The following code compiles on VS Express Edition 2008, yet I get the following errors when trying to debug/release:
1>Linking...
1>MSVCRT.lib(crtexew.obj) : error LNK2001: unresolved external symbol _WinMain@16
1>E:\Documents and Settings\Administrator\Desktop\Proyecto 2 gràficas\testing\Release\testing.exe : fatal error LNK1120: 1 unresolved externals
is it because it's unable to link a library? How can I solve this?
#include <windows.h> // use as needed for your system
#include <gl/Gl.h>
#include <gl/glut.h>
#include <iostream>
#include <fstream>
using namespace std;
//**************Global Data
char ifileName[30];
char oFileName[30];
fstream inFile;
fstream outFile;
//************ Data structure
struct GLfloatPoint
{ GLfloat x,y;
};
const int MAX = 100;
class GLfloatPointArray
{
public:
int num;
GLfloatPoint pt[MAX];
};
//***************** subprograms
typedef GLfloat colorType[3];
// subprogram used to draw the control points separately
void drawDot (GLfloat x, GLfloat y, GLfloat r, GLfloat g, GLfloat b)
{ glColor3f(r,g,b);
glBegin (GL_POINTS);
glVertex2f (x,y);
glEnd();
}
// Drawing subprogram - this will draw the curve from a set of points
void drawFloatPolyLine (GLfloatPointArray P, colorType c)
{ glColor3fv (c);
glBegin(GL_LINE_STRIP);
for (int i=0; i < P.num; i++)
glVertex2f (P.pt[i].x,P.pt[i].y);
glEnd();
}
//******************** myInit
void myInit(void)
{
glClearColor(1.0,1.0,1.0,0.0); // set white background color
glColor3f (0.0f,0.0f,0.0f); //default color
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0, 640.0, 0.0, 480.0);
// get data files
cout << "Enter the input file name: ";
cin >> ifileName;
inFile.open (ifileName,ios::in);
if (inFile.fail())
return;
// if want to see points for debugging add output
// cout << "Enter the output file name: ";
// cin >> oFileName;
// outFile.open (oFileName,ios::out);
// if (outFile.fail())
// return;
}
//***************** BEZIER Curve subprograms
// Read the control points
void readControlPoints (GLfloatPointArray &P)
{
inFile >> P.num;
for (int j = 0; j < P.num; j++)
inFile >> P.pt[j].x >> P.pt[j].y;
}
// output control points to a text file - if you want to see the
// computations
void printPointArray (GLfloatPointArray P)
{
outFile << "Size: " << P.num << endl << "Points:" << endl;
for (int j = 0; j < P.num; j++)
outFile << "(" << P.pt[j].x << "," << P.pt[j].y << ")" << endl;
}
const int MAXCONTPTS = 100;
int c[MAXCONTPTS]; // the binomial coefficients
//helper routines - compute the coefficient
void ComputeCoeff (int n)
{ int j,k;
for (k=0;k<=n;k++)
{ //compute n! / (k!*(n-k)!)
c[k] = 1;
for (j = n;j>=k+1;j--)
c[k] *=j;
for (j = n-k;j>=2;j--)
c[k] /= j;
}
}
// compute the blending value
float BlendingValue (int n, int k, float t)
{ int j;
float bv;
// compute c[k]*t^k * (1-t)^(n-k)
bv = c[k];
for (j=1; j<=k;j++)
bv *= t;
for (j = 1;j<=n-k;j++)
bv *= (1-t);
return bv;
}
// compute one point on the Bezier curve - fixed value of t
void ComputePoint (float t, int n, GLfloatPoint & p,
GLfloatPointArray ctrlPts)
{ int k;
float b;
p.x = 0.0;
p.y = 0.0;
for (k = 0; k<=n;k++)
{ b = BlendingValue (n,k,t);
p.x += ctrlPts.pt[k].x*b;
p.y += ctrlPts.pt[k].y*b;
}
}
// compute the array of Bezier points - drawing done separately
void Bezier ( GLfloatPointArray controlPts, int numInter,
GLfloatPointArray & curve)
{ // there are numContPts+1 control points and numInter t values to evaluate the curve
int k;
float t;
ComputeCoeff (controlPts.num-1);
curve.num = numInter+1;
for (k=0; k<=numInter; k++)
{ t = (float) k / (float) numInter;
ComputePoint (t, controlPts.num-1,curve.pt[k],controlPts);
}
}
//************************ myDisplay
void myDisplay(void)
{
int numbCurves;
GLfloatPointArray ControlPts,BezCurve;
colorType C = {0.0f,1.0f,0.0f};
glClear(GL_COLOR_BUFFER_BIT); // clear the screen
inFile >> numbCurves;
for (int i = 0; i < numbCurves; i++)
{
// read control points and draw them in red big points
readControlPoints (ControlPts);
glPointSize (4.0);
for (int j = 0; j < ControlPts.num; j++)
drawDot (ControlPts.pt[j].x,ControlPts.pt[j].y,1,0,0);
glPointSize (1.0);
// Compute the Bezier curve points and draw
Bezier (ControlPts,50,BezCurve);
// draw the Bezier curve
drawFloatPolyLine (BezCurve,C);
glFlush ();
}
}
//**************************** main
void main(int argc, char** argv)
{
glutInit(&argc, argv); // initialize the toolkit
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
glutInitWindowSize(640,480); // set window size
glutInitWindowPosition(100, 150); // set window position on screen
glutCreateWindow("Bezier Curve drawing"); // open the screen window
glutDisplayFunc(myDisplay); // register redraw function
myInit();
glutMainLoop(); // go into a perpetual loop
}