Witch of Git - lovr-particles/blob - main.lua

   1 local mat4 = lovr.math.mat4
   2
   3 local nParticles = 2 ^ 16
   4 local batchSize = 128
   5 local batches = nParticles / batchSize
   6
   7 local features
   8 local shaders = {}
   9 local blocks = {}
  10 local meshes = {}
  11
  12 function lovr.load()
  13     features = lovr.graphics.getFeatures()
  14     shaders.particles = lovr.graphics.newShader("shaders/particles.vert", "shaders/particles.frag")
  15     blocks.particles = lovr.graphics.newShaderBlock("compute", {
  16         particles = {"mat4", nParticles},
  17     }, { readable = true, writable = true })
  18     shaders.particles:sendBlock('particleData', blocks.particles)
  19     shaders.particles:send("batchSize", batchSize)
  20     meshes.particle = makeParticleMesh(batchSize)
  21     local initial = initialParticleData(nParticles, range(-2, 2), range(0, 4), range(-2, 2), range(0.005, 0.01))
  22     blocks.particles:send("particles", initial)
  23 end
  24
  25 function lovr.draw()
  26     lovr.graphics.clear()
  27     local x, y, z = lovr.headset.getPose("head")
  28     shaders.particles:send("headPos", {x, y, z})
  29
  30     lovr.graphics.setColor(0.6, 0.1, 0)
  31     lovr.graphics.setShader(nil)
  32     for _, hand in ipairs(lovr.headset.getHands()) do
  33         local x, y, z, a, ax, ay, az = lovr.headset.getPose(hand)
  34         lovr.graphics.cube("fill", x, y, z, 0.1, a, ax, ay, az)
  35     end
  36
  37     withDepthTest("lequal", false, function()
  38         lovr.graphics.setColor(1, 1, 1)
  39         lovr.graphics.setShader(shaders.particles)
  40         meshes.particle:draw(mat4(), batches)
  41     end)
  42 end
  43
  44 function makeParticleMesh(size)
  45     local format = { {'vertPosition', 'float', 2}, }
  46     local verts = {}
  47     local vertMap = {}
  48     local insert = table.insert
  49     for chunk = 1, size do
  50         insert(verts, { 1,  1})
  51         insert(verts, { 1, -1})
  52         insert(verts, {-1, -1})
  53         insert(verts, {-1,  1})
  54         local base = 4 * (chunk - 1)
  55         insert(vertMap, 3 + base)
  56         insert(vertMap, 2 + base)
  57         insert(vertMap, 1 + base)
  58         insert(vertMap, 4 + base)
  59         insert(vertMap, 3 + base)
  60         insert(vertMap, 1 + base)
  61     end
  62     local mesh = lovr.graphics.newMesh(format, verts, "triangles", "static")
  63     mesh:setVertexMap(vertMap)
  64     return mesh
  65 end
  66
  67 function range(min, max)
  68     local scale = max - min
  69     return function()
  70         return min + lovr.math.random() * scale
  71     end
  72 end
  73
  74 function initialParticleData(size, xRange, yRange, zRange, sRange)
  75     local particles = {}
  76     local insert = table.insert
  77     for i = 1, size do
  78         insert(particles, {
  79             xRange(), yRange(), zRange(), sRange(),
  80             xRange(), yRange(), zRange(), 1,
  81             0, 0, 0, 0,
  82             0, 0, 0, 0,
  83         })
  84     end
  85     return particles
  86 end
  87
  88 function withDepthTest(compareMode, write, callback)
  89     local oldComp, oldWrite = lovr.graphics.getDepthTest()
  90     lovr.graphics.setDepthTest(compareMode, write)
  91     callback()
  92     lovr.graphics.setDepthTest(oldComp, oldWrite)
  93 end