Lynx sprite format. Editing sprites programmatically.

[CabaretVoltaire]

What's the easiest way of editing sprites on the lynx?

 

I haven't done anything like this in a while so I'm a bit rusty.. I used to do alot of C but for the last few years I've been working in web development (html, javascript, etc) which has made me stupid So please go easy on me.

 

 

I have a sprite:

 

Image[]={0x00,0x00, etc

 

Which I want to be solid black for 64*32 pixels. First, how do I define a new line in the sprite? There doesn't seem to be anything in the sprite struct to define height and width, just hscale and vscale.

 

Second how can I toggle individual pixels in this sprite between black white?

 

Would something like this work?

 

void TogglePixel(int x,int y,unsigned char *Image){

int ArrayPosition = (64 * y)+x; //gets the pixel position

int nibble = (ArrayPosition & 1)<<4; //is pixel position odd or even?

 

//two pixels per byte so divide by 2

Image[(ArrayPosition>>1)]^=(0xf0>>nibble); //xor by 0xf0, or if pixel is odd xor by 0xf

}

 

 

Thanks

[eric_ruck]

You define a one pixel black sprite, then use hscale and vscale to cover the area you want...I'm feeling a bit hurried to look up the code now, PM me if you need and I can find it.

 

Eric

[CabaretVoltaire]

Hi Eric,

 

I can't use hscale/vscale as I want to be able to set individual pixels in the sprite.

 

 

I think I've worked out the sprite format now, I'm using a 64*32*1bpp sprite and I am able to toggle pixels on it fine

 

However I'm having problems with the compiler and pointers, grr.