VoxelEngine/src/physics/PhysicsSolver.cpp
2024-08-06 18:41:35 +03:00

296 lines
9.5 KiB
C++

#include "PhysicsSolver.hpp"
#include "Hitbox.hpp"
#include <maths/aabb.hpp>
#include <voxels/Block.hpp>
#include <voxels/Chunks.hpp>
#include <voxels/voxel.hpp>
#include <iostream>
#include <algorithm>
#define GLM_ENABLE_EXPERIMENTAL
#include <glm/gtx/norm.hpp>
const float E = 0.03f;
const float MAX_FIX = 0.1f;
PhysicsSolver::PhysicsSolver(glm::vec3 gravity) : gravity(gravity) {
}
void PhysicsSolver::step(
Chunks* chunks,
Hitbox* hitbox,
float delta,
uint substeps,
entityid_t entity
) {
float dt = delta / static_cast<float>(substeps);
float linearDamping = hitbox->linearDamping;
float s = 2.0f/BLOCK_AABB_GRID;
const glm::vec3& half = hitbox->halfsize;
glm::vec3& pos = hitbox->position;
glm::vec3& vel = hitbox->velocity;
float gravityScale = hitbox->gravityScale;
bool prevGrounded = hitbox->grounded;
hitbox->grounded = false;
for (uint i = 0; i < substeps; i++) {
float px = pos.x;
float py = pos.y;
float pz = pos.z;
vel += gravity * dt * gravityScale;
if (hitbox->type == BodyType::DYNAMIC) {
colisionCalc(chunks, hitbox, vel, pos, half,
(prevGrounded && gravityScale > 0.0f) ? 0.5f : 0.0f);
}
vel.x *= glm::max(0.0f, 1.0f - dt * linearDamping);
if (hitbox->verticalDamping) {
vel.y *= glm::max(0.0f, 1.0f - dt * linearDamping);
}
vel.z *= glm::max(0.0f, 1.0f - dt * linearDamping);
pos += vel * dt + gravity * gravityScale * dt * dt * 0.5f;
if (hitbox->grounded && pos.y < py) {
pos.y = py;
}
if (hitbox->crouching && hitbox->grounded){
float y = (pos.y-half.y-E);
hitbox->grounded = false;
for (int ix = 0; ix <= (half.x-E)*2/s; ix++) {
float x = (px-half.x+E) + ix * s;
for (int iz = 0; iz <= (half.z-E)*2/s; iz++){
float z = (pos.z-half.z+E) + iz * s;
if (chunks->isObstacleAt(x,y,z)){
hitbox->grounded = true;
break;
}
}
}
if (!hitbox->grounded) {
pos.z = pz;
}
hitbox->grounded = false;
for (int ix = 0; ix <= (half.x-E)*2/s; ix++) {
float x = (pos.x-half.x+E) + ix * s;
for (int iz = 0; iz <= (half.z-E)*2/s; iz++){
float z = (pz-half.z+E) + iz * s;
if (chunks->isObstacleAt(x,y,z)){
hitbox->grounded = true;
break;
}
}
}
if (!hitbox->grounded) {
pos.x = px;
}
hitbox->grounded = true;
}
}
AABB aabb;
aabb.a = hitbox->position - hitbox->halfsize;
aabb.b = hitbox->position + hitbox->halfsize;
for (size_t i = 0; i < sensors.size(); i++) {
auto& sensor = *sensors[i];
if (sensor.entity == entity) {
continue;
}
bool triggered = false;
switch (sensor.type) {
case SensorType::AABB:
triggered = aabb.intersect(sensor.calculated.aabb);
break;
case SensorType::RADIUS:
triggered = glm::distance2(
hitbox->position, glm::vec3(sensor.calculated.radial))
< sensor.calculated.radial.w;
break;
}
if (triggered) {
if (sensor.prevEntered.find(entity) == sensor.prevEntered.end()) {
sensor.enterCallback(sensor.entity, sensor.index, entity);
}
sensor.nextEntered.insert(entity);
}
}
}
static float calc_step_height(
Chunks* chunks,
glm::vec3& pos,
const glm::vec3& half,
float stepHeight,
float s
) {
if (stepHeight > 0.0f) {
for (int ix = 0; ix <= (half.x-E)*2/s; ix++) {
float x = (pos.x-half.x+E) + ix * s;
for (int iz = 0; iz <= (half.z-E)*2/s; iz++) {
float z = (pos.z-half.z+E) + iz * s;
if (chunks->isObstacleAt(x, pos.y+half.y+stepHeight, z)) {
return 0.0f;
}
}
}
}
return stepHeight;
}
template <int nx, int ny, int nz>
static bool calc_collision_neg(
Chunks* chunks,
glm::vec3& pos,
glm::vec3& vel,
const glm::vec3& half,
float stepHeight,
float s
) {
if (vel[nx] >= 0.0f) {
return false;
}
glm::vec3 offset(0.0f, stepHeight, 0.0f);
for (int iy = 0; iy <= (half[ny]-E)*2/s; iy++) {
glm::vec3 coord;
coord[ny] = ((pos+offset)[ny]-half[ny]+E) + iy * s;
for (int iz = 0; iz <= (half[nz]-E)*2/s; iz++){
coord[nz] = (pos[nz]-half[nz]+E) + iz * s;
coord[nx] = (pos[nx]-half[nx]-E);
if (const auto aabb = chunks->isObstacleAt(coord.x, coord.y, coord.z)) {
vel[nx] = 0.0f;
float newx = std::floor(coord[nx]) + aabb->max()[nx] + half[nx] + E;
if (std::abs(newx-pos[nx]) <= MAX_FIX) {
pos[nx] = newx;
}
return true;
}
}
}
return false;
}
template <int nx, int ny, int nz>
static void calc_collision_pos(
Chunks* chunks,
glm::vec3& pos,
glm::vec3& vel,
const glm::vec3& half,
float stepHeight,
float s
) {
if (vel[nx] <= 0.0f) {
return;
}
glm::vec3 offset(0.0f, stepHeight, 0.0f);
for (int iy = 0; iy <= (half[ny]-E)*2/s; iy++) {
glm::vec3 coord;
coord[ny] = ((pos+offset)[ny]-half[ny]+E) + iy * s;
for (int iz = 0; iz <= (half[nz]-E)*2/s; iz++) {
coord[nz] = (pos[nz]-half[nz]+E) + iz * s;
coord[nx] = (pos[nx]+half[nx]+E);
if (const auto aabb = chunks->isObstacleAt(coord.x, coord.y, coord.z)) {
vel[nx] = 0.0f;
float newx = std::floor(coord[nx]) - half[nx] + aabb->min()[nx] - E;
if (std::abs(newx-pos[nx]) <= MAX_FIX) {
pos[nx] = newx;
}
return;
}
}
}
}
void PhysicsSolver::colisionCalc(
Chunks* chunks,
Hitbox* hitbox,
glm::vec3& vel,
glm::vec3& pos,
const glm::vec3 half,
float stepHeight
) {
// step size (smaller - more accurate, but slower)
float s = 2.0f/BLOCK_AABB_GRID;
stepHeight = calc_step_height(chunks, pos, half, stepHeight, s);
const AABB* aabb;
calc_collision_neg<0, 1, 2>(chunks, pos, vel, half, stepHeight, s);
calc_collision_pos<0, 1, 2>(chunks, pos, vel, half, stepHeight, s);
calc_collision_neg<2, 1, 0>(chunks, pos, vel, half, stepHeight, s);
calc_collision_pos<2, 1, 0>(chunks, pos, vel, half, stepHeight, s);
if (calc_collision_neg<1, 0, 2>(chunks, pos, vel, half, stepHeight, s)) {
hitbox->grounded = true;
}
if (stepHeight > 0.0 && vel.y <= 0.0f){
for (int ix = 0; ix <= (half.x-E)*2/s; ix++) {
float x = (pos.x-half.x+E) + ix * s;
for (int iz = 0; iz <= (half.z-E)*2/s; iz++) {
float z = (pos.z-half.z+E) + iz * s;
float y = (pos.y-half.y+E);
if ((aabb = chunks->isObstacleAt(x,y,z))){
vel.y = 0.0f;
float newy = std::floor(y) + aabb->max().y + half.y;
if (std::abs(newy-pos.y) <= MAX_FIX+stepHeight) {
pos.y = newy;
}
break;
}
}
}
}
if (vel.y > 0.0f){
for (int ix = 0; ix <= (half.x-E)*2/s; ix++) {
float x = (pos.x-half.x+E) + ix * s;
for (int iz = 0; iz <= (half.z-E)*2/s; iz++) {
float z = (pos.z-half.z+E) + iz * s;
float y = (pos.y+half.y+E);
if ((aabb = chunks->isObstacleAt(x,y,z))){
vel.y = 0.0f;
float newy = std::floor(y) - half.y + aabb->min().y - E;
if (std::abs(newy-pos.y) <= MAX_FIX) {
pos.y = newy;
}
break;
}
}
}
}
}
bool PhysicsSolver::isBlockInside(int x, int y, int z, Hitbox* hitbox) {
const glm::vec3& pos = hitbox->position;
const glm::vec3& half = hitbox->halfsize;
return x >= floor(pos.x-half.x) && x <= floor(pos.x+half.x) &&
z >= floor(pos.z-half.z) && z <= floor(pos.z+half.z) &&
y >= floor(pos.y-half.y) && y <= floor(pos.y+half.y);
}
bool PhysicsSolver::isBlockInside(int x, int y, int z, Block* def, blockstate state, Hitbox* hitbox) {
const float E = 0.001f; // inaccuracy
const glm::vec3& pos = hitbox->position;
const glm::vec3& half = hitbox->halfsize;
const auto& boxes = def->rotatable
? def->rt.hitboxes[state.rotation]
: def->hitboxes;
for (const auto& block_hitbox : boxes) {
glm::vec3 min = block_hitbox.min();
glm::vec3 max = block_hitbox.max();
if (min.x < pos.x+half.x-x-E && max.x > pos.x-half.x-x+E &&
min.z < pos.z+half.z-z-E && max.z > pos.z-half.z-z+E &&
min.y < pos.y+half.y-y-E && max.y > pos.y-half.y-y+E)
return true;
}
return false;
}
void PhysicsSolver::removeSensor(Sensor* sensor) {
sensors.erase(std::remove(sensors.begin(), sensors.end(), sensor), sensors.end());
}