video_core: report telemetry for gas mode

src/video_core/renderer_opengl/gl_shader_gen.cpp

@@ -8,6 +8,7 @@
 #include "common/assert.h"
 #include "common/bit_field.h"
 #include "common/logging/log.h"
+#include "core/core.h"
 #include "video_core/regs_framebuffer.h"
 #include "video_core/regs_lighting.h"
 #include "video_core/regs_rasterizer.h"
@@ -1155,6 +1156,11 @@ vec4 secondary_fragment_color = vec4(0.0);
 
         // Blend the fog
         out += "last_tex_env_out.rgb = mix(fog_color.rgb, last_tex_env_out.rgb, fog_factor);\n";
+    } else if (state.fog_mode == TexturingRegs::FogMode::Gas) {
+        Core::Telemetry().AddField(Telemetry::FieldType::Session, "VideoCore_Pica_UseGasMode",
+                                   true);
+        LOG_CRITICAL(Render_OpenGL, "Unimplemented gas mode");
+        UNIMPLEMENTED();
     }
 
     out += "gl_FragDepth = depth;\n";