class Z80Lib3D::Primitives::Vertex

Z80Lib3D::Primitives::Vertex ↑

A 3 element Vector and 2 screen coordinates:

Constants

S

A struct to represent Vertex instances

Public Class Methods

make(x, y, z, scrx0:128, scry0:128, scrz0:128, persp_dshift:7) click to toggle source

Creates a Vertex struct object that can be used as a Z80::Program.data argument.

x, y, z are the Vertex coordinates. The coordinates are rounded to integers.

This method raises an error if calculated screen coordinates can't be represented by 8-bit unsigned integers.

Options:

  • scrx0

    A value added to the screen X coordinate.

  • scry0

    A value added to the screen Y coordinate.

  • scrz0

    A value added to the Z coordinate.

  • persp_dshift

    Perspective adjustment (D): 0-7. X and Y coordinates are multiplied by 2 to the power of D (bitwise left shifted) before calculating the screen X,Y.

# File lib/z80lib3d/primitives.rb, line 65
def Vertex.make(x, y, z, scrx0:128, scry0:128, scrz0:128, persp_dshift:7)
  raise ArgumentError, "Vertex.make: invalid persp_dshift argument" unless (0..7).include?(persp_dshift)
  x, y, z = x.round, y.round, z.round
  scrxmax = 0xFF
  scrymax = 0xFF
  xp =  ((x << persp_dshift) / (z + scrz0)) + scrx0
  yp = -((y << persp_dshift) / (z + scrz0)) + scry0 # yp grows downwards
  if xp < 0 || xp > scrxmax || yp < 0 || yp > scrymax
    raise ArgumentError, "Vertex.make: vertex screen coordinates out of bounds"
  end
  S.new(Vector::S.new(z, y, x), xp, yp)
end
make_many(*args, scrx0:128, scry0:128, scrz0:128, persp_dshift:7) click to toggle source

Creates many Vertex data arguments from triplets: [x, y, z] and returns an array of Vertex struct objects.

See also Vertex.make.

# File lib/z80lib3d/primitives.rb, line 83
def Vertex.make_many(*args, scrx0:128, scry0:128, scrz0:128, persp_dshift:7)
  args.map{|x, y, z|
    Vertex.make(x, y, z,
      scrx0:scrx0, scry0:scry0, scrz0:scrz0, persp_dshift:persp_dshift)}
end
scale(sc, vertex, scrx0:128, scry0:128, scrz0:128, persp_dshift:7) click to toggle source

Creates a re-scaled Vertex struct object(s). See also Vertex.make.

sc

A scalar factor.

vertex

A Vertex struct object or an array of objects.

Depending on the vertex argument a single Vertex object or an array of objects is returned.

# File lib/z80lib3d/primitives.rb, line 97
def Vertex.scale(sc, vertex, scrx0:128, scry0:128, scrz0:128, persp_dshift:7)
  if vertex.is_a?(Array)
    vertex.map{|v|
      Vertex.scale(sc, v, scrx0:scrx0, scry0:scry0, scrz0:scrz0, persp_dshift:persp_dshift)}
  else
    vec = vertex.vec
    Vertex.make(vec.x*sc, vec.y*sc, vec.z*sc,
      scrx0:scrx0, scry0:scry0, scrz0:scrz0, persp_dshift:persp_dshift)
  end
end