iOS and Cocos2d - Changing CCSprite's image AND new dimensions = FAIL

Question

One of the powerups in my game is a decrease in size of the main sprite. So for memory sake, instead of looping a sprite.scale through each frame, I resaved the sprite at a percentage size lower than the original sprite, and just wish to replace it. Then once "death" occurs or timer runs out, the original sprite returns.

So, I am using this code for making it small:

[player setTexture:[[CCTextureCache sharedTextureCache] addImage:@"player-small.png"]];

and this code for resetting back to normal:

[player setTexture:[[CCTextureCache sharedTextureCache] addImage:@"player-orig.png"]];

however, the orignal image (both in the init and when reset) looks normal. But when I change it to the new sprite (which has dimensions exactly 75% of the original), it changes it, but shows only a quadrant of the new sprite, but with the original dimensions.

I tried modifying the sprite.contentsize before retexturing the sprite, but all that did was change the size, but not affect the issue with the image messing up.

Here's some visual examples:

Original:

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Retextured Image with contentSize modification:

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Retextured image to the Original image with the contentSize not reset properly (oops, but this isn't a problem at all - i just forgot to readd the size code):

PS -- I do have "-hd.png" versions of all of my sprites, so i just wanted add that incase anyone wanted to know (the images and testing so far has only been on "nonretina" simulator).

THANK YOU!

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EDIT: Issue occurs during testing on retina simulator as well.

Answer 1

Since your main concern is about memory, I recommend to simply use a texture atlas.

I copied your original image into an image editing program to see what its dimensions are. The image is 73x71 pixels in size, that means it's stored in memory as a texture with dimensions 128x128 since textures will have power of two dimensions. This will have the texture use up 64 KB of memory (assuming 32-bit color depth). With a texture atlas you'll be able to pack your textures more tightly, and you can change the frame that is displayed more easily with the CCSprite setDisplayFrame method.

Furthermore, you are using the texture cache:

[CCTextureCache sharedTextureCache] addImage:@"player-small.png"]
[CCTextureCache sharedTextureCache] addImage:@"player-orig.png"]

Unless you explicitly free the memory of that texture, both textures will remain in memory anyway. If you do free the memory of the texture you're not currently using, and exchange these texture often, your game will spend a great deal of time releasing memory and reloading the image from the device's flash memory - even if the image is relatively small.

And if there's more than one sprite using either texture it wouldn't make any sense to try and unload/reload the textures because there will be occurrences where two or more sprites will use either texture.

Finally, we're talking about 64 KB of memory at most. If you're concerned about memory usage AND performance, the thing you should do is to load PVR textures instead, which are a fraction of the size of a PNG file both in memory and on disk (but losing some color vibrancy).

Have a look at TexturePacker for creating texture atlases and PVR images.