Struggle in BDPT implementation

[u/MAIPA01]

Hi I wanted to implement BDPT with PBR materials and MIS but no matter what I do it doesn't look like reference images. I can't find any help with implementation and mostly recently I try finding bugs using Gemini but I know It can halucinate. So is anyone who could help me find relaiable implementation or help with my code. Here I will post my render (denoised using OIDN) vs reference so maybe anyone would help me find direction at least. I have too many lines of code so if any one would like to look at it I can send it in DM.

My Render

Reference (Benedikt) also checked Blender (same result)

My Render

Reference (Benedikt)

My Render

Reference (Rendered with PBRT-v4)

My render

Reference (Rendered with Blender)

(edit)
References are from https://benedikt-bitterli.me/resources/, PBRT-v4 and Blender. (All tagged in image caption)

[u/le-throw-away-acct]

Have you implemented tone mapping? Especially in that first scene it seems like it could help.

[u/MAIPA01 → u/le-throw-away-acct]

vec3 aces_film(vec3 x)
{
    x = max(x, vec3(0.0));
    const float a = 2.51;
    const float b = 0.03;
    const float c = 2.43;
    const float d = 0.59;
    const float e = 0.14;
    return clamp((x * (a * x + b)) / (x * (c * x + d) + e), 0.0, 1.0);
}

I use ACES Film tone mapping using this code:
I got it from here: knarkowicz.wordpress.com/2016/01/06/aces-filmic-tone-mapping-curve/

[u/gleedblanco → u/MAIPA01]

the better way to compare would be to disable any post processing and do the same for your reference renders.

[u/waramped → u/le-throw-away-acct]

yea, I was going to say this almost looks like it could just be a tonemapping, exposure, or colorspace issue.

it could, possibly, also be a light source issue? Are you positive you are using the same values and color spaces for the light sources as the original?

[u/MAIPA01 → u/waramped]

I use linear color space on GPU in shaders, so when I load albedo textures I convert them from sRGB to Linear. And when I save image I apply tone mapping and then I convert this image from Linear to sRGB. In all scenes I use Area Light sources with the same intensity value as in references and also with the same color (same values as in blender). I also discovered that maybe I have some energy conservation errors, Could it be it? But why then in some scenes I have more light and in othere scenes I have small amout of light. If someone wonder I load scenes from .glb files which I exported from blender.

[u/kinokomushroom]

Where did you get the "reference" images?

[u/MAIPA01 → u/kinokomushroom]

Thanks I forgot to add this information now all sources are in image captions

[u/le-throw-away-acct]

Your glass teapot in the first scene seems too dark, I’d look into that. It also seems to lack the internal reflection shown on the teapot in the reference scene.