Crafter.Build/tests/ShaderCompile/main.cpp

import std;
import Crafter.Build;
namespace fs = std::filesystem;
using namespace Crafter;

// Compile a tiny GLSL fragment shader directly via the Shader API. Verifies
// the SPIR-V output lands in the target dir and starts with the SPIR-V magic
// number, without dragging in the full Build() pipeline.
int main() {
    fs::path src = fs::current_path() / "tests" / "ShaderCompile" / "fixture" / "triangle.frag";
    if (!fs::exists(src)) {
        std::println(std::cerr, "fixture missing: {}", src.string());
        return 1;
    }

    fs::path outDir = fs::temp_directory_path() / "crafter-build-shader-test";
    std::error_code ec;
    fs::remove_all(outDir, ec);
    fs::create_directories(outDir);

    Shader shader(fs::path(src), "main", ShaderType::Fragment);

    std::array<fs::path, 0> includeDirs = {};
    std::string err = shader.Compile(outDir, includeDirs);
    if (!err.empty()) {
        std::println(std::cerr, "shader compile failed: {}", err);
        return 1;
    }

    fs::path spv = outDir / "triangle.spv";
    if (!fs::exists(spv)) {
        std::println(std::cerr, "spv not produced at {}", spv.string());
        return 1;
    }

    // SPIR-V binaries start with the magic number 0x07230203 (little-endian
    // when written by glslang on x86). Read the first four bytes to confirm
    // the produced file is real SPIR-V, not a fluke empty file.
    std::ifstream in(spv, std::ios::binary);
    std::uint32_t magic = 0;
    in.read(reinterpret_cast<char*>(&magic), sizeof(magic));
    if (!in || magic != 0x07230203u) {
        std::println(std::cerr, "spv has wrong magic: 0x{:08x}", magic);
        return 1;
    }

    // Compiling again should be a no-op since the source isn't newer.
    if (!shader.Check(outDir)) {
        std::println(std::cerr, "Shader::Check returned false on an up-to-date spv");
        return 1;
    }
    return 0;
}