ShaderScan - better iteration with shaders

• reloads shaders when they're saved
• include shaders into other shaders
• handles circular include dependencies
• output correct filename and line number in errors
• send uniforms to shaders and ignore unused errors

ShaderScan was developed using LÖVE 11.3, but may work on earlier versions.

If you call ShaderScan.update from love.update, it will watch for changes to your shaders and reload them if they've changed. If there are errors, ShaderScan will report the errors but keep using the previous version of the shader.

local ShaderScan = require 'shaderscan'
shaders = ShaderScan()
shaders:load_shader('splitcolor', 'shaders/splitcolor.glsl')
function love.update(dt)
    shaders:update(dt)
end

Tired of getting these errors?

Typo fails without any indication which shader it came from:

Error: Error validating pixel shader code:
Line 20: ERROR: 'pingpon' : no matching overloaded function found 
Line 20: ERROR: '' : compilation terminated 
ERROR: 2 compilation errors.  No code generated.

Sending an unused uniform gives a fatal error:

Error: main.lua:42: Shader uniform 'iSinTime' does not exist.
A common error is to define but not use the variable.

Instead, get errors with file, line number, and the specific line that failed:

Error: shaderscan.lua:126: Loading 'splitcolor' failed: Error validating pixel shader code:
example/splitcolor.glsl:20: in 'splitcolor' ERROR: 'pingpon' : no matching overloaded function found
example/splitcolor.glsl:20: in 'splitcolor' ERROR: '' : compilation terminated
ERROR: 2 compilation errors.  No code generated.
File: example/splitcolor.glsl
Line:
        + overlay * pingpon(iTime / cycle_duration);

Sending a uniform that doesn't exist with ShaderScan.safe_send prints the error once, but doesn't fail.

Ever try to use includes and get these errors:

Line 5: ERROR: '#include' : required extension not requested: GL_GOOGLE_include_directive
Line 5: ERROR: '#include' : must be followed by a header name 

Use #include directives and modularize your shader code. All includes are relative to your project's root (the location of main.lua). They're processed at runtime and error reporting will report the correct file and line number.

Syntax of includes is similar to C++ or some gl shader compilers:

#include "example/lib/math.glsl"

MIT License. See LICENSE.md.