add `jumpRelease` function to `BodyComp`

[joshuacurtiss]

Problem: When jumping with the jump function in BodyComp, a force is applied but thereafter you can't change the velocity. What about if you want to: (a) Change the height of jump based on how long the player holds down the jump key? (b) Want to stomp down in the middle of a jump?

Solution: With this function, you can accomplish the points mentioned above with a jumpRelease function that lets you change the velocity mid-jump.

Example of use can be seen here:
https://www.curtiss.me/build-mario-with-kaboom/

(Notice how short or long jumps can be achieved by how long you hold the jump button, or stomping down by pressing down mid-jump)

How it is accomplished in the sample:

• Stomp
• Release jump key

Thanks for your consideration.

[slmjkdbtl]

What do you think about just expose vel? This should enable most things

[slmjkdbtl]

So you can just

// Accelerate falling when player holding down arrow key
onKeyDown("down", () => {
    if (!player.isGrounded()) {
        player.vel.y += dt() * 1200
    }
})

// Jump higher if space is held
onKeyDown("space", () => {
    if (!player.isGrounded() && player.vel.y < 0) {
        player.vel.y -= dt() * 600
    }
})

[joshuacurtiss]

Hi @slmjkdbtl! Yes, exposing vel would make me happy and would be more versatile. 🎉

[slmjkdbtl]

vel is exposed in v3000.1.17!