I have an app based on "OpenGL Game" Xcode template, for everyday testing/dev I would like to render full screen but at lower resolution in simulator (e.g. 1/2 or 1/4). Any efficient/savvy way to put this in place?
(in case anybody wonder, I want to do this because my app is running very slow in simulator, so rendering at a smaller resolution would make testing/debugging a lot more programmer-friendly)
The contentScaleFactor of the view is 2.0 by default on a Retina display. If you reduce the scale factor, GLKView automatically uses a smaller framebuffer and scales its contents up to screen size for display.
Scale factor 1.0 is half size (or the same number of pixels as a non-Retina screen). 0.5 would be quarter size — big, chunky pixels on any display. Non-integral scale factors between 1.0 and 2.0 work, too, and can be a great way to compromise between quality and performance on a Retina display.
Update: just had a vote remind me of this answer. I'm surprised I wouldn't have said this originally, but I may as well add it now...
The iOS Simulator runs OpenGL ES using a software renderer (i.e. on the host Mac's CPU, not its GPU). That's why it's slow. Performance characteristics and rendering results can vary from renderer to renderer, so never trust the simulator for anything OpenGL/GPU-related (except perhaps in very broad strokes).
Related
Why do we need these 3 particular image types?
If I have a button on my app with a background image say, 50 pixels x 50 pixels, why do I need 3 versions of this image? What's stopping me from just making one image that's much higher in res, say, 700x700 so when it shrinks down on any iPhone it won't fall under the max res the device would want?
Only thing I can think of is it just takes up more space, but for simple apps / a simple button it seems like it wouldn't cause any issues. I've tried it on a few devices and see no difference between them when I simulate it and do this method. However, as I dive more into apps and stuff I'm sure there is substance behind this technique.
If you don't have the exact size, there are two things that can happen:
Upscaling
#3x or #2x can be upscaled from #1x but usually the visual result is blurry, with thick lines and doesn't look good. Upscaling #3x from #2x can be even worse because subpixels must be used.
Downscaling
In general, the results are much better than with upscaling, however, that doesn't apply for all the images. If you have a 1px border on a #3x image, after downscaling it to #1x the border won't be visible (0.33px). The same applies for any small objects in the image. Downscaling destroys all details.
In general - for an image to look perfect, you want to avoid both downscaling and upscaling. You can always go with only #2x or #3x images and add other scales only if you see visual problems. Using higher resolution won't improve downscaling. High resolutions are used only to avoid upscaling. Downscaling from a high scale (e.g. #100x) to #1x won't create better results than downscaling from #3x.
You need 3 kinds of images in Image Assets because in terms of Scaling or Pixels
There are 3 kinds of Apple Devices (iPhone and iPad) that is
Normal device which terms to 1 pixel = 1 point#1x (Older iPhone and iPad devices)
Retina device which terms to 4 pixels(2 x 2) = 1 point#2x (iPhone 4+)
Retina iPhone6 and iPad which terms to 9 pixels (3 x 3) = 1 point#3x (iPhone6+)
Thus for providing same image in 3 scales iOS decides which image to show for which devices.Hope could help you understand this.
EDIT
It is because if you provide one high resolution graphic it would be waste of space on a users' device. Thanks to app slicing the device will download (from App Store) only the parts that actually fits the device (so retina device won't download non retina graphics). This is why Apple created assets catalogs and this kind of rules to follow. They describe it in their sessions.
In short it is to decrease memory/disk usage so it is all about increasing performance and user experience
First of all, you need to know points vs. pixels behaviour. On non-retina devices, point vs pixels ratio is 1point=1pixel. On retina devices, there are two ratios: 1point = 2x2 pixels depending on screen size, and 1point=3x3 pixels, because of pixels density, that is quadrupled watching on non retina. That's why you need this 3 types of images, to be shown on its highest resolution.
Complementing what Sulthan said:
Because you didn't propitiated proper images for a specific device, it has to downscale or upscale. These processes will use up your memory and processing, resulting maybe in a decrease of performance, depending on how many images at a time you're doing it and the size of image.
If you provide only one big image you encounter several problems:
Downscaling leads to the loss of quality (even if it is not huge)
It takes more computational power to downscale the image than to display the already pre-rendered image
The size of your binary gets increased and you are not able to benefit from app thinning which is introduced with iOS 9.
As you can see, producing only one image will impact the performance and quality of your app and it will disproportionately hit those with older devices. This is because:
They need to downscale more. Also, the performance of their devices is not as good as that of the new ones, so they are much more likely to notice the lags with your app
They do not have as much storage space so you really want to be able to use app thinning to help them
The loss of quality will be the highest for them and considering the fact that the resolution of their devices is low, they will notice it.
Due to this users are likely to be unhappy and this is bad for you. Because, from my experience, unhappy users are 10 times more likely to rate your app than happy users. You don't want that, do you? :)
I've been experimenting with createjs to convert some flash as3 animations to HTML5. everything works fine in desktop browsers, but on an i-pad the animation are considerably slower. Where there are complex vector objects they are so slow as to be unusable. I can speed things up by caching the objects, but the quality of the resulting graphics is poor. Are there any solutions to this problem?
Thanks in advance
Pete
take a look on canvas size. after a centain size the mobile vídeo boards cannot accelerate the graphics like pc does.
Tip #4. Watch The Size of Your Canvas
Obviously, the larger the canvas the more costly the drawing
operation, but if you’re targeting mobile devices, there are some size
limits you must keep in mind.
From Safari Web Content Guide:
The maximum size for a canvas element is 3 megapixels for devices with
less than 256 MB RAM and 5 megapixels for devices with greater or
equal than 256 MB RAM
So if you want to support Apple’s older hardware, the size of your
canvas cannot exceed 2048×1464.
But that’s not all! Even with smaller sizes, you have to keep your
canvas’s aspect ratio between ~3/4 and ~4/3. If you step outside those
boundaries, webkit seems to switch to a totally different rendering
mode splitting the canvas into multiple fixed-size areas and rendering
them separately with a noticeable delay between them.
There doesn’t seem to be any documentation on this but I have
confirmed this happens on both Chrome and Safari on iOS versions 6.0.1
and 5.1.1.
source http://blog.toggl.com/2013/05/6-performance-tips-for-html-canvas-and-createjs/
If you have an app that works fine on non retina devices, and then you deploy it on a retina device, without providing the requisite #2x images, what side effects could occur?
high memory usage? crashing of the application?
No, the events you mentioned will not occur. However, obviously your images will look terrible as they will not scale properly (therefore they will be pixelated and incorrect sizes etc.).
There isn't any point in not using retina images - all you have to do is add #2x to the images and double the image size, and they will scale correctly for both non-retina and retina display.
If you do not include #2x images, then the device will automatically stretch the image on a retina device to take up the same room (enlarge the image).
The scaling method that UIKit uses does not do any interpolation. Instead, it merely doubles the size of every pixel ("nearest neighbor" scaling). For images of squares with hard edges, that works fine. However, for photos or most artwork, the image ends up looking very pixelated (has artifacts).
Scaling the images up on a retina device is not performance intensive because of the simple scaling method that is employed. It is not likely to affect performance, only image quality.
If you include only high resolution images, they are not automatically scaled down for the non-retina device. Instead, for an UIImageView, for instance, you would set the view mode to Scale to Fill, so that the image scales down to fit the frame. However, again, UIKit uses the nearest neighbor, but when scaling down, artifacts are less noticeable.
The newer, retina devices are more performant, so they are able to handle high resolution images at the same speed as non-retina devices can handle the low resolution images, and scaling images up is trivial for them. However, older non-retina devices will simply be slower with high-resolution images which require more memory and more graphics power, especially since it has to scale them down as well.
This is very noticeable if you have high resolution images in a UITableView. Your retina device will scroll the table very smoothly, whereas you will notice some jitter on the non-retina device. It will not crash, it just won't be smooth. If the user experience is too bad, your app could be rejected. For static, non-moving images, there is unlikely to be much noticeable performance difference.
If you have room in your bundle, you should include both retina and non-retina images. Even if you simply double the image size in a nice photo editor like Photoshop to create your #2x images, the images will be of much nicer quality than what UIKit produces.
Remember that if your zipped app bundle is over 50 MB, it can only be downloaded via WiFi from the App Store. PNGs and JPEGs do not compress much since they are already compressed. That is one reason why you might choose to only include high resolution images (to keep the size of your app bundle down, especially for a universal app, where you might end up having 4 sets of images).
Of course you can provide only retina or even only non-retina images.
We did some testing on this matter a few month ago.
Only non-retina images resulted - as expected - in poor graphics. Even an non-trained eye could notice the blurrines.
Only retina images: it works. But memory footprint is bigger (for non-retina devices that would otherwise load non-retina images) and some lag could be noticed. Though we had to measure it to be sure.
To answer your question: zenith provided the answer. If you only provide non-retina images the graphics on retina devices will be blurry, but no low-memory condition could emerge because of this.
EDIT:
Unless you are doing some kind of research on graphics capabilities of different iOS devices i'd strongly suggest to provide both types of images: retina and non-retina.
If your designer is giving you hard time because of this you can do few things:
get a new designer
provide him some kind of tool to make his job easier: Unretiner for example
Kind of a fun question. I am hoping that is generates a lot of good thinking.
I am in the design, early alpha stage of my current orthogonal game project. I am experimenting with different tile sizes. A few questions as I would like to step off on the right foot.
Should we differentiate tile size (80x80, 32x32 etc) on retina vs. non retina displays, iPhone vs iPad displays?
What is a good recommended tile size that accommodates both the designer and the artist... and why?
Goals:
I would like to a clean, crisp visuals no matter the display format. Cartoony, colorful 16bit to 32bit images no matter the display.
I would like to keep to a 1024x1024 texture size for my atlas. I am hoping this will give me enough tiles to make the world look good and not crush my tile map system.
My current map size is 200 tiles wide x 120 tiles high. The map will be a a low detail (nautically focused) mercator projection of Earth.
Thanks in advance for all the good advice.
E
I usually try to make my games for iPad screen aspect where I'm making sure that the important elements are in a smaller Safe Zone. And the UI can be anchored on specified distance from the edges. Then for iPhone screen aspect I crop a small portion of the screen and layout the UI accordingly.
So if you are working in landscape here are the sizes you need to support:
480x320 - iPhone (0.5)
960x640 - iPhone Retina (1)
1024x768 - iPad (1)
2048x1736 - iPad Retina (2)
The number in brackets indicate the scale. I just like picking iPad (1024x768) for my ingame units. At this point I have all textures in 3 sizes, since I'm using OpenGL I use different mipmaps for each resolution I need. My texture loading function can skip mipmap levels so that on devices that I don't need high res I safe memory and loading time.
Depends if you need to click on individual tiles. In case you need to I'll suggest using 64x64 on iPhone (480x320) 256x256 on iPad Retina (2048x1736). Having all your art in power of 2 is always good. If the size is too large then consider 48x48 for iPhone and 192x192 for iPad Retina. If your game requires you can have smaller tiles but consider having larger active zone around the entities that you have to click (hopefully not every tile will be clickable).
I faced a similar issue a while ago and realized I was tackling the problem from the wrong angle.
You first need to consider the average finger/thumb size of the user and determine how many pixels/points consume that space.
From there you can derive the non-Retina Display pixel units and Retina Display point units to use.
N.B. that a game that might play well on the iPad might not work on the iPhone if the user's fingers obscure the view.
I'm planning on making my first game in xna (simple 2d game) and i wonder which screen resolution that would be appropriate to target the game against.
Resolution for a 2D game is a difficult issue.
Some people ignore it. World of Goo (for PC), for one very famous example, simply always runs at 800x600 on the PC, no matter what. And look how successful it was.
It helps to think about what kind of device you will be targeting. Here are some common resolutions and the devices they apply to:
1280x720 (720p, Xbox 360 "safe" resolution - free hardware scaling, works everywhere)
1920x1080 (1080p, Xbox 360 maximum resolution - can't auto-scale to all resolutions)
800x480 (Windows Phone 7)
1024x768 (iPad)
480x320 (iPhone 3GS and earlier)
960x640 (iPhone 4 retina display)
Android devices also have similar resolutions to WP7 and iOS devices.
(Note that consoles require you to render important elements inside a "title-safe" area or "action-safe" area. Typically 80% and 90% of the full resolution.)
Here is the Valve Hardware Survey, which you can see lists the common PC resolutions (under "Primary Display Resolution").
Targeting 800x480 for a mobile game, or 1280x720 for a desktop/console game, is a good place to start.
If you do want to support multiple resolutions, it is important to think about aspect ratio. Here is an excellent question that lists off some options. Basically your options are letter/pillar-boxing or bleeding (allowing for extra rendering outside "standard" screen bounds - like a title-safe area), or some combination of the two.
If your graphics need to be "pixel perfect" and simply scaling them won't work, then I would recommend targeting a series of base resolutions, and then boxing/bleeding to cover any excess screen on a particular device. When I do this, I usually provide assets for these target screen heights: 320, 480, 640, 720, 1080. Note that providing 5 versions of each asset is a huge amount of work - so try to use scaling wherever possible.
Many choices about resolution handling will depend on what style of game you are making. For example: whether you try to match a horizontal or vertical screen size will depend largely on what direction your game will mostly scroll in.
When I first started with c++ graphics I used 320*240, or 800*600 when I had to use larger images. But it's really up to you, whatever you prefer. As long as you don't use stupid values like 123*549 or something.
'normal' resolutions include but are not limited to:
160*120
320*240
640*480 (probably the most common)
800*600
1024*768