Automatically reloading GLSL shaders when coding widgets
Posted: 01 Jun 2022, 08:30
Wouldnt it be nice if a widget would automatically detect changes to the code of a widget, recompile it and apply it upon success?
This code checks the shader sources every 0.25s, and tries to recompile it. So you can have Spring open in one window, your editor in the next, and just have to hit save on the shader code changes!
All the needed bits of this are supplied by the engine, so here is a bit of example code how:
This code checks the shader sources every 0.25s, and tries to recompile it. So you can have Spring open in one window, your editor in the next, and just have to hit save on the shader code changes!
All the needed bits of this are supplied by the engine, so here is a bit of example code how:
Code: Select all
local luaShaderDir = "LuaUI/Widgets/Include/"
local LuaShader = VFS.Include(luaShaderDir.."LuaShader.lua")
local vsSrcPath = "LuaUI/Widgets/Shaders/decals_gl4.vert.glsl"
local fsSrcPath = "LuaUI/Widgets/Shaders/decals_gl4.frag.glsl"
local gsSrcPath = "LuaUI/Widgets/Shaders/decals_gl4.geom.glsl"
local lastshaderupdate = nil
local shaderSourceCache = {}
local function checkShaderUpdates(vssrcpath, fssrcpath, gssrcpath, shadername, delaytime)
if lastshaderupdate == nil or
Spring.DiffTimers(Spring.GetTimer(), lastshaderupdate) > (delaytime or 0.25) then
lastshaderupdate = Spring.GetTimer()
local vsSrcNew = vssrcpath and VFS.LoadFile(vssrcpath)
local fsSrcNew = fssrcpath and VFS.LoadFile(fssrcpath)
local gsSrcNew = gssrcpath and VFS.LoadFile(gssrcpath)
if vsSrcNew == shaderSourceCache.vsSrc and
fsSrcNew == shaderSourceCache.fsSrc and
gsSrcNew == shaderSourceCache.gsSrc then
--Spring.Echo("No change in shaders")
return nil
else
local compilestarttime = Spring.GetTimer()
shaderSourceCache.vsSrc = vsSrcNew
shaderSourceCache.fsSrc = fsSrcNew
shaderSourceCache.gsSrc = gsSrcNew
local engineUniformBufferDefs = LuaShader.GetEngineUniformBufferDefs()
if vsSrcNew then
vsSrcNew = vsSrcNew:gsub("//__ENGINEUNIFORMBUFFERDEFS__", engineUniformBufferDefs)
vsSrcNew = vsSrcNew:gsub("//__DEFINES__", LuaShader.CreateShaderDefinesString(shaderConfig))
end
if fsSrcNew then
fsSrcNew = fsSrcNew:gsub("//__ENGINEUNIFORMBUFFERDEFS__", engineUniformBufferDefs)
fsSrcNew = fsSrcNew:gsub("//__DEFINES__", LuaShader.CreateShaderDefinesString(shaderConfig))
end
if gsSrcNew then
gsSrcNew = gsSrcNew:gsub("//__ENGINEUNIFORMBUFFERDEFS__", engineUniformBufferDefs)
gsSrcNew = gsSrcNew:gsub("//__DEFINES__", LuaShader.CreateShaderDefinesString(shaderConfig))
end
local reinitshader = LuaShader(
{
vertex = vsSrcNew,
fragment = fsSrcNew,
geometry = gsSrcNew,
uniformInt = {
heightmapTex = 0,
miniMapTex = 1,
},
uniformFloat = {
fadeDistance = 3000,
},
},
shadername
)
local shaderCompiled = reinitshader:Initialize()
Spring.Echo(shadername, " recompiled in ", Spring.DiffTimers(Spring.GetTimer(), compilestarttime, true), "ms at", Spring.GetGameFrame())
if shaderCompiled then
return reinitshader
else
return nil
end
end
end
return nil
end
function widget:Update()
decalShader = checkShaderUpdates(vsSrcPath, fsSrcPath, gsSrcPath, "Decals GL4") or decalShader
end
function widget:Initialize()
decalShader = checkShaderUpdates(vsSrcPath, fsSrcPath, gsSrcPath, "Decals GL4") or decalShader
end