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fix aabb transforms

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bailehuni 2024-07-29 23:51:58 +01:00
parent 9efc001e26
commit d5389caea0
1 changed files with 34 additions and 14 deletions
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48
src/system_collisions.cpp
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@ -11,6 +11,35 @@
namespace engine {
static AABB transformBox(const AABB& box, const glm::mat4& matrix)
{
const std::array<glm::vec3, 8> points{glm::vec3{box.min.x, box.min.y, box.min.z}, glm::vec3{box.min.x, box.min.y, box.max.z},
glm::vec3{box.min.x, box.max.y, box.min.z}, glm::vec3{box.min.x, box.max.y, box.max.z},
glm::vec3{box.max.x, box.min.y, box.min.z}, glm::vec3{box.max.x, box.min.y, box.max.z},
glm::vec3{box.max.x, box.max.y, box.min.z}, glm::vec3{box.max.x, box.max.y, box.max.z}};
AABB new_box{};
new_box.min.x = std::numeric_limits<float>::infinity();
new_box.min.y = new_box.min.x;
new_box.min.z = new_box.min.x;
new_box.max.x = -std::numeric_limits<float>::infinity();
new_box.max.y = new_box.max.x;
new_box.max.z = new_box.max.x;
// transform points of AABB to new positions and adjust min and max accordingly
for (glm::vec3 point : points) {
point = matrix * glm::vec4(point, 1.0f);
new_box.min.x = fminf(new_box.min.x, point.x);
new_box.min.y = fminf(new_box.min.y, point.y);
new_box.min.z = fminf(new_box.min.z, point.z);
new_box.max.x = fmaxf(new_box.max.x, point.x);
new_box.max.y = fmaxf(new_box.max.y, point.y);
new_box.max.z = fmaxf(new_box.max.z, point.z);
}
return new_box;
}
static glm::vec3 GetBoxCentroid(const AABB& box)
{
glm::vec3 v{};
@ -80,6 +109,8 @@ void CollisionSystem::onUpdate(float ts)
{
(void)ts;
// TODO: the bvh will not update if an equal number of colliders are removed and added.
// This is not a problem yet, as entitites cannot be removed from the scene.
if (colliders_size_last_update_ != colliders_size_now_) {
std::vector<PrimitiveInfo> prims{};
@ -88,20 +119,7 @@ void CollisionSystem::onUpdate(float ts)
const auto t = m_scene->GetComponent<TransformComponent>(entity);
const auto c = m_scene->GetComponent<ColliderComponent>(entity);
AABB transformed_box{};
transformed_box.min = t->world_matrix * glm::vec4(c->aabb.min, 1.0f);
transformed_box.max = t->world_matrix * glm::vec4(c->aabb.max, 1.0f);
// if a mesh is not rotated a multiple of 90 degrees, the box will not fit the mesh
// TODO fix it
// correct min and max
AABB box{};
box.min.x = fminf(transformed_box.min.x, transformed_box.max.x);
box.min.y = fminf(transformed_box.min.y, transformed_box.max.y);
box.min.z = fminf(transformed_box.min.z, transformed_box.max.z);
box.max.x = fmaxf(transformed_box.min.x, transformed_box.max.x);
box.max.y = fmaxf(transformed_box.min.y, transformed_box.max.y);
box.max.z = fmaxf(transformed_box.min.z, transformed_box.max.z);
const AABB box = transformBox(c->aabb, t->world_matrix);
prims.emplace_back(box, entity);
}
@ -110,6 +128,7 @@ void CollisionSystem::onUpdate(float ts)
bvh_.reserve(m_entities.size() * 3 / 2); // from testing, bvh is usually 20% larger than number of objects
BuildNode(prims, bvh_);
#ifndef NDEBUG
// check AABB mins and maxes are the correct order
for (const auto& node : bvh_) {
if (node.type1 != BiTreeNode::Type::Empty) {
@ -123,6 +142,7 @@ void CollisionSystem::onUpdate(float ts)
if (node.box2.max.z < node.box2.min.z) abort();
}
}
#endif
LOG_DEBUG("BUILT BVH!");