I want to port a game I've made which renders the screen itself 50 fps (doesn't use opengl).
What is the best way to port this to the iPhone?
I was reading about Framebuffer Objects. Is this a good approach to render a buffer of pixels to the screen at high speeds?
The fastest way to get pixels on the screen is via OpenGL.
Need more info about how your game currently renders to the screen, but I don't see how FBOs will help as they're usually used for getting a copy of the render buffer, i.e. for creating a screen recording, or compositing custom textures on fly.
If i ever need to create an app where I have to access the pixels directly and dont have direct access to the hardware I use SDL as it just requires you to create a surface and from there you can manipulate the pixels directly. and as far as im aware you can use SDL on the Iphone, maybe even accelerate it using opengl too
Related
This is for Unity3D 4.3+
I have a ridiculously large background I wish to use for a 2D scroller game. The background is 10 times the width of a landscape device (10240 x 1024). (The basic loop background goes behind that and is not an issue.)
I understand I can cut the background into 10 images of 1024 x 1024 each (basic sprites). But, I'm unsure of the best approach to go forward...
One way is to pre-load all the background sprites and then do a simple scrolling of them all. But take too much memory.
However, keeping in mind this is aimed for mobiles and tablets, isn't possible to do a loading/offloading of the background as the player progresses? Like this: Initially load 2 background images (bg-1 and bg-2).
Once the camera has passed bg-1, the unload bg-1 and load bg-3. Then when player passes bg-2, then offload bg-2 and load bg-4 and repeat. Thus only 2 bg images loaded at a time.
The player can not go backwards, so that helps me in this scenario.
Any thoughts on the best approach?
Thank you.
You can use Resources.Load function to load assets dynamically(link). Or just load them all in a list and reference from there.
Im just wondering what would the best way to display multiple instances of a small (10x1) image. I have an array of about 480 points and I would like to draw the image at each of these points to draw path. Would it be faster to use Core Graphics or should I be using something like cocos2d?
It depends on whether you need it to animate. Core Graphics is probably fine if you are drawing it once and then displaying it as an image, but it it will be really slow if you need to redraw it each frame.
UIKit is actually much quicker because UIView drawing is hardware accelerated, so you could just add a UIImageView for each point in the graph, but from my own experiments that will probably be too slow for realtime interaction if there is more than about 200 image views (at least if you want it to run on anything older than an iPhone 4S).
If you do need realtime performance, that really only leaves OpenGL, which is quite fiddly to set up unless you use a library like Cocos2D or Sparrow to simplify it. I'd suggest Sparrow for your purposes because Sparrow views can be used in a regular UIKit application, whereas Cocos2D provides a whole app framework and is harder to use for just a single view in an otherwise regular UIKit app.
http://www.sparrow-framework.org/
Without more context, another option is to use OpenGL and create a display list for the composite image.
Im working on an iphone platforms game developed using cocos2d and box2d which has to use a very large image as a background, my question is this:
-which is the better way to load the image?? (I'm talking about an image which can be 14K pixels long), is it better to cut in smaller images an keep loading them as the player moves??
-Should I keep in memory as invisible or use the addChild method to load them as I need them and the removeChild to remove the previous one?
Thanks in advance, any answer will be welcome :)
You can't use textures larger then 1024x1024 or 2048x2048 for iphone/ipod 4 (maybe iPad too). So the only way to render such big image is rendering it's parts.
I would try to load the parts as the player moves (better in a separate thread).
Also maybe it is possible for you to use Parallax background. If so - use it.
If your image is made from a lot of identical parts then it's a good idea to use CCTMXTiledMap.
I want to render a splash screen on the iPhone whilst using an Open GL view. The iPhone screen as we know is 320x480, which is not a power of 2.
Before I enter into the world of chopping the texture up and rendering sub parts, or embedding the screen on another texture page I was wondering if there was another way?
Is it possible to overlay another view that I could render to using CoreGraphics functions? Or is it possible to render to a Open GL surface using Core Graphics functions.
What would you recommend?
Cheers
Rich
Its entirely possible to write some code, which creates a 512x512 texture, load an image into it and then render only a portion of that texture (by mapping onto a polygon and altering the texture mapping UV co-ordinates).
This method is best for static images only, you couldn't really perform pixel-by-pixel real-time updates for this; updating the texture via open GL ES is currently too slow.
I would recommend that you read Apple's Human Interface Guidelines for iPhone, especially the several parts where they warn you over and over not to make splash screens.
I'm developing a 2D game for the iPhone using OpenGL ES and I'd like to use a 320x480 bitmapped image as a persistent background.
My first thought was to create a 320x480 quad and then map a texture onto it that represents the background. So... I created a 512x512 texture with a 320x480 image on it. Then I mapped that to the 320x480 quad.
I draw this background every frame and then draw animated sprites on top of it. This works fine except that the drawing of all of these objects (background + sprites) is too slow.
I did some testing and discovered that my slowdown is in the pixel pipeline. Not surprisingly, the large background image is the main culprit. To prove this, I removed the background draw and everything else rendered very fast.
I am looking for advice on how to keep my background and also improve performance.
Here's some more info:
1) I am currently testing on the Simulator (still waiting on Apple for the license)
2) The background is a PVR texture squeezed down to 128k
3) I had hoped that there might be a way to cache this background into a color buffer but haven't had any luck with that. that may be due to my inexperience with OpenGL ES or it just might be a stupid idea that won't work :)
4) I realize that the entire background does not always have to refresh, just the parts that have been drawn over by the moving sprites. I started to look into techniques for refreshing (as necessary) parts of the the background either as separate textures or with a scissor box, however this seems less than elegant.
Any tips/advice would be greatly appreciated...
Thank you.
Do not do performance testing on the simulator. Ever!
The differences to the real hardware are huge. In both directions.
If you draw the background every frame:
Do not clear the framebuffer. The background will overdraw the whole thing anyway.
Do you really need a background texture ?
What about using a color gradient via vertex colors ?
Try using the 2bit mode for the texture.
Turn of all render steps that you do not need for the background.
E.g.: Lighting, Blending, Depth-Test, ...
If you could post some of your drawing code it would be a lot easier to help you.
If you're making a 2D game, is there any reason you aren't using an existing library? Specifically, the cocos2d for iPhone may be worth your time. I can't answer your question about how to fix the issue doing it all yourself, but I can say that I've done exactly what you're talking about (having one full screen background with sprites on top) with cocos2d and it works great. (Assuming 60 fps is fast enough for you.) You may have your reasons for doing it yourself, but if you can, I would highly suggest at least doing a quick prototype with cocos2d and seeing if that doesn't help you along. (Details and source for the iPhone version are here: http://code.google.com/p/cocos2d-iphone/)
Thanks to everyone who provided info on this. All of the advice helped out in one way or another.
However, I wanted to make it clear that the main issue here turned out to be the behavior of simulator itself (as implied by Andreas in his response). Once I was able to get the application on the device, it performed much, much better. I mention this because, prior to developing my game, I had seen a lot of posts that indicated that the device was much slower than the simulator. This might be true in some instances (e.g. general application logic) but in my experience, animation (particularly 3d transformations) are much faster on the device.
I dont have much experience with OpenGL ES, but this problem occurs generally.
Your idea about the 'color buffer' is good intuition, essentially you want to be storing your background as a frame buffer and loading it directly onto your rendering buffer before drawing the foreground.
In OpenGL this is fairly straight forward with Frame Buffer Objects (FBO's). Unfortunatly I dont think OpenGL ES supports them, but it might give you somewhere to start looking.
you may want to try using VBOs (Vertex Buffer Objects) and see if that speeds up things. Tutorial is here
In addition, I just saw, that since OpenGL ES v1.1, there is a function called glDrawTex (Draw Texture) that is designed for
fast rendering of background paintings, bitmapped font glyphs, and 2D framing elements in games
You could use frame buffer objects similar to the GLPaint example from Apple.
Use a texture atlas to minimize the number of draw calls you make. You can use glTexCoordPointer for setting your texture coordinates that maps each image to its correct position. Remember to set your vertex buffer too. Ideally one draw call will render your entire 2D scene.
Avoid enabling/disabling states where possible.