chat: work around Direct3D 11 rendering artifacts on win11 arm (#3450)

Signed-off-by: Jared Van Bortel <jared@nomic.ai>

gpt4all-chat/src/config.h.in

@@ -0,0 +1,7 @@
+#pragma once
+
+#define APP_VERSION "@APP_VERSION@"
+
+#define G4A_CONFIG(name) (1/G4A_CONFIG_##name == 1)
+
+#define G4A_CONFIG_force_d3d12 @GPT4ALL_CONFIG_FORCE_D3D12@

gpt4all-chat/src/main.cpp

@@ -25,6 +25,10 @@
 #include <QVariant>
 #include <Qt>
 
+#if G4A_CONFIG(force_d3d12)
+#   include <QSGRendererInterface>
+#endif
+
 #ifndef GPT4ALL_USE_QTPDF
 #   include <fpdfview.h>
 #endif
@@ -83,6 +87,10 @@ int main(int argc, char *argv[])
         return 0;
     }
 
+#if G4A_CONFIG(force_d3d12)
+    QQuickWindow::setGraphicsApi(QSGRendererInterface::Direct3D12);
+#endif
+
 #ifdef Q_OS_LINUX
     app.setWindowIcon(QIcon(":/gpt4all/icons/gpt4all.svg"));
 #endif