I'm developing an iPhone Cocos2D game and reading about optimization. some say use spritesheet whenever possible. others say use atlassprite whenever possible and others say sprite is fine.
I don't get the "whenever possible", when each one can and can't be used?
Also what is the best case for each type?
My game will typically use 100 sprites in a grid, with about 5 types of sprites and some other single sprites. What is the best setup for that? guidelines for deciding for general cases will help too.
Here's what you need to know about spritesheets vs. sprites, generally.
A spritesheet is just a bunch of images put together onto one big image, and then there will be a separate file for image location data (i.e. image 1 starts at coordinate 0,0 with a size of 100,100, image 2 starts at coordinate 100,0, etc).
The advantage here is that loading textures (sprites) is a pretty I/O and memory-alloc intensive operation. If you're trying to do this continually in your game, you may get lags.
The second advantage is memory optimization. If you're using transparent PNGs for your images, there may be a lot of blank pixels -- and you can remove those and "pack" your texture sizes way down than if you used individual images. Good for both space & memory concerns. (TexturePacker is the tool I use for the latter).
So, generally, I'd say it's always a good idea to use a sprite sheet, unless you have non-transparent sprites.
Related
I'm playing about with OpenGL ES 2.0. If I'm working with a simple 2D projection, if I have a large 2D grid of vertices which are pretty much static (think map tiles), of which only a small proportion are visible at any one time, would it be better to...
Work out in the CPU which vertices are visible, and and create a VBO to draw just those triangles that make up the visible tiles in each frame?
or
Keep a static VBO with the entire tiled grid, and then just rely on the graphics card (RPi, in my case) to clip out the off-screen triangles?
Or perhaps some combination of the two (like sets of overlapping pre-computed grids)? How big does the grid have to be before the latter option becomes unworkable?
Edit
I decided to make several calls to glDrawElements(), drawing sub-ranges of the index buffer that I knew would overlap the viewport. At the scale I'm working at it doesn't seem to make any difference to the speed over drawing the entire element array, even on a Pi Zero.
However, this approach would require more computation to determine which ranges of elements needed to be rendered if there was any rotation of the grid involved - effectively rasterising my own quad. I'm interested to hear if this is a reasonable approach.
There are some other options like a more exotic structure for breaking up the plane into sub areas, I guess. Still not sure if any of this is really necessary, though.
Thanks!
Please note: I don't want to discuss drawing tiles in the fragment shader, I'm more interested in the correct way to work with the vertex shader than actually solving the described problem.
If that's a regular grid, I'd split it in large chunks, so the screen width (larger side) would fit 2-3 such chunks. They don't need to overlap if it's regular grid.
Checking one chunk's visibility is trivial and cheap, as well as finding/selecting those few that must be drawn. And the wasted/clipped area is small enough to not worry about it. You don't have to go crazy and trim every single vertex that's outside of the screen.
Each chunk would have own VBO, and it would be weakly cached when it goes fully outside of screen, so you don't have to rebuild/reload resources needed to draw that chunk if you quickly return to this part of the map.
Splitting in chunks minimizes the memory requirements and speeds up the level loading. You spend time only loading the part of the screen that user will see immediately. This also allows quite huge maps, since you can prefetch the areas that you're going towards to.
TL;DR: From within my MTKView's delegate drawInMTKView: method, part of my rendering pass involves adding an MPSImageBilinearScale performance shader and zero or more MTLBlitCommandEncoder requests for generateMipmapsForTexture. Is that a smart thing to do from within drawInMTKView:, which happens on the main thread? Do either of them block the main thread while running or are they only being encoded and then executed later and entirely on the GPU?
Longer Version:
I'm playing around with Metal within the context of an imaging application. I use Core Image to load an image and apply filters. The output image is displayed as a 2D plane in a metal view with a single texture. This works, but to improve performance I wanted to experiment with Core Image's ability to render out smaller tiles at a time. Each tile is rendered into its own IOSurface.
On each render pass, I check if there are any tiles that have been recently rendered. For each rendered tile (which is now an IOSurface), I create a Metal texture from a CVMetalTextureCache that is backed by the surface.
I think use a scaling MPS to copy from the tile-texture into the "master" texture. If a tile was copied over, then I issue a blit command to generate the mipmaps on the master texture.
What I'm seeing is that if my master texture is quite large, then generate the mipmaps can take "a bit of time". The same is true if I have a lot of tiles. It appears this is blocking the main thread because my FPS drops significantly. (The MTKView is running at the standard 60fps.)
If I play around with tile sizes, then I can improve performance in some areas but decrease it in others. For example, increasing the tile size that Core Image renders it creates less tiles, and thus less calls to generate mipmaps and blits, but at the cost of Core Image taking longer to render a region.
If I decrease the size of my "master" texture, then mipmap generation goes faster since only the dirty textures are updates, but there appears to be a lower bounds on how small I should make the master texture because if I make it too small, then I need to pass in a large number of textures to the fragment shader. (And it looks like that limit might be 128?)
What's not entirely clear to me is how much of this I can move off the main thread while still using MTKView. If part of the rendering pass is going to block the main thread, then I'd prefer to move it to a background through so that UI elements (like sliders and checkboxes) remain fully responsive.
Or maybe this isn't the right strategy in the first place? Is there a better way to display really large images in Metal other than tiling? (i.e.: Images larger than Metal's texture size limit of 16384?)
I've seen quite a bit of questions regarding how to draw isometric tiles, and most all point at being drawn back to front, top down. However I'm trying to find a way to prevent clipping with a single isometric image.
While normally drawing a sprite ontop of a single image would not prevent overdrawing on walls and such, I split up the image into 3 layers. A floor, lower wall, and top wall. Where the player checks the floor for collision, is drawn in front of the lower wall always, and drawn behind the top wall always. The result looks like the following
While this seems to work decently well, I'd like to know what the most efficient way to draw these sort of isometric scenes are. I've considered tiles, however that raises the question of how to draw multi-tiled buildings and such. If tiling becomes a better option I will create a new question regarding those questions. For now lets assume I'm using a single image broken into layers.
This is somewhat easier, however, for my artist. To be able to draw a single scene in isometric, and split it up into layers, eliminating the need for a map creator. And then using pixel collision to get precise collision with the enviroment.
Is using a multi-layered scene even a good approach for this? My biggest concern is preventing overdrawing and breaking perspective. I've also seen many good examples of drawing everything using tiles, however then I'm limited to a certain scale, and that arises even more questions. Do you know of the best way to approach this? Should I use tiles instead of a single image split into layers?
I plan to code this in either MonoGame or Processing.
(I would have posted this on gamedev but I can not post images there)
I want to make a pool game where the user can pinch the pool table to zoom so he can
precisely shoot the pocket.
So, this means I need a large pool table graphic.
What is the best way to handle such a situation in cocos2d?
How do I load the graphic? What is the limitation on graphic size?
I have a lot of doubts because Im not sure which path to take.
Regards
Mirza
For something as simple as a pool table it might be better to render it all using vector graphics. This means you will need less graphics (perhaps only a few for textures) and you get infinite zooming without all the graphic image overhead.
How to correctly implement the blocks in the drawing view, so that when they could cut the line in two parts. Using UIImageView or UIImage?
After the cut blocks should fall under the influence of physics.
First, how many cuts could happen in total? How many independent pieces of block could result? 10? 100? Before implementing any of these, test moving that number of objects around on an iPhone or iPod touch. Just because it works on the simulator does not mean it will be fast enough on the actual device.
Second, as already noted, there are libraries for game graphics and physics that may do a lot of the work for you. Cocos2D appears to be a popular option, combining OpenGL drawing with relatively easy access to physics libraries.
Anyway, to do your own drawing, here are the choices:
Move all the graphics into OpenGL. This should not be undertaken lightly - you lose a lot of the ease of working in Cocoa Touch. You also have maximum control over your graphics and animation, and can achieve the smoothest performance if you take the time to optimise it.
Have a single UIView, adding CALayer sublayers to its main layer for every independent block. CALayers are designed for rapid moving and compositing. However, if you're running a physics simulation, your first step will be to remove their animation behavior. This tutorial series may be useful.
Have a separate UIView for each block. This will have similar performance to using CALayers, as UIViews are actually drawn with CALayer. This option will use up more memory, (you have at least as many layers and more views than before), but you have all of the power of CALayers plus a few drawing options that are easier on views.
Have a single UIView, and draw every block during its drawRect method. This may look easy to implement, but it will almost certainly be too slow.
If at all possible, test each of these. Before you continue with the cutting and physics parts, how many blocks can you animate across the screen before it slows down too far? Can you make a game with that Remember that your physics system will slow the game down when it does work.