I have a map, containing many objects in an area sized 5000*5000.
my screen size is 800*600.
how can i scroll my map, i don't want to move all my objects left and right, i want the "camera" to move, But unfortunately i didn't found any way to move it.
Thanks
I think you are looking for the transformMatrix parameter to SpriteBatch.Begin (this overload).
You say you don't want the objects to move, but you want the camera to move. But, at the lowest level, in both 2D and 3D rendering, there is no concept of a "camera". Rendering always happens in the same region - and you must use transformations to place your vertices/sprites into that region.
If you want the effect of a camera, you have to implement it by moving the entire world in the opposite direction.
Of course, you don't actually store the moved data. You just apply an offset when you render the data. Emartel's answer has you do that for each sprite. However using a matrix is cleaner, because you don't have to duplicate the code for every single Draw - you just let the GPU do it.
To finish with an example: Say you want your camera placed at (100, 200). To achieve this, pass Matrix.CreateTranslation(-100, -200, 0) to SpriteBatch.Begin.
(Performing a frustum cull yourself, as per emartel's answer, is probably a waste of time, unless your world is really huge. See this answer for an explanation of the performance considerations.)
Viewport
You start by creating your camera viewport. In the case of a 2D game it can be as easy as defining the bottom left position where you want to start rendering and expand it using your screen resolution, in your case 800x600.
Rectangle viewportRect = new Rectangle(viewportX, viewportY, screenWidth, screenHeight);
Here's an example of what your camera would look like if it was offset off 300,700 (the drawing is very approximate, it's just to give you a better idea)
Visibility Check
Now, you want to find every sprite that intersects the red square, which can be understood as your Viewport. This could be done with something similar to (this is untested code, just a sample of what it could look like)
List<GameObject> objectsToBeRendered = new List<GameObject>();
foreach(GameObject obj in allGameObjects)
{
Rectangle objectBounds = new Rectangle(obj.X, obj.Y, obj.Width, obj.Height);
if(viewportRect.IntersectsWith(objectBounds))
{
objectsToBeRendered.Add(obj);
}
}
Here's what it would look like graphically, the green sprites are the ones added to objectsToBeRendered. Adding the objects to a separate list makes it easy if you want to sort them from Back to Front before rendering them!
Rendering
Now that we found which objects were intersecting we need to figure out where on the screen the will end up.
spriteBatch.Begin();
foreach(GameObject obj in objectsToBeRendered)
{
Vector2 pos = new Vector2(obj.X - viewportX, obj.Y - viewportY);
spriteBatch.Draw(obj.GetTexture(), pos, Color.White);
}
spriteBatch.End();
As you can see, we deduce the X and Y position of the viewport to bring the world position of the object into Screen Coordinates within the viewport. This means that the small square that could be at 400, 800 in World Coordinates would be rendered at 100, 100 on the screen given the viewport we have here.
Edit:
While I agree with the change of "correct answer", keep in mind that what I posted here is still very useful when deciding which animations to process, which AIs to update, etc... letting the camera and the GPU make the work alone prevents you from knowing which objects were actually on screen!
Related
I am talking about the Camera settings in Unity3D.
I'm trying to figure out if I can change (at least) the background color of the gray area in the screenshot. The limits of the camera are changed programmatically. The motivation lies in the fact that the playing area has to change dynamically based on whether a child or an adult is playing. The screen is huge around more than 83 inches. When rescaling the playing area, the area that is not drawn is gray and a bit ugly, I would like to know if you can define at least the color, or better still if possible with an image.
The screenshot you see is the screen capture in fullscreen mode, so it includes all the pixels.
After this brief explanation in words and images, let's go to the specifics of the technical details. This is how I resize the room design area:
public static void SetViewportCalibration()
{
var camera = Camera.main;
camera.pixelRect = new Rect(MinX, MinY, MaxX, MaxY);
}
Is it possible to set the color of that gray area outside the new Rect(MinX, MinY, MaxX, MaxY)?
There's two ways off the top of my head to accomplish this. Both ways use two Cameras.
The first way. Create a second Camera. The second Camera should have Depth LESS than the dynamic camera. This second, "Background" camera can then display anything you'd like, for example, a separate Skybox, a separate UI, other scene content, etc. etc.
The second way. Your dynamic camera is actually not resized dynamically. Instead, render your camera to a Target Texture. Use this texture in a material, and assign the material to a Quad mesh (most appropriate). This mesh can then be used in your scene like any other 3D object, which means not only can you position it, but scale it and even rotate it. The new camera that you added can have it's own Skybox, UI etc. etc.
I would opt for the second way. Partly personal preference, but also because it sounds like it might suit your situation better and be easier to implement. You can also implement many more effects for extra "wow".
Try to create another camera with no objects in its view and the following settings:
Clear Flags: Solid Color,
Background: Pick a color,
ViewPort Rect: X = 0, y = 0, w = 1, h = 1,
Depth: A smaller value than the other camera (Set the depth of this camera to 0 and the depth of the other camera to 1)
This camera will work as background of your screen.
I hope that I understood the question :)
I am trying to draw a line animation outline various shapes as in the image below. I am very well aware that it's best practice that I mention what I've been able to achieve to get specific help, but I am not sure where to begin, just that I know that using a Line Renderer could be a good approach to achieving this. That said, how can I achieve this?
UPDATE
I think I didn't explain a few things clearly enough. I am interested in animating the outline of objects without arrows, just a line traced round the outline like the image below:
I would do the following: (pseudocode, untested)
For every prefab or gameobject, store a List of edges that define your outline.
I wouldn't recommend using the mesh's edges, it's probably better to have a specific predefined list of edges per shape to avoid the inner edges of the object. Every entry in the list is defined by two Vector3's which are the two vertices.
List<Vector3[]> outline = new List<Vector3[]>();
Now, you have many ways to actually draw the arrows, like having them as individual gameobjects (probably not a good idea), particle system, or just drawn automatically from the parent objects update function. I would recommend the latter.
Now you would store a bunch of floats that define where your arrows are
public List<float> arrow_locations = new List<float>();
//adding one arrow
arrow_locations.Add(0.0);
//now in the update function of your parent object, update the arrow locations
private float cycle = 0.0f;
void Update()
{
float segment_size = 360.0f/outline.Count;
for(int i=0; i < arrow_locations.Count; i++)
{
arrow_locations[i] += 0.05f; //speed of spinning
if( arrow_locations[i] >= 360.0f ) arrow_locations[i] = 0;
//now to get the actual location of the arrow
int which_edge = Mathf.Floor((arrow_locations[i]/360.0f)*outline.Count);
//this will give us a number 0..1 telling us where along the edge the arrow is
float weight_within_edge=(arrow_locations[i] - segment_size*which_edge)/segment_size;
//here we lerp between the two vertices of the edge
Vector3 new_loc = outline[which_edge][0]*(1.0-weight_within_edge) + outline[which_edge][1]*(weight_within_edge);
//now that we have the location of the arrow, draw it
//note, you can get more efficient if using instancing for all arrows
//You can also use line drawing, but i wouldn't recommend that.
DrawMesh(arrow_mesh, new_loc, Quaternion.identity);
}
}
Please note, that when you have the positions of the arrows, you can opt to draw them in 2D in the UI by projecting them onto the camera plane. The lines aside from the arrows are themselves static, so you can draw them as part of the mesh very easily. Also note, I make no mention of the objects position, all values should probably be defined in local space, then transformed with the object. You can transform the drawn stuff in the the DrawMesh function by supplying a a transform matrix.
I think a shader with a parameterized radial mask would be the best way to do this. I have never done one myself, so I only have a general idea of how it's done, but here is how it would work AFAIK:
Create some kind of cell shader that can draw the edges of objects.
Create a filter/mask that has an angle shape extruding radially from the center to the edges; you can control the shape/angle using a parameter. Unity already has something similar to this in the Tanks! tutorial - Tank Health lesson.
Note: The tutorial might even be exactly this idea, but I don't remember with enough details to confirm; I'll update the answer after I take a look again.
The tutorial has the same idea, but it applies it using unity's builtin UI stuff.
Using this mask, only the masked area of the shape's edge will be drawn the screen.
By increasing the angle parameter of the mask over time, you can create the effect of the edge of the object getting revealed radially over time. Which seems to be exactly what you want.
To help visualize, a very professional diagram made in paint:
light blue = mask.
dark blue = "revealed" part of the mask (angle parameter). Plus how it would behave if the angle is increased (arrow).
green = object.
black = outline being drawn to the screen.
I'm currently creating a large map, that consists of a lot of rectangles (33,844), that all have a unique name (label), which I'm drawing on top of them using a SpriteFont.
Drawing all of the rectangles takes no performance hit at all. But, as soon as I try to write all of their labels with DrawString(), my performance goes into the dumps.
In my head, I would like to draw all my rectangles and text to one texture all at once, and only have to keep redrawing that entire finished texture. My issue is, this is an enormous map, and some of the coordinates for the rectangles are very high (example: one slot's x is 14869 and y is 23622), and they're far bigger than a Texture2D allows.
Since this is a map, I really only need to draw the entire thing once, and then allow the user to scroll/move around it. There's no need for me to continually redraw all of the individual rectangles and their labels.
Does anyone have experience with this type of situation?
Try to only render the labels that you can see on the screen and if you can zoom back far enough, just don't render them.
Textrendering is expensive, since it is basically creating a rectangle to draw on for every character in the font and then applying the same RGBA texture to it. So depending on the number of characters you write, the number of rectangles increases. This means four new vertices per character.
Depending on what you write you could simply create a texture with the text already on it and render that, but it won't be very dynamic.
EDIT: I need to clarify something.
There's no need for me to continually redraw all of the individual rectangles and their labels.
This is wrong. You have to draw the whole thing every frame. Sure, it doesn't increase memorywise, but it still is a lot to render and you will need to render it every frame.
But as I said: Try to only render the labels and the rectangles that collide with the screenboundaries, then you should be fine.
There are two ways to solve your problem.
You can either render your map to a RenderTarget(2D/3D) or you can cull the rectangles/text that are offscreen. However, I am not 100% sure that RenderTargets can go as large as you would need, but you could always segment your map into multiple smaller RenderTargets.
From more information on RenderTargets, you might want to check out RB Whitaker's article on them, http://rbwhitaker.wikidot.com/render-to-texture
Culling, in case you are familiar with the term when used in this context, means to only render what is visible to the end-user. There are various ways that culling can be implemented. This does however require you to have already implemented a camera (or some type of view region) and you perform a basic axis-aligned bounding box collision (AABB collision, which MonoGame's Rectangle supports out of the box) of the rectangles against the camera's viewport and only render it if there is a collision.
A basic implementation of culling would look something like this:
Rectangle myRect = new Rectangle(100, 100, 48, 32);
public void DrawMapItem(SpriteBatch batch, Rectangle viewRegion)
{
if (viewRegion.Contains(myRect))
{
//Render your object here with the SpriteBatch
}
}
Where 'viewRegion' is the area of you world that the camera/end-user can actually see.
You can also combine the two methods, and render the map to multiple render targets, and then cull the render targets.
Hope this helps!
To be honest I am quite lost with world, screen and viewport coordinates in Unity.
My question is rather simple: in a 2d game how do I place an object in bottom left corner no matter what the resolution and screen aspect ratio is?
It is a little vague your description, but I think your talking about this:
Vector3 screenPos = new Vector3(x,y,z);
camera.ScreenToWorldPoint(screenPos);
As a side note, there are specific algorithms for 2D Unity, search for that also.
For Orthographic check this unity space which might help you:
http://answers.unity3d.com/questions/501893/calculating-2d-camera-bounds.html
I see no one ever followed up on this. Let's get some terms straight first:
Camera.main = the main camera that is looking at your game world
"game world" = the entire game map you've drawn
World Point = an absolute, unique position in the game world. Can be 2D or 3D (x,y,z)
Screen Point = a 2D x,y location of a pixel on the screen
So, when you want to place an object (i.e.transform its location) what you are really doing is placing it somewhere within the Game World. If the camera happens to be looking at that location in the World then it will appear on screen.
To figure out what parts of the World are currently on screen, you must convert a Screen Point to a World Point. So...assuming your object's size is 20x20, try this:
//Attach this script to the item you want "pinned" to the bottom, left corner of the screen
void Update() {
//fetch the rectangle for the whole screen
Rect viewportRect = Camera.main.pixelRect; //again, this has nothing to do with the World, just the 2D screen "size", basically
//now, let's pick out a point on the screen - bottom, left corner - but leave room for the size of our 20x20 object
Vector3 newPos = new Vector3(viewportRect.xMin + 20, Camera.main.pixelHeight - 20, 0);
//now calculate where we need to place this item in the World so that it appears in our Camera's view (and, thus, the screen)
this.transform.position = Camera.main.ScreenToWorldPoint(newPos);
}
I'm 98% certain this is all accurate info but if someone sees a mistake please point it out.
I'm adding lighting to my XNA 2D tile based game.
I found this article useful, but the way its done it does not support collision. What I'd like is a method to do the following
Have always lit point
Collision (If the light ray hits a block, then dim the next block by whatever amount until its dark to simulate shadows)
I've been searching around for quite a while but no luck (I did find Catalin's tutorial, but it seemed a bit advanced for me, and didn't apply to tiles well due to redrawing the entire game for each point)
I'll share my method for applying a smooth lighting effect to a 2D tile grid. ClassicThunder's answer provides a nice link for shadows.
First off, we will need to calculate the lighting values of each tile which will be blurred later. Let me illustrate how this works before I get into the code.
Basicly what we do is loop through all the tiles, starting from the top, if a tile is blank, set the CurrentLight variable to max brightness, if we find a solid tile, set it as the CurrentLight variable and subtract an "absorbsion" amount from the CurrentLight. This way, on our next solid tile, when we set the tile to the CurrentLight value, it will be slightly less. This process is repeated until the array is iterated.
Now there will be a nice top to bottom lighting effect, but it isn't that great. We must repeat this process 3 more times, for bottom to top, left to right, and right to left. And it can be repeated more times for better quality.
Basically running this code on every tile in the loop
if (tile.Light > CurrentLight) //If this tile is brighter than the last, set the current light to the tiles light
CurrentLightR = tile.Light;
else if (CurrentLight != 0f) //If it is less, and isnt dark, then set the tile to the current light
tile.Light = CurLightR;
if (tile.Light == CurLightR) //If it is the same, subtract absorb values
CurrentLight -= tile.Absorb;
And there you go, nice tile lighting. However if you want a less "pixelized" look, you can check out my question on gamedev for that.
For per-pixel lighting, you might have to look somewhere else, because I don't know about that.
For per-tile lighting,
in SpriteBatch.draw, a few of the overloaded methods takes a color. When you use Color.White, the sprite that the SpriteBatch draws is normal colored.
Use Color multiplication by creating a new Color(Color.yourcolor.r*float, Color.yourcolor.y*float, Color.yourcolor.z*float, 255)
Basically, to get the float, try to find out a formula that calculates the brightness of the block due to nearby lights (stored in an array or list, probably). Since there's no normals needed for 2D games, this formula should be relatively easy.