mirror of
https://github.com/MihailRis/voxelcore.git
synced 2026-10-04 18:41:51 +00:00
450 lines
15 KiB
C++
450 lines
15 KiB
C++
#include "PhysicsSolver.hpp"
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#include "Hitbox.hpp"
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#include "maths/aabb.hpp"
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#include "voxels/Block.hpp"
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#include "voxels/GlobalChunks.hpp"
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#include "voxels/voxel.hpp"
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#include "objects/Entities.hpp"
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#include "debug/Logger.hpp"
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#include <algorithm>
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#define GLM_ENABLE_EXPERIMENTAL
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#include <glm/gtx/norm.hpp>
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inline constexpr float E = 0.03f;
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inline constexpr float MAX_FIX = 0.1f;
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static debug::Logger logger("physics-solver");
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PhysicsSolver::PhysicsSolver(const GlobalChunks& chunks, glm::vec3 gravity)
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: chunks(chunks), gravity(std::move(gravity)) {
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}
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static glm::vec3 calc_collsion_velocity_result(
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const Hitbox& a, const Hitbox& b
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) {
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const auto& vA = a.velocity;
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const auto& vB = b.velocity;
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if (glm::isinf(a.mass)) {
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return vA;
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}
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if (glm::isinf(b.mass)) {
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return vB - a.elasticity * (vA - vB);
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}
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const auto& mA = a.mass;
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const auto& mB = b.mass;
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return (mA * vA + mB * vB + a.elasticity * mB * (vB - vA)) / (mA + mB);
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}
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static float calc_step_height(
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const GlobalChunks& chunks,
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const glm::vec3& pos,
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const glm::vec3& half,
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float stepHeight
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) {
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AABB aabb(-half, +half);
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aabb.scale(glm::vec3(1.0f - E * 2, 1.0f, 1.0f - E * 2));
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aabb = aabb + pos + glm::vec3(0.0f, stepHeight, 0.0f);
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if (stepHeight <= 0.0f) {
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return stepHeight;
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}
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for (int ix = 0; ix <= glm::ceil((half.x - E) * 2); ix++) {
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float x = (pos.x - half.x) + ix;
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for (int iz = 0; iz <= glm::ceil((half.z - E) * 2); iz++) {
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float z = (pos.z - half.z) + iz;
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if (chunks.isObstacleAt(x, pos.y + half.y + stepHeight, z, aabb)) {
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return 0.0f;
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}
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}
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}
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return stepHeight;
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}
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// todo: reduce code duplication
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template <int nx, int ny, int nz, int sign>
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static void calc_collision(
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Hitbox& hitbox,
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const GlobalChunks& chunks,
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const std::vector<Hitbox*>& solidHitboxes,
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const glm::vec3& half,
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float stepHeight
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) {
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auto& pos = hitbox.position;
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auto& vel = hitbox.velocity;
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glm::vec3 offset(0.0f, stepHeight + E, 0.0f);
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for (auto box : solidHitboxes) {
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if (glm::distance2(box->position, pos) < E) {
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continue;
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}
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auto boxhalf = box->getHalfSize();
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auto aabb = AABB(pos - half, pos + half);
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glm::vec3 scale(1.0f);
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scale[nz] = 1.0f - E * 8.0f;
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scale[ny] = 1.0f - E * 2.0f;
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aabb.scale(scale);
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aabb = aabb + offset;
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aabb.b.y -= stepHeight + E * 2;
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if ((box->position[nx] - pos[nx]) * sign <= 0.0f || !box->getAABB().intersects(aabb)) {
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continue;
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}
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float newnegx = box->position[nx] - boxhalf[nx] - half[nx];
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float newposx = box->position[nx] + boxhalf[nx] + half[nx];
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float newx;
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if ((glm::abs(newnegx - pos[nx]) - glm::abs(newposx - pos[nx]))*sign < 0.0f) {
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newx = sign > 0 ? newnegx : newposx;
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} else {
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continue;
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}
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if ((pos[nx] - newx) * sign > 0.0f && glm::abs(pos[nx] - newx) < MAX_FIX) {
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auto velA = calc_collsion_velocity_result(hitbox, *box);
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auto velB = calc_collsion_velocity_result(*box, hitbox);
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if ((vel[nx] - box->velocity[nx]) * sign > 0.0f) {
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vel[nx] = velA[nx];
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box->velocity[nx] = velB[nx];
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}
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pos[nx] = newx;
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}
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}
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if (vel[nx] * sign <= 0.0f && hitbox.groundVelocity[nx] * sign <= 0.0f) {
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return;
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}
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for (int iy = 0; iy <= glm::ceil(((half - offset * 0.5f)[ny] - E) * 2); iy++) {
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glm::vec3 coord;
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coord[ny] = ((pos + offset)[ny] - half[ny] + E) + iy;
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for (int iz = 0; iz <= glm::ceil((half[nz] - E) * 2); iz++) {
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coord[nz] = (pos[nz] - half[nz] + E) + iz;
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coord[nx] = pos[nx] + (half[nx] + E * 2) * sign;
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auto aabb = AABB(pos - half, pos + half);
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glm::vec3 scale(1.0f);
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scale[nz] = 1.0f - E * 8.0f;
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aabb.scale(scale);
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aabb = aabb + offset;
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aabb.b.y -= stepHeight + E * 2;
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if (const auto obstacle = chunks.isObstacleAt(coord.x, coord.y, coord.z, aabb)) {
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float newx = std::floor(coord[nx]) - half[nx] * sign +
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(sign > 0 ? obstacle->min() : obstacle->max())[nx];
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if ((pos[nx] - newx) * sign > 0.0f && glm::abs(pos[nx] - newx) < MAX_FIX) {
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vel[nx] = -hitbox.elasticity * vel[nx];
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pos[nx] = newx;
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}
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return;
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}
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}
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}
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}
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bool PhysicsSolver::calcCollisionNegY(
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Hitbox& hitbox, const glm::vec3& half, float dt
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) {
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auto& pos = hitbox.position;
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auto& vel = hitbox.velocity;
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for (auto box : solidHitboxes) {
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if (glm::distance2(box->position, pos) < E) {
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continue;
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}
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auto aabb = AABB(pos - half, pos + half);
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glm::vec3 scale(1.0f);
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scale.x = 1.0f - E * 4.0f;
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scale.z = 1.0f - E * 4.0f;
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aabb.scale(scale);
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auto boxhalf = box->getHalfSize();
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if (box->position.y < pos.y && box->getAABB().intersects(aabb)) {
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float newy = box->position.y + boxhalf.y + half.y;
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if (pos.y < newy && glm::abs(pos.y - newy) < boxhalf.y) {
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pos.y = newy;
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}
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auto velA = calc_collsion_velocity_result(hitbox, *box);
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auto velB = calc_collsion_velocity_result(*box, hitbox);
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hitbox.groundVelocity = (box->position - box->prevPosition) / dt;
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if (vel.y < hitbox.groundVelocity.y) {
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vel.y = velA.y;
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box->velocity.y = velB.y;
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if (hitbox.groundMaterial.empty() && !box->material.empty()) {
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hitbox.groundMaterial = box->material;
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}
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return true;
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}
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}
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}
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if (vel.y >= 0.0f) {
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return false;
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}
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hitbox.groundVelocity = {};
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for (int ix = 0; ix <= glm::ceil((half.x - E) * 2); ix++) {
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glm::vec3 coord;
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coord.x = (pos.x - half.x + E) + ix;
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for (int iz = 0; iz <= glm::ceil((half.z - E) * 2); iz++) {
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coord.z = (pos.z - half.z + E) + iz;
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coord.y = pos.y - half.y - E * 2;
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auto aabb = AABB(pos - half, pos + half);
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glm::vec3 scale(1.0f);
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scale.x = 1.0f - E * 4.0f;
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scale.z = 1.0f - E * 4.0f;
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aabb.scale(scale);
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if (const auto obstacle =
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chunks.isObstacleAt(coord.x, coord.y, coord.z, aabb)) {
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float newy = std::floor(coord.y) + half.y + obstacle->max().y;
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if (newy >= pos.y) {
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vel.y = -hitbox.elasticity * vel.y;
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pos.y = newy;
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}
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return true;
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}
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}
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}
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return false;
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}
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void PhysicsSolver::calcCollisions(
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Hitbox& hitbox,
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glm::vec3& vel,
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glm::vec3& pos,
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const glm::vec3& half,
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float stepHeight,
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float dt
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) {
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stepHeight = calc_step_height(chunks, pos, half, stepHeight);
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auto prevPos = pos;
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calc_collision<0, 1, 2, -1>(hitbox, chunks, solidHitboxes, half, stepHeight);
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calc_collision<0, 1, 2, 1>(hitbox, chunks, solidHitboxes, half, stepHeight);
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float xpos = pos.x;
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pos.x = prevPos.x;
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calc_collision<2, 1, 0, -1>(hitbox, chunks, solidHitboxes, half, stepHeight);
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calc_collision<2, 1, 0, 1>(hitbox, chunks, solidHitboxes, half, stepHeight);
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pos.x = xpos;
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if (calcCollisionNegY(hitbox, half, dt)) {
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hitbox.grounded = true;
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}
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if (vel.y > 0.0f){
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AABB boxAABB = AABB(-half, +half);
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boxAABB.scale(glm::vec3(1.0f - E * 4, 1.0f + E * 2, 1.0f - E * 4));
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boxAABB = boxAABB.translated(pos);
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for (int ix = 0; ix <= glm::ceil((half.x - E) * 2); ix++) {
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float x = (pos.x - half.x + E) + ix;
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for (int iz = 0; iz <= glm::ceil((half.z - E) * 2); iz++) {
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float z = (pos.z - half.z + E) + iz;
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float y = (pos.y + half.y + E) + 0.5f;
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if (auto aabb = chunks.isObstacleAt(x, y, z, boxAABB)) {
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float newy = std::floor(y) - half.y + aabb->min().y - E;
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if (pos.y >= newy) {
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vel.y = -hitbox.elasticity * vel.y;
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pos.y = newy;
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}
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break;
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}
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}
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}
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for (auto box : solidHitboxes) {
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if (glm::distance2(box->position, pos) < E) {
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continue;
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}
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auto boxhalf = box->getHalfSize();
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if (box->position.y > pos.y && box->getAABB().intersects(boxAABB)) {
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float newy = box->position.y - boxhalf.y - half.y;
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if (pos.y > newy && glm::abs(pos.y - newy) < 0.5f) {
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pos.y = newy;
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}
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auto velA = calc_collsion_velocity_result(hitbox, *box);
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auto velB = calc_collsion_velocity_result(*box, hitbox);
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if (vel.y > hitbox.groundVelocity.y) {
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vel.y = velA.y;
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box->velocity.y = velB.y;
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break;
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}
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}
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}
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}
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// step on
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if (stepHeight > 0.0 && vel.y <= 0.0f) {
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AABB boxAABB = AABB(pos - half, pos + half);
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boxAABB.scale(glm::vec3(1.0f - E * 2, 1.0f - E * 2, 1.0f - E * 2));
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for (int ix = 0; ix <= glm::ceil((half.x - E) * 2); ix++) {
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float x = (pos.x - half.x) + ix;
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for (int iz = 0; iz <= glm::ceil((half.z - E) * 2); iz++) {
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float z = (pos.z - half.z) + iz;
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float y = (pos.y - half.y + E) + E;
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if (auto aabb = chunks.isObstacleAt(x, y, z, boxAABB)) {
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if (vel.y < 0.0f) {
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vel.y = 0.0f;
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}
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float newy = std::floor(y) + aabb->max().y + half.y;
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if (std::abs(newy - pos.y) <= stepHeight) {
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pos.y = newy;
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}
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break;
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}
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}
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}
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for (auto box : solidHitboxes) {
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if (glm::distance2(box->position, pos) < E) {
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continue;
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}
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auto boxhalf = box->getHalfSize();
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if (box->getAABB().intersects(boxAABB)) {
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vel.y = 0.0f;
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float newy = box->position.y + boxhalf.y + half.y;
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if (std::abs(newy - pos.y) <= stepHeight + E * 4) {
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pos.y = newy;
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}
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}
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}
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}
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}
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void PhysicsSolver::calcSubstep(
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Hitbox& hitbox, glm::vec3& vel, glm::vec3& pos, float dt
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) {
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auto initpos = pos;
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auto half = hitbox.getHalfSize();
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float gravityScale = hitbox.gravityScale;
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if (hitbox.type == BodyType::DYNAMIC) {
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calcCollisions(
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hitbox,
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vel,
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pos,
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half,
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(hitbox.prevGrounded && gravityScale > 0.0f) ? hitbox.stepHeight
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: 0.0f,
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dt
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);
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}
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vel += gravity * dt * gravityScale;
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pos += vel * dt + gravity * gravityScale * dt * dt * 0.5f;
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// crouching
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if (!hitbox.crouching || !hitbox.grounded) {
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return;
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}
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float y = (pos.y - half.y - E);
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for (int axis = 0; axis <= 2; axis += 2) {
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hitbox.grounded = false;
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auto checkPos = pos;
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checkPos.x = axis != 0 ? initpos.x : pos.x;
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checkPos.z = axis == 0 ? initpos.z : pos.z;
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AABB boxAABB(checkPos - half, checkPos + half);
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boxAABB.scale(glm::vec3(1.0f - E * 4, 1.5f, 1.0f - E * 4));
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for (int ix = 0; ix <= glm::ceil((half.x - E) * 2); ix++) {
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float x = (pos.x - half.x + E) + ix;
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for (int iz = 0; iz <= glm::ceil((half.z - E) * 2); iz++){
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float z = (pos.z - half.z + E) + iz;
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if (chunks.isObstacleAt(x, y, z, boxAABB)){
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hitbox.grounded = true;
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break;
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}
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}
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}
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for (auto box : solidHitboxes) {
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if (glm::distance2(box->position, pos) < E) {
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continue;
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}
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if (box->position.y < pos.y && box->getAABB().intersects(boxAABB)) {
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hitbox.grounded = true;
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break;
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}
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}
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if (!hitbox.grounded) {
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pos[axis] = initpos[axis];
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vel[axis] = 0.0f;
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}
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}
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hitbox.grounded = true;
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}
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void PhysicsSolver::step(
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const GlobalChunks& chunks, float delta, uint substeps
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) {
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for (auto hitbox : hitboxes) {
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hitbox->groundMaterial.clear();
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hitbox->prevGrounded = hitbox->grounded;
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hitbox->grounded = false;
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hitbox->prevVelocity = hitbox->velocity;
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}
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float dt = delta / static_cast<float>(substeps);
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for (uint i = 0; i < substeps; i++) {
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for (auto hitbox : hitboxes) {
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glm::vec3& pos = hitbox->position;
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hitbox->prevPosition = hitbox->position;
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calcSubstep(*hitbox, hitbox->velocity, pos, dt);
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}
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}
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for (auto hitbox : hitboxes) {
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float linearDamping = hitbox->linearDamping;
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glm::vec3& vel = hitbox->velocity;
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auto diff = hitbox->groundVelocity - vel;
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vel.x += diff.x * delta * linearDamping;
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vel.z += diff.z * delta * linearDamping;
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if (hitbox->verticalDamping > 0.0f) {
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vel.y /= 1.0f + delta * linearDamping * hitbox->verticalDamping;
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}
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if (!hitbox->grounded) {
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hitbox->groundVelocity = {};
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}
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updateSensors(*hitbox);
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}
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}
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void PhysicsSolver::updateSensors(Hitbox& hitbox) {
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auto aabb = hitbox.getAABB();
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for (size_t i = 0; i < sensors.size(); i++) {
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auto& sensor = *sensors[i];
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if (sensor.entity == hitbox.entity) {
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continue;
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}
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bool triggered = false;
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switch (sensor.type) {
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case SensorType::AABB:
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triggered = aabb.intersects(sensor.calculated.aabb);
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break;
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case SensorType::RADIUS:
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triggered = glm::distance2(
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hitbox.position, glm::vec3(sensor.calculated.radial))
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< sensor.calculated.radial.w;
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break;
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}
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if (!triggered) {
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continue;
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}
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if (sensor.prevEntered.find(hitbox.entity) == sensor.prevEntered.end()) {
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sensor.enterCallback(sensor.entity, sensor.index, hitbox.entity);
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}
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sensor.nextEntered.insert(hitbox.entity);
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}
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}
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void PhysicsSolver::removeSensor(Sensor* sensor) {
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sensors.erase(
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std::remove(sensors.begin(), sensors.end(), sensor), sensors.end()
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);
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}
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