diff options
Diffstat (limited to 'src/graphics')
| -rw-r--r-- | src/graphics/Frustrum.cpp | 111 | ||||
| -rw-r--r-- | src/graphics/Frustrum.hpp | 24 |
2 files changed, 135 insertions, 0 deletions
diff --git a/src/graphics/Frustrum.cpp b/src/graphics/Frustrum.cpp new file mode 100644 index 0000000..75f47c5 --- /dev/null +++ b/src/graphics/Frustrum.cpp @@ -0,0 +1,111 @@ +#include "Frustrum.hpp" + +enum FrustumSide { + RIGHT = 0, // The RIGHT side of the frustum + LEFT = 1, // The LEFT side of the frustum + BOTTOM = 2, // The BOTTOM side of the frustum + TOP = 3, // The TOP side of the frustum + BACK = 4, // The BACK side of the frustum + FRONT = 5 // The FRONT side of the frustum +}; + +enum PlaneData { + A = 0, // The X value of the plane's normal + B = 1, // The Y value of the plane's normal + C = 2, // The Z value of the plane's normal + D = 3 // The distance the plane is from the origin +}; + +void normalizePlane(glm::vec4 &frustum_plane) { + float magnitude = (float) sqrt(frustum_plane[A] * frustum_plane[A] + frustum_plane[B] * frustum_plane[B] + + frustum_plane[C] * frustum_plane[C]); + frustum_plane[A] /= magnitude; + frustum_plane[B] /= magnitude; + frustum_plane[C] /= magnitude; + frustum_plane[D] /= magnitude; +} + +void Frustum::CalculateFrustum(glm::mat4 &view_matrix, glm::mat4 &proj_matrix) { + float proj[16]; + float modl[16]; + const float *projP = glm::value_ptr(proj_matrix); + const float *modlP = glm::value_ptr(view_matrix); + for (int i = 0; i < 16; i++) { + proj[i]=projP[i]; + modl[i]=modlP[i]; + } + + float clip[16]; //clipping planes + + clip[0] = modl[0] * proj[0] + modl[1] * proj[4] + modl[2] * proj[8] + modl[3] * proj[12]; + clip[1] = modl[0] * proj[1] + modl[1] * proj[5] + modl[2] * proj[9] + modl[3] * proj[13]; + clip[2] = modl[0] * proj[2] + modl[1] * proj[6] + modl[2] * proj[10] + modl[3] * proj[14]; + clip[3] = modl[0] * proj[3] + modl[1] * proj[7] + modl[2] * proj[11] + modl[3] * proj[15]; + + clip[4] = modl[4] * proj[0] + modl[5] * proj[4] + modl[6] * proj[8] + modl[7] * proj[12]; + clip[5] = modl[4] * proj[1] + modl[5] * proj[5] + modl[6] * proj[9] + modl[7] * proj[13]; + clip[6] = modl[4] * proj[2] + modl[5] * proj[6] + modl[6] * proj[10] + modl[7] * proj[14]; + clip[7] = modl[4] * proj[3] + modl[5] * proj[7] + modl[6] * proj[11] + modl[7] * proj[15]; + + clip[8] = modl[8] * proj[0] + modl[9] * proj[4] + modl[10] * proj[8] + modl[11] * proj[12]; + clip[9] = modl[8] * proj[1] + modl[9] * proj[5] + modl[10] * proj[9] + modl[11] * proj[13]; + clip[10] = modl[8] * proj[2] + modl[9] * proj[6] + modl[10] * proj[10] + modl[11] * proj[14]; + clip[11] = modl[8] * proj[3] + modl[9] * proj[7] + modl[10] * proj[11] + modl[11] * proj[15]; + + clip[12] = modl[12] * proj[0] + modl[13] * proj[4] + modl[14] * proj[8] + modl[15] * proj[12]; + clip[13] = modl[12] * proj[1] + modl[13] * proj[5] + modl[14] * proj[9] + modl[15] * proj[13]; + clip[14] = modl[12] * proj[2] + modl[13] * proj[6] + modl[14] * proj[10] + modl[15] * proj[14]; + clip[15] = modl[12] * proj[3] + modl[13] * proj[7] + modl[14] * proj[11] + modl[15] * proj[15]; + + frustum_planes[RIGHT][A] = clip[3] - clip[0]; + frustum_planes[RIGHT][B] = clip[7] - clip[4]; + frustum_planes[RIGHT][C] = clip[11] - clip[8]; + frustum_planes[RIGHT][D] = clip[15] - clip[12]; + normalizePlane(frustum_planes[RIGHT]); + + frustum_planes[LEFT][A] = clip[3] + clip[0]; + frustum_planes[LEFT][B] = clip[7] + clip[4]; + frustum_planes[LEFT][C] = clip[11] + clip[8]; + frustum_planes[LEFT][D] = clip[15] + clip[12]; + normalizePlane(frustum_planes[LEFT]); + + frustum_planes[BOTTOM][A] = clip[3] + clip[1]; + frustum_planes[BOTTOM][B] = clip[7] + clip[5]; + frustum_planes[BOTTOM][C] = clip[11] + clip[9]; + frustum_planes[BOTTOM][D] = clip[15] + clip[13]; + normalizePlane(frustum_planes[BOTTOM]); + + frustum_planes[TOP][A] = clip[3] - clip[1]; + frustum_planes[TOP][B] = clip[7] - clip[5]; + frustum_planes[TOP][C] = clip[11] - clip[9]; + frustum_planes[TOP][D] = clip[15] - clip[13]; + normalizePlane(frustum_planes[TOP]); + + frustum_planes[BACK][A] = clip[3] - clip[2]; + frustum_planes[BACK][B] = clip[7] - clip[6]; + frustum_planes[BACK][C] = clip[11] - clip[10]; + frustum_planes[BACK][D] = clip[15] - clip[14]; + normalizePlane(frustum_planes[BACK]); + + frustum_planes[FRONT][A] = clip[3] + clip[2]; + frustum_planes[FRONT][B] = clip[7] + clip[6]; + frustum_planes[FRONT][C] = clip[11] + clip[10]; + frustum_planes[FRONT][D] = clip[15] + clip[14]; + normalizePlane(frustum_planes[FRONT]); +} + +bool Frustum::TestInsideFrustrum(glm::vec4 Min, glm::vec4 Max) { + bool inside = true; + //test all 6 frustum planes + for (int i = 0; i < 6; i++) { + //pick closest point to plane and check if it behind the plane + //if yes - object outside frustum + float d = std::max(Min.x * frustum_planes[i].x, Max.x * frustum_planes[i].x) + + std::max(Min.y * frustum_planes[i].y, Max.y * frustum_planes[i].y) + + std::max(Min.z * frustum_planes[i].z, Max.z * frustum_planes[i].z) + + frustum_planes[i].w; + inside &= d > 0; + //return false; //with flag works faster + } + return inside; +} diff --git a/src/graphics/Frustrum.hpp b/src/graphics/Frustrum.hpp new file mode 100644 index 0000000..e8a6fd6 --- /dev/null +++ b/src/graphics/Frustrum.hpp @@ -0,0 +1,24 @@ +#ifndef _FRUSTUM_H +#define _FRUSTUM_H + + +#include <cmath> +#include <algorithm> +#include <GL/glew.h> +#include <glm/glm.hpp> +#include <glm/gtc/type_ptr.hpp> + +class Frustum { +public: + Frustum() = default; + + ~Frustum() = default; + + void CalculateFrustum(glm::mat4 &view_matrix, glm::mat4 &proj_matrix); + + glm::vec4 frustum_planes[6]; + + bool TestInsideFrustrum(glm::vec4 Min, glm::vec4 Max); +}; + +#endif
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