pbr_pixel_value = pbr_albedo * pbr_light
If we assume pbr_light = pow(vanilla_light, 1.5), then
vanilla_pixel_value = pow(pbr_pixel_value, 1.5)
Also, vanilla_pixel_value is directly outputed as if it is srgb
which is equivalent to tonemapping with a 2.2 gamma curve
Therefore, we can say the final presented pixels are equivalent to pbr values tonemapped with a gamma curve of 2.2/1.5 = 1.44, and true physically based light luminance is the 1.5 power of vanilla light.
PP is not edited in this commit in order to preserve vanilla visual, but pbr integration has been altered:
Light colour conversion using 1.5 gamma
Landscape albedo are blended in vanilla space to preserve visuals, then converted to linear for PBR, finally back to gamma for saving
From Exist, empirically we have:
vanilla_albedo = pow(equivalent_pbr_albedo, 1.5)Then consider the equations:
vanilla_pixel_value = vanilla_albedo * vanilla_lightpbr_pixel_value = pbr_albedo * pbr_lightIf we assumepbr_light = pow(vanilla_light, 1.5), thenAlso,
vanilla_pixel_valueis directly outputed as if it is srgb which is equivalent to tonemapping with a 2.2 gamma curveTherefore, we can say the final presented pixels are equivalent to pbr values tonemapped with a gamma curve of
2.2/1.5 = 1.44, and true physically based light luminance is the 1.5 power of vanilla light.PP is not edited in this commit in order to preserve vanilla visual, but pbr integration has been altered:
EDIT: using sqrt(2.2) = 1.48 gamma now.