BVH-raycast: Use watertight intersections

By default watertight intersections are used,
For callbacks where its not needed,
BLI_bvhtree_ray_cast_ex can be called without the BVH_RAYCAST_WATERTIGHT flag.

Fixes T45286

2 files changed, 71 insertions, 14 deletions

diff --git a/source/blender/blenlib/BLI_kdopbvh.h b/source/blender/blenlib/BLI_kdopbvh.h
index ce7f3ab25fe..0c359c7f090 100644
--- a/source/blender/blenlib/BLI_kdopbvh.h
+++ b/source/blender/blenlib/BLI_kdopbvh.h
@@ -41,6 +41,7 @@ extern "C" {
 
 struct BVHTree;
 typedef struct BVHTree BVHTree;
+#define USE_KDOPBVH_WATERTIGHT
 
 typedef struct BVHTreeOverlap {
 	int indexA;
@@ -59,6 +60,9 @@ typedef struct BVHTreeRay {
 	float origin[3];    /* ray origin */
 	float direction[3]; /* ray direction */
 	float radius;       /* radius around ray */
+#ifdef USE_KDOPBVH_WATERTIGHT
+	struct IsectRayPrecalc *isect_precalc;
+#endif
 } BVHTreeRay;
 
 typedef struct BVHTreeRayHit {
@@ -68,6 +72,12 @@ typedef struct BVHTreeRayHit {
 	float dist;         /* distance to the hit point */
 } BVHTreeRayHit;
 
+enum {
+	/* calculate IsectRayPrecalc data */
+	BVH_RAYCAST_WATERTIGHT		= (1 << 0),
+};
+#define BVH_RAYCAST_DEFAULT (BVH_RAYCAST_WATERTIGHT)
+
 /* callback must update nearest in case it finds a nearest result */
 typedef void (*BVHTree_NearestPointCallback)(void *userdata, int index, const float co[3], BVHTreeNearest *nearest);
 
@@ -105,12 +115,21 @@ float BLI_bvhtree_getepsilon(const BVHTree *tree);
 int BLI_bvhtree_find_nearest(BVHTree *tree, const float co[3], BVHTreeNearest *nearest,
                              BVHTree_NearestPointCallback callback, void *userdata);
 
-int BLI_bvhtree_ray_cast(BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
-                         BVHTree_RayCastCallback callback, void *userdata);
-
-/* Calls the callback for every ray intersection */
-int BLI_bvhtree_ray_cast_all(BVHTree *tree, const float co[3], const float dir[3], float radius,
-                             BVHTree_RayCastCallback callback, void *userdata);
+int BLI_bvhtree_ray_cast_ex(
+        BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
+        BVHTree_RayCastCallback callback, void *userdata,
+        int flag);
+int BLI_bvhtree_ray_cast(
+        BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
+        BVHTree_RayCastCallback callback, void *userdata);
+
+int BLI_bvhtree_ray_cast_all_ex(
+        BVHTree *tree, const float co[3], const float dir[3], float radius,
+        BVHTree_RayCastCallback callback, void *userdata,
+        int flag);
+int BLI_bvhtree_ray_cast_all(
+        BVHTree *tree, const float co[3], const float dir[3], float radius,
+        BVHTree_RayCastCallback callback, void *userdata);
 
 float BLI_bvhtree_bb_raycast(const float bv[6], const float light_start[3], const float light_end[3], float pos[3]);
 
diff --git a/source/blender/blenlib/intern/BLI_kdopbvh.c b/source/blender/blenlib/intern/BLI_kdopbvh.c
index 1b9b6e38208..ddb61e415ac 100644
--- a/source/blender/blenlib/intern/BLI_kdopbvh.c
+++ b/source/blender/blenlib/intern/BLI_kdopbvh.c
@@ -139,6 +139,10 @@ typedef struct BVHRayCastData {
 
 	BVHTreeRay ray;
 
+#ifdef USE_KDOPBVH_WATERTIGHT
+	struct IsectRayPrecalc isect_precalc;
+#endif
+
 	/* initialized by bvhtree_ray_cast_data_precalc */
 	float ray_dot_axis[13];
 	float idot_axis[13];
@@ -1626,7 +1630,7 @@ static void iterative_raycast(BVHRayCastData *data, BVHNode *node)
 }
 #endif
 
-static void bvhtree_ray_cast_data_precalc(BVHRayCastData *data)
+static void bvhtree_ray_cast_data_precalc(BVHRayCastData *data, int flag)
 {
 	int i;
 
@@ -1642,10 +1646,24 @@ static void bvhtree_ray_cast_data_precalc(BVHRayCastData *data)
 		data->index[2 * i]   += 2 * i;
 		data->index[2 * i + 1] += 2 * i;
 	}
+
+#ifdef USE_KDOPBVH_WATERTIGHT
+	if (flag & BVH_RAYCAST_WATERTIGHT) {
+		isect_ray_tri_watertight_v3_precalc(&data->isect_precalc, data->ray.direction);
+		data->ray.isect_precalc = &data->isect_precalc;
+	}
+	else {
+		data->ray.isect_precalc = NULL;
+	}
+#else
+	UNUSED_VARS(flag);
+#endif
 }
 
-int BLI_bvhtree_ray_cast(BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
-                         BVHTree_RayCastCallback callback, void *userdata)
+int BLI_bvhtree_ray_cast_ex(
+        BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
+        BVHTree_RayCastCallback callback, void *userdata,
+        int flag)
 {
 	BVHRayCastData data;
 	BVHNode *root = tree->nodes[tree->totleaf];
@@ -1661,10 +1679,11 @@ int BLI_bvhtree_ray_cast(BVHTree *tree, const float co[3], const float dir[3], f
 	copy_v3_v3(data.ray.direction, dir);
 	data.ray.radius = radius;
 
-	bvhtree_ray_cast_data_precalc(&data);
+	bvhtree_ray_cast_data_precalc(&data, flag);
 
-	if (hit)
+	if (hit) {
 		memcpy(&data.hit, hit, sizeof(*hit));
+	}
 	else {
 		data.hit.index = -1;
 		data.hit.dist = FLT_MAX;
@@ -1682,6 +1701,13 @@ int BLI_bvhtree_ray_cast(BVHTree *tree, const float co[3], const float dir[3], f
 	return data.hit.index;
 }
 
+int BLI_bvhtree_ray_cast(
+        BVHTree *tree, const float co[3], const float dir[3], float radius, BVHTreeRayHit *hit,
+        BVHTree_RayCastCallback callback, void *userdata)
+{
+	return BLI_bvhtree_ray_cast_ex(tree, co, dir, radius, hit, callback, userdata, BVH_RAYCAST_DEFAULT);
+}
+
 float BLI_bvhtree_bb_raycast(const float bv[6], const float light_start[3], const float light_end[3], float pos[3])
 {
 	BVHRayCastData data;
@@ -1707,8 +1733,13 @@ float BLI_bvhtree_bb_raycast(const float bv[6], const float light_start[3], cons
 	
 }
 
-int BLI_bvhtree_ray_cast_all(BVHTree *tree, const float co[3], const float dir[3], float radius,
-                             BVHTree_RayCastCallback callback, void *userdata)
+/**
+ * Calls the callback for every ray intersection
+ */
+int BLI_bvhtree_ray_cast_all_ex(
+        BVHTree *tree, const float co[3], const float dir[3], float radius,
+        BVHTree_RayCastCallback callback, void *userdata,
+        int flag)
 {
 	BVHRayCastData data;
 	BVHNode *root = tree->nodes[tree->totleaf];
@@ -1724,7 +1755,7 @@ int BLI_bvhtree_ray_cast_all(BVHTree *tree, const float co[3], const float dir[3
 	copy_v3_v3(data.ray.direction, dir);
 	data.ray.radius = radius;
 
-	bvhtree_ray_cast_data_precalc(&data);
+	bvhtree_ray_cast_data_precalc(&data, flag);
 
 	data.hit.index = -1;
 	data.hit.dist = FLT_MAX;
@@ -1736,6 +1767,13 @@ int BLI_bvhtree_ray_cast_all(BVHTree *tree, const float co[3], const float dir[3
 	return data.hit.index;
 }
 
+int BLI_bvhtree_ray_cast_all(
+        BVHTree *tree, const float co[3], const float dir[3], float radius,
+        BVHTree_RayCastCallback callback, void *userdata)
+{
+	return BLI_bvhtree_ray_cast_all_ex(tree, co, dir, radius, callback, userdata, BVH_RAYCAST_DEFAULT);
+}
+
 /**
  * Range Query - as request by broken :P
  *