Michael Fabian 'Xaymar' Dirks
61 lines
1.7 KiB
C++
61 lines
1.7 KiB
C++
#include "frustum.hpp"
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Frustum::Frustum() {}
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Frustum::Frustum(float nr, float fr, float w, float h)
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{
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verts[VERT_TLNEAR] = Vector(w * -.5f, h * +.5f, nr);
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verts[VERT_TRNEAR] = Vector(w * +.5f, h * +.5f, nr);
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verts[VERT_BRNEAR] = Vector(w * +.5f, h * -.5f, nr);
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verts[VERT_BLNEAR] = Vector(w * -.5f, h * -.5f, nr);
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float t = fr / nr;
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verts[VERT_TLFAR] = verts[VERT_TLNEAR] * t;
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verts[VERT_TRFAR] = verts[VERT_TRNEAR] * t;
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verts[VERT_BRFAR] = verts[VERT_BRNEAR] * t;
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verts[VERT_BLFAR] = verts[VERT_BLNEAR] * t;
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verts[VERT_EYE] = Vector();
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makePlanes();
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}
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Frustum::Frustum(const Frustum& f, const Transform& t)
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{
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for (int k = 0; k < 9; ++k) {
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verts[k] = t * f.verts[k];
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}
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makePlanes();
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}
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bool Frustum::cull(const Vector v[], int cnt) const
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{
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for (int n = 0; n < 6; ++n) {
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int k;
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for (k = 0; k < cnt && planes[n].distance(v[k]) < 0; ++k) {
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}
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if (k == cnt)
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return false;
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}
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return true;
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}
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bool Frustum::cull(const Box& b) const
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{
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Vector v[8];
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for (int k = 0; k < 8; ++k)
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v[k] = b.corner(k);
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return cull(v, 8);
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}
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void Frustum::makePlanes()
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{
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planes[PLANE_TOP] = Plane(verts[VERT_EYE], verts[VERT_TRFAR], verts[VERT_TLFAR]);
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planes[PLANE_LEFT] = Plane(verts[VERT_EYE], verts[VERT_TLFAR], verts[VERT_BLFAR]);
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planes[PLANE_BOTTOM] = Plane(verts[VERT_EYE], verts[VERT_BLFAR], verts[VERT_BRFAR]);
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planes[PLANE_RIGHT] = Plane(verts[VERT_EYE], verts[VERT_BRFAR], verts[VERT_TRFAR]);
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planes[PLANE_NEAR] = Plane(verts[VERT_TRNEAR], verts[VERT_TLNEAR], verts[VERT_BLNEAR]);
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planes[PLANE_FAR] = Plane(verts[VERT_TLFAR], verts[VERT_TRFAR], verts[VERT_BRFAR]);
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if (planes[PLANE_NEAR].distance(verts[VERT_EYE]) > 0) {
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for (int k = 0; k < 6; ++k)
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planes[k] = -planes[k];
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}
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}
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