initial commit

lib/VoxelGrid.lua

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+-- Voxel world mode: the voxel wireframe, 3D Dot Game Heroes style.
+--
+-- Every mesh in this mode is built on a one-unit-per-voxel grid in its OWN
+-- model space -- terrain in world pixels, a character slab in the sprite's
+-- own pixels, a carved model in its voxels. So the seams are simply the
+-- integer planes of that space, and drawing them is a pixel-shader job:
+-- measure how far the fragment is from the nearest integer plane, in
+-- DISPLAY pixels, and darken the ones within half a pixel of it. Sitting in
+-- model space is what keeps the wireframe glued to a thing however it is
+-- posed -- a character's slab leans back by the camera's pitch and its
+-- seams lean with it, instead of the world's grid sliding across the
+-- sprite.
+--
+-- Deriving "in display pixels" needs shader derivatives (fwidth), which is
+-- the one part of this that a driver can refuse. So the grid is a SECOND
+-- COMPILATION of the scene shader rather than a branch inside the first
+-- one: if it will not build, the mod loses the wireframe and nothing else
+-- (see Voxel3D.shader).
+--
+-- This file owns the toggle rather than the drawing: the level, where it
+-- persists, and the row the player finds it on.
+
+-- the mod namespace (see main.lua): V.require loads a sibling module
+local V = ...
+
+local ModSetting = V.require("ModSetting")
+
+local VoxelGrid = {}
+
+-- the key under options.modOptions.DRAMATIC_SHAPE, shared by the row in
+-- OPTIONS and the mod manager's own settings page for this mod
+VoxelGrid.KEY = "grid"
+VoxelGrid.LABEL = "V-GRID"
+
+-- How far toward black a seam pulls the surface it cuts across. The
+-- wireframe reads as a shading of the model rather than an overlay drawn
+-- on top of it, so it darkens what is already there instead of painting a
+-- colour -- a seam across dark grass and one across a white roof both stay
+-- in the palette they belong to.
+VoxelGrid.DARK = 0.45
+
+-- Line width, in display pixels. The scene canvas renders at window
+-- resolution and composites 1:1, so a canvas pixel IS a display pixel and
+-- 1.0 here is the one-pixel wireframe.
+VoxelGrid.WIDTH = 1.0
+
+-- where it persists and the rows that cycle it (see ModSetting)
+VoxelGrid.setting = ModSetting.new(VoxelGrid.KEY, VoxelGrid.LABEL,
+                                   { false, true }, { "OFF", "ON" })
+
+function VoxelGrid.enabled()
+  return VoxelGrid.setting:get() and true or false
+end
+
+function VoxelGrid.set(enabled, game)
+  return VoxelGrid.setting:setIndex(enabled and 2 or 1, game)
+end
+
+function VoxelGrid.toggle(game)
+  return VoxelGrid.setting:cycle(game)
+end
+
+function VoxelGrid.sync(value)
+  VoxelGrid.setting:sync(value and true or false)
+end
+
+function VoxelGrid.row()
+  return VoxelGrid.setting:row()
+end
+
+return VoxelGrid