tree moving

common.asm

@@ -82,18 +82,19 @@ road_row:
     adc #6               ; road runs from char row 6 to row 24
     tax
     jsr row_ptr
-    lda #19              ; left edge: one column left per row
+    ldx drtmp            ; use perspective curve for the edge offset
+    lda #19
     sec
-    sbc drtmp
+    sbc road_off,x
     tay
     sty drleft
     lda #$4e             ; '/' diagonal
     sta (scrlo),y
     lda #COL_EDGE
     sta (collo),y
-    lda #20              ; right edge: one column right per row
+    lda #20
     clc
-    adc drtmp
+    adc road_off,x
     tay
     lda #$4d             ; '\' diagonal
     sta (scrlo),y
@@ -158,6 +159,33 @@ draw_tree:
     sta (collo),y
     rts
 
+; ---- erase one tree (write spaces at trow/tcol positions) ----
+erase_tree:
+    ldx trow
+    dex
+    jsr row_ptr
+    ldy tcol
+    iny
+    lda #$20
+    sta (scrlo),y
+    ldx trow
+    jsr row_ptr
+    ldy tcol
+    lda #$20
+    sta (scrlo),y
+    iny
+    sta (scrlo),y
+    iny
+    sta (scrlo),y
+    ldx trow
+    inx
+    jsr row_ptr
+    ldy tcol
+    iny
+    lda #$20
+    sta (scrlo),y
+    rts
+
 tree_ball:
     lda #$51             ; foliage ball
     sta (scrlo),y
@@ -165,11 +193,10 @@ tree_ball:
     sta (collo),y
     rts
 
-NTREES = 6
 tree_tbl:                ; middle row, left column - far trees sit
     !byte  9,  4         ;   higher and closer to the road
     !byte 14,  6
-    !byte 19,  3
+    !byte 18,  2
     !byte  8, 31
     !byte 12, 34
     !byte 17, 36

defs.asm

@@ -63,6 +63,8 @@ T_BIG     = 112          ; rabbit distance where the big frames start
 T_EXP     = 192          ; ... and where the sprite gets double-sized
 REP_HOLD  = 12           ; frames before a held direction auto-repeats
 REP_PERIOD = 6           ; frames between auto-repeat steps
+TREE_SPEED = 3           ; frames between tree scroll steps
+NTREES    = 6            ; roadside trees per side-pair
 RAS_SYNC  = 251          ; raster line polled for the frame sync
 RAS_SPLIT = 97           ; horizon line: sky/grass background split
 

play.asm

@@ -13,6 +13,20 @@ play_init:
     jsr clear_screen
     jsr draw_road
 
+    ; Copy static tree positions into dynamic arrays
+    ldx #0
+    ldy #0
+pti_loop:
+    lda tree_tbl,y
+    sta t_row,x
+    iny
+    lda tree_tbl,y
+    sta t_col,x
+    iny
+    inx
+    cpx #NTREES
+    bne pti_loop
+
     ; HUD: score on the left, miss slots on the right
     +prtext 0, 1, BLACK, txt_score, 5
     +prtext 0, 30, BLACK, txt_miss, 4
@@ -25,6 +39,7 @@ play_init:
     sta miss
     sta flash
     sta spawnt
+    sta tree_timer
     sta lcnt
     sta rcnt
     sta p2lcnt
@@ -236,6 +251,7 @@ pu_rnext:
     bpl pu_rab
 
     jsr write_shadows
+    jsr animate_trees
 
     ; -- third miss ends the round --
     lda miss
@@ -315,6 +331,96 @@ sr_ramp:
     sta r_sphi,x
     rts
 
+; ---- animate roadside trees: scroll down + fan outward ----
+animate_trees:
+    inc tree_timer
+    lda tree_timer
+    cmp #TREE_SPEED
+    bcs at_go
+    rts
+at_go:
+    lda #0
+    sta tree_timer
+
+    ; Phase 1: erase all trees at current positions
+    ldx #NTREES-1
+at_erase:
+    stx at_idx
+    lda t_row,x
+    sta trow
+    lda t_col,x
+    sta tcol
+    jsr erase_tree
+    ldx at_idx
+    dex
+    bpl at_erase
+
+    ; Phase 2: update all positions
+    ldx #NTREES-1
+at_move:
+    inc t_row,x
+    lda t_col,x
+    cmp #20
+    bcs at_mright
+    ; left side: move one column left
+    lda t_col,x
+    beq at_mresp
+    dec t_col,x
+    jmp at_mcheck
+at_mright:
+    ; right side: move one column right
+    lda t_col,x
+    cmp #37
+    bcs at_mresp
+    inc t_col,x
+at_mcheck:
+    lda t_row,x
+    cmp #23
+    bcc at_mnext
+at_mresp:
+    ; respawn near the horizon
+    lda t_col,x
+    cmp #20
+    bcs at_mrespr
+    ; left side: random col 10-13
+    jsr rand8
+    and #3
+    clc
+    adc #10
+    sta t_col,x
+    jmp at_mresprow
+at_mrespr:
+    ; right side: random col 24-27
+    jsr rand8
+    and #3
+    clc
+    adc #24
+    sta t_col,x
+at_mresprow:
+    jsr rand8
+    and #1
+    clc
+    adc #7
+    sta t_row,x
+at_mnext:
+    dex
+    bpl at_move
+
+    ; Phase 3: redraw all trees at new positions
+    ldx #NTREES-1
+at_draw:
+    stx at_idx
+    lda t_row,x
+    sta trow
+    lda t_col,x
+    sta tcol
+    jsr draw_tree
+    ldx at_idx
+    dex
+    bpl at_draw
+at_done:
+    rts
+
 ; ---- score: bump the decimal digits and the difficulty byte ----
 add_score:
     lda score8
@@ -379,6 +485,12 @@ rcnt:        !byte 0
 p2lcnt:      !byte 0     ; the same for player 2's steering
 p2rcnt:      !byte 0
 
+; ---- dynamic tree state ----
+t_row:      !fill NTREES, 0  ; current row of each tree
+t_col:      !fill NTREES, 0  ; current column of each tree
+tree_timer: !byte 0           ; frames since last tree scroll
+at_idx:     !byte 0           ; animate_trees loop index
+
 ; ---- rabbit slots (hardware sprites 1-7) ----
 r_act:  !fill NRABBITS, 0
 r_lane: !fill NRABBITS, 0

tables.asm

@@ -45,3 +45,9 @@ sprxreg:
 ; rabbit slot -> sprite enable/MSB/expand bit
 sprbit:
     !byte 2, 4, 8, 16, 32, 64, 128
+
+; road edge offset per row (0-18): perspective curve
+; wider at the horizon (offset 2) so it looks like a real road,
+; not a sharp pyramid; only delta 0/1 steps, no visible jumps
+road_off:
+    !byte 2, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 18