I have been having a bit of trouble with this issue with a while and have decided to ask for help!
I have a textured 1024 x 1024 area in my iphone application. I am texturing it using an image that i converted to .pvr4 format using Apples texturetool.
Now the user has the option of zooming in on this textured object....
The issue is that the quality of the image is not good enough when it is at the highest zoom level.
How can i improve this?
Should i be looking at mip mapping?
Any pointers in the right direction would be greatly appreciated.
Thanks
Tom
If you zoom in enough on any texture, you won't see much detail.
Here are your options:
You can change the magnification filtering mode so that instead of being blocky (nearest filtering), it's blurry (linear filtering). (Or vice-versa.)
Don't use PVR texture compression. This will make your texture more detailed. (But at the usual cost: larger size, slower rendering.)
When zooming in, switch to a more detailed texture for that specific area.
The last option is the most work, but will likely give the best results. (But try the other two, they're easy.)
Also, mip-mapping likely won't help your situation. In general, enabling mip-mapping can make textured objects far away from the camera look better. It usually doesn't have any effect when the camera is close to a textured object.
PVR4-compression is rather destructive. Simply choose another format if texture quality is crucial.
Related
I have a problem with an smartphone (android so far) app I am programming in unity3d.
I got the following set up:
I have a sphere on which, so far, I have a texture of the world. It's resolution is already set to the maximum but when I "zoom in" on it it just looks disgusting. I'd like to reload texture tiles like in Google maps to have a higher resolution without having a too big impact on the memory. Is that approach a good one at all? And if so: how do I do that?
Haven't found the right things so far or I just got them wrong.
EDIT: As some people probably get me wrong I try it again with some more details.
What I am trying to set up is the Earth as a sphere with a map. That map is okay as long as you dont zoom in too far, which is obvious because of the textures finit resolution. Now, to still have good graphic quality, when being zoomed in that far that one could see streets in a city I want to load additional "satelite pictures" like Google Maps does it (you know: you zoom in and Google Maps always reloads the images in that specific area to still provide a good graphic quality). How do I achieve that specific behaviour? Providing all the tiles i need is no problem, I got a Vector Graphic from which I could export all the needed tiles, but i don't know how to reload those tiles when zooming in at that specific area (to reduce memory consumption, drawcalls, etc).
Any help is really appreciated as I am a beginner in programming with unity. Thank you very much in advance!
Dustin
Are you actually zooming in or moving the camera physically closer? Unity has some internal filters that make textures easier to load at a longer distance. When zooming, the camera isnt actually moving closer meaning the more detailed version of it will not load correctly.
Also check your Max Texture Size setting for the texture you are using. Maybe it is turned down too low. Try turning it up to a higher resolution.
If it still looks blurry up close with Max Texture Size turned higher, your texture may not be high enough resolution to begin with. Make it a high enough resolution that it looks good up close. Then begin lowering the Max Texture Size resolution until up close it is "good enough".
Next, typically, it will start looking blurry in the distance or have distinct linear transitions from looking good to blurry. You can fix this by turning up the Ansio Level. Use this with caution because it increases the rendering load. Only use what you need, especially for mobile games.
I am trying to make some real looking roads in my game,but the problem is ,when i am using roads so they are little bit blurry at distance and look like a real one.Can any one please guide me to solve this.I have uploaded my pic here
Is there possible solution for this?
Yes, it is a common problem, for textures' rendering at a certain distance/angle. You should enhance the aniso level, in order to apply an anisotropic filtering on the blurry texture (you can also change the aniso level from the texture's component, as in the picture below).
If the road is created via a Terrain component (which I doubt, since you already have a sandy terrain at the bottom), you should change the basemap distance.
Check also Quality settings, it might have Anisotropic textures disabled.
At a high level (or low level if you'd like), what's a good way to implement a smudge affect for a drawing program on the iPad using Quartz2D (Core Graphics)? Has anyone tried this?
(source: pixlr.com)
Thanks so much in advance for your wisdom!
UPDATE I found this great article for those interested, check it!
Link now at: http://losingfight.com/blog/2007/09/05/how-to-implement-smudge-and-stamp-tools/
I would suggest implementing a similar algorithm to what is detailed in that article using OpenGL ES 2.0 to get the best performance.
Get the starting image as a texture
Set up a render-to-texture framebuffer
Render initial image in a quad
Render another quad the size of your brush with a slightly shifted view of the image, multiplied by an alpha mask stored in a texture or defined by, for example, a gaussian function. Use alpha-blending with the background quad.
Render this texture into a framebuffer associated with your CAEAGLLayer-backed view
Go to 1 on the next -touchesMoved event, with the result from your previous rendering as the input. Keep in mind you'll want to have 2 texture objects to "ping-pong" between as you can't read from and write to the same texture at once.
I think it's unlikely you're going to get great performance on the CPU, but it's definitely easier to set up that way. In this setup, though, you can have essentially unlimited brush size, etc and you're not looping over image drawing code.
Curious about what sort of performance you do get on the CPU, though. Take care :)
I need in antialiasing in iPhone 3G (OpenGL ES1.1), NOT iPhone 3Gs with OpenGL ES.2.0.
I've draw 3d model and have next: pixels on the edges of the model look like teeth.
I've try set any filters for texture, but this filters making ONLY texture INSIDE look better.
How can i make good antialising ?
May be i should use any smooth for drawing triangles ? If yes, then how it possible in OpenGL ES1.1 ?
thanks.
As of iOS 4.0, full-screen anti-aliasing is directly supported via an Apple extension to OpenGL. The basic concept is similar to epatel's suggestion: render the scene onto a larger framebuffer, then copy that down to a screen-sized framebuffer, then copy that buffer to the screen. The difference is, instead of creating a texture and rendering it onto a quad, the copy/sample operation is performed by a single function call (specifically, glResolveMultisampleFramebufferAPPLE()).
For details on how to set up the buffers and modify your drawing code, you can read a tutorial on the Gando Games blog which is written for OpenGL ES 1.1; there is also a note on Apple's Developer Forums explaining the same thing.
Thanks to Bersaelor for pointing this out in another SO question.
You can render into a larger FBO and then use that as a texture on a square.
Have a look at this article for an explanation.
Check out the EGL_SAMPLE_BUFFERS and EGL_SAMPLES parameters to eglChooseConfig(), as well as glEnable(GL_MULTISAMPLE).
EDIT: Hrm, apparently you're out of luck, at least as far as standardized approaches go. As mentioned in that thread you can render to a large off-screen texture and scale to a smaller on-screen quad or jitter the view matrix several times.
We found another way to achieve this. If you edit your textures and add for example a 2 pixel frame of transparent pixels, the colored pixels in the texture are blended with the transparent pixels when necessary giving a basic anti-aliasing effect. You can read the full article here in our blog.
The advantage of this approach is that you are not rendering a bigger image, or copying a buffer, or even worse, making a texture from a buffer, so there is no impact in performance.
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.