feat: enhance Linux rendering support and clean up unused UI code

Minecraft.Client/Minecraft.cpp

@@ -1849,6 +1849,16 @@ void Minecraft::run_middle()
 						}
 					}
 				}
+#ifdef __linux__
+				// On Linux, Iggy Flash UI is not available. If no players were rendered
+				// (menu / title-screen state), call GameRenderer directly so mc->screen draws.
+				if (bFirst)
+				{
+					localPlayerIdx = 0;
+					RenderManager.StateSetViewport(C4JRender::VIEWPORT_TYPE_FULLSCREEN);
+					gameRenderer->render(timer->a, true);
+				}
+#endif
 				// If there's an unoccupied quadrant, then clear that to black
 				if( unoccupiedQuadrant > -1 )
 				{

Minecraft.Client/Platform/Linux/Linux_Minecraft.cpp

@@ -689,6 +689,12 @@ do
 } while (minecraftThread->isRunning());
 delete minecraftThread;
 
+// Re-acquire the GL context in the main thread.
+// StartMinecraftThreadProc calls InitialiseContext() which moves the context
+// to the init thread for texture loading; we must reclaim it here before
+// any further OpenGL calls in the main render loop.
+RenderManager.InitialiseContext();
+
 Minecraft *pMinecraft=Minecraft::GetInstance();
 
 app.InitGameSettings();
@@ -727,9 +733,11 @@ g_NetworkManager.DoWork();
 PIXEndNamedEvent();
 
 // Render game graphics.
+// On Linux, always call run_middle() so mc->screen (TitleScreen etc.) renders
+// even when the game session has not yet started (Iggy Flash UI is unavailable).
+pMinecraft->run_middle();
 if(app.GetGameStarted())
 {
-    pMinecraft->run_middle();
     app.SetAppPaused( g_NetworkManager.IsLocalGame() && g_NetworkManager.GetPlayerCount() == 1 && ui.IsPauseMenuDisplayed(ProfileManager.GetPrimaryPad()) );
 }
 else

Minecraft.Client/UI/Screen.cpp

@@ -170,22 +170,7 @@ void Screen::renderBackground(int vo)
 
 void Screen::renderDirtBackground(int vo)
 {
-	// 4J Unused
+    // 4J Unused - Iggy Flash UI renders the background on consoles
-#if 0
-    glDisable(GL_LIGHTING);
-    glDisable(GL_FOG);
-    Tesselator *t = Tesselator::getInstance();
-    glBindTexture(GL_TEXTURE_2D, minecraft->textures->loadTexture(L"/gui/background.png"));
-    glColor4f(1, 1, 1, 1);
-    float s = 32;
-    t->begin();
-    t->color(0x404040);
-    t->vertexUV((float)(0), (float)( height), (float)( 0), (float)( 0), (float)( height / s + vo));
-    t->vertexUV((float)(width), (float)( height), (float)( 0), (float)( width / s), (float)( height / s + vo));
-    t->vertexUV((float)(width), (float)( 0), (float)( 0), (float)( width / s), (float)( 0 + vo));
-    t->vertexUV((float)(0), (float)( 0), (float)( 0), (float)( 0), (float)( 0 + vo));
-    t->end();
-#endif
 }
 
 bool Screen::isPauseScreen()

Minecraft.Client/UI/Screens/TitleScreen.cpp

@@ -126,35 +126,5 @@ void TitleScreen::buttonClicked(Button *button)
 
 void TitleScreen::render(int xm, int ym, float a)
 {
-	// 4J Unused
+    // 4J Unused - Iggy Flash UI renders the title screen on consoles
-#if 0
-    renderBackground();
-    Tesselator *t = Tesselator::getInstance();
-
-    int logoWidth = 155 + 119;
-    int logoX = width / 2 - logoWidth / 2;
-    int logoY = 30;
-
-    glBindTexture(GL_TEXTURE_2D, minecraft->textures->loadTexture(L"/title/mclogo.png"));
-    glColor4f(1, 1, 1, 1);
-    blit(logoX + 0, logoY + 0, 0, 0, 155, 44);
-    blit(logoX + 155, logoY + 0, 0, 45, 155, 44);
-    t->color(0xffffff);
-    glPushMatrix();
-    glTranslatef((float)width / 2 + 90, 70, 0);
-
-    glRotatef(-20, 0, 0, 1);
-    float sss = 1.8f - Mth::abs(Mth::sin(System::currentTimeMillis() % 1000 / 1000.0f * PI * 2) * 0.1f);
-
-    sss = sss * 100 / (font->width(splash) + 8 * 4);
-    glScalef(sss, sss, sss);
-    drawCenteredString(font, splash, 0, -8, 0xffff00);
-    glPopMatrix();
-
-    drawString(font, ClientConstants::VERSION_STRING, 2, 2, 0x505050);
-    wstring msg = L"Copyright Mojang AB. Do not distribute.";
-    drawString(font, msg, width - font->width(msg) - 2, height - 10, 0xffffff);
-
-    Screen::render(xm, ym, a);
-#endif
 }