Finalspace

Hi everybody,

 

i have implemented discrete SAT (Separating Axis Theorem) in the past successfully.

Therefore i have now remade this to fix the "fast moving issue" - calculate the time when the collision first happens - to get a value for scaling the velocity to remove the penetration in the first place.

 

What i basically do is to test two OBB with two fixed axis of (1, 0) and (0, 1) with the following algorythm:

 

- Get the relative position (distance) between the 2 OBBs (pA - pA)

- Get the relative velocity between the 2 OBBs (vA - Vb) - Just to remove the second velocity to make the second one static.

- For loop over the two axes

- Project the relative position onto the axis to get an offset based on current axis

- Project A onto current axes and get min/max projection

- Add the offset to projection of A

- Project B onto current axes and get min/max projection

- Calculate distances between min/max projections of A and B (d0, d1)

- Calculate time enter and time leave factor by divide both distances by projected velocity on axis

- Swap time enter with time leave if required (Time enter must always be smaller than time leave)

- Get the highest overlap to skip out collisions which not happens or are too late

- Time Enter is the factor used to fix the velocity.

 

These steps are implemented a simple JSFiddle demo i have written to visualize the entire process, see here:

http://jsfiddle.net/dku72/

 

 

It would be really great if you can help me to fix these problems.

 

Thanks,

Final

Hi,

i am currently writing a 2D Platformer with Java and LWJGL. I am at the point where i want
to display a hud - for displaying player lives, score, etc. and render an UI for my integrated level editor.

The game is designed to run with every screen resolution, the entire orthographic projection is scaled and positioned with a simple factor based on the designed screen size and current screen size. No need to calculate ratio, add cinematic borders, etc. Not sure if that is the correct way for handling different screen resolutions but works for my game, cause the camera is always centered on the player and zoomed based on the above factor.

But how to design/render and UI/HUD for my game which works my different screen resolutions too, i havent figured that out yet.

If i use a fixed screen size for hud/ui rendering everything will be fine, until the screen resolution is changed to an different aspect ratio, for example switching from 4/3 to 16/9 will stretch rendering. But switching from 800 x 600 to 1600 x 1200 will work fine.

Is there a good explanation how to design/render HUD´s for different screen resolutions / aspect ratios?

Here is a small video for showing the current handling of the zoom based on screen size:
http://www.youtube.com/watch?v=rnmBIJmOKzk

Thanks in advance,
Final

Hello, i am trying to write a simple 2D Platform Game but having trouble implementing simple platform physics.
Unfortunatly i dont have any experience in game programming or game math and i dont understand complex formulas.

What i have so far, is a player with a position rectangle a velocity vector and a list of platform objects.
I can freely move the player by controls and i have done some simple collision detection.

This is achieved by increasing the position by the velocity * (speed * frametime) and works for non platform games.
In case of a collision, the velocity is set to zero, but this has a bad side effect for platform physics which does not allow any movement on a platform where the player already collides.

I think the the player should always be pushed down by gravity until he hits a platform (falling), but should be able to move in X axis and can collide with other objects or platforms as well.

It would be really great if you can give me some advice how i can do this.

Thanks,
Final