395 lines
5.2 KiB
ArmAsm
395 lines
5.2 KiB
ArmAsm
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KEEN_SPEED = $80
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YDEFAULT = 20
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HARD_TILES = 32 ; start at 32
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;=========================
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; move keen
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;=========================
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move_keen:
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lda #0
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sta SUPPRESS_WALK
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jsr keen_get_feet_location ; get location of feet
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jsr check_falling ; check for/handle falling
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jsr keen_collide ; check for right/left collision
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jsr handle_jumping ; handle jumping
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lda KEEN_WALKING
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beq done_move_keen
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lda SUPPRESS_WALK
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bne done_move_keen
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lda KEEN_DIRECTION
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bmi move_left
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lda KEEN_X
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cmp #22
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bcc keen_walk_right
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keen_scroll_right:
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clc
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lda KEEN_XL
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adc #KEEN_SPEED
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sta KEEN_XL
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bcc skip_keen_scroll_right
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inc TILEMAP_X
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jsr copy_tilemap_subset
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skip_keen_scroll_right:
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jmp done_move_keen
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keen_walk_right:
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lda KEEN_XL
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clc
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adc #KEEN_SPEED
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sta KEEN_XL
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bcc dwr_noflo
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inc KEEN_X
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dwr_noflo:
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jmp done_move_keen
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move_left:
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lda KEEN_X
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cmp #14
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bcs keen_walk_left
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keen_scroll_left:
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sec
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lda KEEN_XL
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sbc #KEEN_SPEED
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sta KEEN_XL
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bcs skip_keen_scroll_left
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dec TILEMAP_X
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jsr copy_tilemap_subset
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skip_keen_scroll_left:
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jmp done_move_keen
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keen_walk_left:
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lda KEEN_XL
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sec
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sbc #KEEN_SPEED
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sta KEEN_XL
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bcs dwl_noflo
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dec KEEN_X
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dwl_noflo:
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jmp done_move_keen
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done_move_keen:
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rts
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;=========================
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; keen collide
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;=========================
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keen_collide:
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;==================
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; check for item
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;==================
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keen_check_item:
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lda KEEN_FOOT_OFFSET
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sec
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sbc #16
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tax
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jsr check_item
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;===================
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; collide with head
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;===================
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keen_check_head:
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; only check above head if jumping
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lda KEEN_JUMPING
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beq collide_left_right
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lda KEEN_FOOT_OFFSET
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sec
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sbc #16 ; above head is -2 rows
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tax
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lda tilemap,X
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; if tile# < HARD_TILES then we are fine
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cmp #HARD_TILES
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bcc collide_left_right ; blt
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lda #0
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sta KEEN_JUMPING
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lda #1
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sta KEEN_FALLING
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jsr head_noise
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collide_left_right:
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;===================
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; collide left/right
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;===================
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lda KEEN_DIRECTION
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beq done_keen_collide
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bmi check_left_collide
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check_right_collide:
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lda KEEN_FOOT_OFFSET
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clc
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adc #1 ; right is one to right
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tax
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lda tilemap,X
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; if tile# < HARD_TILES then we are fine
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cmp #HARD_TILES
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bcc done_keen_collide ; blt
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lda #1 ;
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sta SUPPRESS_WALK
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jmp done_keen_collide
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check_left_collide:
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lda KEEN_FOOT_OFFSET
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sec
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sbc #2 ; left is one to left
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; +1 fudge factor
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tax
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lda tilemap,X
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; if tile# < HARD_TILES then we are fine
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cmp #HARD_TILES
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bcc done_keen_collide ; blt
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lda #1
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sta SUPPRESS_WALK
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jmp done_keen_collide
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done_keen_collide:
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rts
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;=========================
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; check_jumping
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;=========================
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handle_jumping:
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lda KEEN_JUMPING
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beq done_handle_jumping
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lda KEEN_Y
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beq dont_wrap_jump
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dec KEEN_Y
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dec KEEN_Y
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dont_wrap_jump:
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dec KEEN_JUMPING
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bne done_handle_jumping
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lda #1 ; avoid gap before falling triggered
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sta KEEN_FALLING
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done_handle_jumping:
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rts
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;=======================
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; keen_get_feet_location
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;=======================
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; xx 0
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; xx 1
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;------ -----
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; xx 0 xx 2
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; xx 1 xx 3
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; xx 2 xx 4
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; xx 3 xx 5
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;------ -------
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; xx 4 xx 6
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; xx 5 xx 7
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; xx 6
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; xx 7
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;-----------------------
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; YY = block
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;========================
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; YYYY YYYY
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; -XX- -XX-
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; -XX- -XX-
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; left, foot = (X+1)/2
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; right, foot = (X+2)/2
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keen_get_feet_location:
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; + 1 is because sprite is 4 pixels wide?
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; screen is 16 wide, but offset 4 in
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; to get to feet add 6 to Y?
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; block index of foot is (feet approximately 6 lower than Y)
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; INT((y+4)/4)*16 + (x-4+1/2)
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; FIXME: if 18,18 -> INT(26/4)*16 = 96 + 7 = 103 = 6R7
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; 0 = 32 (2)
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; 1 = 32 (2)
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; 2 = 32 (2)
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; 3 = 32 (2)
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; 4 = 48 (3)
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; 5 = 48 (3)
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; 6 = 48 (3)
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; 7 = 48 (3)
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lda KEEN_Y
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clc
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adc #4 ; +4
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lsr ; / 4 (INT)
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lsr
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asl ; *4
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asl
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asl
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asl
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sta KEEN_FOOT_OFFSET
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; lda KEEN_DIRECTION
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; bmi foot_left
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foot_right:
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lda KEEN_X
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clc
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adc #2
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; jmp foot_done
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;foot_left:
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; lda KEEN_X
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; sec
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; sbc #1
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foot_done:
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lsr
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; offset by two block at edge of screen
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sec
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sbc #2
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clc
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adc KEEN_FOOT_OFFSET
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sta KEEN_FOOT_OFFSET
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rts
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;=========================
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; check_falling
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;=========================
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check_falling:
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lda KEEN_JUMPING
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bne done_check_falling ; don't check falling if jumping
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lda KEEN_FOOT_OFFSET
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clc
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adc #16 ; underfoot is on next row (+16)
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tax
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lda tilemap,X
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; if tile# < HARD_TILES then we fall
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cmp #HARD_TILES
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bcs feet_on_ground ; bge
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;=======================
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; falling
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lda #1
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sta KEEN_FALLING
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; scroll but only if Y>=20 (YDEFAULT)
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lda KEEN_Y
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cmp #YDEFAULT
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bcs scroll_fall ; bge
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inc KEEN_Y
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inc KEEN_Y
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jmp done_check_falling
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scroll_fall:
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inc TILEMAP_Y
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jsr copy_tilemap_subset
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jmp done_check_falling
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feet_on_ground:
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;===========================
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; if had been falling
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; kick up dust, make noise
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; stop walking?
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lda KEEN_FALLING
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beq was_not_falling
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; clear falling
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lda #0
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sta KEEN_FALLING
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lda #2
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sta KICK_UP_DUST
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lda #0
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sta KEEN_WALKING
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jsr land_noise
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was_not_falling:
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; check to see if Y still hi, if so scroll back down
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lda KEEN_Y
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cmp #YDEFAULT
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bcs done_check_falling ; bge
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; too high up on screen, adjust down and also adjust tilemap down
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inc KEEN_Y
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inc KEEN_Y
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dec TILEMAP_Y ; share w above?
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jsr copy_tilemap_subset
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done_check_falling:
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rts
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