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author | Clément Foucault <foucault.clem@gmail.com> | 2021-05-27 18:15:39 +0300 |
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committer | Clément Foucault <foucault.clem@gmail.com> | 2021-05-27 18:15:39 +0300 |
commit | 8590cb26a979c7eee6af5fba09b5edaf47cb4e8e (patch) | |
tree | 0a222c3fab3b21fb0f0ee630c9997cd5eb27a6d8 /intern/cycles/kernel/shaders | |
parent | 3025c348253a66f9c316259aa03f8884bf56d779 (diff) | |
parent | ba4228bcf77e50368a7c84affd5e380bd45789a7 (diff) |
Merge branch 'blender-v2.93-release'
Diffstat (limited to 'intern/cycles/kernel/shaders')
-rw-r--r-- | intern/cycles/kernel/shaders/stdcycles.h | 69 |
1 files changed, 53 insertions, 16 deletions
diff --git a/intern/cycles/kernel/shaders/stdcycles.h b/intern/cycles/kernel/shaders/stdcycles.h index af7b645d9a2..dd604da68ce 100644 --- a/intern/cycles/kernel/shaders/stdcycles.h +++ b/intern/cycles/kernel/shaders/stdcycles.h @@ -84,30 +84,67 @@ closure color principled_hair(normal N, closure color henyey_greenstein(float g) BUILTIN; closure color absorption() BUILTIN; -normal ensure_valid_reflection(normal Ng, normal I, normal N) +normal ensure_valid_reflection(normal Ng, vector I, normal N) { /* The implementation here mirrors the one in kernel_montecarlo.h, * check there for an explanation of the algorithm. */ - vector R; - float NI = dot(N, I); - float NgR, threshold; - - if (NI > 0) { - R = (2 * NI) * N - I; - NgR = dot(Ng, R); - threshold = min(0.9 * dot(Ng, I), 0.01); - if (NgR >= threshold) { - return N; + + float sqr(float x) + { + return x * x; + } + + vector R = 2 * dot(N, I) * N - I; + + float threshold = min(0.9 * dot(Ng, I), 0.01); + if (dot(Ng, R) >= threshold) { + return N; + } + + float NdotNg = dot(N, Ng); + vector X = normalize(N - NdotNg * Ng); + + float Ix = dot(I, X), Iz = dot(I, Ng); + float Ix2 = sqr(Ix), Iz2 = sqr(Iz); + float a = Ix2 + Iz2; + + float b = sqrt(Ix2 * (a - sqr(threshold))); + float c = Iz * threshold + a; + + float fac = 0.5 / a; + float N1_z2 = fac * (b + c), N2_z2 = fac * (-b + c); + int valid1 = (N1_z2 > 1e-5) && (N1_z2 <= (1.0 + 1e-5)); + int valid2 = (N2_z2 > 1e-5) && (N2_z2 <= (1.0 + 1e-5)); + + float N_new_x, N_new_z; + if (valid1 && valid2) { + float N1_x = sqrt(1.0 - N1_z2), N1_z = sqrt(N1_z2); + float N2_x = sqrt(1.0 - N2_z2), N2_z = sqrt(N2_z2); + + float R1 = 2 * (N1_x * Ix + N1_z * Iz) * N1_z - Iz; + float R2 = 2 * (N2_x * Ix + N2_z * Iz) * N2_z - Iz; + + valid1 = (R1 >= 1e-5); + valid2 = (R2 >= 1e-5); + if (valid1 && valid2) { + N_new_x = (R1 < R2) ? N1_x : N2_x; + N_new_z = (R1 < R2) ? N1_z : N2_z; + } + else { + N_new_x = (R1 > R2) ? N1_x : N2_x; + N_new_z = (R1 > R2) ? N1_z : N2_z; } } + else if (valid1 || valid2) { + float Nz2 = valid1 ? N1_z2 : N2_z2; + N_new_x = sqrt(1.0 - Nz2); + N_new_z = sqrt(Nz2); + } else { - R = -I; - NgR = dot(Ng, R); - threshold = 0.01; + return Ng; } - R = R + Ng * (threshold - NgR); - return normalize(I * length(R) + R * length(I)); + return N_new_x * X + N_new_z * Ng; } #endif /* CCL_STDOSL_H */ |