SET IMAGE COLORKEY 255,0,255
sync on : sync rate 0
set text font "arial" : set text size 16
set text to bold : set text transparent
rem Nice backdrop
rem load bitmap "parchment.jpg"
rem Produce Title
set display mode 640,480,32

ink rgb(255,255,255),0

load image "ship.bmp",1
sprite 1,0,20,1
sprite 100,0,20,1
create bitmap 3,640,480
create bitmap 2,640,480

rem Create an array to hold pixeldatas
bitsperpixel=bitmap depth()/8
workA = make memory(640*480*bitsperpixel)
maskmem = make memory(640*480*bitsperpixel)

fill memory workA, 384, 640*480*bitsperpixel
fill memory maskmem, 84, 640*480*bitsperpixel
lock pixels
pitch=get pixels pitch() : ptr=get pixels pointer()
workAptr=workA : linesize=640*bitsperpixel

unlock pixels

rem daves annoying mask test
shipxpos=350
shipypos=100
rem copy mask object to maskmem

imagenumber=1
enemyx=100
enemyy=100

boxcheckwidth=32
boxcheckheight=32
clboxy=20
clboxx=0

maskboxcheckwidth=36
maskboxcheckheight=32

rem Main loop

do
set current bitmap 0
set cursor 00,40
print screen fps(),"Y",shipypos," X",shipxpos
paste sprite imagenumber,enemyx,enemyy
paste sprite 100,shipxpos,shipypos

Gosub _GrabMaskArea

Gosub _GrabCollisionArea

Gosub _DrawMemoryToScreen

Gosub _xorCollisionData


if leftkey()=1 then shipxpos=shipxpos-1
if rightkey()=1 then shipxpos=shipxpos+1
if upkey()=1 then shipypos=shipypos-1
if downkey()=1 then shipypos=shipypos+1

sync
rem End loop
loop

rem Free memory
delete memory workA
delete memory maskmem


REM
REM ********** SUBROUTINES
REM

_GrabMaskArea:
REM grab mask area
   set current bitmap 3
   paste image 1,0,0
   lock pixels
   pitch=get pixels pitch() : ptr=get pixels pointer()
   workAptr=maskmem : linesize=640*bitsperpixel:widthsize=maskboxcheckwidth*bitsperpixel

   for y=0 to maskboxcheckheight
   copy memory workAptr, ptr, widthsize : inc workAptr,linesize : inc ptr,pitch
   next y
   unlock pixels
Return

_GrabCollisionArea:
REM grab collision area
clboxy=shipypos
clboxx=shipxpos
   set current bitmap 2

   paste image imagenumber,enemyx,enemyy

   lock pixels
   pitch=get pixels pitch() : ptr=get pixels pointer()
   workAptr=workA : linesize=640*bitsperpixel:widthsize=boxcheckwidth*bitsperpixel

   for y=0 to boxcheckheight
   copy memory workAptr, ptr+(clboxy*linesize)+(clboxx*bitsperpixel), widthsize : inc workAptr,linesize : inc ptr,pitch
   next y
   unlock pixels
Return

_DrawMemoryToScreen:
REM Draw Memory to screen
   set current bitmap 0
   lock pixels
   workAptr=worka
   pitch=get pixels pitch()
   linesize=pitch

   ptr=get pixels pointer()
   for y=0 to boxcheckheight
   copy memory ptr,workAptr, widthsize
   inc workAptr,linesize
   inc ptr,pitch
   next y
   unlock pixels
Return

_xorCollisionData:
REM xor collision data
   forceexit=0
   linesize=640*bitsperpixel
   for cheight=0 to maskboxcheckheight-1
   counter=1

   for cwidth=0 to maskboxcheckwidth-1
   objshape=maskmem
   collarea=worka

   inc  objshape,(cheight*linesize)+(cwidth*bitsperpixel)
   inc  collarea,(cheight*linesize)+(cwidth*bitsperpixel)

   inc counter,1
   x1 as byte
   x2 as byte
   x1=*objshape
   x2=*collarea

   collide = x1 && x2
   rem if collide=0 then print "O";
   if collide>0 then print "collide":forceexit=1:exit

   next cwidth
   if forceexit=1 then exit
   next cheight
Return