Problem with graphics.c

Tydude4Christ · Post by **Tydude4Christ** » Wed Jan 21, 2009 10:35 am

I'm currently using this lib to display a background and then my character sprite. When I move the character, which actually is moving my background pic, I see that the bottom half of my screen is getting "refreshed" faster than the top half of my screen.

Here's what I am doing.

Code: Select all

clearScreen&#40;black&#41;;
blitAlphaImageToScreen&#40;0 ,0 ,480 ,272 , background, x, y&#41;;
blitAlphaImageToScreen&#40;0 ,0 ,32 , 32, currentMainImage, mainCharXPos, mainCharYPos&#41;;
flipScreen&#40;&#41;;

Does anyone have any thoughts or suggestions?

Art · Post by **Art** » Wed Jan 21, 2009 11:16 am

Well there's going to be a problem when you draw the background image 480x272 at any coords other than 0,0
because you'll be trying to draw some of the background off the screen otherwise.

So look into a tile engine.

Tydude4Christ · Post by **Tydude4Christ** » Wed Jan 21, 2009 11:37 am

The background image is actually just temporary. Currently, I'm just testing my character's movement. Eventually, I'll create a tile engine. I was just wondering whether the scanning problem would occur then. Thanks for the reply.

Art · Post by **Art** » Wed Jan 21, 2009 11:42 am

You've also forgotten the sceDisplayWaitVblankStart(); before the flipscreen.

Tydude4Christ · Post by **Tydude4Christ** » Wed Jan 21, 2009 11:50 am

It appears sceDisplayWaitVblankStart() was my problem all along. It now works even when my background is not at (0,0). Thanks for the help.

Heimdall · Post by **Heimdall** » Wed Jan 21, 2009 6:28 pm

Sorry for the naive question, what library is that? can you give a link?

Thanks!

Torch · Post by **Torch** » Wed Jan 21, 2009 6:58 pm

You of all people should know, its from lua player.

However it will be inefficient for games because it syncs the gu after each of those function calls. You can't queue up all your drawing into the dlist before execution.