r-lyeh · December 28, 2022 17:12 · Dec 28, 2022
diff --git a/snippets32.c b/snippets32.c
@@ -0,0 +1,77 @@
+// useful code snippets gathered from the network (via phillip trudeau)
+
+static float euclidean_mod(float x, float y) { return x - floorf(x / y) * y; }
+static bool rect_is_onscreen(RECT rect) { return (MonitorFromRect(&rect, MONITOR_DEFAULTTONULL) != NULL); }
+static bool window_is_onscreen(HWND hwnd) { return (MonitorFromWindow(hwnd, MONITOR_DEFAULTTONULL) != NULL); }
+
+// Win32: Set the window icon for every window in your app (including MessageBox() calls and assertion failures) instead of just your primary window.
+static LRESULT set_window_icon_callback(int type, WPARAM wparam, LPARAM lparam) {
+    if (type == HCBT_CREATEWND) {
+        HANDLE instance_hdl = GetModuleHandleA(NULL);
+        SendMessage((HWND)wparam, WM_SETICON, ICON_BIG  , (LPARAM)LoadIconA(instance_hdl, MAKEINTRESOURCEA(IDI_ICON1)));
+        SendMessage((HWND)wparam, WM_SETICON, ICON_SMALL, (LPARAM)LoadIconA(instance_hdl, MAKEINTRESOURCEA(IDI_ICON1)));
+    }
+    return CallNextHookEx(NULL, type, wparam, lparam);
+}
+static void set_all_window_icons() {
+    SetWindowsHookEx(WH_CBT, set_window_icon_callback, NULL, GetCurrentThreadId());
+}
+
+bool console_belongs_to_self(void) {
+    DWORD pid = 0;
+    GetWindowThreadProcessId(GetConsoleWindow(), &pid);
+    return pid == GetCurrentProcessId();
+}
+
+        //NOTE: these calls are the closest i'm aware you can get to /SUBSYSTEM:CONSOLE
+        //      in a gui program while cleanly handling existing consoles (cmd.exe),
+        //      pipes (ninja) and no console (VS/RemedyBG; double-clicking the game).
+        //      the other option is to compile with /SUBSYSTEM:CONSOLE and call FreeConsole()
+        //      if no console is needed but it is amateur to flash a console for a second
+        if (!AttachConsole(ATTACH_PARENT_PROCESS) && GetLastError() != ERROR_ACCESS_DENIED) assert(AllocConsole());
+        printf("\n"); //print >= 1 byte to distinguish empty stdout from a redirected stdout (fgetpos() position <= 0)
+        fpos_t pos = {};
+        if (fgetpos(stdout, &pos) != 0 || pos <= 0) {
+            assert(freopen("CONIN$" , "r", stdin ));
+            assert(freopen("CONOUT$", "w", stderr));
+            assert(freopen("CONOUT$", "w", stdout));
+        }
+
+
+
+Win10: Get RDTSC interval in constant time, with slow Sleep() path for older versions of Windows
+double s_per_tsc = 3.33e-10;
+bool fast_path = false;
+HMODULE ntdll = LoadLibrary("ntdll.dll");
+if (ntdll) {
+    void (*NtQuerySystemInformation)() = (void (*)())GetProcAddress(ntdll, "NtQuerySystemInformation");
+    if (NtQuerySystemInformation) {
+        uint64_t system_information;
+        uint32_t out_size;
+        int32_t result = ((int32_t __stdcall (*)(int32_t, void *, uint32_t, uint32_t *))NtQuerySystemInformation)(0xc5, &system_information, sizeof(system_information), &out_size);
+        if (out_size == sizeof(system_information) && result >= 0) {
+            volatile uint8_t* RtlpHypervisorSharedUserVa = (uint8_t *)system_information;
+
+            // printf("tsc_freq: %7llu\n", (10000000ull << 32) / (*(uint64_t*)(RtlpHypervisorSharedUserVa + 0x08) >> 32));
+
+            s_per_tsc = *(uint64_t*)(RtlpHypervisorSharedUserVa + 0x08) / 184467440737095516160000000.0;
+            // printf("s_per_tsc: %.30f\n", s_per_tsc);
+
+            fast_path = true;
+        }
+
+    }
+    FreeLibrary(ntdll);
+}
+if (!fast_path) {
+    LARGE_INTEGER frequency; QueryPerformanceFrequency(&frequency);
+    LARGE_INTEGER qpc_begin; QueryPerformanceCounter(&qpc_begin);
+    uint64_t tsc_begin = __rdtsc();
+    Sleep(10);
+    LARGE_INTEGER qpc_end; QueryPerformanceCounter(&qpc_end);
+    uint64_t tsc_end = __rdtsc();
+    s_per_tsc = ((double)(qpc_end.QuadPart - qpc_begin.QuadPart) / frequency.QuadPart) / (tsc_end - tsc_begin);
+}
+
+
+