Warn when using GPU particles with GLES2

Closes #25733.

scene/3d/particles.cpp

@@ -29,6 +29,8 @@
 /*************************************************************************/
 
 #include "particles.h"
+
+#include "core/os/os.h"
 #include "scene/resources/particles_material.h"
 
 #include "servers/visual_server.h"
@@ -224,6 +226,10 @@ bool Particles::get_fractional_delta() const {
 
 String Particles::get_configuration_warning() const {
 
+	if (OS::get_singleton()->get_current_video_driver() == OS::VIDEO_DRIVER_GLES2) {
+		return TTR("GPU-based particles are not supported by the GLES2 video driver.\nUse the CPUParticles node instead. You can use the \"Convert to CPUParticles\" option for this purpose.");
+	}
+
 	String warnings;
 
 	bool meshes_found = false;