![]() ![]() For metallic surfaces, we vary F0 by linearly interpolating between the original F0 and the albedo value given the metallic property. Vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0) Īs you can see, for non-metallic surfaces F0 is always 0.04. In the PBR metallic workflow we make the simplifying assumption that most dielectric surfaces look visually correct with a constant F0 of 0.04, while we do specify F0 for metallic surfaces as then given by the albedo value. The F0 varies per material and is tinted on metals as we find in large material databases. The Fresnel-Schlick approximation expects a F0 parameter which is known as the surface reflection at zero incidence or how much the surface reflects if looking directly at the surface. Vec3 fresnelSchlick(float cosTheta, vec3 F0) We know from the previous chapter that the Fresnel equation calculates just that (note the clamp here to prevent black spots): ![]() ![]() The first thing we want to do is calculate the ratio between specular and diffuse reflection, or how much the surface reflects light versus how much it refracts light. Let's start by re-visiting the final reflectance equation from the previous chapter: In this chapter we'll focus on translating the previously discussed theory into an actual renderer that uses direct (or analytic) light sources: think of point lights, directional lights, and/or spotlights. In the previous chapter we laid the foundation for getting a realistic physically based renderer off the ground. ![]()
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