247 lines
3.3 KiB
ArmAsm
247 lines
3.3 KiB
ArmAsm
; Move that Peasant!
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move_peasant:
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; redraw peasant if moved
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lda PEASANT_XADD
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ora PEASANT_YADD
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bne really_move_peasant
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jmp peasant_the_same
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really_move_peasant:
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; restore bg behind peasant
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jsr erase_peasant
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;=========================
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;=========================
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; move peasant
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;=========================
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;=========================
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;==========================
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; first move in X direction
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clc
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lda PEASANT_X
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adc PEASANT_XADD ; A = new X
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bmi peasant_x_negative ; if newx <0, handle
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cmp #40
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bcs peasant_x_toobig ; if newx>=40, hanfle (bge)
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;======================================
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; not off screen, so check if collision
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pha
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tay
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; FIXME: should we add YADD first, like we do in peasant_move_tiny?
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ldx PEASANT_Y
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jsr peasant_collide
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pla
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bcc do_move_peasant_y ; no X collide
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;==================================
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; we collided in X, so stop moving
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jsr stop_peasant ; stop moving
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; leave PEASANT_X same as was
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lda PEASANT_X
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jmp do_move_peasant_y
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;============================
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peasant_x_toobig:
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jsr move_map_east
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lda #0 ; new X location
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jmp done_movex
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;============================
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peasant_x_negative:
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jsr move_map_west
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lda #39 ; new X location
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jmp done_movex
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; check edge of screen
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done_movex:
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; if we get here we changed screens
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sta PEASANT_X ; update new location
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jmp peasant_the_same ; skip checking for Y collision
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; Move Peasant Y
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do_move_peasant_y:
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sta PEASANT_X
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clc
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lda PEASANT_Y
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adc PEASANT_YADD ; newy in A
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cmp #45 ; if <45 then off screen
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bcc peasant_y_negative ; blt
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cmp #160 ; if >=150 then off screen
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bcs peasant_y_toobig ; bge
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; check collide
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pha
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ldy PEASANT_X
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tax ; newy
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jsr peasant_collide
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pla
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bcc done_movey ; no collide
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jsr stop_peasant ; stop moving
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lda PEASANT_Y ; leave same
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jmp done_movey
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;============================
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peasant_y_toobig:
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jsr move_map_south
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lda #45 ; new X location
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jmp done_movey
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;============================
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peasant_y_negative:
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jsr move_map_north
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lda #160 ; new X location
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jmp done_movey
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; check edge of screen
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done_movey:
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sta PEASANT_Y
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; if we moved off screen, don't re-draw peasant ?
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peasant_the_same:
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rts
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;===========================
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; erase peasant
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;===========================
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; restore bg behind peasant
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erase_peasant:
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lda PEASANT_Y
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sta SAVED_Y1
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clc
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adc #28
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sta SAVED_Y2
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ldx PEASANT_X
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txa
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inx
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jmp hgr_partial_restore ; tail call
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; when peasants collide
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;===================
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; peasant_collide
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;===================
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; newx/7 in Y
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; newy in X
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; returns C=0 if no collide
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; C=1 if collide
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peasant_collide:
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; rrrr rtii top 5 bits row, bit 2 top/bottom
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; add 28 to collide with feet
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txa
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clc
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adc #28
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tax
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txa
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and #$04 ; see if odd/even
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beq peasant_collide_even
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peasant_collide_odd:
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lda #$f0
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bne peasant_collide_mask ; bra
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peasant_collide_even:
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lda #$0f
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peasant_collide_mask:
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sta MASK
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txa
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lsr
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lsr ; need to divide by 8 then * 2
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lsr ; can't just div by 4 as we need to mask bottom bit
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asl
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tax
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lda gr_offsets,X
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sta INL
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lda gr_offsets+1,X
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sta INH
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lda (INL),Y ; get value
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and MASK
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; ldy MASK
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; cpy #$f0
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; beq in_top
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;in_bottom:
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; and #$0f
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; jmp done_feet
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;in_top:
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; lsr
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; lsr
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; lsr
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; lsr
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;done_feet:
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beq collide_true ; true if color 0
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;bne collide_false
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collide_false:
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clc
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rts
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collide_true:
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sec
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rts
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.include "gr_offsets.s"
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