feat(console): allow graphics device to be initialized using hints from CVar as well as a command-line override

src/console/Device.cpp

@@ -11,11 +11,39 @@ CVar* s_cvGxMaximize;
 CVar* s_cvGxResolution;
 CVar* s_cvGxWidescreen;
 CVar* s_cvGxWindow;
+CVar* s_cvGxApi;
 DefaultSettings s_defaults;
 bool s_hwDetect;
 bool s_hwChanged;
 CGxFormat s_requestedFormat;
 
+const char* g_gxApiNames[GxApis_Last] = {
+    "OpenGL", // GxApi_OpenGl
+    "D3D9",   // GxApi_D3d9
+    "D3D9Ex", // GxApi_D3d9Ex
+    "D3D10",  // GxApi_D3d10
+    "D3D11",  // GxApi_D3d11
+    "GLL",    // GxApi_GLL
+    "GLSDL"   // GxApi_GLSDL
+};
+
+EGxApi g_gxApiSupported[] = {
+#if defined(WHOA_SYSTEM_WIN)
+    GxApi_D3d9,
+    GxApi_GLSDL
+#endif
+
+#if defined(WHOA_SYSTEM_MAC)
+    GxApi_GLL
+#endif
+
+#if defined(WHOA_SYSTEM_LINUX)
+    GxApi_GLSDL
+#endif
+};
+
+size_t g_numGxApiSupported = sizeof(g_gxApiSupported) / sizeof(EGxApi);
+
 bool CVGxMaximizeCallback(CVar*, const char*, const char*, void*) {
     // TODO
     return true;
@@ -35,6 +63,49 @@ bool CVGxWindowCallback(CVar*, const char*, const char*, void*) {
     return true;
 }
 
+bool CVGxApiCallback(CVar* h, const char* oldValue, const char* newValue, void* arg) {
+    for (size_t api = 0; api < g_numGxApiSupported; api++) {
+        auto apiString = g_gxApiNames[g_gxApiSupported[api]];
+        if (SStrCmpI(newValue, apiString, STORM_MAX_STR) == 0) {
+            // New gxApi is supported, pass
+            ConsoleWrite("GxApi set pending gxRestart", DEFAULT_COLOR);
+            return true;
+        }
+    }
+
+    // Supported gxApi not supplied, show available apis
+    constexpr size_t msgsize = 1024;
+    char msg[msgsize] = {0};
+    SStrPack(msg, "unsupported api, must be one of ", msgsize);
+
+    for (size_t api = 0; api < g_numGxApiSupported; api++) {
+        if (api > 0) {
+            SStrPack(msg, ", ", msgsize);
+        }
+        auto apiString = g_gxApiNames[g_gxApiSupported[api]];
+        SStrPack(msg, "'", msgsize);
+        SStrPack(msg, apiString, msgsize);
+        SStrPack(msg, "'", msgsize);
+    }
+
+    ConsoleWrite(msg, DEFAULT_COLOR);
+    return false;
+}
+
+EGxApi GxApiDefault() {
+#if defined(WHOA_SYSTEM_WIN)
+    return GxApi_D3d9;
+#endif
+
+#if defined(WHOA_SYSTEM_MAC)
+    return GxApi_GLL;
+#endif
+
+#if defined(WHOA_SYSTEM_LINUX)
+    return GxApi_GLSDL;
+#endif
+}
+
 void RegisterGxCVars() {
     auto& format = s_defaults.format;
 
@@ -97,6 +168,19 @@ void RegisterGxCVars() {
     // TODO s_cvGxRefresh
     // TODO s_cvGxTripleBuffer
     // TODO s_cvGxApi
+
+    s_cvGxApi = CVar::Register(
+        "gxApi",
+        "graphics api",
+        0x1 | 0x2,
+        g_gxApiNames[GxApiDefault()],
+        CVGxApiCallback,
+        1,
+        false,
+        nullptr,
+        false
+    );
+
     // TODO s_cvGxVSync
     // TODO s_cvGxAspect
     // TODO s_cvGxCursor
@@ -194,17 +278,24 @@ void ConsoleDeviceInitialize(const char* title) {
     CGxFormat format;
     memcpy(&format, &s_requestedFormat, sizeof(s_requestedFormat));
 
-    // TODO proper api selection
+    // Select gxApi based on user CVars and command-line parameters
-    EGxApi api = GxApi_OpenGl;
+    EGxApi api = GxApiDefault();
-#if defined(WHOA_SYSTEM_WIN)
-    api = GxApi_D3d9;
 
-    if (CmdLineGetBool(CMD_OPENGL)) {
+    auto gxApiName = s_cvGxApi->GetString();
-        api = GxApi_OpenGl;
+
+    auto gxOverride = CmdLineGetString(WOWCMD_GX_OVERRIDE);
+    if (*gxOverride != '\0') {
+        gxApiName = gxOverride;
+    }
+
+    // Sanitize chosen gxApi against list of supported gxApis
+    for (size_t i = 0; i < g_numGxApiSupported; i++) {
+        EGxApi supportedApi = g_gxApiSupported[i];
+        if (SStrCmp(gxApiName, g_gxApiNames[supported], STORM_MAX_STR) == 0) {
+            api = supportedApi;
+            break;
+        }
     }
-#elif defined(WHOA_SYSTEM_MAC)
-    api = GxApi_GLL;
-#endif
 
     CGxDevice* device = GxDevCreate(api, OsWindowProc, format);