RayAABox.h

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// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
// SPDX-License-Identifier: MIT
 
#pragma once
 
JPH_NAMESPACE_BEGIN
 
class RayInvDirection
{
public:
    inline          RayInvDirection() = default;
    inline explicit RayInvDirection(Vec3Arg inDirection) { Set(inDirection); }
 
    inline void     Set(Vec3Arg inDirection)
    {
        // if (abs(inDirection) <= Epsilon) the ray is nearly parallel to the slab.
        mIsParallel = Vec3::sLessOrEqual(inDirection.Abs(), Vec3::sReplicate(1.0e-20f));
 
        // Calculate 1 / direction while avoiding division by zero
        mInvDirection = Vec3::sSelect(inDirection, Vec3::sReplicate(1.0f), mIsParallel).Reciprocal();
    }
 
    Vec3            mInvDirection;                  
    UVec4           mIsParallel;                    
};
 
JPH_INLINE float RayAABox(Vec3Arg inOrigin, const RayInvDirection &inInvDirection, Vec3Arg inBoundsMin, Vec3Arg inBoundsMax)
{
    // Constants
    Vec3 flt_min = Vec3::sReplicate(-FLT_MAX);
    Vec3 flt_max = Vec3::sReplicate(FLT_MAX);
 
    // Test against all three axes simultaneously.
    Vec3 t1 = (inBoundsMin - inOrigin) * inInvDirection.mInvDirection;
    Vec3 t2 = (inBoundsMax - inOrigin) * inInvDirection.mInvDirection;
 
    // Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
    // use the results from any directions parallel to the slab.
    Vec3 t_min = Vec3::sSelect(Vec3::sMin(t1, t2), flt_min, inInvDirection.mIsParallel);
    Vec3 t_max = Vec3::sSelect(Vec3::sMax(t1, t2), flt_max, inInvDirection.mIsParallel);
 
    // t_min.xyz = maximum(t_min.x, t_min.y, t_min.z);
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // t_max.xyz = minimum(t_max.x, t_max.y, t_max.z);
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // if (t_min > t_max) return FLT_MAX;
    UVec4 no_intersection = Vec3::sGreater(t_min, t_max);
 
    // if (t_max < 0.0f) return FLT_MAX;
    no_intersection = UVec4::sOr(no_intersection, Vec3::sLess(t_max, Vec3::sZero()));
 
    // if (inInvDirection.mIsParallel && !(Min <= inOrigin && inOrigin <= Max)) return FLT_MAX; else return t_min;
    UVec4 no_parallel_overlap = UVec4::sOr(Vec3::sLess(inOrigin, inBoundsMin), Vec3::sGreater(inOrigin, inBoundsMax));
    no_intersection = UVec4::sOr(no_intersection, UVec4::sAnd(inInvDirection.mIsParallel, no_parallel_overlap));
    no_intersection = UVec4::sOr(no_intersection, no_intersection.SplatY());
    no_intersection = UVec4::sOr(no_intersection, no_intersection.SplatZ());
    return Vec3::sSelect(t_min, flt_max, no_intersection).GetX();
}
 
JPH_INLINE Vec4 RayAABox4(Vec3Arg inOrigin, const RayInvDirection &inInvDirection, Vec4Arg inBoundsMinX, Vec4Arg inBoundsMinY, Vec4Arg inBoundsMinZ, Vec4Arg inBoundsMaxX, Vec4Arg inBoundsMaxY, Vec4Arg inBoundsMaxZ)
{
    // Constants
    Vec4 flt_min = Vec4::sReplicate(-FLT_MAX);
    Vec4 flt_max = Vec4::sReplicate(FLT_MAX);
 
    // Origin
    Vec4 originx = inOrigin.SplatX();
    Vec4 originy = inOrigin.SplatY();
    Vec4 originz = inOrigin.SplatZ();
 
    // Parallel
    UVec4 parallelx = inInvDirection.mIsParallel.SplatX();
    UVec4 parallely = inInvDirection.mIsParallel.SplatY();
    UVec4 parallelz = inInvDirection.mIsParallel.SplatZ();
 
    // Inverse direction
    Vec4 invdirx = inInvDirection.mInvDirection.SplatX();
    Vec4 invdiry = inInvDirection.mInvDirection.SplatY();
    Vec4 invdirz = inInvDirection.mInvDirection.SplatZ();
 
    // Test against all three axes simultaneously.
    Vec4 t1x = (inBoundsMinX - originx) * invdirx;
    Vec4 t1y = (inBoundsMinY - originy) * invdiry;
    Vec4 t1z = (inBoundsMinZ - originz) * invdirz;
    Vec4 t2x = (inBoundsMaxX - originx) * invdirx;
    Vec4 t2y = (inBoundsMaxY - originy) * invdiry;
    Vec4 t2z = (inBoundsMaxZ - originz) * invdirz;
 
    // Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
    // use the results from any directions parallel to the slab.
    Vec4 t_minx = Vec4::sSelect(Vec4::sMin(t1x, t2x), flt_min, parallelx);
    Vec4 t_miny = Vec4::sSelect(Vec4::sMin(t1y, t2y), flt_min, parallely);
    Vec4 t_minz = Vec4::sSelect(Vec4::sMin(t1z, t2z), flt_min, parallelz);
    Vec4 t_maxx = Vec4::sSelect(Vec4::sMax(t1x, t2x), flt_max, parallelx);
    Vec4 t_maxy = Vec4::sSelect(Vec4::sMax(t1y, t2y), flt_max, parallely);
    Vec4 t_maxz = Vec4::sSelect(Vec4::sMax(t1z, t2z), flt_max, parallelz);
 
    // t_min.xyz = maximum(t_min.x, t_min.y, t_min.z);
    Vec4 t_min = Vec4::sMax(Vec4::sMax(t_minx, t_miny), t_minz);
 
    // t_max.xyz = minimum(t_max.x, t_max.y, t_max.z);
    Vec4 t_max = Vec4::sMin(Vec4::sMin(t_maxx, t_maxy), t_maxz);
 
    // if (t_min > t_max) return FLT_MAX;
    UVec4 no_intersection = Vec4::sGreater(t_min, t_max);
 
    // if (t_max < 0.0f) return FLT_MAX;
    no_intersection = UVec4::sOr(no_intersection, Vec4::sLess(t_max, Vec4::sZero()));
 
    // if bounds are invalid return FLOAT_MAX;
    UVec4 bounds_invalid = UVec4::sOr(UVec4::sOr(Vec4::sGreater(inBoundsMinX, inBoundsMaxX), Vec4::sGreater(inBoundsMinY, inBoundsMaxY)), Vec4::sGreater(inBoundsMinZ, inBoundsMaxZ));
    no_intersection = UVec4::sOr(no_intersection, bounds_invalid);
 
    // if (inInvDirection.mIsParallel && !(Min <= inOrigin && inOrigin <= Max)) return FLT_MAX; else return t_min;
    UVec4 no_parallel_overlapx = UVec4::sAnd(parallelx, UVec4::sOr(Vec4::sLess(originx, inBoundsMinX), Vec4::sGreater(originx, inBoundsMaxX)));
    UVec4 no_parallel_overlapy = UVec4::sAnd(parallely, UVec4::sOr(Vec4::sLess(originy, inBoundsMinY), Vec4::sGreater(originy, inBoundsMaxY)));
    UVec4 no_parallel_overlapz = UVec4::sAnd(parallelz, UVec4::sOr(Vec4::sLess(originz, inBoundsMinZ), Vec4::sGreater(originz, inBoundsMaxZ)));
    no_intersection = UVec4::sOr(no_intersection, UVec4::sOr(UVec4::sOr(no_parallel_overlapx, no_parallel_overlapy), no_parallel_overlapz));
    return Vec4::sSelect(t_min, flt_max, no_intersection);
}
 
JPH_INLINE void RayAABox(Vec3Arg inOrigin, const RayInvDirection &inInvDirection, Vec3Arg inBoundsMin, Vec3Arg inBoundsMax, float &outMin, float &outMax)
{
    // Constants
    Vec3 flt_min = Vec3::sReplicate(-FLT_MAX);
    Vec3 flt_max = Vec3::sReplicate(FLT_MAX);
 
    // Test against all three axes simultaneously.
    Vec3 t1 = (inBoundsMin - inOrigin) * inInvDirection.mInvDirection;
    Vec3 t2 = (inBoundsMax - inOrigin) * inInvDirection.mInvDirection;
 
    // Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
    // use the results from any directions parallel to the slab.
    Vec3 t_min = Vec3::sSelect(Vec3::sMin(t1, t2), flt_min, inInvDirection.mIsParallel);
    Vec3 t_max = Vec3::sSelect(Vec3::sMax(t1, t2), flt_max, inInvDirection.mIsParallel);
 
    // t_min.xyz = maximum(t_min.x, t_min.y, t_min.z);
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // t_max.xyz = minimum(t_max.x, t_max.y, t_max.z);
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // if (t_min > t_max) return FLT_MAX;
    UVec4 no_intersection = Vec3::sGreater(t_min, t_max);
 
    // if (t_max < 0.0f) return FLT_MAX;
    no_intersection = UVec4::sOr(no_intersection, Vec3::sLess(t_max, Vec3::sZero()));
 
    // if (inInvDirection.mIsParallel && !(Min <= inOrigin && inOrigin <= Max)) return FLT_MAX; else return t_min;
    UVec4 no_parallel_overlap = UVec4::sOr(Vec3::sLess(inOrigin, inBoundsMin), Vec3::sGreater(inOrigin, inBoundsMax));
    no_intersection = UVec4::sOr(no_intersection, UVec4::sAnd(inInvDirection.mIsParallel, no_parallel_overlap));
    no_intersection = UVec4::sOr(no_intersection, no_intersection.SplatY());
    no_intersection = UVec4::sOr(no_intersection, no_intersection.SplatZ());
    outMin = Vec3::sSelect(t_min, flt_max, no_intersection).GetX();
    outMax = Vec3::sSelect(t_max, flt_min, no_intersection).GetX();
}
 
JPH_INLINE bool RayAABoxHits(Vec3Arg inOrigin, const RayInvDirection &inInvDirection, Vec3Arg inBoundsMin, Vec3Arg inBoundsMax, float inClosest)
{
    // Constants
    Vec3 flt_min = Vec3::sReplicate(-FLT_MAX);
    Vec3 flt_max = Vec3::sReplicate(FLT_MAX);
 
    // Test against all three axes simultaneously.
    Vec3 t1 = (inBoundsMin - inOrigin) * inInvDirection.mInvDirection;
    Vec3 t2 = (inBoundsMax - inOrigin) * inInvDirection.mInvDirection;
 
    // Compute the max of min(t1,t2) and the min of max(t1,t2) ensuring we don't
    // use the results from any directions parallel to the slab.
    Vec3 t_min = Vec3::sSelect(Vec3::sMin(t1, t2), flt_min, inInvDirection.mIsParallel);
    Vec3 t_max = Vec3::sSelect(Vec3::sMax(t1, t2), flt_max, inInvDirection.mIsParallel);
 
    // t_min.xyz = maximum(t_min.x, t_min.y, t_min.z);
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_min = Vec3::sMax(t_min, t_min.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // t_max.xyz = minimum(t_max.x, t_max.y, t_max.z);
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>());
    t_max = Vec3::sMin(t_max, t_max.Swizzle<SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y>());
 
    // if (t_min > t_max) return false;
    UVec4 no_intersection = Vec3::sGreater(t_min, t_max);
 
    // if (t_max < 0.0f) return false;
    no_intersection = UVec4::sOr(no_intersection, Vec3::sLess(t_max, Vec3::sZero()));
 
    // if (t_min > inClosest) return false;
    no_intersection = UVec4::sOr(no_intersection, Vec3::sGreater(t_min, Vec3::sReplicate(inClosest)));
 
    // if (inInvDirection.mIsParallel && !(Min <= inOrigin && inOrigin <= Max)) return false; else return true;
    UVec4 no_parallel_overlap = UVec4::sOr(Vec3::sLess(inOrigin, inBoundsMin), Vec3::sGreater(inOrigin, inBoundsMax));
    no_intersection = UVec4::sOr(no_intersection, UVec4::sAnd(inInvDirection.mIsParallel, no_parallel_overlap));
 
    return !no_intersection.TestAnyXYZTrue();
}
 
JPH_INLINE bool RayAABoxHits(Vec3Arg inOrigin, Vec3Arg inDirection, Vec3Arg inBoundsMin, Vec3Arg inBoundsMax)
{
    Vec3 extents = inBoundsMax - inBoundsMin;
 
    Vec3 diff = 2.0f * inOrigin - inBoundsMin - inBoundsMax;
    Vec3 abs_diff = diff.Abs();
 
    UVec4 no_intersection = UVec4::sAnd(Vec3::sGreater(abs_diff, extents), Vec3::sGreaterOrEqual(diff * inDirection, Vec3::sZero()));
 
    Vec3 abs_dir = inDirection.Abs();
    Vec3 abs_dir_yzz = abs_dir.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_Z>();
    Vec3 abs_dir_xyx = abs_dir.Swizzle<SWIZZLE_X, SWIZZLE_Y, SWIZZLE_X>();
 
    Vec3 extents_yzz = extents.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_Z>();
    Vec3 extents_xyx = extents.Swizzle<SWIZZLE_X, SWIZZLE_Y, SWIZZLE_X>();
 
    Vec3 diff_yzx = diff.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>();
 
    Vec3 dir_yzx = inDirection.Swizzle<SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X>();
 
    no_intersection = UVec4::sOr(no_intersection, Vec3::sGreater((inDirection * diff_yzx - dir_yzx * diff).Abs(), extents_xyx * abs_dir_yzz + extents_yzz * abs_dir_xyx));
 
    return !no_intersection.TestAnyXYZTrue();
}
 
JPH_NAMESPACE_END