:
-	SAVE_AXY
-
-	sec
-	sbc SCRATCHL2
-	asl
-	tax
-	FASTGRAPHICS
-
-renderCharBounce:		; Self modifying code. Don't panic
-	jmp ($1234,x)
-
-renderCharJumpReturn:	; Compiled glyphs jump back here. Can't rts because stack is turboborked
-	SLOWGRAPHICS
-
-	RESTORE_AXY
-	rts
-
 fontJumpTable:
-	.addr font8characterJumpTable
-	.addr font16characterJumpTable
-	.addr num4characterJumpTable
+	.addr renderString_tinyNum
+	.addr renderString_font8
 
-fontCharWidthTable:	; In bytes
-	.word 4
-	.word 8
-	.word 2
 
-fontFirstCharTable:	; ASCII codes
-	.word 32
-	.word 32
-	.word 48
+.include "fonts.s"
 
-.include "tinyNumbers.s"
-.include "font8x8.s"
-.include "font16x16.s"
 
 ; Suppress some linker warnings - Must be the last thing in the file
 ; This is because Quinn doesn't really know how to use ca65 properly

graphics.s

@@ -229,7 +229,7 @@ drawNumber:
 	lda #intToStringResult
 	sta PARAML0
 	txy
-	ldx #0
+	lda #1
 	jsl renderStringFar
 
 	RESTORE_AXY

inventory.s

@@ -135,7 +135,7 @@ renderInventoryItem_unselected:
 	tay
 	lda #intToStringPrefix
 	sta PARAML0
-	ldx #2
+	lda #0
 	jsl renderStringFar
 
 renderInventoryItem_done:

player.s

@@ -439,7 +439,7 @@ renderPlayerHeader:
 	sta PARAML0
 	phy
 	ldy #$25c0
-	ldx #0
+	lda #1
 	jsl renderStringFar
 	ply
 
@@ -462,8 +462,8 @@ renderPlayerHeader:
 	lda #treatsStr
 	sta PARAML0
 	ldy #$25f2
-	ldx #0
-	jsl renderStringFromLeftFar
+	lda #1
+	jsl renderStringFar
 
 	RESTORE_AXY
 	rts