maxwell_3d: Reset vertex counts after drawing.

src/video_core/engines/maxwell_3d.cpp

@@ -208,6 +208,16 @@ void Maxwell3D::DrawArrays() {
 
     const bool is_indexed{regs.index_array.count && !regs.vertex_buffer.count};
     VideoCore::g_renderer->Rasterizer()->AccelerateDrawBatch(is_indexed);
+
+    // TODO(bunnei): Below, we reset vertex count so that we can use these registers to determine if
+    // the game is trying to draw indexed or direct mode. This needs to be verified on HW still -
+    // it's possible that it is incorrect and that there is some other register used to specify the
+    // drawing mode.
+    if (is_indexed) {
+        regs.index_array.count = 0;
+    } else {
+        regs.vertex_buffer.count = 0;
+    }
 }
 
 void Maxwell3D::ProcessCBBind(Regs::ShaderStage stage) {