Misaki
bfc94f0008
Added new function signatures in `assimp-vc143-mt.lib` for improved logging, parsing, and vector operations. Added new metadata and configuration information in `assimp-vc143-mt.dll` for versioning and licensing compliance. Added Sobol sequence generation in `Sobol.c` for quasi-random sampling. Added window message handling in `Window.c` for rendering graphics. Added ray-triangle intersection tests in `RayIntersection.c` for collision detection. Added functions for loading mesh data in `Mesh.c` to support 3D model import. Added functions for managing triangle collections in `Triangle.c` to enhance geometric data handling. Added light evaluation functions in `LightEvaluation.c` and `SkyLight.c` for realistic rendering. Added sampling and evaluation functions for simple lit materials in `SimpleLit.c`. Changed various header files to include copyright and licensing information. Changed existing functions in multiple files to improve performance and clarity. Removed unused code in several files to streamline the library.
69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
#ifndef BSDF_H
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#define BSDF_H
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#include "cglm/struct/vec3.h"
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inline float power_heuristic(float pdf_a, float pdf_b)
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{
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float a2 = pdf_a * pdf_a;
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float b2 = pdf_b * pdf_b;
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return a2 / (a2 + b2);
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}
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inline float roughness_to_blinn_phong_specular_exponent(float roughness)
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{
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return glm_clamp(2.0f * 1.0f / (fmaxf(roughness * roughness, FLT_EPSILON)) - 2.0f, FLT_EPSILON, 1.0f / FLT_EPSILON);
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}
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inline vec3s fresnel_schlick_vec3(vec3s f0, float cos_theta)
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{
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float x = 1.0f - cos_theta;
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float x5 = x * x * x * x * x;
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return glms_vec3_adds(glms_vec3_scale(f0, (1.0f - x5)), x5);
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}
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inline float pdf_cosine_weighted_hemisphere(const vec3s normal, const vec3s wi)
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{
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return fmaxf(glms_vec3_dot(wi, normal), 0.0f) / (float)M_PI;
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}
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inline float pdf_blinn_phong_lobe(const vec3s normal, const vec3s wi, const vec3s wo, const float roughness)
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{
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// Check if wo and wi are on the same side of the surface normal geometry
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if (glms_vec3_dot(wo, normal) <= 0.0f || glms_vec3_dot(wi, normal) <= 0.0f)
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{
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return 0.0f; // Cannot scatter from below horizon to above, or vice versa
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}
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// Calculate the half-vector h based on input wo and wi
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vec3s wo_n = glms_vec3_normalize(wo); // Ensure normalized inputs if not guaranteed
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vec3s wi_n = glms_vec3_normalize(wi);
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vec3s h = glms_vec3_add(wo_n, wi_n);
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float h_len_sq = glms_vec3_norm2(h);
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if (h_len_sq < FLT_EPSILON)
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{
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return 0.0f; // wo and wi are opposite, highly unlikely for reflection
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}
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h = glms_vec3_scale(h, 1.0f / sqrtf(h_len_sq)); // Normalize h
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// Calculate Blinn-Phong specular exponent
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float specular_exponent = roughness_to_blinn_phong_specular_exponent(roughness);
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// PDF of sampling h (Blinn-Phong distribution)
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// D(h) = (specular_exponent + 1) / (2 * PI) * pow(max(0, dot(n, h)), specular_exponent)
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float n_dot_h = fmaxf(0.0f, glms_vec3_dot(normal, h));
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float pdf_h = (specular_exponent + 1.0f) / (2.0f * (float)M_PI) * powf(n_dot_h, specular_exponent);
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// Jacobian of the transformation from h to wi
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// jacobian = 1 / (4 * dot(wo, h))
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float wo_dot_h = fmaxf(FLT_EPSILON, glms_vec3_dot(wo_n, h)); // Use normalized wo, ensure > 0
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float jacobian = 1.0f / (4.0f * wo_dot_h);
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// PDF of sampling wi is pdf(h) * jacobian
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float pdf_spec = pdf_h * jacobian;
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return pdf_spec;
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}
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#endif // BSDF_H
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