Plane::Plane(GzCoord aVertexList[]){
GzCoord temp1, temp2;
for(int i = 0; i < 3; i++){
for(int j = 0; j < 3; j++){
vertexList[i][j] = aVertexList[i][j];
}
}
vectorConstruct(vertexList[0], vertexList[1], temp1);
vectorConstruct(vertexList[0], vertexList[2], temp2);
vectorCrossProduct(temp1, temp2, normal);
vectorNormalize(normal);
distance = vectorDotProduct(normal, vertexList[0]);
}
int Plane::findIntersectPoint(Ray& aRay, GzCoord aPoint){
GzCoord w0, temp;
if(vectorZero(normal)) return -1; //triangle degenerate to a point
vectorConstruct(vertexList[0], aRay.origin, w0);
float a = -vectorDotProduct(normal, w0);
float b = vectorDotProduct(normal, aRay.direction);
if(fabs(b) < SMALL_NUM){ //ray is parallel to triangle
if(a == 0){
return 2; //ray lies in triangle plane
}else{
return 0; //ray disjoint from triangle plane
}
}
float r = a/b;
if(r < 0.0) return 0; //ray goes away from triangle
vectorScale(r, aRay.direction, temp);
vectorAdd(aRay.origin, temp, aPoint);
return 1; //one intersect point
}
/* DESCRIPTION:
* ------------
* The function calculates the sum of the parameter vectors v1 and v2, both
* containing s elements. The memory for the result must be dynamically
* allocated.
*
* The sum between the two vectors is simply calculated by adding the
* corresponding values of the two vectors and using the sums as the values of
* the new vector:
*
* result[i] = v1[i] + v2[i]
*
* The function should check that neither of the parameter vectors is NULL by
* using assert.
*
* PARAMETERS:
* ------------
* double const* v1: a vector containing s elements.
* double const* v2: a vector containing s elements.
* size_t s: number of elements in the parameter vectors.
*
* RETURNS:
* ------------
* A dynamically allocated vector, containing the sum of the two parameter
* vectors.
*/
double* vectorSum(double const* v1, double const* v2, size_t size) {
assert(v1);
assert(v2);
double* result = vectorConstruct(size, 0.0);
for (size_t i = 0; i < size; i++) {
result[i] = v1[i] + v2[i];
}
return result;
}
bool Plane::checkPointInTriangle(GzCoord aPoint){
GzCoord vector0, vector1, vector2;
//compute vectors
vectorConstruct(vertexList[0], vertexList[2], vector0);
vectorConstruct(vertexList[0], vertexList[1], vector1);
vectorConstruct(vertexList[0], aPoint, vector2);
//compute dot products
float dot00 = vectorDotProduct(vector0, vector0);
float dot01 = vectorDotProduct(vector0, vector1);
float dot02 = vectorDotProduct(vector0, vector2);
float dot11 = vectorDotProduct(vector1, vector1);
float dot12 = vectorDotProduct(vector1, vector2);
//compute barycentric coordinates
float invDenom = 1.0/(dot00*dot11 - dot01*dot01);
float u = (dot11*dot02 - dot01*dot12) * invDenom;
float v = (dot00*dot12 - dot01*dot02) * invDenom;
//check if point is in the triangle
return (u >= 0) && (v >= 0) && (u + v < 1.0);
}
/* DESCRIPTION:
* ------------
* The function appends all the elements of v2 (size s2) to the end of v1.
*
* The memory allocated for v1 must be reallocated to fit the new elements and
* the new address and size are returned via the pointer parameters v1 and s1
* as pass-by-pointer.
*
* Pass-by-pointer means, that the function doesn't use return to return the
* values, but stores the results to the address pointed to by a parameter
* pointer.
*
* All the parameter pointer values should be asserted as not NULL.
*
* PARAMETERS:
* ------------
* double** v1: a vector containing s1 elements.
* size_t* s1: the number of elements in v1.
* double const* v2: a vector containing s2 elements.
* size_t s2: the number of elements in v2.
*
* RETURNS:
* ------------
* Nothing.
*/
void vectorAppend(double** pv1, size_t* psize1, double const* v2, size_t size2) {
assert(pv1);
assert(psize1);
assert(v2);
double* v1 = *pv1;
size_t size1 = *psize1;
size_t result_size = size1 + size2;
double* result = vectorConstruct(result_size, 0.0);
for (size_t i = 0; i < size1; i++) {
result[i] = v1[i];
}
for (size_t i = 0; i < size2; i++) {
result[i + size1] = v2[i];
}
free(*pv1);
*pv1 = result;
*psize1 = result_size;
}