ShaderDebugger

ShaderDebugger is a library built for SHADERed. It can be used to run shaders on CPU or debug them (get variable values, run them line by line, etc...).

How?

ShaderDebugger uses glsl-parser to parse GLSL into AST. The AST is converted to the bytecode with the aGen library. The bytecode can then be executed using the BlueVM.

How to compile

Run these commands to set up and compile the project:

git clone https://github.com/dfranx/ShaderDebugger.git
cd ShaderDebugger
git submodule init
git submodule update
cmake .
make

Run the program:

./bin/ShaderDebugger

Example

std::string src = ... your shader code ...;

sd::ShaderDebugger dbg;
dbg.SetSource<sd::GLSLCompiler>(sd::ShaderType::Pixel, src, "main", NULL, sd::Library::GLSL());

dbg.SetValue("iFactor", 0.7f);
dbg.SetValue("iColor", "vec3", glm::vec3(0.5f, 0.6f, 0.7f));

bv_variable ret = dbg.Execute();

glm::vec3 outColor = sd::AsVector<3, float>(*dbg.GetValue("outColor"));
printf("outColor = vec3(%.2f, %.2f, %.2f);\n", outColor.x, outColor.y, outColor.z);

bv_variable_deinitialize(&ret);

return 0;

Or execute line by line:

while (vs.Step()) {
    // get various info using these functions: GetCurrentFunction, GetFunctionStack, GetValue, GetLocalValue, etc...
}
// if you want to get return value:
//    bv_variable ret = vs.GetReturnValue();
//    ...
//    bv_variable_deinitialize(&ret);

You can also execute code on the fly using the ShaderDebugger::Immediate:

bv_variable result = dbg.Immediate("sin(a * 2.0f) + texture(tex, uv).x");
// ...
bv_variable_deinitialize(&result);

List of other cool functions: StepOver(), StepOut(), Continue(), Jump(), AddBreakpoint(), AddConditionalBreakpoint()

Limitations

List of things that currently don't work (I plan to fix/add them):

GLSL

• doesn't support interface blocks, local & structure member arrays & global variable initalization (unless it has const keyword)
• parsed, but not stored & not implemented: auxilary, precision, memory, invariant
• parsed & stored but not implemented: smooth, flat, noperspective

HLSL

• classes / interfaces
• namespaces
• switch statement

Both

• preprocessor
• cubemaps
• initialize structure members