Material System Adapter

local ffi = require "ffi"

local RenderAdapterInfo_t = ffi.typeof([[
    struct {
        char __m_pDriverName[512];
        unsigned int __m_VendorID;
        unsigned int __m_DeviceID;
        unsigned int __m_SubSysID;
        unsigned int __m_Revision;
        int __m_nDXSupportLevel;
        int __m_nMinDXSupportLevel;
        int __m_nMaxDXSupportLevel;
        unsigned int __m_nDriverVersionHigh;
        unsigned int __m_nDriverVersionLow;
        int64_t pad_0;
    }
]])

local RenderAdapterInfo_mt = { __index = {} }

local native_GetCurrentAdapter = vtable_bind("materialsystem.dll", "VMaterialSystem080", 25, "int(__thiscall*)(void*)")
local native_GetAdapterInfo = vtable_bind("materialsystem.dll", "VMaterialSystem080", 26, "void(__thiscall*)(void*, int, $*)", RenderAdapterInfo_t)

function get_current_adapter()
    return native_GetCurrentAdapter()
end

local fallback = {
    drivername = function(self) return ffi.string(self.__m_pDriverName) end,
    vendorid = function(self) return string.match(tostring(self.__m_VendorID), "%d+") end,
    deviceid = function(self) return string.match(tostring(self.__m_DeviceID), "%d+") end,
    subsysid = function(self) return string.match(tostring(self.__m_SubSysID), "%d+") end,
    revision = function(self) return string.match(tostring(self.__m_Revision), "%d+") end
}

function RenderAdapterInfo_mt:__index(index)
    local fallback_fn = fallback[index]
    if not fallback_fn then return nil end

    return fallback[index](self)
end

ffi.metatype(RenderAdapterInfo_t, RenderAdapterInfo_mt)

function get_adapter_info(adapter)
    local info = RenderAdapterInfo_t()
    native_GetAdapterInfo(adapter, info)

    return info
end