Refactored text renderer

game/text.asm

@@ -82,9 +82,10 @@ ClearWindow:
 ; @return hl - Workram position for text pointer
 ; @return de - Memory address to source string
 StartText:
+    ld a, 10
+    ld [textwriter_curdelay], a
     ld a, 0
     ld [textwriter_curletter], a
-    ld [textwriter_curdelay], a
     ld [textwriter_posx], a
     ld [textwriter_posy], a
     ld a, 1
@@ -102,17 +103,16 @@ StartText:
 DrawActiveText:
     ld a, [textwriter_active] ; Check if text is currently active
     and a
-    jp z, .exit
+    ret z
 
     ; Delay writing a letter by 10 frames
     ld a, [textwriter_curdelay]
-    inc a
+    dec a
     ld [textwriter_curdelay], a
-    cp 10
-    jr c, .exit
+    ret nz
 
     ; Reset the curdelay
-    ld a, 0
+    ld a, 10
     ld [textwriter_curdelay], a
 
 .startdrawtext
@@ -124,34 +124,23 @@ DrawActiveText:
     ld e, [hl] ; Store the next byte address to e
     ; We now have the current letter being drawn at [de]
 
-    ld hl, _SCRN1 ; Load the top-left map position to our map
-    ld a, [textwriter_posy]
-    ld c, a
+    ; Get the current X position for the text on screen
+    ld hl, (_SCRN1 + $21) ; Load the top-left window position for our text
+    ; Load the x position for current text position and 
     ld a, [textwriter_posx]
     ld b, a
-.moveyaxis
-    ; Our first objective is to position the text to correct position
-    ; We do so shifting the position by $20 for each y axis
-    ; and position by $01 for each x axis that needs movement
-    ld a, c ; Load the y position to our accumilator
+    ld a, l
+    add b ; Add the x position 
+    ld l, a
+
+    ; Get the current Y position for the text on screen
+    ld a, [textwriter_posy]
     and a ; Check if it's zero
-    jr z, .movexaxis ; Jump to x axis if it's zero and no moving necessary
-    ld a, l ; Load the first half of the destination position
-    add a, $20 ; Add $20 (one vertical line)
-    ld l, a ; Store the position back 
-    ld a, h ; Grab the second part of the address
-    adc a, $00 ; Add only the accumilator
-    ld h, a ; Store the position back
-    dec c ; Decrement our y parameter
-    jr .moveyaxis ; Repeat
-.movexaxis
-    ; Now we check and move the position based on the x position
-    ld a, b ; Load the x position to our accimulator
-    and a ; Check if it's zero
-    jr z, .drawletter ; Jump to drawletter if it's zero already
-    inc hl ; Increment the map position by one since we need to move by x position
-    dec b ; Decrement our x parameter
-    jr .movexaxis ; Repeat
+    jr z, .drawletter
+    ; If not, jump forward by a whole line.
+    ld a, l
+    add a, $20
+    ld l, a
 .drawletter
     ld a, [de] ; Load the first byte in the string
     ld bc, textwriter_map ; Get the map for the ASCII->Tile map
@@ -176,12 +165,12 @@ DrawActiveText:
 
     ; The byte we printed was a new line so we increment Y position
     ; and reset our X position.
-    ld a, 0 ; Usually we'd print into first position but since we're jumping
+    ld a, -1 ; Usually we'd print into first position but since we're jumping
             ; into continue, continue will automatically increment x for us.
     ld [textwriter_posx], a
-    ld a, [textwriter_posy]
-    inc a
-    ld [textwriter_posy], a
+    ld a, 1
+    ld [textwriter_posy], a ; Set our Y position to 1
+    ld [textwriter_curdelay], a ; Also set curdelay to 1 as well
 
     ; We already know we printed empty character so we can skip checking
     ; if we need to repeat once again and just set the b flag
@@ -195,7 +184,8 @@ DrawActiveText:
     ; Check if we printed an empty letter
     cp a, $50
     jr nz, .continue
-    ld b, 1
+    ld a, 1
+    ld [textwriter_curdelay], a ; Set curdelay to 1 so it immediately prints next character
 
 .continue
     ; Time to update our work ram
@@ -213,13 +203,6 @@ DrawActiveText:
     ; Update the current letter being drawn in ram
     ld a, [textwriter_curletter]
     inc a
-
-    ; Check if we need to repeat whole thing due to printing empty character
-    ld a, b
-    and b
-    jr nz, .startdrawtext
-
-    ; We didn't print an empty
     ld [textwriter_curletter], a
 
 .exit

test.map

@@ -1,17 +1,13 @@
 ROM Bank #0 (HOME):
   SECTION: $0200-$027F ($0080 bytes) ["rom_textmap"]
            $0200 = textwriter_map
-  SECTION: $1280-$137D ($00FE bytes) ["TextWriter"]
-           $137A = DrawActiveText.exit
-           $1326 = DrawActiveText.movexaxis
-           $1317 = DrawActiveText.moveyaxis
-           $132E = DrawActiveText.drawletter
-           $1342 = DrawActiveText.checkNewline
-           $1360 = DrawActiveText.continue
-           $1357 = DrawActiveText.checkRepeatOnce
-           $1306 = DrawActiveText.startdrawtext
+  SECTION: $1280-$136C ($00ED bytes) ["TextWriter"]
+           $131D = DrawActiveText.drawletter
+           $1331 = DrawActiveText.checkNewline
+           $1353 = DrawActiveText.continue
+           $1347 = DrawActiveText.checkRepeatOnce
            $12D3 = StartText
-           $12EF = DrawActiveText
+           $12F1 = DrawActiveText
            $1280 = InitWindow
   SECTION: $0031-$003E ($000E bytes) ["Game Loop"]
            $0037 = GameLoop.mainloop
@@ -34,12 +30,12 @@ ROM Bank #0 (HOME):
   SECTION: $0280-$127F ($1000 bytes) ["Font"]
            $0280 = Page1
            $1280 = Page1End
-    SLACK: $2DAD bytes
+    SLACK: $2DBE bytes
 
 WRAM Bank #0:
   SECTION: $C000-$C006 ($0007 bytes) ["ram_textwriter"]
-           $C002 = textwriter_curletter
            $C005 = textwriter_curdelay
+           $C002 = textwriter_curletter
            $C003 = textwriter_posx
            $C004 = textwriter_posy
            $C006 = textwriter_active

test.sym

@@ -1,16 +1,12 @@
 ; File generated by rgblink
 
 00:0200 textwriter_map
-00:137A DrawActiveText.exit
-00:1326 DrawActiveText.movexaxis
-00:1317 DrawActiveText.moveyaxis
-00:132E DrawActiveText.drawletter
-00:1342 DrawActiveText.checkNewline
-00:1360 DrawActiveText.continue
-00:1357 DrawActiveText.checkRepeatOnce
-00:1306 DrawActiveText.startdrawtext
+00:131D DrawActiveText.drawletter
+00:1331 DrawActiveText.checkNewline
+00:1353 DrawActiveText.continue
+00:1347 DrawActiveText.checkRepeatOnce
 00:12D3 StartText
-00:12EF DrawActiveText
+00:12F1 DrawActiveText
 00:1280 InitWindow
 00:0037 GameLoop.mainloop
 00:0031 GameLoop
@@ -22,8 +18,8 @@
 00:0061 Start
 00:0280 Page1
 00:1280 Page1End
-00:C002 textwriter_curletter
 00:C005 textwriter_curdelay
+00:C002 textwriter_curletter
 00:C003 textwriter_posx
 00:C004 textwriter_posy
 00:C006 textwriter_active