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#define BLINN
#if STUDIOLIGHT_SH_BANDS == 2
vec3 spherical_harmonics(vec3 N, vec3 sh_coefs[STUDIOLIGHT_SH_MAX_COMPONENTS])
{
/* http://www.geomerics.com/wp-content/uploads/2015/08/CEDEC_Geomerics_ReconstructingDiffuseLighting1.pdf */
/* Highly optimized form, precompute as much as we can. */
/**
* R1 = 0.5 * vec3(L3.r, L2.r, L1.r);
* sh_coefs[0..2] = R1 / length(R1);
**/
vec3 q;
q.x = dot(sh_coefs[1], N);
q.y = dot(sh_coefs[2], N);
q.z = dot(sh_coefs[3], N);
q = 0.5 * q + 0.5;
/**
* R0 = L0.r;
* lr1_r0 = lenR1 / R0;
* p = 1.0 + 2.0 * lr1_r0;
* a = (1.0 - lr1_r0) / (1.0 + lr1_r0);
* return R0 * (a + (1.0 - a) * (p + 1.0) * pow(q, p));
*
* sh_coefs[4] = p;
* sh_coefs[5] = R0 * a;
* sh_coefs[0] = R0 * (1.0 - a) * (p + 1.0);
**/
q = pow(q, sh_coefs[4]);
return sh_coefs[0] * q + sh_coefs[5];
}
#else
vec3 spherical_harmonics(vec3 N, vec3 sh_coefs[STUDIOLIGHT_SH_MAX_COMPONENTS])
{
vec3 sh = 0.282095 * sh_coefs[0];
# if STUDIOLIGHT_SH_BANDS > 1
float nx = N.x;
float ny = N.y;
float nz = N.z;
sh += -0.488603 * nz * sh_coefs[1];
sh += 0.488603 * ny * sh_coefs[2];
sh += -0.488603 * nx * sh_coefs[3];
# endif
# if STUDIOLIGHT_SH_BANDS > 2
float nx2 = nx * nx;
float ny2 = ny * ny;
float nz2 = nz * nz;
sh += 1.092548 * nx * nz * sh_coefs[4];
sh += -1.092548 * nz * ny * sh_coefs[5];
sh += 0.315392 * (3.0 * ny2 - 1.0) * sh_coefs[6];
sh += -1.092548 * nx * ny * sh_coefs[7];
sh += 0.546274 * (nx2 - nz2) * sh_coefs[8];
# endif
# if STUDIOLIGHT_SH_BANDS > 4
float nx4 = nx2 * nx2;
float ny4 = ny2 * ny2;
float nz4 = nz2 * nz2;
sh += (2.5033429417967046 * nx * nz * (nx2 - nz2)) * sh_coefs[9];
sh += (-1.7701307697799304 * nz * ny * (3.0 * nx2 - nz2)) * sh_coefs[10];
sh += (0.9461746957575601 * nz * nx * (-1.0 +7.0*ny2)) * sh_coefs[11];
sh += (-0.6690465435572892 * nz * ny * (-3.0 + 7.0 * ny2)) * sh_coefs[12];
sh += ((105.0*ny4-90.0*ny2+9.0)/28.359261614) * sh_coefs[13];
sh += (-0.6690465435572892 * nx * ny * (-3.0 + 7.0 * ny2)) * sh_coefs[14];
sh += (0.9461746957575601 * (nx2 - nz2) * (-1.0 + 7.0 * ny2)) * sh_coefs[15];
sh += (-1.7701307697799304 * nx * ny * (nx2 - 3.0 * nz2)) * sh_coefs[16];
sh += (0.6258357354491761 * (nx4 - 6.0 * nz2 * nx2 + nz4)) * sh_coefs[17];
# endif
return sh;
}
#endif
vec3 get_world_diffuse_light(WorldData world_data, vec3 N)
{
return spherical_harmonics(N, world_data.spherical_harmonics_coefs);
}
vec3 get_camera_diffuse_light(WorldData world_data, vec3 N)
{
return spherical_harmonics(vec3(N.x, -N.z, N.y), world_data.spherical_harmonics_coefs);
}
/* N And I are in View Space. */
vec3 get_world_specular_light(vec4 specular_data, LightData light_data, vec3 N, vec3 I)
{
#ifdef V3D_SHADING_SPECULAR_HIGHLIGHT
vec3 specular_light = specular_data.rgb * light_data.specular_color.rgb * light_data.specular_color.a;
float shininess = exp2(10.0 * (1.0 - specular_data.a) + 1);
# ifdef BLINN
float normalization_factor = (shininess + 8.0) / (8.0 * M_PI);
vec3 L = -light_data.light_direction_vs.xyz;
vec3 halfDir = normalize(L + I);
float spec_angle = max(dot(halfDir, N), 0.0);
float NL = max(dot(L, N), 0.0);
float specular_influence = pow(spec_angle, shininess) * NL * normalization_factor;
# else
vec3 reflection_vector = reflect(I, N);
float spec_angle = max(dot(light_data.light_direction_vs.xyz, reflection_vector), 0.0);
float specular_influence = pow(spec_angle, shininess);
# endif
vec3 specular_color = specular_light * specular_influence;
#else /* V3D_SHADING_SPECULAR_HIGHLIGHT */
vec3 specular_color = vec3(0.0);
#endif /* V3D_SHADING_SPECULAR_HIGHLIGHT */
return specular_color;
}
vec3 get_world_specular_lights(WorldData world_data, vec4 specular_data, vec3 N, vec3 I)
{
vec3 specular_light = vec3(0.0);
/* Manual loop unrolling provide much better perf. */
if (world_data.num_lights > 0) {
specular_light += get_world_specular_light(specular_data, world_data.lights[0], N, I);
}
if (world_data.num_lights > 1) {
specular_light += get_world_specular_light(specular_data, world_data.lights[1], N, I);
}
if (world_data.num_lights > 2) {
specular_light += get_world_specular_light(specular_data, world_data.lights[2], N, I);
}
return specular_light;
}
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