Continuing the discussion about memory problems.

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Continuing the discussion about memory problems.

(8 posts) (3 voices)

Started 2 years ago by Nicke
Latest reply from Steve Oldmeadow

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Nicke
Member

Since Evil Google decided our charming little group is in fact a terrible gang of evil Sith lords bent on spam domination, I figured I'd continue this topic:

http://groups.google.com/group/cocos2d-iphone-discuss/browse_thread/thread/693de2fbaa0bfa42#

On these boards instead...

Now, in response to Steve:
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What is 2Mb, the combined total of the files? If so, that is
irrelevant. What matters is the dimensions of your images, the bit
depth and how many you have. My guess is you really are running out
of memory and probably need to look at using sprite sheets to use
texture memory more optimally.
------------------------------------------------------

2 Mb is indeed the combined total of all the files. My game works now, after "tuning down" the quality of the sprites using the new features in 0.7.3:

[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGB5A1];

But it's still using way too much memory. Now, I've been able to gather bits and pieces of information suggesting that using an AtlasSpriteManager, and storing my animations in a sprite sheet would be much more memory-friendly. Now, I've got a couple of questions which I'd be happy if someone could answer or link to relevant articles/wikipedia pages for (not just for me, but as future reference material).

1. Why is one 1024x1024 image more memory-friendly than ten 102x102 images?

2. What is the easiest way to convert a bunch of animation frames, stored as individual PNG's, to a sprite sheet on a Mac ?

3. Is there something further I should keep in mind when generating these sprite sheets, like the optimal size of the sheet? Should it be 1:1, rather than 1:2 in width/height ?

4. Say I have 10 frames measuring 187x140 in size and I line them up in a sprite sheet in five rows and two columns.

I create my sprite manager:

AtlasSpriteManager *mgr = [AtlasSpriteManager spriteManagerWithFile:@"ninja_dance.png" capacity:10];

I then create an AtlasSprite which would be the default state of my player character: (not 100% sure this is correct)

AtlasSprite *sprite = [AtlasSprite spriteWithRect:CGRectMake(x,y,187,140) spriteManager:mgr];

Now, how do I go about adding the rest of the frames to an AtlasAnimation and how do I activate the animation itself? Does it work like the regular Animation class or do I have to keep something special in mind when using it ?

I know I'm asking for a lot but I think there are lots of new developers pondering the same questions and hopefully the answers in this topic will answer the questions of many people, myself just being one of them.

Best regards,

Nicke.

Posted 2 years ago #
Steve Oldmeadow
Administrator

Question 1 - because 10 102x102 images actually require 10 128x128 textures.

Question 2 - there was a topic specifically on spritesheet tools in the old forum.

Question 3 - textures have to be square with power of two dimensions on current iDevices.

Question 4 - look at the demo.

Posted 2 years ago #
Nicke
Member

Steve to the rescue again it seems :). Thanks for your answers.

A bit of follow-up:

1. Is there a maximum texture size ? I assume there is or people would just stick all their sprites into one huge image.

2. Which texture sizes are supported? from 2x2 to 4x4, ......, 128x128, 256x256, 512x512 and so on?

3. Does anyone have any good links where I can read up more on the subject of textures and optimizing graphics for embedded systems?

Thanks again,

Nicke

Posted 2 years ago #
Steve Oldmeadow
Administrator

On current devices max size is 1024x1024. On the new iPhone it is 2048x2048.

Power of two dimensions are supported, but from memory there may be an issue with 8x8 and/or below.

The Apple iPhone developer web site has lots of good information. The manufacturers of the GPU also have some good info, Google "PowerVR". Finally, the old group had lots of good info. You can still search it via Google.

Posted 2 years ago #
Codemattic
Moderator

"Question 3 - textures have to be square with power of two dimensions on current iDevices."

Is this true? I thought that regular textures could be non-square as long as each side was a power of two. Although PVRTC textures are required to be square.

Posted 2 years ago #
Codemattic
Moderator

"1. Why is one 1024x1024 image more memory-friendly than ten 102x102 images?"

As Steve explained, a 102x102 image is stored on a 128x128 sized texture. But just fyi your math is still off bc you cant take a squared number and just divide by X and get X # of new smaller squares with the same area. You need X^2.

1,024 x 1,024 = 1,048,576 pixels
10 x 102 x 102 = 104,040 pixels

Posted 2 years ago #
Nicke
Member

Codemattic: What can I say, not enough coffee =). My little example is indeed extremely flawed.

As reference for others interested in the same thing, here are some links I found helpful:

http://www.amake.us/software/pngcrusher/ - reduce the size of your PNG's, improve loadtimes (does -not- affect device memory consumption)

http://jbullfrog.com/froglog/?p=323 - Create PVRTC images from .PNG files. PNG's size -must- be power of 2, e.g 128x128

http://csx.riaforge.org/ - Plugin to Photoshop, generates sprite sheets from single animation frames.

http://www2.tech.purdue.edu/cg/Courses/cgt211/lectures/CGT211-Lect02-Raster%20Graphics%20and%20Resolution.pdf - Nice info about graphics, calculating size of textures (page 5).

I hope this helps people facing the same problem as me.

Best regards,

Nicke

Posted 2 years ago #
Steve Oldmeadow
Administrator

Disregard what I said about textures having to be square. Codemattic is correct, only PVRTC images need to be square.

I did a test with 32x1024 textures at 32 bits and each new instance only increased texture memory usage by 131,072 bytes.

The GARTResident Object Size measurement in instruments can be a bit confusing because there seems to be around 1 - 2Mb of it used for something other than your textures but by adding in textures and examining the memory increase I was able to determine how much memory usage was due to the texture.

Posted 2 years ago #

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