Maratis forum - Having a ray perpendicular to the ground

Re: Having a ray perpendicular to the ground

dummy@example.com (anael) — Sat, 24 Nov 2012 11:45:12 +0000

We need to add some ready made functions to manipulate vectors,
but for now you can do it in lua with something like that :

function rotateX(vec, angle)

    zAngle = math.rad(angle)
    sinZ = math.sin(zAngle)
    cosZ = math.cos(zAngle)

    return {vec[0], vec[1] * cosZ - vec[2] * sinZ, vec[1] * sinZ + vec[2] * cosZ}

end

function rotateY(vec, angle)

    zAngle = math.rad(angle)
    sinZ = math.sin(zAngle)
    cosZ = math.cos(zAngle)

    return {vec[0] * cosZ + vec[2] * sinZ, vec[1], -vec[0] * sinZ + vec[2] * cosZ}

end

function rotateZ(vec, angle)

    zAngle = math.rad(angle)
    sinZ = math.sin(zAngle)
    cosZ = math.cos(zAngle)

    return {vec[0] * cosZ - vec[1] * sinZ, vec[0] * sinZ + vec[1] * cosZ, vec[2]}

end

Re: Having a ray perpendicular to the ground

dummy@example.com (ChickenRunFast) — Fri, 23 Nov 2012 20:43:09 +0000

Alright, the idea is good I guess, thanks for the reply.
But there's something I have to do about the definition of my floating. Because currently it is set to 10m above the ground (=10m on the z-axis) which obviously is not right. So I have to redefine my ray. I am aware of trigonometry, but I can't get this working. I have to get the ray rotating with the object, but I don't know why. Any idea?

Re: Having a ray perpendicular to the ground

dummy@example.com (anael) — Fri, 23 Nov 2012 16:55:27 +0000

Hi,

an idea, use an invisible small cube placed in front of the floating object.
Make the floating obj looking at the small cube (using the look-at behavior).
Send a ray from the transparent cube and make it float at the same height, and it should be parallell.

Having a ray perpendicular to the ground

dummy@example.com (ChickenRunFast) — Fri, 23 Nov 2012 15:51:34 +0000

Hey there!
So I'm just messing around with this engine and I'm feeling pretty comfortable with it. And lately I have played with some raycasts. There's one thing that I am really not able to do. I've got my object. It's floating. Works. But now the point is, that I want the object to always be parallel to the ground. So I thought, I could do this by shooting a ray into the ground and check if that is perpendicular. But I can't get this working. Maybe you could help me.

In case you are wondering what I am trying to do, go drive that ramp up. Controls are W A S D, have fun! http://www.file-upload.net/download-684 … t.zip.html

Edit: Im kinda unexperienced in coding and this helps me getting used to it a lot. I would prefer ideas of how to do it over real code snippets. Thanks in advance