Module: Kamelopard::Multicam

Defined in:
lib/kamelopard/multicam.rb

Class Method Summary collapse

Class Method Details

.cross_product(v1, v2) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 6

def self.cross_product(v1, v2)
    x =   ( (v1[1] * v2[2]) - (v1[2] * v2[1]) )
    y = - ( (v1[0] * v2[2]) - (v1[2] * v2[0]) )
    z =   ( (v1[0] * v2[1]) - (v1[1] * v2[0]) )
    return Vector[x, y, z]
end

.dotprod_angle(a, b, negate = false) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 13

def self.dotprod_angle(a, b, negate = false)
    begin
        d = 180.0 * (Math.acos(a.inner_product(b) / a.r / b.r)) / Math::PI
    rescue
        d = 0
        #puts "argument was #{a.inner_product(b)}, from vectors #{a} and #{b}"
    end
    d = 0 if d.respond_to? :nan? and d.nan?
    raise "#{a}, #{b}, #{a.inner_product(b)}" if d == Float::INFINITY

    # Complicating factor: dot product goes from 0 to 180, not 0 to 360. We'll
    # have to know whether to negate based on external input (like if the
    # original angle involved was close to the threshold)
    d = -d if negate

    return d
end

.get_camera(heading, tilt, roll, cam_num, cam_angle, cam_count = nil) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 105

def self.get_camera(heading, tilt, roll, cam_num, cam_angle, cam_count = nil)
    if cam_angle.nil? then
        cam_angle = cam_num * 360.0 / cam_count
    else
        cam_angle = cam_angle * cam_num
    end
    # The camera vector is [0,0,1] rotated around the Y axis the amount
    # of the camera angle
    camera = rot_y(cam_angle) * Vector[0,0,1]

    # The up vector is the same for all cameras
    up = Vector[0,1,0]
    matrix = rot_z(heading) * rot_x(tilt) * rot_z(roll)
    (h, t, r) = vector_to_camera(matrix * camera, matrix * up)
    # XXX What am I getting wrong, to require the negated roll?
    return [h, t, -1 * r]
end

.get_camera_view(v, cam_num, cam_angle, cam_count = nil) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 123

def self.get_camera_view(v, cam_num, cam_angle, cam_count = nil)
    (h, t, r) = get_camera(v.heading, v.tilt, v.roll, cam_num, cam_angle, cam_count)
    v.heading = h
    v.tilt = t
    v.roll = r
    v
end

.make_placemark(name, lat, lon, alt, tilt, roll, heading) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 97

def self.make_placemark(name, lat, lon, alt, tilt, roll, heading)
    p = point(lon, lat, alt, :relativeToGround)
    l = camera p, :heading => heading, :tilt => tilt, :roll => roll, :altitudeMode => :relativeToGround
    pl = placemark(name, :geometry => p, :abstractView => l)
    f = get_folder
    f << pl
end

.rot_x(a) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 31

def self.rot_x(a)
    # This, and the other two rotation matrix functions, must convert
    # the angle to radians
    a = a * Math::PI / 180.0
    return Matrix[[1, 0, 0], [0, Math.cos(a), -1 * Math.sin(a)], [0, Math.sin(a), Math.cos(a)]]
end

.rot_y(a) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 38

def self.rot_y(a)
    a = a * Math::PI / 180.0
    return Matrix[[Math.cos(a), 0, Math.sin(a)], [0, 1, 0], [-1 * Math.sin(a), 0, Math.cos(a)]]
end

.rot_z(a) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 43

def self.rot_z(a)
    a = a * Math::PI / 180.0
    return Matrix[[Math.cos(a), -1 * Math.sin(a), 0], [Math.sin(a), Math.cos(a), 0], [0, 0, 1]]
end

.same_quadrant(a, b) ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 48

def self.same_quadrant(a, b)
    (0..2).each do |i|
        return false if (a[i] > 0 and b[i] < 0) or (a[i] < 0 and b[i] > 0)
    end
    return true
end

.test(kml_name = 'multicam_test.kml') ⇒ Object


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# File 'lib/kamelopard/multicam.rb', line 131

def self.test(kml_name = 'multicam_test.kml')
    name_document 'tourvid'
    get_document().open = 1

    [:roll, :tilt, :heading].each do |which|
        camera = Vector[0,0,1]
        heading = 0
        tilt = 45
        roll = 0
        lat = 40
        lon = -111
        alt = 100

        puts "------------------"
        puts "Running #{which}"
        folder which.to_s
        get_folder().open = 1

        up = Vector[0,1,0]
        (0..36).each do |i|
            if which == :roll then
                roll = -180 + i * 10
                heading = 23
            elsif which == :heading then
                heading = i * 10
                heading = heading - 360 if heading >= 180
            else
                tilt = i * 5
            end

            # This has been verified visually as the right matrix
            matrix = rot_z(heading) * rot_x(tilt) * rot_z(roll)

            trans_up = matrix * up
            trans_cam = matrix * camera
            trans_cross = cross_product(trans_cam, trans_up)
            (screen_head, screen_tilt, screen_roll) = vector_to_camera(trans_cam, trans_up)

            diff_limit = 3
            a = dotprod_angle(trans_up, trans_cam)
            if ((heading - screen_head).abs > diff_limit or (tilt - screen_tilt).abs > diff_limit or (roll - screen_roll).abs > diff_limit) then
            #if which == :roll then
                puts "  PLACEMARK #{i}"
#                        puts "    Camera vector: #{trans_cam}, mag: #{trans_cam.r}"
#                        puts "    Up vector: #{trans_up}, mag: #{trans_up.r}"
#                        puts "    Cross prod: #{trans_cross}, mag: #{trans_cross.r}"
                puts "    UpZ: #{trans_up[2]}"
                puts "    Orig H/T/R: #{heading}/#{tilt}/#{roll}"
                puts "    Screen H/T/R: #{screen_head}/#{screen_tilt}/#{screen_roll}"
            end
            make_placemark(i, lat, lon, alt, screen_tilt, screen_roll, screen_head)
        end
        puts
        write_kml_to kml_name
    end
end

.vector_to_camera(vec, up_vec) ⇒ Object

Vec is the camera vector. up_vec is the vector out the top of the camera


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# File 'lib/kamelopard/multicam.rb', line 56

def self.vector_to_camera(vec, up_vec)
    # The heading is the angle between two planes, the first formed by the
    # camera vector and the original Z axis, and the second formed by the
    # original Y and Z axes. This angle between two planes is the same
    # as the angle between their two normals. The normal of the first
    # plane is the cross product of the two vector, and that of the
    # second is simply the X axis. The first cross product will be zero
    # if the camera position vector is parallel to the Z axis; in that
    # case we want the angle between the up vector and the y axis
    # This will only find values up to 180 degrees, and won't
    # distinguish direction correctly. For that, look at the Z
    # component of the cross product of the two normals.
    cam_z_norm = cross_product(vec, Vector[0,0,-1])
    if cam_z_norm.r == 0
        heading = dotprod_angle(up_vec, Vector[0,1,0],
            (cross_product(up_vec, Vector[0,1,0])[2] > 0))
    else
        heading = dotprod_angle(cam_z_norm, Vector[1,0,0],
            (cross_product(cam_z_norm, Vector[1,0,0])[2] > 0))
    end

    # Tilt is calculated from the vector alone, and is the angle between it and
    # the original Z axis, calculated via the dot product
    tilt = dotprod_angle(vec, Vector[0,0,1])

    # For roll, take the original UP vector, and now that I've got
    # valid heading and tilt, transform it by those values. Take the
    # angle between it and my current UP vector. Make it negative if
    # their cross product, up vector first, isn't the same direction as
    # the camera vector.
    transformed_up = rot_z(heading) * rot_x(tilt) * Vector[0,1,0]
    if cross_product(up_vec, transformed_up).r == 0
        negate = ! (same_quadrant(up_vec, transformed_up))
    else
        negate = same_quadrant(vec, cross_product(up_vec, transformed_up))
    end
    roll = dotprod_angle(up_vec, transformed_up, negate)

    return [heading, tilt, roll]
end