I'm trying to develop a 2D game to android using opengl.
I know how to print images on the screen and animate them. But in my game I have a map and a want to zoom in and out and scroll the map. But I can't figure out the best way of doing it.
Can anybody help me?
I don't have any api examples but I did games design at college so I'll give my two bits.
The method you use will depend on your map style, size, functionality and format.
For example if you are looking for a very static non changing map, use a simple picture image. You can use the API frame for a picture view, enabling you to zoom in and out as you do in the gallery and to scroll on zoomed images, or in this case, zoom locations on your map.
Alternatively, if your map is based off a tiling system, a good example of this is the original Pokémon and Legend of Zelda games from the old game boy, then each area stores a tile 'thumbnail' for itself as a bitmap. These are then put into their appropriate locations on a grid depending on what areas are discovered.
This is the probably the most flexible way to build your map as you are not relying on a set bitmap for the entirety your map meaning it can change its look efficiently; you can build it as desired to show areas of choice (useful for if the map only reveals places the gamer has covered) and it also means you can do tile based overlay:
ie - if a certain area should contain treasure, theres a treasure icon overlayed on that tiles x,y position on the map grid.
I used the tiling option in my game projects from college and it made everything else map related easier. It also made the map side of things smaller storage wise.
The simplest approach would be to just call glTranslatef(-scrollX,-scrollY,0) followed by glScalef(zoom,zoom,zoom) before you render your map.
Related
I want to create a 2D Game with Java and LWJGL. It is a retro styled RPG game. So there is a really big map(about 1000x1000 or bigger). I want to do it with tiles but I don't know how to save it/how to render it.
I thought at something like a 2D-Array with numbers in it and the render just sets the right tile at the right place.
But i think the bigger the map gets the more it will slow down.
I hope you can help me. :)
My second suggestion was to make a big image and just pick a part of it(the part where the player is) but than its hard to know where I have to do a collision detection, so this ist just an absurd idea.
Thank you for your suggestions!
As one of the comments mentioned, this subject is far too large to be easily covered with a single answer. But I will give you some advice from personal experience.
As far as saving the map in a 2D array, as long as the map is fairly simple in nature there is no problem. I have created similar style maps (tiled) using 2D integer arrays to represent the map. Then have a drawing method to render the map to an image which I can display. I use multiple layers so I just render each layer of the map separately. Mind you most of my maps are 100x100 or smaller.
I would recommend for such large maps to use some sort of buffer. For example, render only the playable screen plus a slight offset area outside of the map. E.g. if your screen if effectively 30x20 tiles, render 35x25, and just change what is rendered based on current location. One way that you could do this would be to load the map in "chunks". Basically have your map automatically break the map into 50x50 chunks, and only render a chunk if you get close enough that it might be used.
I also recommend having the drawing methods run in their own thread outside of the main game methods. This way you constantly draw the map, without having random blinking or delays.
I'm maintaining my 400*400 tiles map in the Tiled map editor and render it with the Slick2D framework. It provides support for rendering only visible subsections of the map. (TiledMap class).
I've tried both approaches - Image based and tiled based map creation and ended up with the latter. With tiles you can not only create the view of your map but also invisible meta data layers, like collision, spawn spots, item locations etc.
I'm having quite a bit of difficulty wrapping my head around the actual display side of things with libgdx. That is, it just seems fairly jumbled in terms of what needs to be done in order to actually put something up onto the screen. I guess my confusion can sort of be separated into two parts:
What exactly needs to be done in terms of creating an image? There's
Texture, TextureRegion, TextureAtlas, Sprite, Batch, and probably a
few other art related assets that I'm missing. How do these all
relate and tie into each other? What's the "production chain" among
these I guess would be a way of putting it.
In terms of putting
whatever is created from the stuff above onto the monitor or
display, how do the different coordinate and sizing measures relate
and translate to and from each other? Say there's some image X that
I want to put on the screen. IT's got it's own set of dimensions and
coordinates, but then there's also a viewport size (is there a
viewport position?) and a camera position (is there a camera size?).
On top of all that, there's also the overall dispaly size that's
from Gdx.graphics. A few examples of things I might want to do could
be as follow:
X is my "global map" that is bigger than my screen
size. I want to be able to scroll/pan across it. What are the
coordinates/positions I should use when displaying it?
Y is bigger
than my screen size. I want to scale it down and have it always be
in the center of the screen/display. What scaling factor do I use
here, and which coordinates/positions?
Z is smaller than my screen
size. I want to stick it in the upper left corner of my screen and
have it "stick" to the global map I mentioned earlier. Which
positioning system do I use?
Sorry if that was a bunch of stuff... I guess the tl;dr of that second part is just which set of positions/coordinates, sizes, and scales am I supposed to do everything in terms of?
I know this might be a lot to ask at once, and I also know that most of this stuff can be found online, but after sifting through tutorial after tutorial, I can't seem to get a straight answer as to how these things all relate to each other. Any help would be appreciated.
Texture is essentially the raw image data.
TextureRegion allows you to grab smaller areas from a larger texture. For example, it is common practice to pack all of the images for your game/app into a single large texture (the LibGDX “TexturePacker” is a separate program that does this) and then use regions of the larger texture for your individual graphics. This is done because switching textures is a heavy and slow operation and you want to minimize this process.
When you pack your images into a single large image with the TexturePacker it creates a “.atlas” file which stores the names and locations of your individual images. TextureAtlas allows you to load the .atlas file and then extract your original images to use in your program.
Sprite adds position and color capabilities to the texture. Notice that the Texture API has no methods for setting/getting position or color. Sprites will be your characters and other objects that you can actually move around and position on the screen.
Batch/SpriteBatch is an efficient way of drawing multiple sprites to the screen. Instead of making drawing calls for each sprite one at a time the Batch does multiple drawing calls at once.
And hopefully I’m not adding to the confusion, but another I option I really like is using the “Actor” and “Stage” classes over the “Sprite” and “SpriteBatch” classes. Actor is similar to Sprite but adds additional functionality for moving/animating, via the act method. The Stage replaces the SpriteBatch as it uses its own internal SpriteBatch so you do not need to use the SpriteBatch explicitly.
There is also an entire set of UI components (table, button, textfield, slider, progress bar, etc) which are all based off of Actor and work with the Stage.
I can’t really help with question 2. I stick to UI-based apps, so I don’t know the best practices for working with large game worlds. But hopefully someone more knowledgeable in that area can help you with that.
This was to long to reply as a comment so I’m responding as another answer...
I think both Sprite/SpriteBatch and Actor/Stage are equally powerful as you can still animate and move with Sprite/SpriteBatch, but Actor/Stage is easier to work with. The stage has two methods called “act” and “draw” which allows the stage to update and draw every actor it contains very easily. You override the act method for each of your actors to specify what kind of action you want it to do. Look up a few different tutorials for Stage/Actor with sample code and it should become clear how to use it.
Also, I was slightly incorrect before that “Actor” is equivalent to Sprite, because Sprite includes a texture, but Actor by itself does not have any kind of graphical component. There is an extension of Actor called “Image” that includes a Drawable, so the Image class is actually the equivalent to Sprite. Actor is the base class that provides the methods for acting (or “updating”), but it doesn’t have to be graphical. I've used Actors for other purposes such as triggering audio sounds at specific times.
Atlas creates the large Texture containing all of your png files and then allows you to get regions from it for individual png's. So the pipeline for getting a specific png graphic would be Atlas > Region > Sprite/Image. Both Image and Sprite classes have constructors that take a region.
Ok, so I have this map and I have various sliders on the right. After changing slider values and pressing 'Execute' button, some provinces in the map below should change colour.
However, I don't know how to implement the map below. I have used 33 png drawable for each province. I have set them all to have a same big rectangle dimension so that they'd align themselves.
I am getting an 'Out of memory on byte allocation' error.
I assume this is because of all the large drawables I have.
I'm new to android and I want to ask, is there a way to implement this without the error?
Also the map should always be displayed on the left side of the screen so the images always have to be visible.
I would recommend making a SVG and changing the colors programmatically.
Graphics are hard to scale and are heavy space users, scalable graphics are slim, look great everywhere (device size and dpi) and easy to manage (single file instead of 33).
I heard SO people like diagrams so I took the time to draw one :D
I need to design an activity that roughly looks like the following:
The map is just an image file of city, terrain etc. Users are able to enter values inside the x-coord and y-coord textbox and when both of them have been entered, a triangular icon (also an image file) will appear on top of the map with respect to the coordinates on the map. The min,max of coordinates are fixed as 0,0 to 10000,10000 for all maps. Users can click the triangular icon (button) and it just takes them to another activity.
What is a sensible approach of designing something as above?
As far as I'm concerned, there are several things I need to take into consideration:
1)Mapping the coordinates with respect to the screen size. An obvious workaround for this is to use absolutelayout and use pixels for positioning the triangular icon, but this solution is terrible for obvious reasons.
2)Laying a button on top of the map (image file). After playing around with bunch of layouts, I couldn't figure out how to do this via Java.
I'm just looking for a really simple guidance, just to get myself going in the right direction.
I would use a SurfaceView. You can draw anything in the onDraw method. Youll get a Canvas object to draw on so it shouldn't be difficult to transform your coordinates and do what you want.
take a look at this tutorial:
http://www.mindfiresolutions.com/Using-Surface-View-for-Android-1659.php
I'm working on small project which requires: Change clothes (shirt/pants etc.) of a person in any 2D image he chooses to upload. So somehow edges needs to be detected and relevant areas are supposed to be filled with new patterns. I do see a lot of other complications, but let's assume simple patterns have to be filled only.
For a web application, is it possible to do it in HTML5? Any other alternatives?
For a standalone application, what kind of technology would be preferred, C++/Java?
Update
Based on Bart's comment:
Any useful pointer like Bart's would be really useful
Assumption: Clear traceable 'standing' human figure in 2d image
Since it's an image, there is no real-time scenario
Assumption: Clear traceable 'standing' human figure in 2d image
A way to do this is to require the user to take two pictures. One picture is the one with the user in it, the other picture must be taken in the same camera position and orientation, but the user steps out of the frame for that one.
Since both pictures will have the same background you can compare pixel by pixel between the two images and flag those pixels that have a difference over some threshold. Of course the threshold must be selected so that camera noise isn't detected as a difference. Once you have the collection of pixels that are different you can filter them and calculate an approximate silhouette for the user from the pixels on the edge.
A simplification of the above method can be done if you have control over the background. You could use a bluescreen to avoid having to have a second picture with the background.