Properly remap roughness when reading from radiance map

This ensures that we consistently use perceptual roughness which matches the behaviour of most other PBR renderers like Blender, Ue4 and Godot 3

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gles3/shaders/scene.glsl b/drivers/gles3/shaders/scene.glsl
index 04dba602dd..75b28dbf2b 100644
--- a/drivers/gles3/shaders/scene.glsl
+++ b/drivers/gles3/shaders/scene.glsl
@@ -1100,7 +1100,7 @@ void main() {
 		ref_vec = mix(ref_vec, normal, roughness * roughness);
 		float horizon = min(1.0 + dot(ref_vec, normal), 1.0);
 		ref_vec = scene_data.radiance_inverse_xform * ref_vec;
-		specular_light = textureLod(radiance_map, ref_vec, roughness * RADIANCE_MAX_LOD).rgb;
+		specular_light = textureLod(radiance_map, ref_vec, sqrt(roughness) * RADIANCE_MAX_LOD).rgb;
 		specular_light = srgb_to_linear(specular_light);
 		specular_light *= horizon * horizon;
 		specular_light *= scene_data.ambient_light_color_energy.a;