From 0d54aa9c024261851bef24a3ebfd2bd875fec380 Mon Sep 17 00:00:00 2001 From: Sergey Sharybin Date: Thu, 22 Oct 2015 20:29:52 +0500 Subject: [PATCH] Fix T46521: Python: bvh.ray_cast doesn't find a plane facing in the other direction under certain circumstances The issue was caused by wrong sign check. It originally came from more optimized Cycles code where because of other reasons it wasn't visible yet. But in fact it should be solved there as well. --- source/blender/blenlib/intern/math_geom.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c index e5fb5533728..82da1e4ef58 100644 --- a/source/blender/blenlib/intern/math_geom.c +++ b/source/blender/blenlib/intern/math_geom.c @@ -1373,16 +1373,14 @@ bool isect_ray_tri_watertight_v3( const float cy = c_ky - sy * c_kz; /* Calculate scaled barycentric coordinates. */ - float u = cx * by - cy * bx; - int sign_mask = (float_as_int(u) & (int)0x80000000); - float v = ax * cy - ay * cx; - float w, det; + const float u = cx * by - cy * bx; + const float v = ax * cy - ay * cx; + const float w = bx * ay - by * ax; + float det; - if (sign_mask != (float_as_int(v) & (int)0x80000000)) { - return false; - } - w = bx * ay - by * ax; - if (sign_mask != (float_as_int(w) & (int)0x80000000)) { + if ((u < 0.0f || v < 0.0f || w < 0.0f) && + (u > 0.0f || v > 0.0f || w > 0.0f)) + { return false; } @@ -1395,8 +1393,9 @@ bool isect_ray_tri_watertight_v3( /* Calculate scaled z-coordinates of vertices and use them to calculate * the hit distance. */ + const int sign_det = (float_as_int(det) & (int)0x80000000); const float t = (u * a_kz + v * b_kz + w * c_kz) * sz; - const float sign_t = xor_fl(t, sign_mask); + const float sign_t = xor_fl(t, sign_det); if ((sign_t < 0.0f) /* differ from Cycles, don't read r_lambda's original value * otherwise we won't match any of the other intersect functions here...