92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
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// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
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// SPDX-License-Identifier: MIT
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#pragma once
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#include <Jolt/Math/Vec8.h>
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JPH_NAMESPACE_BEGIN
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/// Intersect ray with 8 triangles in SOA format, returns 8 vector of closest points or FLT_MAX if no hit
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JPH_INLINE Vec8 RayTriangle8(Vec3Arg inOrigin, Vec3Arg inDirection, Vec8Arg inV0X, Vec8Arg inV0Y, Vec8Arg inV0Z, Vec8Arg inV1X, Vec8Arg inV1Y, Vec8Arg inV1Z, Vec8Arg inV2X, Vec8Arg inV2Y, Vec8Arg inV2Z)
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{
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// Epsilon
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Vec8 epsilon = Vec8::sReplicate(1.0e-12f);
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// Zero & one
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Vec8 zero = Vec8::sZero();
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Vec8 one = Vec8::sReplicate(1.0f);
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// Find vectors for two edges sharing inV0
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Vec8 e1x = inV1X - inV0X;
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Vec8 e1y = inV1Y - inV0Y;
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Vec8 e1z = inV1Z - inV0Z;
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Vec8 e2x = inV2X - inV0X;
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Vec8 e2y = inV2Y - inV0Y;
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Vec8 e2z = inV2Z - inV0Z;
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// Get direction vector components
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Vec8 dx = Vec8::sSplatX(Vec4(inDirection));
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Vec8 dy = Vec8::sSplatY(Vec4(inDirection));
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Vec8 dz = Vec8::sSplatZ(Vec4(inDirection));
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// Begin calculating determinant - also used to calculate u parameter
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Vec8 px = dy * e2z - dz * e2y;
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Vec8 py = dz * e2x - dx * e2z;
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Vec8 pz = dx * e2y - dy * e2x;
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// if determinant is near zero, ray lies in plane of triangle
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Vec8 det = e1x * px + e1y * py + e1z * pz;
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// Check which determinants are near zero
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UVec8 det_near_zero = Vec8::sLess(det.Abs(), epsilon);
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// Set components of the determinant to 1 that are near zero to avoid dividing by zero
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det = Vec8::sSelect(det, Vec8::sReplicate(1.0f), det_near_zero);
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// Calculate distance from inV0 to ray origin
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Vec8 sx = Vec8::sSplatX(Vec4(inOrigin)) - inV0X;
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Vec8 sy = Vec8::sSplatY(Vec4(inOrigin)) - inV0Y;
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Vec8 sz = Vec8::sSplatZ(Vec4(inOrigin)) - inV0Z;
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// Calculate u parameter and flip sign if determinant was negative
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Vec8 u = (sx * px + sy * py + sz * pz) / det;
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// Prepare to test v parameter
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Vec8 qx = sy * e1z - sz * e1y;
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Vec8 qy = sz * e1x - sx * e1z;
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Vec8 qz = sx * e1y - sy * e1x;
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// Calculate v parameter and flip sign if determinant was negative
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Vec8 v = (dx * qx + dy * qy + dz * qz) / det;
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// Get intersection point and flip sign if determinant was negative
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Vec8 t = (e2x * qx + e2y * qy + e2z * qz) / det;
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// Check if there is an intersection
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UVec8 no_intersection =
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UVec8::sOr
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(
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UVec8::sOr
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(
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UVec8::sOr
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(
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det_near_zero,
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Vec8::sLess(u, zero)
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),
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UVec8::sOr
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(
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Vec8::sLess(v, zero),
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Vec8::sGreater(u + v, one)
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)
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),
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Vec8::sLess(t, zero)
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);
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// Select intersection point or FLT_MAX based on if there is an intersection or not
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return Vec8::sSelect(t, Vec8::sReplicate(FLT_MAX), no_intersection);
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}
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JPH_NAMESPACE_END
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