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A C64 Game - Step 75

Posted by Endurion, in C64 03 November 2012 · 817 views

And more! Now the executable hit the load barrier, so Exomizer is the only way to go onwards (before it was optional). Added a new waterfall char with the same effect as low water.

Attached Image

At the same location the other char is initiated we add this:

ldx #0
-		
		  lda $F800 + 143 * 8,x
		  sta ANIM_TILE2_BYTES,x
		  sta ANIM_TILE2_BYTES + 8,x
		
		  inx
		  dey
		  cpx #8
		  bne -

At the location where we animate the first char we add this. Note that the second sta at $c000 is for the second char set.

;animate water tile
		  lda DELAYED_GENERIC_COUNTER
		  and #$03
		  bne +
		
		  inc ANIM_POS
		  lda ANIM_POS
		  and #$07
		  tay
		
		  lda ANIM_TILE_BYTES,y
		  sta $F800 + 111 * 8
		  sta $C000 + 111 * 8
		  lda ANIM_TILE_BYTES + 8,y
		  sta $F800 + 111 * 8 + 1
		  sta $C000 + 111 * 8 + 1
		  sty PARAM1
		  lda #7
		  sec
		  sbc PARAM1
		  tay
		  ldx #0
-		
		  lda ANIM_TILE2_BYTES,y
		  sta $F800 + 143 * 8,x
		  sta $C000 + 143 * 8,x
		
		  inx
		  iny
		  cpx #8
		  bne -
		
		
+


And finally, the actual check for the water char (143) is enhanced:

;check if we're in water
		  ldy SPRITE_CHAR_POS_Y,x
		  lda SCREEN_LINE_OFFSET_TABLE_LO,y
		  sta ZEROPAGE_POINTER_1
		  lda SCREEN_BACK_LINE_OFFSET_TABLE_HI,y
		  sta ZEROPAGE_POINTER_1 + 1
		  lda SPRITE_CHAR_POS_X,x
		  tay
		  lda (ZEROPAGE_POINTER_1),y
		  cmp #111
		  beq .NextObject
		  cmp #143
		  beq .NextObject

Another enhancement, due to packing. Now that the packer takes care of putting the sprites and characters sets at their target location we can comment them out (plus their copy routines).
With ACME or the C64 Studio assembler you do it like this:

!ifndef CRUNCHED {
CHARSET
		  !binary "j.chr"
CHARSET_2		
		  !binary "j2.chr"
		
SPRITES
		  !binary "j.spr"
END_OF_FILE
}

That's all there is to this step, have fun!


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