56 lines
1.7 KiB
C++
56 lines
1.7 KiB
C++
#include "Utility/RayTriangle.h"
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#include <bit>
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// OFFSET: 0x00554060
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// FUNCTION: fn_02020
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bool IntersectRayTriangle(
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const float* ray,
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const float* first,
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const float* second,
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const float* third,
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float& u,
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float& v,
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float& distance
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) {
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const float edgeX = second[0] - first[0];
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const float edgeY = second[1] - first[1];
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const float edgeZ = second[2] - first[2];
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const float otherY = third[1] - first[1];
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const float otherZ = third[2] - first[2];
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const float otherX = third[0] - first[0];
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const float crossX = otherZ * ray[4] - otherY * ray[5];
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const float crossY = otherX * ray[5] - otherZ * ray[3];
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const float crossZ = otherY * ray[3] - otherX * ray[4];
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const float determinant = (crossY * edgeY + crossX * edgeX) + crossZ * edgeZ;
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constexpr float epsilon = 0.00001f;
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constexpr float negativeEpsilon = -0.00001f;
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if (determinant > negativeEpsilon && epsilon > determinant) {
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return false;
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}
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const float x = ray[0] - first[0];
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const float y = ray[1] - first[1];
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const float z = ray[2] - first[2];
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const float inverse = 1.0f / determinant;
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const float firstCoordinate = ((y * crossY + x * crossX) + z * crossZ) * inverse;
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u = firstCoordinate;
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if (firstCoordinate < 0.0f || firstCoordinate > 1.0f) {
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return false;
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}
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const float qX = edgeZ * y - edgeY * z;
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const float qY = edgeX * z - x * edgeZ;
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const float qZ = x * edgeY - edgeX * y;
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const float secondCoordinate = ((qY * ray[4] + qX * ray[3]) + qZ * ray[5]) * inverse;
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v = secondCoordinate;
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if (secondCoordinate < 0.0f || secondCoordinate + u > 1.0f) {
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return false;
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}
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distance = ((qY * otherY + qX * otherX) + qZ * otherZ) * inverse;
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return true;
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}
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