/* * Created by Brett Terpstra 6920201 on 17/10/22. * Copyright (c) 2022 Brett Terpstra. All Rights Reserved. */ #ifndef STEP_2_COLLIDERS_H #define STEP_2_COLLIDERS_H #include "vectors.h" namespace Raytracing { // 3D Axis Aligned Bounding Box for use in a BVH struct AABBHitData { bool hit; PRECISION_TYPE tMin, tMax; }; enum AABBAxis { X = 0, Y = 1, Z = 2 }; /** * Simple minimal Axis Aligned Bounding Box implementation. Based on my C++ Game Engine's AABB which is based on my Java Game Engine's AABB * which is based on my Minecraft Clone v2's AABB which is based on a decompiled AABB class from Minecraft Beta 1.7.3 */ class AABB { protected: Vec4 min; Vec4 max; public: /** * Creates an empty AABB. Not useful for anything. */ AABB(): min({0, 0, 0}), max({0, 0, 0}) {}; /** * Creates an AABB using the provided min/max coords */ AABB(PRECISION_TYPE minX, PRECISION_TYPE minY, PRECISION_TYPE minZ, PRECISION_TYPE maxX, PRECISION_TYPE maxY, PRECISION_TYPE maxZ): min{minX, minY, minZ}, max{maxX, maxY, maxZ} { } /** * Creates an AABB using the provided min/max vector coords */ AABB(const Vec4& min, const Vec4& max): min(min), max(max) {} /** * creates an AABB extending of size centered on x, y, z * @param size radius of the AABB */ AABB(PRECISION_TYPE x, PRECISION_TYPE y, PRECISION_TYPE z, PRECISION_TYPE size): min{x - size, y - size, z - size}, max{x + size, y + size, z + size} { } /** * translates the AABB to position x,y,z for world collision detection * This creates a copy AABB. * @return a copy of this AABB translated by Vec4{x,y,z} */ [[nodiscard]] AABB translate(PRECISION_TYPE x, PRECISION_TYPE y, PRECISION_TYPE z) const { Vec4 pos = {x, y, z}; return {min + pos, max + pos}; } /** * Translates this AABB using a vector instead of individual coords * @return a copy of this AABB translated by vec */ [[nodiscard]] AABB translate(const Vec4& vec) const { Vec4 pos = {vec.x(), vec.y(), vec.z()}; return {min + pos, max + pos}; } /** * returns an expanded version of this AABB is the other AABB is larger then this AABB * @param other other AABB to expand against * @return a AABB which includes this AABB and the other AABB. If this AABB is empty it will return other. */ [[nodiscard]] AABB expand(const AABB& other) const { // terrible hack // a 0 init AABB was having issues when being "expanded" to a place which is larger // this should prevent that by side stepping the issue. Which is a TODO: if (isEmpty()) return other; PRECISION_TYPE minX = std::min(min.x(), other.min.x()); PRECISION_TYPE minY = std::min(min.y(), other.min.y()); PRECISION_TYPE minZ = std::min(min.z(), other.min.z()); PRECISION_TYPE maxX = std::max(max.x(), other.max.x()); PRECISION_TYPE maxY = std::max(max.y(), other.max.y()); PRECISION_TYPE maxZ = std::max(max.z(), other.max.z()); return {minX, minY, minZ, maxX, maxY, maxZ}; } /** * Checks if this AABB interests with the AABB described in individual coordinates * @return true if intersection occurs */ [[nodiscard]] inline bool intersects( PRECISION_TYPE minX, PRECISION_TYPE minY, PRECISION_TYPE minZ, PRECISION_TYPE maxX, PRECISION_TYPE maxY, PRECISION_TYPE maxZ ) const { return min.x() <= maxX && max.x() >= minX && min.y() <= maxY && max.y() >= minY && min.z() <= maxZ && max.z() >= minZ; } /** * Checks if this AABB interests with the AABB described in vector coordinates * @return true if intersection occurs */ [[nodiscard]] inline bool intersects(const Vec4& minV, const Vec4& maxV) const { return intersects(minV.x(), minV.y(), minV.z(), maxV.x(), maxV.y(), maxV.z()); } /** * Checks if this AABB intersects with the other AABB * @return true if intersection */ [[nodiscard]] inline bool intersects(const AABB& other) const { return intersects(other.min, other.max); } /** * Checks if the provided ray intersects with this AABB between tmin and tmax using an implementation defined method. * @return true if intersected */ AABBHitData intersects(const Ray& ray, PRECISION_TYPE tmin, PRECISION_TYPE tmax); /** * Slap method of checking for intersection, see the comment in the cpp file. DO NOT USE OUTSIDE THIS CLASS. */ AABBHitData simpleSlabRayAABBMethod(const Ray& ray, PRECISION_TYPE tmin, PRECISION_TYPE tmax); /** * Creates a transform matrix using information contained within the AABB, done to prevent repeating code. * @return a transform (model) matrix for this AABB. */ [[nodiscard]] Mat4x4 getTransform() const; /** * @return the exact center of the AABB */ [[nodiscard]] inline Vec4 getCenter() const { return {min.x() + (max.x() - min.x()) * 0.5, min.y() + (max.y() - min.y()) * 0.5, min.z() + (max.z() - min.z()) * 0.5}; } /** * @return the longest axis distance from the center point of the AABB */ [[nodiscard]] PRECISION_TYPE longestDistanceFromCenter() const; /** * 0 - x * 1 - y * 2 - z */ [[nodiscard]] int longestAxis() const; /** * @return the complete length from min to max of the longest axis */ [[nodiscard]] PRECISION_TYPE longestAxisLength() const; /** * @return a pair of AABB which are subsets of this AABB split by the longest axis of this AABB */ [[nodiscard]] std::pair splitByLongestAxis(); /** * @param axis axis to split on * @return a pair of AABB which are subsets of this AABB split along the axis provided */ [[nodiscard]] std::pair splitAlongAxis(AABBAxis axis); /** * Splits the AABB by a rotating axis. Not recommended to use. Not thread safe across ALL AABB objects. */ [[nodiscard]] std::pair splitAlongAxis(); /** * @return average distance to the center of this object, subject to axis bias (really small or really big) */ [[nodiscard]] PRECISION_TYPE avgDistanceFromCenter() const; /** * Returns true if the min and max are equal, which tells us this AABB wasn't assigned * or was properly created. Either way it isn't responsible to use the AABB in said case. */ [[nodiscard]] inline bool isEmpty() const { return min == max; } [[nodiscard]] Vec4 getMin() const { return min; } [[nodiscard]] Vec4 getMax() const { return max; } [[nodiscard]] inline PRECISION_TYPE getXRadius(const Vec4& center) const { return max.x() - center.x(); } [[nodiscard]] inline PRECISION_TYPE getYRadius(const Vec4& center) const { return max.y() - center.y(); } [[nodiscard]] inline PRECISION_TYPE getZRadius(const Vec4& center) const { return max.z() - center.z(); } /* * Minecraft code below this */ [[nodiscard]] inline bool isInside(PRECISION_TYPE x, PRECISION_TYPE y, PRECISION_TYPE z) const { return x >= min.x() && x <= max.x() && y >= min.y() && y <= max.y() && z >= min.z() && z <= max.z(); } [[nodiscard]] inline bool intersectsWithYZ(PRECISION_TYPE y, PRECISION_TYPE z) const { return y >= min.y() && y <= max.y() && z >= min.z() && z <= max.z(); } [[nodiscard]] inline bool intersectsWithXZ(PRECISION_TYPE x, PRECISION_TYPE z) const { return x >= min.x() && x <= max.x() && z >= min.z() && z <= max.z(); } [[nodiscard]] inline bool intersectsWithXY(PRECISION_TYPE x, PRECISION_TYPE y) const { return x >= min.x() && x <= max.x() && y >= min.y() && y <= max.y(); } }; inline bool operator==(const AABB& a, const AABB& b) { const auto& aMax = a.getMax(); const auto& aMin = a.getMin(); const auto& bMax = b.getMax(); const auto& bMin = b.getMin(); return aMax == bMax && aMin == bMin; } inline std::ostream& operator<<(std::ostream& out, const AABB& v) { auto max = v.getMax(); auto min = v.getMin(); auto center = v.getCenter(); return out << "AABB {\n\t min{" << min.x() << ", " << min.y() << ", " << min.z() << "},\n\t max{" << max.x() << ", " << max.y() << ", " << max.z() << "},\n\t diff{" << max.x() - min.x() << ", " << max.y() - min.y() << ", " << max.z() - min.z() << "},\n\t " << "center{" << center.x() << ", " << center.y() << ", " << center.z() << "},\n\t " << "radi{" << v.getXRadius(center) << ", " << v.getYRadius(center) << ", " << v.getZRadius(center) << "}\n};\n"; } } #endif //STEP_2_COLLIDERS_H