diff --git a/include/Engine/Collision/Collision.h b/include/Engine/Collision/Collision.h index b32d190a..4e764905 100644 --- a/include/Engine/Collision/Collision.h +++ b/include/Engine/Collision/Collision.h @@ -26,6 +26,12 @@ bool RayVsAABB(const Ray& ray, const AABB& box); //Return true if the ray hits the box, also outputs distance from ray origin to intersection point in [outDistance]. bool RayVsAABB(const Ray& ray, const AABB& box, float& outDistance); +//Return true if the ray hits the triangle. +bool RayVsTriangle(const Ray& ray, + const glm::vec3& v0, + const glm::vec3& v1, + const glm::vec3& v2, + bool trueOnNegativeDistance = false); //Return true if the ray hits the triangle, and the distance is less than outDistance. bool RayVsTriangle(const Ray& ray, const glm::vec3& v0, diff --git a/src/Engine/Collision/Collision.cpp b/src/Engine/Collision/Collision.cpp index d174eb86..d44c97be 100644 --- a/src/Engine/Collision/Collision.cpp +++ b/src/Engine/Collision/Collision.cpp @@ -116,30 +116,41 @@ bool AABBVsAABB(const AABB& a, const AABB& b, glm::vec3& minimumTranslation) return glm::all(axisesIntersecting); } +bool RayVsTriangle(const Ray& ray, + const glm::vec3& v0, + const glm::vec3& v1, + const glm::vec3& v2, + bool trueOnNegativeDistance) +{ + glm::vec3 e1 = v1 - v0; //v1 - v0 + glm::vec3 e2 = v2 - 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) { + return false; + } + 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) { + return false; + } + //Here, u and v are positive, u+v <= 1, and if distance is positive - triangle is hit. + return trueOnNegativeDistance || 0 <= glm::dot(e2, MxE1) * DetInv; +} + bool RayVsModel(const Ray& ray, const std::vector& modelVertices, const std::vector& 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) { + glm::vec3 v1 = modelVertices[modelIndices[++i]].Position; + glm::vec3 v2 = modelVertices[modelIndices[++i]].Position; + if (RayVsTriangle(ray, v0, v1, v2)) { return true; } } @@ -300,7 +311,7 @@ bool AABBvsTriangle(const AABB& box, const glm::vec3& v0, const glm::vec3& v1, c triNormal = glm::normalize(triNormal); glm::vec3 diagonal = -signNonZero(triNormal) * half; -#define EARLY_OUT_OR_MAYBE_JUST_EXTRA_WORK +#define EARLY_OUT_OR_MAYBE_JUST_EXTRA_WORK //TODO: We should probably performance test with this on/off. #ifdef EARLY_OUT_OR_MAYBE_JUST_EXTRA_WORK //The triangle plane contains all points P in dot(triNormal, P) == dot(triNormal, v0) //The diagonal line contains all points P in P = origin + diagonal * t. @@ -310,15 +321,16 @@ bool AABBvsTriangle(const AABB& box, const glm::vec3& v0, const glm::vec3& v1, c if (glm::abs(t) > 1) { return false; } - //glm::vec3 intersection = origin + t * diagonal; #endif //Check if intersection point is on the triangle. ray.SetOrigin(origin); ray.SetDirection(diagonal); +#ifdef EARLY_OUT_OR_MAYBE_JUST_EXTRA_WORK + if (RayVsTriangle(ray, v0, v1, v2, true)) { +#else float dist = INFINITY, u, v; if (RayVsTriangle(ray, v0, v1, v2, dist, u, v, true)) { -#ifndef EARLY_OUT_OR_MAYBE_JUST_EXTRA_WORK if (glm::abs(dist) > glm::length(diagonal)) { return false; }