Can't call my function using an array elemant as a parametre

[Envergure]

I wrote a function to find the point of intersection of a line and a plane in three-space. This function works fine and returns the correct result.

However, when I call it using an element from an array of triangles for the first param I get a compile error:
error: no match for call to ‘(point) (triangle&, line&)’

Any ideas what may be causing this?

Compiled (or not) with G++:
g++ -Wall "MovesShootDete ct.cpp" -lGL -lGLU `sdl-config --cflags --libs` -lSDL_image -o MovesShootDetec t
under Linux (Ubuntu 7.10) on my PC.



These structures are all used by the function:

/*  ___________________________________________________________________
 *  Structures
 */
struct point
{
    long signed int X, Y, Z;  // Point at (X, Y, Z)
    char Real;  // A point is returned for the intersection of a plane and a line, and they may not intersect
};
 
struct line
{
    short unsigned int P1, P2;  //  Line from P1 to P2
    double A1, B1, C1, D1;  // A line in three dimensions is defined as the intersection of two planes
    double A2, B2, C2, D2;  // A1*X + B1*Y + C1*Z = D1 and A2*X + B2*Y + C2*Z = D2
};
 
struct triangle
{
    short unsigned int P1, P2, P3;  // Verteces of the triangle
    double A, B, C, D;  // Formula of the plane: AX + BY + CZ + D
    char Real;  // A triangle is "real" unless the three points are colinear
};
 

This is the function that finds the intersection. Nobody has to check my math, I already have and I know it works (and it took me an hour!):

/*  ___________________________________________________________________
 *  Find the point of intersection of a line and a plane
 */
point Intersect (triangle Triangle, line Line)
{
    //  Nessecary variables
    point Result;
 
    double EqMatrix[3][3];
    double InvMatrix[3][3];
    double ResMatrix[3];
    double Det;
 
    //  Fill the equasion matrix
    EqMatrix[0][0] = Triangle.A;
    EqMatrix[0][1] = Triangle.B;
    EqMatrix[0][2] = Triangle.C;
    EqMatrix[1][0] = Line.A1;
    EqMatrix[1][1] = Line.B1;
    EqMatrix[1][2] = Line.C1;
    EqMatrix[2][0] = Line.A2;
    EqMatrix[2][1] = Line.B2;
    EqMatrix[2][2] = Line.C2;
    //  Fill the result matrix
    ResMatrix[0] = Triangle.D;
    ResMatrix[1] = Line.D1;
    ResMatrix[2] = Line.D2;
 
    //  Find the determinant
    Det = EqMatrix[0][0] * (EqMatrix[1][1]*EqMatrix[2][2] - EqMatrix[1][2]*EqMatrix[2][1]);
    Det -= EqMatrix[0][1] * (EqMatrix[1][0]*EqMatrix[2][2] - EqMatrix[1][2]*EqMatrix[2][0]);
    Det += EqMatrix[0][2] * (EqMatrix[1][0]*EqMatrix[2][1] - EqMatrix[1][1]*EqMatrix[2][0]);
    if (!Det)  // If the determinant is zero, there is no intersection
    {
        Result.Real = 0;
        return Result;
    }
 
    //  Find the determinant
    InvMatrix[0][0] = (EqMatrix[1][1]*EqMatrix[2][2] - EqMatrix[1][2]*EqMatrix[2][1]);
    InvMatrix[1][0] = - (EqMatrix[1][0]*EqMatrix[2][2] - EqMatrix[1][2]*EqMatrix[2][0]);
    InvMatrix[2][0] = (EqMatrix[1][0]*EqMatrix[2][1] - EqMatrix[1][1]*EqMatrix[2][0]);
    InvMatrix[0][1] = - (EqMatrix[0][1]*EqMatrix[2][2] - EqMatrix[0][2]*EqMatrix[2][1]);
    InvMatrix[1][1] = (EqMatrix[0][0]*EqMatrix[2][2] - EqMatrix[0][2]*EqMatrix[2][0]);
    InvMatrix[2][1] = - (EqMatrix[0][0]*EqMatrix[2][1] - EqMatrix[0][1]*EqMatrix[2][0]);
    InvMatrix[0][2] = (EqMatrix[0][1]*EqMatrix[1][2] - EqMatrix[0][2]*EqMatrix[1][1]);
    InvMatrix[1][2] = - (EqMatrix[0][0]*EqMatrix[1][2] - EqMatrix[0][2]*EqMatrix[1][0]);
    InvMatrix[2][2] = (EqMatrix[0][0]*EqMatrix[1][1] - EqMatrix[0][1]*EqMatrix[1][0]);
 
    //  Divide the adjugate by the determinant in order to find the inverse matrix
    int i, j;
    for (i=0;  i<3;  i++)  for (j=0;  j<3;  j++)  InvMatrix[i][j] /= Det;  // I didn't think you could do that xD
 
    //  Multiply the inverse by the result to get the resulting point
    Result.X = (int)(InvMatrix[0][0]*ResMatrix[0] + InvMatrix[0][1]*ResMatrix[1] + InvMatrix[0][2]*ResMatrix[2]);
    Result.Y = (int)(InvMatrix[1][0]*ResMatrix[0] + InvMatrix[1][1]*ResMatrix[1] + InvMatrix[1][2]*ResMatrix[2]);
    Result.Z = (int)(InvMatrix[2][0]*ResMatrix[0] + InvMatrix[2][1]*ResMatrix[1] + InvMatrix[2][2]*ResMatrix[2]);
    Result.Real = 1;
 
    //  Return a result
    return Result;
}
 

[Savage]

Can we see that call?

Savage

[Envergure]

point P;  // A point
triangle Tri;  // A triangle
triangle T[3];  // An array of triangles
line L;  // A line
 
P = Intersect (Tri, L);  // This works
P = Intersect (T[0], L);  // This doesn't
 

[weaknessforcats]

This code compiles and links OK with Visual Studio.NET 2005.

I had your code in this order:

1) the structs
2) the intersect function
3) main().

[Savage]

point P;  // A point
triangle Tri;  // A triangle
triangle T[3];  // An array of triangles
line L;  // A line
 
P = Intersect (Tri, L);  // This works
P = Intersect (T[0], L);  // This doesn't
 

This should work..have you tried writing same function,but with references as the parameters?
In worst case,copy data from array to a new variable and then call the function..
(maybe the worst thing would be rather changing compiler and/or OS)

Savage

[Envergure]

to weaknessforcats :
Yeah, I just did the same and it worked... Maybe it's just a weird artifact.


I should maybe have said earlier this is just part of a much larger program (550 lines so far, it's eventually going to be a shooter engine).

In the past I've found it sometimes works just to erase part of a program and rewrite it, so I'll try that and post back.


In the meantime, what does "error: no match for call to ‘(point) (triangle&, line&)’" actually mean? I've never seen this error before. Also, ‘(point) (triangle&, line&)’ looks more like a typecast than a function.