eRETURN_TYPE DoIntersect(const cTRIANGLE3 &triangle,
const cSEGMENT3 &lseg, BOOL doDebug)
{
if(DoIntersect(triangle.ComputeBbox(),
lseg.ComputeBbox()) == FAILURE)
return FAILURE;
cPLANE3 supportingPlane = triangle.SupportingPlane();
cSEGMENT3 resultingSegment;
cPOINT3 resultingPoint;
if (doDebug){
printf("supportingPlane: ");
supportingPlane.Print();
}
if(DoIntersect(supportingPlane, lseg) != SUCCESS)
return FAILURE;
eRETURN_TYPE result = Intersection(supportingPlane, lseg,
resultingPoint, resultingSegment);
eCOORD maxCoord = supportingPlane.Normal().AbsMaxCoord();
cTRIANGLE2 transformedTriangle(triangle.Vertex(0).DropCoord(maxCoord),
triangle.Vertex(1).DropCoord(maxCoord),
triangle.Vertex(2).DropCoord(maxCoord));
if(result == RT_POINT3) { //Intersection is a point.
cPOINT2 transformedPoint = resultingPoint.DropCoord(maxCoord);
if(transformedTriangle.IsPointInside(transformedPoint))
return SUCCESS;
else
return FAILURE;
}
else {
//Intersection is a line segment.
//The segment is on the triangle plane.
//Check for actual intersection.
//Transform the problem to 2-D problem and try to compute the result.
cSEGMENT2 transformedSegment(lseg.Source().DropCoord(maxCoord),
lseg.Target().DropCoord(maxCoord));
if(DoIntersect(transformedTriangle,
transformedSegment) == SUCCESS)
return SUCCESS;
return FAILURE;
}
ASSERT(0); //Should be decided even before it gets here.
return FAILURE;
}
void Renderer3DRasterization::render()
{
setMaxDepth(1.0);
TransformMatrix3D lookat = camera_->getLookatMatrix();
TransformMatrix3D proj = camera_->getProjectionMatrix();
TransformMatrix3D screen = camera_->getScreenMatrix();
TransformMatrix3D transform = screen * proj * lookat;
std::vector<Surface3D*> list = scene_->getTriangleList();
std::cout << "Renderer3DRasterization: Found " << list.size() << " triangles" << std::endl;
for (Surface3D* triangle : list)
{
Color color = triangle->getColor();
// color shading according to Lambert
// normally we need a light source, but we use camera this time
Vector3D normal = triangle->getNormal();
Vector3D center = triangle->getCenter();
// get direction to camera
Vector3D d = camera_->getCenter() - center;
d.normalize();
double lambert = Mathtools::dot(d, normal);
color = color * (lambert < 0.0 ? 0.0 : lambert);
Vector3D p0 = transform * *(triangle->getP0());
Vector3D p1 = transform * *(triangle->getP1());
Vector3D p2 = transform * *(triangle->getP2());
// in case we used perspective projection: divide by homogeneous coordinate "w"
p0.homogeneousDivide();
p1.homogeneousDivide();
p2.homogeneousDivide();
Surface3D transformedTriangle(p0, p1, p2, &color, triangle->getTexture());
transformedTriangle.setTextureAnchorPoints(triangle->getT0(), triangle->getT1(), triangle->getT2());
rasterization(&transformedTriangle);
}
}
