38 lines
No EOL
1 KiB
GLSL
38 lines
No EOL
1 KiB
GLSL
#include "triangle.glsl"
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/*
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contributors: Thomas Müller & Alex Evans
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description: Does the position lie within the triangle
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use: <vec3> contain(<Triangle> tri, <vec3> _pos)
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*/
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#ifndef FNC_TRIANGLE_CONTAIN
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#define FNC_TRIANGLE_CONTAIN
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bool contain(Triangle _tri, vec3 _pos) {
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// Move the triangle so that the point becomes the
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// triangles origin
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vec3 local_a = _tri.a - _pos;
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vec3 local_b = _tri.b - _pos;
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vec3 local_c = _tri.c - _pos;
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// The point should be moved too, so they are both
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// relative, but because we don't use p in the
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// equation anymore, we don't need it!
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// p -= p;
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// Compute the normal vectors for triangles:
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// u = normal of PBC
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// v = normal of PCA
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// w = normal of PAB
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vec3 u = cross(local_b, local_c);
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vec3 v = cross(local_c, local_a);
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vec3 w = cross(local_a, local_b);
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// Test to see if the normals are facing the same direction.
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// If yes, the point is inside, otherwise it isn't.
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return dot(u, v) >= 0.0 && dot(u, w) >= 0.0;
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}
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#endif |