native renderer: game world at MT_RENDER_SCALE (0.75 on Android), MSAA default 2

Draws recorded inside CPythonApplication::RenderGame are marked Render3DDraw::scene and
drawn by a scene pass compatible with pass_ into a reduced-resolution image, composited
where RenderGame drew; the UI stays full resolution. --render-scale / MT_RENDER_SCALE,
desktop default 1.0 (unchanged path).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/platform/EterLib/RecordingDevice.cpp

@@ -15,6 +15,7 @@
 namespace {
 std::mutex g_draws_mutex;
 std::vector<Render3DDraw> g_draws;
+bool g_in_scene = false;
 int g_native_terrain_override = -1;
 bool g_gpu_render_targets = false;
 
@@ -1256,9 +1257,13 @@ void Render3DBeginFrame()
 void Render3DAdd(Render3DDraw draw)
 {
 	std::lock_guard<std::mutex> lock(g_draws_mutex);
+	draw.scene = g_in_scene;
 	g_draws.push_back(std::move(draw));
 }
 
+void Render3DBeginScene() { g_in_scene = true; }
+void Render3DEndScene() { g_in_scene = false; }
+
 const std::vector<Render3DDraw>& Render3DDraws() { return g_draws; }
 
 // D3D8 fixed-function texture coordinate processing for one stage (the native renderer's

src/platform/EterLib/RenderCommands3D.h

@@ -22,6 +22,9 @@ struct Render3DDraw {
     // PORT: UIRenderOffsetX() when recorded (a draw from a shifted window layer); the host moves the
     // viewport (and a pretransformed draw's screen positions) right by it.
     float ui_offset_x = 0;
+    // PORT: recorded inside CPythonApplication::RenderGame (Render3DBeginScene/EndScene). The native
+    // renderer may draw these into a reduced-resolution scene image composited under the UI.
+    bool scene = false;
 
     // IDirect3DDevice8::Clear on the back buffer, kept in draw order. A clear entry has no geometry;
     // clear_flags holds D3DCLEAR_TARGET / D3DCLEAR_ZBUFFER / D3DCLEAR_STENCIL.
@@ -138,4 +141,8 @@ std::string Render3DRenderTargetName(std::uint32_t id, std::uint32_t width, std:
 
 void Render3DBeginFrame();
 void Render3DAdd(Render3DDraw draw);
+// PORT: brackets the game world's draws (CPythonApplication::RenderGame); Render3DAdd marks the draws
+// in between with Render3DDraw::scene.
+void Render3DBeginScene();
+void Render3DEndScene();
 const std::vector<Render3DDraw>& Render3DDraws();

src/platform/UserInterface/PythonApplication.cpp

@@ -202,6 +202,8 @@ void CPythonApplication::GetMousePosition(POINT* ppt)
 void CPythonApplication::RenderGame()
 {
 	MtPerf::CScope kPerf(MtPerf::SECTION_RENDER_GAME);
+	// PORT: marks the world's draws so the native renderer can draw them at a reduced resolution.
+	struct SceneScope { SceneScope() { Render3DBeginScene(); } ~SceneScope() { Render3DEndScene(); } } kScene;
 	float fAspect=UI::CWindowManager::Instance().GetAspect();
 	float fFarClip=CPythonBackground::Instance().GetFarClip();