XNA 2d arcade game sprite follow - c#

I am going to make a game like XNA example game "Platformer1" which comes with the XNA. But I need longer levels which doesn't fit in the screen (like Super Mario levels). How can I manage this kind of level? Do I need to use a 2d camera that follows the sprite? If I do this way how can I load the level? I am a bit confused and I am not sure if I could explain my problem clearly. Hope someone can help?

The tutorial based on Platformer Starter Kit in MSDN has a step Adding a Scrolling Level which guides you through creation of longer levels. The tutorial is very detailed, I highly recommend it.
I couldn't find the tutorial in the section for XNA Game Studio 4.0, but differences should be minimal. According to the comment at the bottom of the page, all you need to change is replace
spriteBatch.Begin(SpriteBlendMode.AlphaBlend, SpriteSortMode.Immediate, SaveStateMode.None, cameraTransform);
with
spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default, RasterizerState.CullCounterClockwise, null, cameraTransform);
in the tutorial code.

If you want to create a side scrolling game, then I would look into parallax scrolling. A quick google/bing will help you find lots of tutorials. Also, another useful tip is to search YouTube for XNA videos has we a lot of posters share their source code .
Here is a link to Microsofts Parallax Scrolling.

Sounds like you have a few problems ahead of you.
But I need longer levels which doest'n fit in the screen(like super mario levels). How can I manage this kind of levels.
There are several ways to do this, but a fairly easy way would be to have a 2d array (or sparse array, depending on how large your levels are) of a class named Tile that stores info about the tile image, animation, ...whatever.
Yes, you'll probably want a "camera". This can be as simple as only drawing a certain range of that array or a more featured camera that uses transforms to zoom out and translate across your level.
Hopefully this will help get you started.

I've done a decent amount of work in XNA, and from my experience, there are 2 ways to draw a 2D scene:
1) Strictly 2D. This method is much easier, but has a few limitations. There is no "camera" per se, what you do is move everything underneath the fixed 2D "camera". I say "camera" in quotes because the camera is fixed (as far as I know). The upside is that it's easy, the downside is that you can't easily zoom in or out or do other camera effects.
2) 2D in 3D. Set up a 3D world with a 2D plane. This is more flexible, but is also more challenging to work with because you will need to set up a 3D world and 3D camera. If this is your first attempt with making a game, I would highly recommend against this method.
I'm really only familiar with the strictly 2D method, and you would want a list of map objects that have a 2D coordinate. You would also want to store which section of the map you are looking at, I do this with a Rectangle or Vector2 that stores this. This value would move forward as the character moves. You can then take your 2D map objects' coordinate and subtract the (X,Y) of the top-left of what you are looking at to determine an object's screen position. So:
float screenX = myMapObject.X - focusPoint.X;
float screenY = myMapObject.Y - focusPoint.Y;
An other thing to note, use floats or Vector2/3 to store locations, you may not think it's required now, but it will be down the line.
It might be overkill, but my SF project uses XNA to draw a Strictly 2D scene that you can move around: http://sourceforge.net/projects/asteroidoutpost/
I hope this helps.

Have a look at Nick Gravelyns tutorials. They helped me tonne when I was first starting out - Really really worth a look for learning a lot on 2D games.
All the videos are now on youtube here

Related

How can I get a 2D cross-section of a 3D object using a shader?

I have an idea for a 2D game that uses 3D models that are cut at the center of the Z axis. However, I have found no way to properly get just the intersection to show.
Culling the front and back of the camera to be extremely thin leaves a small outline of the model, since there's no way for it to render the inside. I could use ray marching, but it would limit me to primitive objects and seems a little overkill for what I need. I've found a lot of cross-section shaders online, but they require the back of the camera to not be culled.
Below is a visual example of what I need (demonstrated with Blender's boolean tool rather than a shader), any help is appreciated as I've been looking for a way to do this for months.
Before Intersection vs After Intersection

How to Combine Vertices and edges into one In Unity

I'm new to Unity and I'm making a car racing Game. Now, I'm stuck at some point. I was looking for some solution of my problem, but couldn't succeed.
My problem is:
When I run my game on my phone, it sticks badly because whenever there are several buildings in front of the car camera, like one building behind another building, it lags. Reason for this is there are so many vertices and edges at that time, So the Car Camera is unable to capture all that stuff at same time.
How do I preload the 2nd Scene while loading 1st Scene?
I am using Unity free version.
In graphics programming, there is a common routine to simply don't draw objects that aren't in the field of view. I'm sure Unity can handle this. Check link: Unity description on this topic
I'm not hugely knowledgeable about Unity, but as a 3D modeller there's a bunch of things you can do to improve performance:
Create a simplified version of your buildings with fewer polygons for use when buildings are a long way away. A skyscraper, for example, can be as simple as a textured box.
If you've done that already, reduce the distance at which the simpler imposters are substituted for the complex versions.
Reduce the number of polygons by other means. A good example is if you've got a window ledge sticking out of the side of a building, don't try and make it an extension of the body. Instead, make it a separate box, delete the facet that won't be seen, and move it to intersect with the rest of the building.
Another good trick is to use bump maps or normal maps to approximate smaller features, rather than trying to model everything.
Opaqueness. Try not to have transparent windows in your buildings. It's computationally cheaper to make them just reflect the skybox or a suitably blurred reflection imposter. Also make sure that the material's shader is in Opaque mode, if it supports this.
You might also benefit a little from checking the 'Static' box on the game object, assuming that buildings aren't able to be moved (i.e. by smashing through them in a bulldozer).
Collision detection can also be a big drain. Be sure to use the simplest possible detection mesh you can - either a box, cylinder, sphere or a combination.

How to implement rigid body dynamics previewed by WPF 3D

I'm currently facing a problem with WPF 3D using C#. To put it simple, I need to animate some simple mechanical part by only moving two of them (one at a time or both together). Here is a simple drawing depicting the situation :
So by moving (translating) vertically P1 or/and P2 parts, the whole thing needs to move accordingly.
I guess it may be possible to do by computing a lot of angles and applying numerous transformations but this is not my goal.
Therefore I would imagine something like attaching the parts together by the means of a pivot point.
What is the preferred way to do this to preview it using WPF 3D?
WPF 3D, Ogre, Mogre, OpenTK... are libraries for display. They have nothing to do with mechanical constraints calculations. But they goes well with physics engines.
WPF 3D is a subset of WPF dedicated to 3D drawing. If you need 2D, then WPF is enough.
As your project looks 2D, you might want to have a look to Farseer Physics which is a port of Box 2D. The feature you need is called joints. Both libraries target 2D games development, but they can be used for simple kinematics animations, and Farseer Physics is doing very well with WPF.
It's a simple problem for any 2D kinematics package.
http://books.google.com/books?id=IGtIWmM2GWIC&pg=PR12&lpg=PR12&dq=c%23+kinematics&source=bl&ots=eCJZLq_i6R&sig=wC42cNOdtw4VX9ElTk4IBDAYtzc&hl=en&sa=X&ei=3YkXU4u1EeHu2wXum4GYDA&ved=0CFsQ6AEwBQ#v=onepage&q=c%23%20kinematics&f=false

What is best way to create scrolling WORLD?

In this game im trying to create, players are going to be able to go in all directions
I added one single image(1024x768 2d texture) as background, or terrain.
Now, when player moves around I want to display some stuff.
For example, lets say a lamp, when player moves enough, he will see lamp. if he goes back, lamp will disappear because it wont be anymore in screen
If Im unclear, think about mario. when you go further, coin-boxes will appear, if you go back they will disappear. but background will always stay same
I thought if I spawn ALL my sprites at screen, but in positions like 1599, 1422 it will be invisible because screen is only 1024x768, and when player moves, I will set place of that sprite to 1599-1,1422-1 and so. Is it a good way to do this ?
Are there better ways?
There are two ways you can achieve this result.
Keep player and camera stationary, move everything else.
Keep everything stationary except the player and the camera.
It sounds like you are trying to implement the first option. This is a fine solution, but it can become complicated quickly as the number of items grows. If you use a tile system, this can become much easier to manage. I recommend you look into using a tile engine of some sort. There are a lot of great tile map editors as well.
Some resources for using Tiles:
Tiled -- Nice Map Editor
TiledLib -- XNA Library for using Tiled Maps
What you're describing there is a Viewport, which describes a portion of the 'world' that is currently visible.
You need to define the contents of your 'world' somehow. This can be done with a data structure such as a scene graph, but for the simple 2D environment you're describing, you could probably store objects in an array. You would need to bind your direction keys to change the coordinates of the viewport (and your character if you want them to stay centered).
It's a good idea to only draw objects that are currently visible. Without knowing which languages or packages you are using it's difficult to comment on that.
I would look into Parallax scrolling. Here is an example of it in action.
If this is what you require, then here is a tutorial with source code.
XNA Parallax Scrolling
After you are finished with basic scrolling, try to implement some frustum culling. That is only draw objects which are actually visible on the screen and avoid unnecessary drawing of stuff that cannot be seen anyway.
I would prefer solution number 2 (move player and camera) - It would be easier for me, but maybe its just personal preference.

Simple 3D Graphics in C#

I'm currently working on an application where I need to do some visualization, and the most complicated thing I'll be doing is displaying point-like objects.
Anything beyond that is complete overkill for my purposes, since I won't be doing anything but drawing point-like objects.
That being said, what would be the simplest solution to my needs?
The simplest is probably to use WPF 3D. This is a retained mode graphics system, so if you don't have huge needs (ie: special shaders for effects, etc), it's very easy to setup and use directly.
Otherwise, a more elaborate 3D system, such as XNA, may be more appropriate. This will be more work to setup, but give you much more control.
I recommend you take a look on Microsoft XNA for C#
Are they to be rendered as true points or as spheres? (where you see the 'points' that are closer using the visible size of the sphere as a reference.) In the former case, I would recommend simply multiplying the appropriate transformation matrices yourself to project the points to your viewing plane, rather than using a full-blown 3D engine (as you're not rendering any triangles or performing lighting/shading)
For some theoretical background on 3D projection to a 2D plane, see this Wiki article. If you use XNA, it has Matrix helper functions that generate the appropriate transformation matrices for you, even if you don't use it for any actual rendering. The problem becomes very trivial for points, as there are no normals to consider. You simply multiply the composed View Projection matrix by each point, clip any points that lie outside the viewing frustrum (i.e. behind the viewing plane, too far away, or outside the 2d range of your viewport) and render the points in X,Y. The calculation does you give feedback as to how 'deep' each point is relative to your viewing plane, so you could use this to scale or color the points appropriately, as otherwise it's very difficult to quickly understand the 3d placement of the points.

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