Sprite Tile Order Corruption

[TechnoZealot]

So I've noticed that if I load a 32x32 bitmap with VDP_loadBMPTileData() that displays entirely correctly if I display it to the screen on Plane A with VDP_fillTileMapRectInc() will have it's 8x8 tiles all jumbled up when displayed as a sprite.

I am loading it (to swap the picture) periodically in my game loop, and this probably is suboptimal, but nevertheless, I don't think it is the problem.

Here is my sprite code:

Code: Select all

#include <genesis>
#include "ship1.h"

int main()
{
	VDP_setPalette(PAL0, ship1.palette);

	VDP_loadBMPTileData((u32*) ship1.image, TILE1, ship1.w/8, ship1.h/8, ship1.w/8);

//This works!
	VDP_fillTileMapRectInc(APLAN, TILE_ATTR_FULL(PAL0, 0, 0, 0, TILE1), 15, 15, ship1.w/8, ship1.h/8);


	SpriteDef myShip;
	
	myShip.posx = (320-ship1.w)/2;
	myShip.posy = (224-ship1.h)/2;
	myShip.size = SPRITE_SIZE(4,4);
	myShip.tile_attr = TILE_ATTR_FULL(PAL0,1,0,0,TILE1);
	myShip.link  = 0;
	

	VDP_setSpriteP(0, &myShip);

	VDP_updateSprites();

	while(1)
	{
		VDP_waitVSync();
	}
}

What's wrong here?

[djcouchycouch]

By "jumbled", do you mean that the tiles are random or that the order is incorrect?

Something like:

What you want:

ABC
DEF
GHI

What you get:
ADG
BEH
CFI

Meaning that the rows and columns are swaped?

[TechnoZealot]

Exactly. they are swapped.

Here's what it should look like:



Here's what it ends up looking like:

[kubilus1]

The tile order will be different for the sprite than the straight up BMP. I posted a link on another question of yours where I address this question exactly with a shell script to arrange the tiles of a BMP into a spriteable format.

I believe there are some other tools to do this (Genres?) Take a look at some of the tutorials on the SGDK website: https://code.google.com/p/sgdk/wiki/SGD ... al#Sprites

Some of the examples are out of date, but the general ideas should hold.

[TechnoZealot]

Thank you very much! This is invaluable!

Somehow I didn't quite understand your link earlier. Now it makes perfect sense! Sorry about that!

[kubilus1]

Not a problem at all! Glad to be of assistance.