Path: chuka.playstation.co.uk!news
From: "Mario Wynands" <mario@sidhe.co.nz>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: Filling the screen with boxes
Date: Sun, 27 Dec 1998 12:28:31 +1300
Organization: Sidhe Interactive
Lines: 94
Message-ID: <763r2u$2299@chuka.playstation.co.uk>
References: <762se1$2296@chuka.playstation.co.uk>
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Rad wrote in message <762se1$2296@chuka.playstation.co.uk>...
>I'm having problems trying to fill the screen (320x240) with boxes
(GsBOXF).
>Now if I use boxes of width and height 1 then I need 76800 boxes to fill
the
>screen - which I have tried and it hasn't worked probably because it
>requires way to much memory. So I changed the box sizes to 4x4 meaning that
>I would only need 4800 to fill the screen but this only works if I start
>drawing the boxes at line 12?
>Here is some example code:
>
>// declaration
>
>GsBOXF box[80][60];


You probably don't need to do this.  Using a single GsBOXF structure and
modifying the attributes on the fly within your drawing loop will save a lot
of memory (once you use a structure to put stuff in an ordering table you
can modify its attributes and reuse it without affect previous entries in
the ordering table).  Same principle also works for sprites etc.

>// drawing
>
>for (y = 0; y < 240; y++)          // this needs to be "for (y = 12; < 240;
>y++) " to work
>  for (x = 0; x < 320; x++)
>    GsSortBoxFill(&box[x][y], &WorldOT[acvtiveBuffer],0);


This doesn't look right.  Given the array declaration at the top you are
overstepping the boundaries of your array (80x60) using this loop (320x240).
Something like

// drawing

for (y = 0; y < (240/4); y++)
  for (x = 0; x < (320/4); x++)
    GsSortBoxFill(&box[x][y], &WorldOT[acvtiveBuffer],0);

would work better (you may not have changed the for loops when you changed
the width of the boxes).

It also sounds like your drawing environment is set up so that coordinate
(0,0) is at the centre of the screen.  Either change it (or compensate in
your code.

Also, for slightly more flexible code try using 'defines' a bit more.  That
way when you change the parameters of your algorithm you don't have to go
through your code and change stuff everywhere.

So, altogether this looks like ....


#define SCREEN_HEIGHT    240
#define SCREEN_WIDTH     320
#define BOX_HEIGHT           4
#define BOX_WIDTH             4

GsBOXF    box;

// .......

box.h = BOX_HEIGHT;
box.w = BOX_WIDTH;

for (y = 0; y < (SCREEN_HEIGHT/BOX_HEIGHT); y++)
  for (x = 0; x < (SCREEN_WIDTH/BOX_WIDTH); x++)
  {
    // put your attribute changing code in here eg
    box.x = x * BOX_WIDTH - ((SCREEN_WIDTH / BOX_WIDTH) / 2);  // last bit
compensates for drawing offset
    box.y = y * BOX_HEIGHT - ((SCREEN_HEIGHT / BOX_HEIGHT) / 2);
    box.r = box.g = box.b = 255;    // colour = white
    // i'll assume you are actually going to do something more creative with
the colour

    // then draw it
    GsSortBoxFill(&box, &WorldOT[acvtiveBuffer],0);
  }



Hope this helps


Mario Wynands

Director/Project Manager, Sidhe Interactive
Sony Playstation Software Development House

Email mario@sidhe.co.nz Website www.sidhe.co.nz