Files
axyz/src/Engine/Collision/Collision.cpp
T
2015-12-18 14:19:28 +01:00

283 lines
10 KiB
C++

#include <algorithm>
#include "Collision/Collision.h"
#include "Engine/GLM.h"
#include "Core/World.h"
#include "Rendering/Model.h"
namespace Collision
{
//note: this one hasnt been delta adjusted like RayVsAABB has
bool RayAABBIntr(const Ray& ray, const AABB& box)
{
glm::vec3 w = 75.0f * ray.Direction();
glm::vec3 v = glm::abs(w);
glm::vec3 c = ray.Origin() - box.Center() + w;
glm::vec3 half = box.HalfSize();
if (abs(c.x) > v.x + half.x) {
return false;
}
if (abs(c.y) > v.y + half.y) {
return false;
}
if (abs(c.z) > v.z + half.z) {
return false;
}
if (abs(c.y*w.z - c.z*w.y) > half.y*v.z + half.z*v.y) {
return false;
}
if (abs(c.x*w.z - c.z*w.x) > half.x*v.z + half.z*v.x) {
return false;
}
return !(abs(c.x*w.y - c.y*w.x) > half.x*v.y + half.y*v.x);
}
bool RayVsAABB(const Ray& ray, const AABB& box)
{
float dummy;
return RayVsAABB(ray, box, dummy);
}
bool RayVsAABB(const Ray& ray, const AABB& box, float& outDistance)
{
glm::vec3 invdir = 1.0f / ray.Direction();
glm::vec3 origin = ray.Origin();
float t1 = (box.MinCorner().x - origin.x)*invdir.x;
float t2 = (box.MaxCorner().x - origin.x)*invdir.x;
float t3 = (box.MinCorner().y - origin.y)*invdir.y;
float t4 = (box.MaxCorner().y - origin.y)*invdir.y;
float t5 = (box.MinCorner().z - origin.z)*invdir.z;
float t6 = (box.MaxCorner().z - origin.z)*invdir.z;
float tmin = std::max(std::max(std::min(t1, t2), std::min(t3, t4)), std::min(t5, t6));
float tmax = std::min(std::min(std::max(t1, t2), std::max(t3, t4)), std::max(t5, t6));
//if (tmax < 0 || tmin > tmax)
//if tmin,tmax are almost the same (i.e. hitting exactly in the corner) then tmin might be slightly
//greater than tmax becuase of floating-precision problems. fixed by adding a small delta to tmax
if (tmax < 0 || tmin>(tmax + 0.0001f))
return false;
outDistance = (tmin > 0) ? tmin : tmax;
return true;
}
bool AABBVsAABB(const AABB& a, const AABB& b)
{
const glm::vec3& aCenter = a.Center();
const glm::vec3& bCenter = b.Center();
const glm::vec3& aHSize = a.HalfSize();
const glm::vec3& bHSize = b.HalfSize();
//Test will probably exit because of the X and Z axes more often, so test them first.
if (abs(aCenter[0] - bCenter[0]) > (aHSize[0] + bHSize[0])) {
return false;
}
if (abs(aCenter[2] - bCenter[2]) > (aHSize[2] + bHSize[2])) {
return false;
}
return (abs(aCenter[1] - bCenter[1]) <= (aHSize[1] + bHSize[1]));
}
bool AABBVsAABB(const AABB& a, const AABB& b, glm::vec3& minimumTranslation)
{
minimumTranslation = glm::vec3(0, 0, 0);
const glm::vec3& aMax = a.MaxCorner();
const glm::vec3& bMax = b.MaxCorner();
const glm::vec3& aMin = a.MinCorner();
const glm::vec3& bMin = b.MinCorner();
const glm::vec3& bSize = b.Size();
const glm::vec3& aSize = a.Size();
float minOffset = INFINITY;
float off;
auto axisesIntersecting = glm::tvec3<bool, glm::highp>(false, false, false);
for (int i = 0; i < 3; ++i) {
off = bMax[i] - aMin[i];
if (off > 0 && off < bSize[i] + aSize[i]) {
if (off < minOffset) {
minimumTranslation = glm::vec3();
minimumTranslation[i] = minOffset = off;
}
axisesIntersecting[i] = true;
}
off = aMax[i] - bMin[i];
if (off > 0 && off < bSize[i] + aSize[i]) {
if (off < minOffset) {
minOffset = off;
minimumTranslation = glm::vec3();
minimumTranslation[i] = -off;
}
axisesIntersecting[i] = true;
}
}
return glm::all(axisesIntersecting);
}
bool RayVsModel(const Ray& ray,
const std::vector<RawModel::Vertex>& modelVertices,
const std::vector<unsigned int>& modelIndices)
{
for (int i = 0; i < modelIndices.size(); ++i) {
glm::vec3 v0 = modelVertices[modelIndices[i]].Position;
glm::vec3 e1 = modelVertices[modelIndices[++i]].Position - v0; //v1 - v0
glm::vec3 e2 = modelVertices[modelIndices[++i]].Position - v0; //v2 - v0
glm::vec3 m = ray.Origin() - v0;
glm::vec3 MxE1 = glm::cross(m, e1);
glm::vec3 DxE2 = glm::cross(ray.Direction(), e2);
float DetInv = glm::dot(e1, DxE2);
if (std::abs(DetInv) < FLT_EPSILON) {
continue;
}
DetInv = 1.0f / DetInv;
float u = glm::dot(m, DxE2) * DetInv;
float v = glm::dot(ray.Direction(), MxE1) * DetInv;
//u,v can be very close to 0 but still negative sometimes. added a deltafactor to compensate for that problem
if ((u + 0.001f) < 0 || (v + 0.001f) < 0 || 1 < u + v) {
continue;
}
//Here, u and v are positive, u+v <= 1, and if distance is positive - triangle is hit.
if (0 <= glm::dot(e2, MxE1) * DetInv) {
return true;
}
}
return false;
}
bool RayVsModel(const Ray& ray,
const std::vector<RawModel::Vertex>& modelVertices,
const std::vector<unsigned int>& modelIndices,
float& outDistance,
float& outUCoord,
float& outVCoord)
{
outDistance = INFINITY;
bool hit = false;
for (int i = 0; i < modelIndices.size(); ++i) {
glm::vec3 v0 = modelVertices[modelIndices[i]].Position;
glm::vec3 e1 = modelVertices[modelIndices[++i]].Position - v0; //v1 - v0
glm::vec3 e2 = modelVertices[modelIndices[++i]].Position - v0; //v2 - v0
glm::vec3 m = ray.Origin() - v0;
glm::vec3 MxE1 = glm::cross(m, e1);
glm::vec3 DxE2 = glm::cross(ray.Direction(), e2);//pVec
float DetInv = glm::dot(e1, DxE2);
if (std::abs(DetInv) < FLT_EPSILON) {
continue;
}
DetInv = 1.0f / DetInv;
float dist = glm::dot(e2, MxE1) * DetInv;
if (dist >= outDistance) {
continue;
}
float u = glm::dot(m, DxE2) * DetInv;
float v = glm::dot(ray.Direction(), MxE1) * DetInv;
//u,v can be very close to 0 but still negative sometimes. added a deltafactor to compensate for that problem
//If u and v are positive, u+v <= 1, dist is positive, and less than closest.
if (0 <= (u + 0.001f) && 0 <= (v + 0.001f) && u + v <= 1 && 0 <= dist) {
outDistance = dist;
outUCoord = u;
outVCoord = v;
hit = true;
}
}
return hit;
}
bool RayVsModel(const Ray& ray,
const std::vector<RawModel::Vertex>& modelVertices,
const std::vector<unsigned int>& modelIndices,
glm::vec3& outHitPosition)
{
float u;
float v;
float dist;
bool hit = RayVsModel(ray, modelVertices, modelIndices, dist, u, v);
outHitPosition = ray.Origin() + dist * ray.Direction();
return hit;
}
bool IsSameBoxProbably(const AABB& first, const AABB& second, const float epsilon)
{
const glm::vec3& ma1 = first.MaxCorner();
const glm::vec3& ma2 = first.MaxCorner();
const glm::vec3& mi1 = second.MinCorner();
const glm::vec3& mi2 = second.MinCorner();
return (std::abs(ma1.x - ma2.x) < epsilon) &&
(std::abs(mi1.x - mi2.x) < epsilon) &&
(std::abs(ma1.z - ma2.z) < epsilon) &&
(std::abs(mi1.z - mi2.z) < epsilon) &&
(std::abs(ma1.y - ma2.y) < epsilon) &&
(std::abs(mi1.y - mi2.y) < epsilon);
}
bool attachAABBComponentFromModel(World* world, EntityID id)
{
if (!world->HasComponent(id, "Model")) {
return false;
}
ComponentWrapper model = world->GetComponent(id, "Model");
ComponentWrapper collision = world->AttachComponent(id, "AABB");
Model* modelRes = ResourceManager::Load<Model>(model["Resource"]);
if (modelRes == nullptr) {
return false;
}
glm::mat4 modelMatrix = modelRes->m_Matrix;
glm::vec3 mini = glm::vec3(INFINITY, INFINITY, INFINITY);
glm::vec3 maxi = glm::vec3(-INFINITY, -INFINITY, -INFINITY);
for (const auto& v : modelRes->m_Vertices) {
const auto& wPos = modelMatrix * glm::vec4(v.Position.x, v.Position.y, v.Position.z, 1);
maxi.x = std::max(wPos.x, maxi.x);
maxi.y = std::max(wPos.y, maxi.y);
maxi.z = std::max(wPos.z, maxi.z);
mini.x = std::min(wPos.x, mini.x);
mini.y = std::min(wPos.y, mini.y);
mini.z = std::min(wPos.z, mini.z);
}
collision["BoxCenter"] = 0.5f * (maxi + mini);
collision["BoxSize"] = maxi - mini;
return true;
}
bool GetEntityBox(World* world, ComponentWrapper& AABBComponent, AABB& outBox)
{
ComponentWrapper& cTrans = world->GetComponent(AABBComponent.EntityID, "Transform");
ComponentWrapper model = world->GetComponent(AABBComponent.EntityID, "Model");
Model* modelRes = ResourceManager::Load<Model>(model["Resource"]);
outBox.CreateFromCenter(AABBComponent["BoxCenter"], AABBComponent["BoxSize"]);
glm::vec3 mini = outBox.MinCorner();
glm::vec3 maxi = outBox.MaxCorner();
if (modelRes == nullptr) {
return false;
}
glm::mat4 modelMatrix = modelRes->m_Matrix *
glm::translate(glm::mat4(), (glm::vec3)cTrans["Position"]) *
glm::scale((glm::vec3)cTrans["Scale"]);
outBox = AABB(modelMatrix * glm::vec4(mini.x, mini.y, mini.z, 1),
modelMatrix * glm::vec4(maxi.x, maxi.y, maxi.z, 1));
return true;
}
bool GetEntityBox(World* world, EntityID entity, AABB& outBox, bool forceBoxFromModel)
{
if (!world->HasComponent(entity, "AABB")) {
if (forceBoxFromModel) {
if (!attachAABBComponentFromModel(world, entity))
return false;
} else {
return false;
}
}
ComponentWrapper& cBox = world->GetComponent(entity, "AABB");
return GetEntityBox(world, cBox, outBox);
}
}