What does the DragCompletedGestureEventArgs.Velocity parameter mean exactly? - c#

The DragCompleted event of a wp7 control has a parameter of type DragCompletedGestureEventArgs that contains the variables HorizontalVelocity and VerticalVelocity.
How are these velocity variables interpreted? I get a value of 0 for a slow drag and a value of >4000 for a fast drag, but I'm not sure how I can relate these numbers into a number of pixels dragged per time interval value.
Background of my question: In my program the user can grab an object and then drag it. I want the object to continue moving (up to a standstill) when the user lets go of the object.

You can't relate them into pixels. But you can create a relative scale according to the velocity, and then how much it should slow down / speed up, based on the velocity.
If you think of the Pictures Hub image viewer, then you can see that you can pan around images, but if you use a high enough velocity, it'll flick to the next/previous image.

Related

Unity - healthbar as outlined line around the screen

I have a game in Unity.
The idea of the game is that an object is spawned on the screen.
It exists for several seconds.
You need to click on it, while it exists.
What I want to do, is that while it exists - I want to show a timer, but not with numbers, but with an outlined line on the perimeter of the screen.
I know, how to make a make a slider and how to make circular health bar, yet I do not really have an idea to make a slider, that is decresing from everywhere to the centre as you can see on the screenshots below.
I would be thankful for the inspiration!
This should be a very good fit using alpha cutoff with a custom shader.
Here's a video explaining it in detail (it's only the first half you will need).
The basic idea is to create a texture with a graded alpha depending on how you want the texture to appear/disappear. In this case the alpha value at the top and the bottom would be close to 0 and then gradually around the line on both sides towards the middle increase to 1. The shader then cuts off the texture below a cutoff threshold which you can change depending on the value of the timer.
As a dumb and simple approach:
Have two images with fill, one goes middle towards top the other middle towards bottom.
Just imagine the pnguin is your outline ^^

Check if one GameObject is placed on top of another in Unity

I have two cubes with one being slightly bigger than the other and can be moved around freely around the scene by the user.
I need to know when the user has placed the smaller one on top of the bigger one and then continue with the script.
I understand that I need to check the collision somehow and maybe check the Y coordinate of both boxes too to make sure the user puts the smaller cube on top of the bigger and not vice versa.
How can I do this?
You could either create a trigger (more on that in the unity docs) and use the respecrive callback to continue or you could constantly check the position of the second object and if the coordinates are above the ones of the big box continue.

How to scroll progressively a game object?

I am developing a game with Unity which has a main menu to allow the user select game mode. In this screenshot you can see an example:
My problem is the following:
I need to create a scroll in which user can put his finger on point 1 and swipe/slide to point 2. On the one hand, while this action is happening the element 2 increase its opacity and its position change progressively to the center. On the other hand, while this action is happening the element 1 decrease its opacity and its position change progressively to the left part of the screen.
Extra information:
The elements are sprites with colliders to detect the selection of the player.
What would you suggest me to do? Have you got any code to solve this? Any other suggestion?
Hey i think i understood your problem,
According to my understanding. You can use a binary tree for this work, u can use a sprite sheet with different level of alpha value. The variable of the binary tree responsible for changing the sprite will depend on the finger's position on the screen which you can easily get by camera.ScreenToWorldPoint(pos). also you can easily change the position of the gameObject by recording the change in initial and final position of the touchPhase.

Generating/building map from file

using a file I want to create a map and I am wondering about the best approach doing so.
Actually I searched the forum but I only found map generation algorithms that randomly creates maps.
Let's look at a minimal example.
e.g. Ihave a file containing
0110
1001
1000
0000
Every 0 shall be water and every 1 shall be earth.
I would handle this by simply havin two different bitmaps and loading them at the right coordinates. That'd be simple.
But let's guess we have a 1000*1000 big map and there is only enough space for 16*16 tiles per frame. Then I'd get the current position and would build the map around it.
Assuming we can only display 3*3 tiles, using the minimal example and being at position (2,2) where x and y is element 1..4 so what the user could see at this time would be:
011
100
100
Solution
I thought about using a text file, where a line represents the x-coordinate direction and
a column represents the y-coordinate direction. The whole file is being loaded at the beginning of the program. This shouldn't use too much ram assuming 1 tile needs 1 byte, what should be enough.
For redrawing the map when the user is moving, I'd get the moving direction and slide the current Bitmap for the height/width of a tile in the opposite direction and only look up the bitmaps for the new blank spaces. So I only need to look up the tile information for m+n-1 (where m is the amount of displayed tiles in y and n in x direction) tiles (max case if moving diagonal) instead of loading m*n tiles everytime the user moves.
Example
I created an example to make the above given example more easily to understand.
this is the whole map:
We can only display 3*3 tiles and the user is at position (2,2) so what we'd actually see is:
now he is moving towards the bottom right corner:
and the black framed section is being move to the opposite direction, so that we get:
now the blank tiles (black framed white areas) have to be looked up and teh final result will be:
Question
is this a good way of building a map? Or are there much faster functions, maybe already implemented in the microsoft xna-gamestudio package ?
I would pre-fetch 1-2 tiles range outside the screen view, so that you won't have weird pop-up as the player move.
But if your game is a top-down tile game, this solution is quite conservative. In most hardware today, you could create a very big range around the player without problem. Just look at the number of block Minecraft can process and display. Since you are reusing the same texture, you just load the asset once and reuse them in a tile, which would probably an object with very little memory footprint.
Have you tried implementing it yet?

resolution independent grid for animations?

I'm working on a game made in XNA,C# and I want to enable xml based animations.
XML will look like this
<Animation>
<AnimatedObject>
<Filename>Spaceship_Jet_01</Filename>
<Flipped>false</Flipped>
<StartPosition_X>300</StartPosition_X>
<StartPosition_Y>500</StartPosition_Y>
<GOTOPosition_X>650</GOTOPosition_X>
<GOTOPosition_Y>500</GOTOPosition_Y>
<Time>10000</Time>
</AnimatedObject>
</Animation>
This will move an object to the side, like this
http://imm.io/odc7 (sorry the X coordinate is wrong)
I noticed there will be problems, when the players display resolution is different from mine because I enter pixel precise information about where the object comes from and where it has to go.
I thought about a grid so I can tell the programm to move the object from (30,27) to (22,27) e.g.. Is this a good solution? The grid has to be independent from the resolution but the number of tiles has to be constant and I have to draw the object to the screen. That means I have to find the right pixle position of the tile at position (22,27) and then "move" the object to that tile.
Is there a better way to do that? How can I solve this with XNA?
If you use a 2D camera you won't have any problem... because calculating the new view to adapt it to the new resolution is not difficult.... and you have not to change anything of your loads methods nor logic...
You can do, but I don`t like
Work with positions in [0..1] range, is difficult to measure.
Fix the position with the new resolution factor when you load the xml... is ugly...
Pos *= NewResolutionSize/DefaultResolutionSize;

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