Merge branch 'OctTree' of github.com:teamfisk/TacticalZ into OctTree

src/Engine/Collision/Collision.cpp

@@ -0,0 +1,165 @@
+#include <algorithm>
+
+#include "Collision/Collision.h"
+#include "Engine/GLM.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;
+
+        float t1 = (box.MinCorner().x - ray.Origin.x)*invdir.x;
+        float t2 = (box.MaxCorner().x - ray.Origin.x)*invdir.x;
+        float t3 = (box.MinCorner().y - ray.Origin.y)*invdir.y;
+        float t4 = (box.MaxCorner().y - ray.Origin.y)*invdir.y;
+        float t5 = (box.MinCorner().z - ray.Origin.z)*invdir.z;
+        float t6 = (box.MaxCorner().z - ray.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 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;
+    }
+
+}