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#include "Box.h"
#include "SyntopiaCore/Math/Vector3.h"
using namespace SyntopiaCore::Math;
namespace SyntopiaCore {
namespace GLEngine {
Box::Box(SyntopiaCore::Math::Vector3f base,
SyntopiaCore::Math::Vector3f dir1 ,
SyntopiaCore::Math::Vector3f dir2,
SyntopiaCore::Math::Vector3f dir3) : base(base), v1(dir1), v2(dir2), v3(dir3)
{
/// Bounding box
from = base;
to = base;
Expand(from,to, base+v1);
Expand(from,to, base+v2);
Expand(from,to, base+v3);
Expand(from,to, base+v1+v2);
Expand(from,to, base+v2+v3);
Expand(from,to, base+v1+v3);
Expand(from,to, base+v1+v2+v3);
n21 = Vector3f::cross(v2,v1).normalized();
n32 = Vector3f::cross(v3,v2).normalized();
n13 = Vector3f::cross(v1,v3).normalized();
ac = base + v1*0.5 + v2*0.5 + v3*0.5;
a[0] = v1.normalized();
a[1] = v2.normalized();
a[2] = v3.normalized();
h[0] = v1.length()/2;
h[1] = v2.length()/2;
h[2] = v3.length()/2;
};
Box::~Box() { };
void Box::draw() const {
glPushMatrix();
glTranslatef( base.x(), base.y(), base.z() );
glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, primaryColor );
glBegin( GL_QUADS );
Vector3f O(0,0,0);
vertex4n(O, v2,v2+v1,v1);
vertex4rn(O+v3, v2+v3, v2+v1+v3, v1+v3);
vertex4n(O, v3, v3+v2,v2);
vertex4rn(O+v1, v3+v1, v3+v2+v1, v2+v1);
vertex4n(O, v1, v3+v1, v3);
vertex4rn(O+v2, v1+v2, v3+v2+v1, v3+v2);
glEnd();
glPopMatrix();
};
void Box::prepareForRaytracing() {
// Determine whether the box is skewed.
// if this is the case, we triangulate it.
// Using triangles for ray checks is much slower (x ~2.4 slower),
// and we could probably avoid it by transforming both box and rayinfo
// into a non-skewed coordinate system.
const double treshold = 1E-4;
useTriangles = false;
if (fabs(Vector3f::dot(v1,v2)) > treshold) useTriangles = true;
if (fabs(Vector3f::dot(v2,v3)) > treshold) useTriangles = true;
if (fabs(Vector3f::dot(v1,v3)) > treshold) useTriangles = true;
if (useTriangles) {
triangles.clear();
RaytraceTriangle::Vertex4(base, base+v1,base+v3+v1,base+v3, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
RaytraceTriangle::Vertex4(base, base+v3,base+v3+v2,base+v2, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
RaytraceTriangle::Vertex4(base+v1, base+v1+v2, base+v3+v1+v2, base+v3+v1, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
RaytraceTriangle::Vertex4(base+v2, base+v3+v2, base+v3+v1+v2, base+v1+v2, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
RaytraceTriangle::Vertex4(base, base+v2,base+v1+v2,base+v1, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
RaytraceTriangle::Vertex4(base+v3, base+v3+v1,base+v3+v1+v2, base+v3+v2, true,triangles,primaryColor[0],primaryColor[1],primaryColor[2],primaryColor[3]);
}
}
bool Box::intersectsRay(RayInfo* ri) {
if (useTriangles) {
for (int i = 0; i < triangles.count(); i++) {
if (triangles[i].intersectsRay(ri)) return true;
}
return false;
} else {
// Following the Real-Time Rendering book p. 574
float tmin = -1.0E37f;
float tmax = 1.0E37f;
float temp = 0;
Vector3f p = ac - ri->startPoint;
int minhit = 0;
int maxhit = 0;
for (int i = 0; i < 3; i++) {
bool reverse = false;
float e = Vector3f::dot(a[i], p);
float f = Vector3f::dot(a[i], ri->lineDirection);
if (fabs(f)>1E-17) {
float t1 = (e+h[i])/f;
float t2 = (e-h[i])/f;
if (t1 > t2) { temp = t1; t1 = t2; t2 = temp; reverse = true; }
if (t1 > tmin) {
tmin = t1;
minhit = reverse ? (i+1) : -i;
}
if (t2 < tmax) {
tmax = t2;
maxhit = reverse ? (i+1) : -i;
}
if (tmin > tmax) return false;
if (tmax < 0) return false;
} else {
if ( (-e-h[i] > 0) || (-e+h[i]<0)) return false;
}
}
if (tmin>0) {
ri->intersection = tmin;
for (int i = 0; i < 4; i++) ri->color[i] = primaryColor[i];
// TODO: Find a better solution or at least make a switch...
if (minhit == 1) { ri->normal = n32; }
else if (minhit == 2) { ri->normal = n13; }
else if (minhit == 3) { ri->normal = n21; }
else if (minhit == 0) { ri->normal = -n32; }
else if (minhit == -1) { ri->normal = -n13; }
else if (minhit == -2) { ri->normal = -n21; }
return true;
} else {
ri->intersection = tmax;
for (int i = 0; i < 4; i++) ri->color[i] = primaryColor[i];
if (maxhit == 0) {ri->normal = n32; ri->color[2] = 1; }
else if (maxhit == 1){ ri->normal = n13; ri->color[2] = 1; }
else { ri->normal = n21; ri->color[2] = 1; }
ri->color[0] = 0; ri->color[1] = 1; ri->color[2] = 1;
return true;
}
}
}
bool Box::intersectsAABB(SyntopiaCore::Math::Vector3f from2, SyntopiaCore::Math::Vector3f to2) {
return
(from.x() < to2.x()) && (to.x() > from2.x()) &&
(from.y() < to2.y()) && (to.y() > from2.y()) &&
(from.z() < to2.z()) && (to.z() > from2.z());
}
}
}
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