road fix

common.asm

@@ -60,6 +60,68 @@ row_ptr:
     sta colhi
     rts
 
+; ---- charset_init: copy the ROM charset into RAM and patch
+; in the custom road / tree glyphs (multicolor bit pairs, see
+; defs.asm); runs once at boot ----
+charset_init:
+    lda #$33             ; char ROM in at $d000 (IO banked out)
+    sta $01
+    lda #0
+    sta scrlo
+    sta collo
+    lda #$d0
+    sta scrhi
+    lda #>CHSET
+    sta colhi
+    ldx #8               ; the full 2K uppercase/graphics set
+    ldy #0
+chs_copy:
+    lda (scrlo),y
+    sta (collo),y
+    iny
+    bne chs_copy
+    inc scrhi
+    inc colhi
+    dex
+    bne chs_copy
+    lda #$37             ; IO back in
+    sta $01
+    ldx #7               ; overlay the five custom glyphs
+chs_patch:
+    lda gl_edgel,x
+    sta CHSET+CH_EDGEL*8,x
+    lda gl_edger,x
+    sta CHSET+CH_EDGER*8,x
+    lda gl_road,x
+    sta CHSET+CH_ROADF*8,x
+    lda gl_leaf,x
+    sta CHSET+CH_LEAF*8,x
+    lda gl_trunk,x
+    sta CHSET+CH_TRUNK*8,x
+    dex
+    bpl chs_patch
+    lda #$1e             ; VIC: screen at $0400, charset at CHSET
+    sta VMEM
+    lda #COL_LEAF
+    sta CHAR_MC1
+    lda #COL_ROAD
+    sta CHAR_MC2
+    rts
+
+; the custom glyphs: 4 double-wide pixels per row as 2-bit
+; pairs (%00 background, %01 CHAR_MC1, %10 CHAR_MC2, %11 the
+; cell's color RAM bits 0-2)
+gl_edgel:                ; grass | white line \ road grey
+    !byte $03, $03, $0e, $0e, $3a, $3a, $ea, $ea
+gl_edger:                ; road grey / white line | grass
+    !byte $c0, $c0, $b0, $b0, $ac, $ac, $ab, $ab
+gl_road:                 ; solid road surface: all %10 pairs
+    !byte $aa, $aa, $aa, $aa, $aa, $aa, $aa, $aa
+gl_leaf:                 ; foliage ball: %01 pairs
+    !byte $14, $55, $55, $55, $55, $55, $14, $00
+gl_trunk:                ; trunk: %11 pairs, red via color RAM
+    !byte $3c, $3c, $3c, $3c, $3c, $3c, $3c, $3c
+
 ; ---- the road: grey surface between two painted edge lines,
 ; from the horizon apex down to the screen corners, then the
 ; trees along both shoulders ----
@@ -88,25 +150,25 @@ road_row:
     sbc road_off,x
     tay
     sty drleft
-    lda #$4e             ; '/' diagonal
+    lda #CH_EDGEL        ; grass, white line and road in one cell
     sta (scrlo),y
-    lda #COL_EDGE
+    lda #MCOL_EDGE
     sta (collo),y
     lda #20
     clc
     adc road_off,x
     tay
-    lda #$4d             ; '\' diagonal
+    lda #CH_EDGER
     sta (scrlo),y
-    lda #COL_EDGE
+    lda #MCOL_EDGE
     sta (collo),y
     dey                  ; fill the surface between the edges
 rr_fill:
     cpy drleft
     beq rr_done
-    lda #$a0             ; inverse space: solid block
+    lda #CH_ROADF        ; solid road surface
     sta (scrlo),y
-    lda #COL_ROAD
+    lda #MCOL_ROAD
     sta (collo),y
     dey
     jmp rr_fill
@@ -153,9 +215,9 @@ draw_tree:
     jsr row_ptr
     ldy tcol
     iny
-    lda #$5d             ; trunk
+    lda #CH_TRUNK
     sta (scrlo),y
-    lda #BROWN
+    lda #MCOL_TRUNK
     sta (collo),y
     rts
 
@@ -187,9 +249,9 @@ erase_tree:
     rts
 
 tree_ball:
-    lda #$51             ; foliage ball
+    lda #CH_LEAF
     sta (scrlo),y
-    lda #LGREEN
+    lda #MCOL_LEAF
     sta (collo),y
     rts
 

defs.asm

@@ -5,9 +5,12 @@
 
 ; ---- hardware registers ----
 RASTER  = $d012          ; current raster line
-XCTRL   = $d016          ; horizontal fine scroll + 38/40 column mode
+XCTRL   = $d016          ; fine scroll + 38/40 cols + text multicolor
+VMEM    = $d018          ; VIC memory pointers: screen + charset
 BORDER  = $d020          ; border color register
 BG      = $d021          ; background color register
+CHAR_MC1 = $d022         ; text multicolor 1 (bit pair %01)
+CHAR_MC2 = $d023         ; text multicolor 2 (bit pair %10)
 SCREEN  = $0400          ; screen RAM (40x25 chars)
 COLRAM  = $d800          ; color RAM
 SPRPTR  = $07f8          ; sprite pointers (screen RAM + $3f8)
@@ -80,8 +83,23 @@ LGREY   = 15
 ; ---- scene palette ----
 COL_SKY   = LBLUE        ; background above the horizon
 COL_GRASS = GREEN        ; background below it
-COL_ROAD  = MGREY        ; road surface (inverse-space fill)
+COL_ROAD  = MGREY        ; road surface (via CHAR_MC2)
-COL_EDGE  = WHITE        ; painted road edge lines
+COL_LEAF  = LGREEN       ; tree foliage (via CHAR_MC1)
+
+; ---- RAM charset: ROM copy + custom multicolor glyphs ----
+; the road and the trees render as multicolor text cells
+; (color RAM bit 3 set): pair %01 = CHAR_MC1 (foliage green),
+; %10 = CHAR_MC2 (road grey), %11 = color RAM bits 0-2
+CHSET     = $3800        ; RAM charset location (VIC bank 0)
+CH_EDGEL  = $4e          ; left road edge: grass|white line|road
+CH_EDGER  = $4d          ; right road edge, mirrored
+CH_ROADF  = $6d          ; solid road surface fill
+CH_LEAF   = $6e          ; tree foliage ball
+CH_TRUNK  = $6f          ; tree trunk
+MCOL_EDGE  = 8 + WHITE   ; bit 3 turns the cell multicolor
+MCOL_ROAD  = 8
+MCOL_LEAF  = 8
+MCOL_TRUNK = 8 + RED
 
 ; ---- joystick port 2 bits (after read_joy, active high) ----
 JOY_LEFT  = 4

main.asm

@@ -68,6 +68,7 @@ sprcol:
     sta SPR_YEX
     sta framectr
     sta fheld
+    jsr charset_init     ; RAM charset with the road/tree glyphs
     jsr sfx_init
 
 !ifdef AUTOPLAY {        ; test builds boot straight into the game
@@ -133,3 +134,6 @@ wf_hit:
 !src "sound.asm"
 !src "music.asm"
 !src "tables.asm"
+!if * > CHSET {
+    !error "program ran into the RAM charset at $3800"
+}

over.asm

@@ -7,6 +7,8 @@ over_init:
     lda #BLACK           ; clean card, the playfield is gone
     sta bg_top
     sta bg_bot
+    lda #$c8             ; plain text mode again
+    sta XCTRL
     lda #0
     sta SPR_EN
     jsr clear_screen

play.asm

@@ -10,6 +10,8 @@ play_init:
     sta bg_top
     lda #COL_GRASS
     sta bg_bot
+    lda #$d8             ; text multicolor on: road + tree cells
+    sta XCTRL
     jsr clear_screen
     jsr draw_road
 

tables.asm

@@ -47,8 +47,8 @@ sprxreg:
 sprbit:
     !byte 2, 4, 8, 16, 32, 64, 128
 
-; road edge offset per row (0-18): perspective curve
+; road edge offset per row (0-18): exactly one column per row,
-; wider at the horizon (offset 2) so it looks like a real road,
+; so the 45-degree edge glyphs join into one unbroken line on
-; not a sharp pyramid; only delta 0/1 steps, no visible jumps
+; both sides, from the apex down to the screen corners
 road_off:
-    !byte 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 18
+    !byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18