diff options
Diffstat (limited to 'src/game/shared/collision.cc')
| -rw-r--r-- | src/game/shared/collision.cc | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/src/game/shared/collision.cc b/src/game/shared/collision.cc new file mode 100644 index 0000000..dd51dd5 --- /dev/null +++ b/src/game/shared/collision.cc @@ -0,0 +1,169 @@ +#include "shared/pch.hh" + +#include "shared/collision.hh" + +#include "core/constexpr.hh" + +#include "shared/coord.hh" +#include "shared/dimension.hh" +#include "shared/globals.hh" +#include "shared/gravity.hh" +#include "shared/grounded.hh" +#include "shared/transform.hh" +#include "shared/velocity.hh" +#include "shared/voxel_registry.hh" + +static int vgrid_collide(const Dimension* dimension, int d, CollisionComponent& collision, TransformComponent& transform, + VelocityComponent& velocity, voxel_surface& touch_surface) +{ + const auto move = globals::fixed_frametime * velocity.value[d]; + const auto move_sign = vx::sign<int>(move); + + const auto& ref_aabb = collision.aabb; + const auto current_aabb = ref_aabb.push(transform.local); + + auto next_aabb = AABB(current_aabb); + next_aabb.min[d] += move; + next_aabb.max[d] += move; + + local_pos lpos_min; + lpos_min.x = vx::floor<local_pos::value_type>(next_aabb.min.x); + lpos_min.y = vx::floor<local_pos::value_type>(next_aabb.min.y); + lpos_min.z = vx::floor<local_pos::value_type>(next_aabb.min.z); + + local_pos lpos_max; + lpos_max.x = vx::ceil<local_pos::value_type>(next_aabb.max.x); + lpos_max.y = vx::ceil<local_pos::value_type>(next_aabb.max.y); + lpos_max.z = vx::ceil<local_pos::value_type>(next_aabb.max.z); + + // Other axes + const int u = (d + 1) % 3; + const int v = (d + 2) % 3; + + local_pos::value_type ddir; + local_pos::value_type dmin; + local_pos::value_type dmax; + + if(move < 0.0f) { + ddir = local_pos::value_type(+1); + dmin = lpos_min[d]; + dmax = lpos_max[d]; + } else { + ddir = local_pos::value_type(-1); + dmin = lpos_max[d]; + dmax = lpos_min[d]; + } + + voxel_touch latch_touch = voxel_touch::NOTHING; + glm::fvec3 latch_values = glm::fvec3(0.0f, 0.0f, 0.0f); + voxel_surface latch_surface = voxel_surface::UNKNOWN; + AABB latch_vbox; + + for(auto i = dmin; i != dmax; i += ddir) { + for(auto j = lpos_min[u]; j < lpos_max[u]; ++j) + for(auto k = lpos_min[v]; k < lpos_max[v]; ++k) { + local_pos lpos; + lpos[d] = i; + lpos[u] = j; + lpos[v] = k; + + const auto vpos = coord::to_voxel(transform.chunk, lpos); + const auto info = voxel_registry::find(dimension->get_voxel(vpos)); + + if(info == nullptr) { + // Don't collide with something + // that we assume to be nothing + continue; + } + + AABB vbox; + vbox.min = glm::fvec3(lpos); + vbox.max = glm::fvec3(lpos) + 1.0f; + + if(!next_aabb.intersect(vbox)) { + // No intersection between the voxel + // and the entity's collision hull + continue; + } + + if(info->touch_type == voxel_touch::SOLID) { + // Solid touch type makes a collision + // response whenever it is encountered + velocity.value[d] = 0.0f; + touch_surface = info->surface; + return move_sign; + } + + // In case of other touch types, they + // are latched and the last ever touch + // type is then responded to + if(info->touch_type != voxel_touch::NOTHING) { + latch_touch = info->touch_type; + latch_values = info->touch_values; + latch_surface = info->surface; + latch_vbox = vbox; + continue; + } + } + } + + if(latch_touch != voxel_touch::NOTHING) { + if(latch_touch == voxel_touch::BOUNCE) { + const auto move_distance = vx::abs(current_aabb.min[d] - next_aabb.min[d]); + const auto threshold = 2.0f * globals::fixed_frametime; + + if(move_distance > threshold) { + velocity.value[d] *= -latch_values[d]; + } else { + velocity.value[d] = 0.0f; + } + + touch_surface = latch_surface; + + return move_sign; + } + + if(latch_touch == voxel_touch::SINK) { + velocity.value[d] *= latch_values[d]; + touch_surface = latch_surface; + return move_sign; + } + } + + return 0; +} + +void CollisionComponent::fixed_update(Dimension* dimension) +{ + // FIXME: this isn't particularly accurate considering + // some voxels might be passable and some other voxels + // might apply some slowing factor; what I might do in the + // future is to add a specific value to the voxel registry + // entries that would specify the amount of force we apply + // to prevent player movement inside a specific voxel, plus + // we shouldn't treat all voxels as full cubes if we want + // to support slabs, stairs and non-full liquid voxels in the future + + auto group = dimension->entities.group<CollisionComponent>(entt::get<TransformComponent, VelocityComponent>); + + for(auto [entity, collision, transform, velocity] : group.each()) { + auto surface = voxel_surface::UNKNOWN; + auto vertical_move = vgrid_collide(dimension, 1, collision, transform, velocity, surface); + + if(dimension->entities.any_of<GravityComponent>(entity)) { + if(vertical_move == vx::sign<int>(dimension->get_gravity())) { + dimension->entities.emplace_or_replace<GroundedComponent>(entity, GroundedComponent { surface }); + } else { + dimension->entities.remove<GroundedComponent>(entity); + } + } else { + // The entity cannot be grounded because the component + // setup of said entity should not let it comprehend the + // concept of resting on the ground (it flies around) + dimension->entities.remove<GroundedComponent>(entity); + } + + vgrid_collide(dimension, 0, collision, transform, velocity, surface); + vgrid_collide(dimension, 2, collision, transform, velocity, surface); + } +} |