Lua Scripts for Audulus

A collection of Lua scripts for Audulus.

Audulus has two Lua-based nodes, the DSP node and the Canvas node. DSP node processes audio and control rate signals. Canvas node draws vector graphics using the Audulus graphics library, vger.

DSP node

For processing audio, synthesis, filters, anything requiring sample rate processing, we process each audio frame (where a frame is the length of one sample) using the frames loop:

function process(frames)
  for i = 1, frames do
      -- assuming you made a function called processAudio()
    output[i] = processAudio()
  end
end

process(frames) processes each block, for i = 1, frames do end processes each frame.

A block is like an audio buffer, the difference being that, depending on how you are using Audulus, as a standalone app or as an AUv3 plugin, block size can dynamically change depending on your audio host. (Not a big deal for almost everything, just happens in the background.)

For control rate signal - and a significant CPU savings compared to processing at audio frame rate - we can process at block rate using fill() instead of the frames loop. This approach fills each block with a constant:

function process(frames)
  -- assuming you made a function called controlSignal()
    fill(output, controlSignal())
end

Canvas node

The canvas node list of functions and global constants:

paint = color_paint(r, g, b, a)
paint = linear_gradient({start_x, start_y}, {end_x, end_y}, r, g, b, a, r, g, b, a)
fill_circle({x, y}, radius, paint)
stroke_circle({x, y} radius, width, paint)
stroke_arc({x, y}, radius, width, rotation, aperture, paint)
stroke_segment({ax, ay}, {bx, by}, width, paint)
fill_rect({min_x, min_y}, {max_x, max_y}, corner_radius, paint)
stroke_rect({min_x, min_y}, {max_x, max_y}, corner_radius, paint)
stroke_bezier({ax, ay}, {bx, by}, {cx, cy}, width, paint)
text("hello world!", r,g,b,a)
min, max = text_bounds("hello world!")
text_box("lorem ipsum...", break_row_width, r,g,b,a)
min, max = text_box_bounds("lorem ipsum...", break_row_width)
move_to{x, y}
line_to{x, y}
quad_to{bx, by, cx, cy}
fill(paint)
translate{tx, ty}
scale{sx, sy}
rotate(theta)
save()
restore()
canvas_width
canvas_height

Audulus has a design color scheme represented by r,g,b,a "theme" colors. For example:

azure = theme.azureHighlight
green = theme.greenHighlight
red = theme.redHighlight
white = theme.text
black = theme.grooves