A86: Erasing Old Sprites

To: <assembly-86@lists.ticalc.org>
Subject: A86: Erasing Old Sprites
From: "Super Llama" <diddy@apci.net>
Date: Mon, 31 Aug 1998 18:40:30 -0500
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-86@lists.ticalc.org


I am trying to learn asm, and I am working on a sprite demo.  This code
should draw a sprite and then when I press a directional key it should
delete the old sprite position and then draw it in the new sprite position
(deleting the old one).  I did not include the PutSprite routine because I
think everyone that could answer this question knows what the answer is.
The problem is it does not do this (what I explained above) so I was
wondering if anyone could help.

Anyway in case you dont know the variables:

cd = x,y coordinates
ix = the sprite to display

Also this is and 8x8 sprite rotuine that i got off of ticalc.org.

If anyone could help me I would be greaty appreciated.  Oh yeah and I
removed the comments for space concerns

#include "asm86.h"
#include "ti86asm.inc"

.org _asm_exec_ram

    call _clrLCD
    call BUSY_OFF
    jr Setup

Setup:
    ld b,0
    ld c,0
    ld ix,0
    ld ix,Dude
    call PutSprite
    jr Test

Test:
    jp ClearOld

Move:
    call GET_KEY
    cp K_EXIT
    jr z,Exit
    cp K_UP
    jr z,Up
    cp K_DOWN
    jr z,Down
    cp K_LEFT
    jr z,Left
    cp K_RIGHT
    jr z,Right
    jr Move

Up:
    ld a,c
    sub 8
    ld c,a
    jp DrawNew

Down:
    ld a,c
    add a,8
    ld c,a
    jp DrawNew

Left:
    ld a,b
    sub 8
    ld b,a
    jp DrawNew

Right:
    ld a,b
    add a,8
    ld b,a
    jp DrawNew

Exit:
    call _clrLCD
    ret

ClearOld:
    ld b,b
    ld c,c
    ld ix,0
    ld ix,Clear
    call PutSprite
    jp Move

DrawNew:
    ld ix,0
    ld ix,Dude
    call PutSprite
    jp Move

Dude:
.db %01110000
.db %01110000
.db %00100000
.db %00100100
.db %01111110
.db %00110100
.db %00111000
.db %01101100

Clear:
.db %00000000
.db %00000000
.db %00000000
.db %00000000
.db %00000000
.db %00000000
.db %00000000
.db %00000000
.db %00000000

.end
.end