Path: chuka.playstation.co.uk!news
From: Robert Swan <rs108@mdx.ac.uk>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: Re: How do I manipulate Pixels?
Date: Thu, 13 Aug 1998 13:56:49 +0100
Organization: I wish!
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References: <6qfcml$ldg12@chuka.playstation.co.uk> <35D05CE9.7B63@writeme.com> <35D1BFD1.434C188E@ndirect.co.uk>
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for a static effect how about creating a sample 32x32 pixel sprite with
16 colours (set to shades of grey) which you would draw on screen tiled,
and then chuck in various random numbers into the image part of the
sprite, before copying it to vram each time? would give random stuff
really.

Pseudo code starts here

#define SPRITE_TIM	(0x8009057843579843) // or whatever :)

u_short	*imageData = (u_short*) (SPRITE_TIM+4));

u_long	tCounterMax = (32/32)*32;
// number of u_shorts to create randomly
// function is (spritewidth/32) * spriteheight;

for (temp=0; temp<tCounterMax; temp++)
	{
	imageData[temp] = (u_short) rand();
	// rand gives a u_short number in a u_long result
	}

MoveImage(&Rectofimage, vramX, vramY);
// copy the new gibberish to vram



should that work? I think so. The random number bit might be crappy, but
you could fill it with other junk data grabbed from anywhere you want in
main memory.

Robert Swan
rs108@mdx.ac.uk