I'm currently working on a MUD project. I'd like to figure out how to use a static background IMAGE as a map. (These maps are like graph paper. Squares represent rooms, and lines connect the squares to show cardinal direction exits.) There will be custom "hand-drawn" maps for each area in the game.
On my GUI, there will be a section of the frame dedicated to showing this static map. When a player MOVES (goes east, west, northwest, etc), a red DOT will be drawn over the current room the player is in.
This is similar to other MUD maps, except in most cases those maps are ASCII/text. I would really like to be able to use an image as the background, and only "draw" the red dot representing player location.
Also, the distance between rooms would not be uniform, so I cannot blindly just move the dot say 50 pixels left for a western movement.
How would I go about programming this? I imagine I will need to pre-define where the dot would be displayed for each room.
Any help in the right direction would be appreciated.
Related
I'm working on a project at school, which basically is: writing an application to make a drone fly autonomously, and through scanning QR-codes hung up on walls, be able to navigate through a room in order to complete a certain task.
What I am currently working on, is for the drone to detect cardboard boxes (working as obstacles). These boxes are white, and have a blue circle on them. How I'm planning to solve this, is by scanning the frame for colors and squares:
If the drone detects a square, check if it's white. If it's white, check if it contains a blue circle. If it does, I can say that it most likely is a cardboard box.
This is what the box looks like:
If anyone would be able to provide some pointers as to how I can start working on the color detection, I would be very happy!
PS: I haven't provided any code, since I don't really know what to provide. I would be more than happy to provide some if needed
UPDATE: for anyone stuck at the same problem as I, a fellow student provided an excellent link for my exact situation:
http://opencv-java-tutorials.readthedocs.io/en/latest/08-object-detection.html
I would go from a different angle to do this by detecting the blue circle first.
Detect base colors
see RGB value base color name
Select all blue pixels neighboring white or gray-ish ones
As your circlehas black border then you have to select all blue pixels near white,gray,black... just to be sure. This is the result (Green are selected pixels):
another (more robust) possibility is to select all black pixels neighboring white and blue at the same time.
do a connected components analysis
so merge all connected pixels into polylines
For each polyline decide if it is circle/ellipse/oval
that can be done by investigating angle between line segments. If has sharp spikes then sharp edges are present and it is not an oval. If the circumference is too far from circle/elipse/oval computed from its bounding box then it is not oval but some more complicated curvature.
For each oval decide if it is filled with blue
so just flood fill mask of the oval circumference and compare how many pixels are int the original image blue against those that are not. if the ratio is closer to 100% blue then it is filled blue oval shape....
As your marker has also some features inside you can compute the ratio of all base colors inside it to more accurately detect the marker.
Look at Algorithms: Ellipse matching for some additional ideas.
now you can similarly check if the background is white/gray-ish
There are a lot of other possible approaches like OCR and character similarity or based on FFT/DCT, Hough transform for circles... also you are not bound only to geometric properties comparation instead you can compare histograms...
Let's say I have a triangular face in 3d space, and I have the 3d coordinates of each vertex of this triangle, and would also have other information about the triangle(angles, lengths of sides, etc.). In Java, if I have the viewing screen and its information, how can I draw that plane, without using libraries like LWJGL, to that image, assuming I can properly project, accounting for perspective, any 3d point to that 2d image.
Would the best course of action just be to run a loop that draws each point on the plain to a point on the image(i.e. setting the corresponding pixel), which will most likely set the same pixel multiple times? If I'd do this, what would be the best way to identify each point in an oblique triangle, or a triangle that doesn't line up nicely with the axes?
tl;dr: I have a triangular face in 3d space, a "camera" looking at the face, and an image in which I can set each pixel. Using no GL libraries, what's the best way to project and draw that face onto the image?
Projection :
won't detail as you seems to know it
Drawing a line
you can look at Bresenham algorithm if you wanna start with the basics
(hardwared in recent graphics card)
Filling
you can fill between left and right borders of the triangle while you use Bresenham on both (you could use a floodfill algorithm starting ... i don't know, maybe at the projection of the center of the triangle)
Your best bet is to check out the g.fillPolygon() function for Java. It allows you to draw polygons with as many sides as possible and theres also g.drawPolygon() if you don't want it solid. Then you can just do some simple maths for the points. Such as each point is basically it's x and y except if the polygon is further away the points move closer to the center of the polygon and if the polygon is closer they move further away from the center of the polygon.
A second idea could be using some sort of array to store pixels and then researching line drawing algorithms and drawing lines then putting all the line data in another array and using some sort of flood-fill. Then whilst it's in that array you could try and do some weird stuff to the pixels if you wanted textures or something.
I know do a horizontal and vertical scroller game (like Mario), in this game type, the character is always in the same distance from user. The character only moves to left and right in horizontal scroller and to down and up in vertical scroller.
But there are games in 2D that the character can move freely in the scene, like for example graphic adventures.
So how can I do that ground in order to move the character freely on the ground with depth sense?
An example can see in this video: http://youtu.be/DbZZVbF8fZY?t=4m17s
Thanks you.
This is how I would do that:
First imagine that you are looking at your scene from the top to the ground. Set your coordinate system like that. So all object on your scene will have X and Y coordinates. All your object movements and checking (when character bumps into a wall or something), calculations do in that 2D world.
Now, to draw your world, if you want simpler thing, without some isometric perspective 3D look you just to draw your background image first, and then order all your objects far to near and draw them that way. Devide your Y coords to squeeze movement area a bit. Add some constant to Y to move that area down. If you characters can jump or fly (move trough Y axe) just move Y coord to for some amount.
But if you want it to be more 3D you'll have to make some kind of perspective transformation - multiply your X coordinate with Y and some constant (start with value 1 for constant and tune it up until optimal value). You can do similar thing with Y coord too, but don't think it's needed for adventure games like this.
This is probably hard to understand without the image, but it's actually very simple transformation.
I am 11 years old, and I program with Java, HTML, and CSS. Well what I have is a game, and its a Minecraft 2D Platformer.
Well I have some water to the side, and what I want to do is when the player intersects that water, I want it to slow down. Here is a example if there was a method to do this, in case you still don't understand my goal.
if (player.intersectsColor("0026FF"))
playerSpeed = 2;
else
playerSpeed = 3;
I suggest you represent the water not by its color but by its location. That way you can check whether the player is in a "tile" representing water, and adjust the speed accordingly.
This you can do with simple comparison on the x/y coordinates (adjusted for the size of the "tile"/"player")
If you don't have nice meshy tiles, but curves/polygons, you will need to read up on geometry and how to calculate (possibly curved) line intersection. The exact algorithm will depend on the curve used.
The reason I discourage you from using the color itself for the intersection many twofold:
"Intersecting" on a single color limits your ability to dynamically color the terrain/objects later
You cannot have two different terrain.object type with the same color
Having the color (e.g. brown) of the terrain/object does not tell you which blue terrain/object the player ran into (e.g. is it the first or the second chest?)
If you really want to represent the terrain with colors, you can translate the players in-game coordinates to screen coordinates and see what color pixel you have at that coordinate on the screen (before the player was rendered on the scene), but this is messy.
Working on 2d top-down tile map game - I've been looking into generating map coordinates (x/y) that the player can use to navigate the ("infinite", perlin/other-generated terrain) map, and to fix an issue with the noise generation.
I've seen solutions and have been told to translate world coords to screen coords and vice versa - but I'm unable to figure out how you can properly define fixed map coordinates because rendering something on the screen is done with coordinates relative to the frame/pane... so 0,0 is always the top-left of the window, no matter where the map is.
I could easily calculate coordinates for the map (there are a tile columns and b tile rows between your character's location and the map center ) but I can't understand how to define a fixed-on-map starting location? The player may start the game in different locations once I enable a save feature so it can't be based off of that.
When doing something like this, all coordinates should be in "world coordinates". So your player location is where it's on the infinite map, not where he is on the screen.
To render everything, you need a method that takes world coordinates and transforms them into screen coordinates and vice versa.
To start rendering, use the screen coordinate 0,0 -> transform to world coordinate to get the tile to render in the top left corner. Same with clicking something: Take mouse coordinates, convert, and then look on the world map what's there.
When moving the player, update it's world coordinate, etc.