Physics, revolute joints, anchors. How does it works?

[Rad3k]

Also, I still don't understand why I have to set a width of 2*window_width (see code) to actually get a width of window_width for the ground.

When you create a rectangle in Box2d, "x" and "y" are the center of the rectangle, not its top left corner. Create the ground rectangle at the bottom-center of the screen.

Also, when you create the world, you can do just

Code: Select all

world = love.physics.newWorld(0, 0, width, height)

instead of

Code: Select all

world = love.physics.newWorld(-width, -height, width, height)

You took this code from the wiki, right? I think it needs to be corrected...

For the correct positioning of joints, try using less magic numbers and more meaningfully named constants in your code. It will be easier to understand it and spot the bug then.

[knarf]

Also, I still don't understand why I have to set a width of 2*window_width (see code) to actually get a width of window_width for the ground.

When you create a rectangle in Box2d, "x" and "y" are the center of the rectangle, not its top left corner. Create the ground rectangle at the bottom-center of the screen.

Yep, I realised this few minutes after posting.

Also, when you create the world, you can do just

Code: Select all

world = love.physics.newWorld(0, 0, width, height)

instead of

Code: Select all

world = love.physics.newWorld(-width, -height, width, height)

You took this code from the wiki, right? I think it needs to be corrected...

Actually I should have payed more attention to the wiki, the center-coordinates thing is explained there.

For the correct positioning of joints, try using less magic numbers and more meaningfully named constants in your code. It will be easier to understand it and spot the bug then.

I know, but too much named constants can also be harder to read.

[knarf]

Okay I've reach a point where I'm not far from what I want. The included love has a body with 2-parts legs, rotation is blocked almost similar to a human and I've even added some gameplay: you have to jump the highest you can. My personal record is 349 at the moment .

The controls are terrible though. I want my thing to behave like the flash game QWOP. QWOP controls are also, ahem, special but you get used to it. (I can finish it)

I know the body creation code is messy and full of hardcoded coordinates, I'm trying things out.

[Rad3k]

Looks fun But yeah, controls need some love. Right now, I can't even figure what precisely does each key, and none of them does what I want
Considering that we have 2 legs, 2 joints per each leg (hips and knees), and 2 basic actions for each joint (contract and extend) wouldn't we need at least 8 keys to effectively control all the joints?

By the way, resetting doesn't work for me. Something happens when I press R, but it's quite far from full reset.

[knarf]

Considering that we have 2 legs, 2 joints per each leg (hips and knees), and 2 basic actions for each joint (contract and extend) wouldn't we need at least 8 keys to effectively control all the joints?

Have you played QWOP? Basically, Q and W control the thights and O and P control the calves.

• Q moves the front thigh to the right and the back one to the left
• W is the opposite of Q, front and back are switched.
• O extends the front calf and contract the back one
• P is the opposite of O, front and back are switched.

By the way, resetting doesn't work for me. Something happens when I press R, but it's quite far from full reset.

yeah it's a quick & dirty reset.

Currently I'm using applyTorque() to move a part but maybe I should set a motor to the joint...

edit: ok I've fiddled some constants, controls are getting better (also added some walls and a surprise).

[knarF.se]

Stupid forum software!

I claims I've been cited in this thread...

Hi other knarf!