Created
July 12, 2017 10:33
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Ready to use frustum culling code. Depends only on GLM. The input is only bounding box and ProjectionView matrix. Based on Inigo Quilez's code.
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| #include <glm/matrix.hpp> | |
| class Frustum | |
| { | |
| public: | |
| Frustum() {} | |
| // m = ProjectionMatrix * ViewMatrix | |
| Frustum(glm::mat4 m); | |
| // http://iquilezles.org/www/articles/frustumcorrect/frustumcorrect.htm | |
| bool IsBoxVisible(const glm::vec3& minp, const glm::vec3& maxp) const; | |
| private: | |
| enum Planes | |
| { | |
| Left = 0, | |
| Right, | |
| Bottom, | |
| Top, | |
| Near, | |
| Far, | |
| Count, | |
| Combinations = Count * (Count - 1) / 2 | |
| }; | |
| template<Planes i, Planes j> | |
| struct ij2k | |
| { | |
| enum { k = i * (9 - i) / 2 + j - 1 }; | |
| }; | |
| template<Planes a, Planes b, Planes c> | |
| glm::vec3 intersection(const glm::vec3* crosses) const; | |
| glm::vec4 m_planes[Count]; | |
| glm::vec3 m_points[8]; | |
| }; | |
| inline Frustum::Frustum(glm::mat4 m) | |
| { | |
| m = glm::transpose(m); | |
| m_planes[Left] = m[3] + m[0]; | |
| m_planes[Right] = m[3] - m[0]; | |
| m_planes[Bottom] = m[3] + m[1]; | |
| m_planes[Top] = m[3] - m[1]; | |
| m_planes[Near] = m[3] + m[2]; | |
| m_planes[Far] = m[3] - m[2]; | |
| glm::vec3 crosses[Combinations] = { | |
| glm::cross(glm::vec3(m_planes[Left]), glm::vec3(m_planes[Right])), | |
| glm::cross(glm::vec3(m_planes[Left]), glm::vec3(m_planes[Bottom])), | |
| glm::cross(glm::vec3(m_planes[Left]), glm::vec3(m_planes[Top])), | |
| glm::cross(glm::vec3(m_planes[Left]), glm::vec3(m_planes[Near])), | |
| glm::cross(glm::vec3(m_planes[Left]), glm::vec3(m_planes[Far])), | |
| glm::cross(glm::vec3(m_planes[Right]), glm::vec3(m_planes[Bottom])), | |
| glm::cross(glm::vec3(m_planes[Right]), glm::vec3(m_planes[Top])), | |
| glm::cross(glm::vec3(m_planes[Right]), glm::vec3(m_planes[Near])), | |
| glm::cross(glm::vec3(m_planes[Right]), glm::vec3(m_planes[Far])), | |
| glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Top])), | |
| glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Near])), | |
| glm::cross(glm::vec3(m_planes[Bottom]), glm::vec3(m_planes[Far])), | |
| glm::cross(glm::vec3(m_planes[Top]), glm::vec3(m_planes[Near])), | |
| glm::cross(glm::vec3(m_planes[Top]), glm::vec3(m_planes[Far])), | |
| glm::cross(glm::vec3(m_planes[Near]), glm::vec3(m_planes[Far])) | |
| }; | |
| m_points[0] = intersection<Left, Bottom, Near>(crosses); | |
| m_points[1] = intersection<Left, Top, Near>(crosses); | |
| m_points[2] = intersection<Right, Bottom, Near>(crosses); | |
| m_points[3] = intersection<Right, Top, Near>(crosses); | |
| m_points[4] = intersection<Left, Bottom, Far>(crosses); | |
| m_points[5] = intersection<Left, Top, Far>(crosses); | |
| m_points[6] = intersection<Right, Bottom, Far>(crosses); | |
| m_points[7] = intersection<Right, Top, Far>(crosses); | |
| } | |
| // http://iquilezles.org/www/articles/frustumcorrect/frustumcorrect.htm | |
| inline bool Frustum::IsBoxVisible(const glm::vec3& minp, const glm::vec3& maxp) const | |
| { | |
| // check box outside/inside of frustum | |
| for (int i = 0; i < Count; i++) | |
| { | |
| if ((glm::dot(m_planes[i], glm::vec4(minp.x, minp.y, minp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(maxp.x, minp.y, minp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(minp.x, maxp.y, minp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(maxp.x, maxp.y, minp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(minp.x, minp.y, maxp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(maxp.x, minp.y, maxp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(minp.x, maxp.y, maxp.z, 1.0f)) < 0.0) && | |
| (glm::dot(m_planes[i], glm::vec4(maxp.x, maxp.y, maxp.z, 1.0f)) < 0.0)) | |
| { | |
| return false; | |
| } | |
| } | |
| // check frustum outside/inside box | |
| int out; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].x > maxp.x) ? 1 : 0); if (out == 8) return false; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].x < minp.x) ? 1 : 0); if (out == 8) return false; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].y > maxp.y) ? 1 : 0); if (out == 8) return false; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].y < minp.y) ? 1 : 0); if (out == 8) return false; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].z > maxp.z) ? 1 : 0); if (out == 8) return false; | |
| out = 0; for (int i = 0; i<8; i++) out += ((m_points[i].z < minp.z) ? 1 : 0); if (out == 8) return false; | |
| return true; | |
| } | |
| template<Frustum::Planes a, Frustum::Planes b, Frustum::Planes c> | |
| inline glm::vec3 Frustum::intersection(const glm::vec3* crosses) const | |
| { | |
| float D = glm::dot(glm::vec3(m_planes[a]), crosses[ij2k<b, c>::k]); | |
| glm::vec3 res = glm::mat3(crosses[ij2k<b, c>::k], -crosses[ij2k<a, c>::k], crosses[ij2k<a, b>::k]) * | |
| glm::vec3(m_planes[a].w, m_planes[b].w, m_planes[c].w); | |
| return res * (-1.0f / D); | |
| } |
God bless your soul mate
thanks, but whats &maxp, & minp
thanks, but whats &maxp, & minp
Thats the max point and min point of the AABB of the object that is being checked
Under what license is the code?
Thanks, very useful.
I used this in my Minecraft clone game to test how it would improve performance. ~3x FPS. Works perfectly, thanks!!
you should probably use constexprs instead of enum templates
Ported to Rust if anyone needs this
https://gist.github.com/griffi-gh/a6ed5ed3bc7e7ac8e29974502abafb40
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This works nicely, thanks a lot!