Modeling human running on a soccer field_问答_开发者

In a soccer game, I am computing a steering force using steering behaviors. This part is ok. However, I am looking for the best way to implement simple 2d human locomotion.

For instance, the players should not "steer" (or simply add acceleration computed from steering force) to its current velocity when the cos(angle) between the steering force and the current velocity or heading vectors is lower than 0.5 because it开发者_开发知识库 looks as if the player is a vehicule. A human, when there is an important change of direction, slows down and when it has slowed enough, it starts accelerating in the new direction.

Does anyone have any advice, ideas on how to achieve this behavior? Thanks in advance.

Make it change direction very quickly but without perfect friction. EG super mario

Edit: but feet should not slide - use procedural animation for feet

This is already researched and developed in an initiative called "Robocup". They have a simulation 2D league that should be really similar to what you are trying to accomplish.

Here's a link that should point you to the right direction: http://wiki.robocup.org/wiki/Main_Page

Maybe you could compute the curvature. If the curvature value is to big, the speed slows down. http://en.wikipedia.org/wiki/Curvature

At low speed a human can turn on a dime. At high speed only very slight turns require no slowing. The speed and radius of the turn are thus strongly correlated.

How much a human slows down when aiming toward a target is actually a judgment call, not an automatic computation. One human might come to almost a complete stop, turn sharply, and run directly toward the target. Another human might slow only a little and make a wide curving arc—even if this increases the total length to the target. The only caveat is that if the desired target is inside the radius of the curve at the current speed, the only reasonable path is to slow since it would take a wide loop far from the target in order to reach it (rather than circling it endlessly).

Here's how I would go about doing it. I apologize for the Imperial units if you prefer metric.

The fastest human ever recorded traveled just under 28 mph. Each of your human units should be given a personal top speed between 1 and 28 mph.
Create a 29-element table of the maximum acceleration and deceleration rates of a human traveling at each whole mph in a straight line. It doesn't have to be exact--just approximate accel and decel values for each value. Create fast, medium, slow versions of the 29-element table and assign each human to one of these tables. The table chosen may be mapped to the unit's top speed, so a unit with a max of 10mph would be a slow accelerator.
Create a 29-element table of the sharpest radius a human can turn at that mph (0-28).

Now, when animating each human unit, if you have target information and must choose an acceleration from that, the task is harder. If instead you just have a force vector, it is easier. Let's start with the force vector.

If the force vector's net acceleration and resultant angle would exceed the limit of the unit's ability, restrict the unit's new vector to the maximum angle allowed, and also decelerate the unit at its maximum rate for its current linear speed.
During the next clock tick, being slower, it will be able to turn more sharply.
If the force vector can be entirely accommodated, but the unit is traveling slower than its maximum speed for that curvature, apply the maximum acceleration the unit has at that speed.

I know the details are going to be quite difficult, but I think this is a good start.

For the pathing version where you have a target and need to choose a force to apply, the problem is a bit different, and even harder. I'm out of ideas for now--but suffice it to say that, given the example condition of the human already running away from the target at top stpeed, there will be a best-time path that is between on the one hand, slowing enough while turning to complete a perfect arc to the target, and on the other hand stopping completely, rotating completely and running straight to the target.