Darker renders on custom renderer

glTF
1

Hello,

I currently am working on a render engine supporting GLTF. I already have the shaders written based upon the online viewer (only for punctual lighting) but my renders always seem darker compared to the online viewer (with only punctual lighting checked). I’m currently trying to know if there are important factors I missed for the comparison.
I have no shadows nor ambient occlusion.
My directional light intensity is 1 and so is the exposure.

I searched for an ambient term but there seems to be none. Is that correct?
When checking some models I saw there are two specular highlights in the online viewer. Is it possible that there are two lights by default?

Thanks in advance for your answers.

2

Given the information, the only thing that comes to my mind is the knee jerk reaction I always have to questions along the lines of “my colors are wrong, what gives?” :wink: :wink: :
Are your lighting calculations in linear color space? Are you correctly handling linear → sRGB conversion for display (or using some mechanism that does it for you)?