SPVM

Tiny SPIR-V virtual machine (interpreter), can be used for shader debugging.

Opcodes support status:

The project is still in progress ...

Spvm-ShaderToy

Spvm-ShaderToy implements shader effects without GPU.

Example

GLSL fragment shader (see example/shaders/simple.frag)

#version 450

layout (location = 0) in vec3 inColor;
layout (location = 0) out vec4 outFragColor;

void main()
{
    outFragColor = vec4(inColor.yxz, 1.0f);
}

run with spvm (see example/main.cpp)

#define HEAP_SIZE 128 * 1024
const char *SPV_PATH = "shaders/simple.frag.spv";

SPVM::SpvmModule module;
SPVM::Runtime runtime;

// decode spir-v file
bool success = SPVM::Decoder::decodeFile(SPV_PATH, &module);
if (!success) {
  std::cout << "error decode spir-v file";
  return -1;
}

// init runtime
success = runtime.initWithModule(&module, HEAP_SIZE);
if (!success) {
  std::cout << "error init module";
  return -1;
}

// get uniform locations
SPVM::SpvmWord inColorLoc = runtime.getLocationByName("inColor");
SPVM::SpvmWord outFragColorLoc = runtime.getLocationByName("outFragColor");

// write input
float inColor[3]{0.2f, 0.3f, 0.4f};
runtime.writeInput(inColor, inColorLoc);

// execute shader entry function 'main'
success = runtime.execEntryPoint();
if (!success) {
  std::cout << "error exec entrypoint function";
  return -1;
}

// read output
float outFragColor[4];
runtime.readOutput(outFragColor, outFragColorLoc);

std::cout << "outFragColor[0]: " << outFragColor[0] << std::endl;
std::cout << "outFragColor[1]: " << outFragColor[1] << std::endl;
std::cout << "outFragColor[2]: " << outFragColor[2] << std::endl;
std::cout << "outFragColor[3]: " << outFragColor[3] << std::endl;

Clone

git clone git@github.com:keith2018/spvm.git
cd spvm
git submodule update --init --recursive

Build

mkdir build
cmake -B ./build -DCMAKE_BUILD_TYPE=Release
cmake --build ./build --config Release

Test

cd build
ctest

License

This code is licensed under the MIT License (see LICENSE).