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Cycles: Deduplicate sphere intersection test #112031

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Alaska wants to merge 10 commits from Alaska/blender:cleanup-sphere-intersect into main
pull from: Alaska/blender:cleanup-sphere-intersect
merge into: blender:main

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Conversation 4 Commits 10 Files Changed 4 +13 -13
1 changed files with 13 additions and 13 deletions
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26
intern/cycles/util/math_intersect.h
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@ -19,6 +19,8 @@ ccl_device bool ray_sphere_intersect(float3 ray_P,
ccl_private float *isect_t,
const bool cull_backface)
{
/* If the object has been scaled, ray_D will not be a normalized vector
* and inv_d_sq will not be equal to 1.0 */
const float inv_d_sq = 1.0f / dot(ray_D, ray_D);
const float3 c0 = sphere_P - ray_P;
@ -27,24 +29,22 @@ ccl_device bool ray_sphere_intersect(float3 ray_P,
const float l_sq = dot(perp, perp);
const float r_sq = sphere_radius * sphere_radius;
if (l_sq > r_sq) {
/* If the distance between the sphere center, and the point on the ray closest to the
* sphere center, is greater than the radius, then the ray does not intersect the sphere. */
return false;
}
float t;
if (len_squared(c0) < r_sq) {
/* Ray origin is inside the sphere */
if (cull_backface) {
return false;
}
const float td = sqrt((r_sq - l_sq) * inv_d_sq);
t = projC0 + td;
}
else {
/* Ray origin is outside the sphere */
const float td = sqrt((r_sq - l_sq) * inv_d_sq);
t = projC0 - td;
/* to_surface_sq is the squared distance from the ray origin to the surface of the sphere.
* Negative numbers denote the ray origin is inside the sphere.
* Positive numbers denote it's outside the sphere. */
const float to_surface_sq = len_squared(c0) - r_sq;
if (cull_backface && to_surface_sq < 0.0f) {
/* Ray origin is inside the sphere, and the ray can only intersect backfaces. */
return false;
}
const float t = projC0 - copysignf(sqrt((r_sq - l_sq) * inv_d_sq), to_surface_sq);
if ((ray_tmin <= t) & (t <= ray_tmax)) {
*isect_t = t;
*isect_P = ray_P + ray_D * t;