Help with 3d camera, first person

Questions
1

Just started learing 3d and having trouble with the camera.
I’m trying to make it first person, so i assume you would rotate the lookat pos around the eye pos.
I have tried a formula i use in 2d, but the distance between the two decreases the more i rotate.
What is the proper way to do this?
Any help would be appreciated :slight_smile:

function setup() 
    lookAt = vec3(0,0,0) --camera direction
    parameter.watch("lookAt")
    parameter.watch("lookAt:dist(vec3(0,0,500))")
    parameter.number("ang",-90,95,85)
    parameter.integer("spriteZ",-100,1000,620)
end

function draw()
    background()perspective()pushMatrix()
    
    dist = 500
    lookAt.x = math.cos(math.rad(ang))*dist
    lookAt.z = math.sin(math.rad(ang))*dist
    
    camera(0, 0, 500, lookAt.x, lookAt.y, lookAt.z)

    translate(-100,0,0) sprite("Planet Cute:Character Cat Girl",0,0)
    translate(500,0,spriteZ) sprite("Planet Cute:Character Horn Girl",0,0)
    
    popMatrix()ortho()viewMatrix(matrix())
    strokeWidth(2)fill(127, 127, 127, 145)translate(WIDTH/2,HEIGHT/2)
    ellipse(0,0,40)
    ellipse(lookAt.x/10,-lookAt.z/10,20)
    popMatrix()
end
2

@Jaybob - Have a look at this

https://coolcodea.wordpress.com/2015/02/12/198-looking-at-objects-in-3d/

It may help you to read the previous posts on dot products and cross products, it will make it easier for you to understand how it works.

I have many other 3D posts on that blog, and I have some ebooks, including one on 3D, you’ll find a link at the top of the index page of the blog

3

@Jaybob Look at the discussion ‘starter game 16’ that I recently posted. That uses simple math to move the camera ‘look at’ position. That might give you a start.

4

Thanks for the help guys, some really interesting stuff there, if a bit daunting ^:)^
I realised what the problem was. I set camEye.z at 500 and then multiplied the sin/cos angles by 500, that doubled the distance between the two and set the point of rotation in the middle.

function setup()
    parameter.number("ang",-360,360,-90)
    parameter.number("y",-2000,2000,500)
    parameter.watch("cam")
    parameter.watch("eye")
    cam = vec3(0, 0, 0)
    eye = vec3(0, 0, 0)
end

function draw()
    background()
    rectMode(CENTER)
    perspective()
    pushMatrix()
    eye.x = math.cos(math.rad(ang))*500
    eye.z = math.sin(math.rad(ang))*500 
    cam.y = y
    camera(cam.x, cam.y, cam.z, eye.x, eye.y, eye.z)
    fill(87, 255, 0, 185)
    for i = 0,7 do
        local x, z = math.cos(math.rad(i*45))*1000, math.sin(math.rad(i*45))*1000
        pushMatrix()
        translate(x,0,z)
        rotate(i*-45+90,0,1,0)
        rect(0,0,100,100)
        popMatrix()
    end
    translate(0,0,0)
    rotate(90,1,0,0)
    fill(95, 0, 255, 96)
    ellipse(0,0,2000)
end