Placing objects on scrolling background in XNA - scroll

How do I place objects that appear only if the background scrolls to a certain point?
Example- I have this long image that keeps scrolling using the technique above. However, after scrolling to part of the image, I want to add a platform there. How would I do that?

In general, you will probably need to save the locations of your objects in a file and then load that file at the beginning of the level (assuming you are making some kind of platformer game). You can do this by creating a class or a struct containing all the relevant information for the platform (position, size, texture, etc) and then using XML serialization to write an array of those classes/structs to a file.
Your level loader would then load and deserialize the level data, which would end up being a list of all the objects in your level (such as platforms). Now that you have the locations of your platforms in memory you have a couple different options on how to get them to the screen.
Draw all the objects (platforms) all the time, whether or not they are in the view of the camera. If your levels don't contain a lot of objects, this would be simple to implement.
Draw only those in the camera's view. Without knowing how you implemented the horizontal scroller, it's kind of hard to make suggestions for this part. Whatever mechanism you currently have to identify the boundaries of what part of the background to show could be used to determine which objects to draw as well.
I'm working on a game that scrolls vertically right now, and I needed a way to do something similar: place objects in a level and have them appear when the background scrolled to them. I used TorqueX 2D (free engine binaries if you've payed to develop for XNA) and its 2D scene editor to set this up pretty easily. I have my camera scrolling up, the background stays in place. When it gets to an object position defined in the XML level file it spawns the object in the level.

Related

Gamemaker Studio2, Draw GUI layer conflict

I would like to preface this by saying I am still quite new to gameMakerstudio and I do not know all there is to know about how the software works and this is probably the root cause of my problem as I do not know why I am having this current layering issue.
I have been having an issue where I have TWO DrawGUI events in separate objects within the same room.
The first object is a Fog Of War that draws a GUI and reveals the map as the player moves, and keeps explored places visible but not in view.
The second object is the joystick where a player will use their thumb to drag the stick to move the player.
Ever since I have implemented the Fog of War. I have been unable to view the joystick. It appears that the fog of war draws overtop of it and I am unable to use it.
I understand there are other draw events where I can do this.
Draw
Draw GUI
Draw Begin
Draw End
Draw GUI BEGIN
Draw GUI END
After changing where I have the code drawing.
Example: At first the joystick and the fog were both in Draw GUI, After moving one from Draw GUI to Draw GUI Begin, the same issue appears.
I have made sure to place the joystick at the top most level in the room and the fog of war at the bottom most layer.
I have tried to apply depth the object
oJoystick_Stick.depth = -100;
this does not achieve anything.
Is there another way to force two objects on the GUI layer to be on top of the other?
To my understanding, DrawGUI always prioritises the objects drawn there above anything in Draw, including Begin Draw and End Draw. This is because DrawGUI is for an interface (like the stats you see about your character like health, ammo ect.), and objects drawn there aren't part of the room itself. You may also have noticed that the objects drawn in DrawGUI also follows the camera/Viewpoint.
So, to clear up the draw priority:
First is the DrawGUI layer that places objects in front of everything, like an interface.
After that, the depth variable and layers inside the room has priority, each layer has also given a depth value, with an interval of 100.
If the depth is also the same (for example when they're in the same layer), then the order of the objects and code loaded decides the order drawn.
The latter is not always reliable when multiple objects are overlapping at the same depth, because if the objects are redrawn in-game again (e.g. a persistent object been loaded into a new room, or pause and unpause using instance_activate_all), then the order of objects drawn may differ. Keep in mind when overlapping objects, that they are placed in different layers to prevent mixed priorities.
I've however not used a Fog of War system myself, so I don't know if it's build-in or not, but I wouldn't recommend placing them in the DrawGUI, as that should be reserved for the interface layout. With the default Draw options, you'll have more flexibility to the layers inside the room.
Some advice about DrawGUI
DrawGUI Begin --> call the event before every drawGUI in that moment
DrawGUI --------> the event is called sync with the screen refresh rate
DrawGUI End ----> call the event after every drawGUI in that moment
so GM-Studio "pipeline" for the DrawGUI is like the step event, we have a BEGIN, a CURRENT, an END.
To prioritize the object render, GM-Studio use the depth in-build variabile. Take the 0 as the reference value. Object with depth value > 0 are rendering as last. Object with depth value < 0 are rendering infront everything.
Check the depth during the calling of the instance_create_depth() function, check where the depth variabile is changing, check in the room editor for each instance layer the depth value. and z-order.

JavaFX DragView Image has lowered opacity compared to actual image... Can that be changed?

I have been working on using Drag and Drop with JavaFX, and one thing I notice is that items are given lowered opacity compared to their actual images, as well as the larger the image the made "Faded/transparent" the image gets. I am working on am application that can drag fairly large items which end up almost invisible when dragging, which defeats the purpose of using a DragView Image in the first place, and makes this unusable for larger items (the way I'm using the DragView I want the images to be a certain size compared to the scene in which I'm dragging onto).
My application essentially has 2 Windows (Stages) where the data is in one Stage and I get the item from a list and drag it onto the scene. The DragView image is a representation of the object going onto the scene, so when I drop the DragView Image, it gets dropped exactly into place on the scene, so the DragView is important to my overall application.
Just a NOTE: There is also backing data in my transfer in order to recreate the box, as well as additional data that gets transferred with the Drag and Drop.
I tried looking at the FX DragView Internal code but didn't find anything that sets the Opacity or anything like that, so one of my assumptions of "it's built into the OS" is something I keep thinking about, as lowered opacity is something I remember being built in, and when trying it it does happen, but very very slight, and not as bad as what I'm experiencing (Also possible that since the icons are much smaller they don't run into the "larger image opacity issue."
I am running Windows 7 64-Bit for those who are wondering.
My question is, is it possible to change the opacity settings of the Drag and Drop ImageView either via JavaFX or possibly Native with using something along the lines of JNI?
I don't have any example code at the moment, but can add if someone is interested, but I'm sure for those who know about Drag and Drop ImageViews should already know about the opacity.
Thank you all.

hiding movieclip, rendering performance

I'm developing a rendering engine for a game i am currently building..
I have a main camera (rectangle) that determines what needs to be rendered (thing within it's boundaires)
I am using a bitmap rendering method for the background and that all works fine.
but for the character i am using a movieclip over the top.
when the character goes out of the camera's view is it 100% neccesary to set visible=false?
atm the game is running at 30 FPS (as intended) and everything is sweet, i just wanted to ask out of curiosity.
Is flash clever enough to not bother with movieclip outside of the scene boundaires?
Thanks in advance,
Rory
According to http://help.adobe.com/en_US/as3/dev/WS5b3ccc516d4fbf351e63e3d118a9b90204-7e3e.html Flash won't render if an object is outside of Stage boundaries:
Display list
The hierarchy of display objects that will be rendered as visible
screen content by Flash Player and AIR. The Stage is the root of the
display list, and all the display objects that are attached to the
Stage or one of its children form the display list (even if the object
isn’t actually rendered, for example if it’s outside the boundaries of
the Stage).
In my experience display objects added to the stage cause a performance hit even if they are not rendered.
Setting visible to false causes a much lower performance hit, but still a small hit.
Removing unnecessary display objects from the display list is a documented performance tip from adobe as well.
Of course, if you only have a few dislay objects it might not be worth the effort, but if we talk about large amounts of display objects I strongly recommend removing them from the display list.

Cocoa control to render a tile map

Is there any Cocoa control that is capable of drawing tile maps with multiple layers and multiple texture sources which can also intercept touches into single tiles? Having multiple layer support is not a real requirement but an optional feature (the views could still be stacked). Hardware acceleration is not needed at all.
So far I have toyed around with NSMatrix, IKImageBrowser and NSCollectionView but non of them felt like a good solution for the problem. Ideally I need an control similar to the one in Tiled.app. Is there anything, third party or built-in, or do I have to handcraft this control?
I fear that you will be hardly able to find a ready-to-use control for managing tile maps.
If I had to implement something like that on my own, I would consider using CATiledLayer, since this is the closest thing to a tile map control that I know of.
From CATiledLayer Reference:
CATiledLayer is a subclass of CALayer providing a way to asynchronously provide tiles of the layer's content, potentially cached at multiple levels of detail.
There is a nice sample by Bill Dudney (the author of "Core Animation for MacOS and the iPhone"). This sample could provide you a solid foundation for your own project, though it only displays one single PDF, allowing you to zoom in the area you clicked on (this requires rereading the tile at a different detail level).
Another interesting introduction can be found here. This is more step-by-step, so you might start with this.
Finally, on Cocoa is my Girlfriend there is a nice article, although it focuses on iOS, but you may find it anyway relevant.
Cocos2D supports building mac applications now
Article on cocos2d stating this: http://www.cocos2d-iphone.org/archives/1444
Aee here for how to do it: http://chris-fletcher.com/tag/cocos2d-os-x/
Aee here on how to use TMX tile maps with Cocos2D to build tile based maps: http://www.cocos2d-iphone.org/wiki/doku.php/prog_guide:tiled_maps
This means you can use the power of Cocos2d and you will have to write much less code to get to where you want with a tile based map.
If you don't want to use Cocos2D:
It seems you would have to code it yourself, but it shouldn't be too hard to do.
First you can create your .TMX file using the tile editor "Tiled.app" then you would need to parse the XML using a standard xml library for Cocoa.
To lay out the tiles use a UIView for the overall container and then create a tile class that holds your tile display information and responds to clicks the tile class should extend UIView. For the tile class allow the assigning of a click delegate and assign your ViewController as the click delegate for all tiles so you can handle clicks easily with the clicked tile being passed to you.
Loop through your xml data and create and position the tiles in the overall UIView by using the tiles width/height and your tilemaps rows/columns.
I think in about a day or 2 you could have the tile map being rendered and clickable using the standard TMX format which will allow you to edit your map in "Tiled.app"
The TMX standard is covered here: https://github.com/bjorn/tiled/wiki/TMX-Map-Format
route-me might fit the bill.

Qt - Drawing a Rect/Frame out of a bigger Pixmap image

I've been banging my head about this seemingly easy task and I could really use some help.
I have a wide Image loaded in the gui (using the designer..) and I want to be able to draw only a portion of it, a rectangle.
I need to be able to change this rectangle position over the large image, in order to draw a different part of the larger image at will. In this process the rect must maintain its size.
Using the Ui::MainWindow object I'm able to access the label holding the image and a solution that involves using this option is preferred (in order to keep up with the rest of the code I've already written )
Any solution will be much appreciated :)
Thanks,
Itamar
I would definitely (for ease of use) just place an empty label as placeholder in Designer.
Then implement the paintEvent for this label (delegate it to your own method). You'll have also have to look into QPainter, QPixMap, etc... Should be doable based on these hints and the documentation.
If you want more, I suggest you provide a small code snippet to work upon.
If you want to do this more or less purely through designer, you could put a QScrollArea where you want the portion of the image to appear. If you set the scroll area's scrollbar policy to be never shown, you can then manually change what part is visible via the scroll area widget. However, this would probably be more complex that creating a derived widget and reimplementing the paint function.

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