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

   1 local mat4 = lovr.math.mat4
   2
   3 local nParticles = 2 ^ 14
   4 local batchSize = 128
   5 local batches = nParticles / batchSize
   6
   7 local features
   8 local shaders = {}
   9 local blocks = {}
  10 local meshes = {}
  11 local compute = {}
  12
  13 function lovr.load()
  14     features = lovr.graphics.getFeatures()
  15     shaders.particles = lovr.graphics.newShader("shaders/particles.vert", "shaders/particles.frag")
  16
  17     blocks.particles = lovr.graphics.newShaderBlock("compute", {
  18         -- Reading a value seems to work around whatever the rendering glitch
  19         -- was. So we include this flag so we only have to ask for a single
  20         -- value, instead of having to copy a large array. Still, annoying :(
  21         -- For reference, see issue comment at:
  22         -- https://github.com/bjornbytes/lovr/issues/211#issuecomment-580985010
  23         reloadFlag = "float",
  24         particles = {"mat4", nParticles},
  25     }, { readable = true })
  26     shaders.particles:sendBlock('particleData', blocks.particles)
  27     shaders.particles:send("batchSize", batchSize)
  28
  29     meshes.particle = makeParticleMesh(batchSize)
  30
  31     compute.particles = lovr.graphics.newComputeShader("shaders/particles.comp")
  32     compute.particles:sendBlock('particleData', blocks.particles)
  33     compute.particles:send("dt", 0.01)
  34
  35     local xr, yr, zr = range(-1, 1), range(1, 3), range(-2, 0)
  36     local sr, vr = range(0.005, 0.01), range(-0.05, 0.05)
  37     local initial = initialParticleData(nParticles, xr, yr, zr, sr, vr)
  38     blocks.particles:send("particles", initial)
  39 end
  40
  41 function lovr.draw()
  42     lovr.graphics.clear()
  43     local x, y, z = lovr.headset.getPose("head")
  44     lovr.graphics.compute(compute.particles, batches)
  45     -- Read the buffer to force SSBO synch of some sort.
  46     blocks.particles:read("reloadFlag")
  47     shaders.particles:send("headPos", {x, y, z})
  48
  49     lovr.graphics.setColor(0.6, 0.1, 0)
  50     lovr.graphics.setShader(nil)
  51     for _, hand in ipairs(lovr.headset.getHands()) do
  52         local x, y, z, a, ax, ay, az = lovr.headset.getPose(hand)
  53         lovr.graphics.cube("fill", x, y, z, 0.1, a, ax, ay, az)
  54     end
  55
  56     withDepthTest("lequal", false, function()
  57         lovr.graphics.setColor(1, 1, 1)
  58         lovr.graphics.setShader(shaders.particles)
  59         meshes.particle:draw(mat4(), batches)
  60     end)
  61 end
  62
  63 function makeParticleMesh(size)
  64     local format = { {'vertPosition', 'float', 2}, }
  65     local verts = {}
  66     local vertMap = {}
  67     local insert = table.insert
  68     for chunk = 1, size do
  69         insert(verts, { 1,  1})
  70         insert(verts, { 1, -1})
  71         insert(verts, {-1, -1})
  72         insert(verts, {-1,  1})
  73         local base = 4 * (chunk - 1)
  74         insert(vertMap, 3 + base)
  75         insert(vertMap, 2 + base)
  76         insert(vertMap, 1 + base)
  77         insert(vertMap, 4 + base)
  78         insert(vertMap, 3 + base)
  79         insert(vertMap, 1 + base)
  80     end
  81     local mesh = lovr.graphics.newMesh(format, verts, "triangles", "static")
  82     mesh:setVertexMap(vertMap)
  83     return mesh
  84 end
  85
  86 function range(min, max)
  87     local scale = max - min
  88     return function()
  89         return min + lovr.math.random() * scale
  90     end
  91 end
  92
  93 function initialParticleData(size, xRange, yRange, zRange, sRange, vRange)
  94     local particles = {}
  95     local insert = table.insert
  96     for i = 1, size do
  97         insert(particles, {
  98             xRange(), yRange(), zRange(), sRange(),
  99             vRange(), vRange(), vRange(), 1,
 100             0, 0, 0, 0,
 101             0, 0, 0, 0,
 102         })
 103     end
 104     return particles
 105 end
 106
 107 function withDepthTest(compareMode, write, callback)
 108     local oldComp, oldWrite = lovr.graphics.getDepthTest()
 109     lovr.graphics.setDepthTest(compareMode, write)
 110     callback()
 111     lovr.graphics.setDepthTest(oldComp, oldWrite)
 112 end