diff --git a/panda/src/dxgsg8/config_dxgsg8.cxx b/panda/src/dxgsg8/config_dxgsg8.cxx
index e8938015bd..5f30ea9f4d 100644
--- a/panda/src/dxgsg8/config_dxgsg8.cxx
+++ b/panda/src/dxgsg8/config_dxgsg8.cxx
@@ -107,7 +107,7 @@ ConfigVariableInt dx_preferred_device_id
 ("dx-preferred-device-id", -1);
 
 #ifdef _DEBUG
-float dx_global_miplevel_bias
+ConfigVariableDouble dx_global_miplevel_bias
 ("dx-global-miplevel-bias", 0.0);
 ConfigVariableBool dx_debug_view_mipmaps
 ("dx-debug-view-mipmaps", false);
diff --git a/panda/src/dxgsg9/config_dxgsg9.cxx b/panda/src/dxgsg9/config_dxgsg9.cxx
index 10c8952fb6..08268b66f3 100755
--- a/panda/src/dxgsg9/config_dxgsg9.cxx
+++ b/panda/src/dxgsg9/config_dxgsg9.cxx
@@ -107,7 +107,7 @@ ConfigVariableInt dx_preferred_device_id
 ("dx-preferred-device-id", -1);
 
 #ifdef _DEBUG
-float dx_global_miplevel_bias
+ConfigVariableDouble dx_global_miplevel_bias
 ("dx-global-miplevel-bias", 0.0);
 ConfigVariableBool dx_debug_view_mipmaps
 ("dx-debug-view-mipmaps", false);