stryker

02-26-2011, 03:30 AM

Hi guys, I'm trying to implement a series of functions to display a spline, but I really don't have any idea what I'm doing and am not sure if I'm even on the right track. It would be awesome if someone could take a look at these functions and see what I'm doing wrong or if I even understand the concepts behind this.

Note: splineCurve is a 2D array of floats with size[3][1000] that is supposed to hold the value of each coordinate of the spline. g_Splines is an array of spline control points.

float CatmullRom( float u, float x0, float x1, float x2, float x3 )

{

float u2 = u * u;

float u3 = u2 * u;

return ((2 * x1) +

(-x0 + x2) * u +

(2*x0 - 5*x1 + 4*x2 - x3) * u2 +

(-x0 + 3*x1 - 3*x2 + x3) * u3) * 0.5f;

}

void initSpline ()

{

for (int i = 1; i < g_iNumOfSplines; i++)

{

for (int u = 0; u < 1; u += 0.001)

{

splineCurve[0][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].x, g_Splines[i].points[i].x, g_Splines[i].points[i+1].x, g_Splines[i].points[i+2].x);

splineCurve[1][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].y, g_Splines[i].points[i].y, g_Splines[i].points[i+1].y, g_Splines[i].points[i+2].y);

splineCurve[2][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].z, g_Splines[i].points[i].z, g_Splines[i].points[i+1].z, g_Splines[i].points[i+2].z);

}

}

/*

for (int i = 0; i < g_iNumOfSplines; i++)

{

for (int k = 0; k < 4; k++)

{

glColor3f(0.5, 0.5, 0.5);

glVertex3f(g_Splines[i].points[k].x, g_Splines[i].points[k].y, g_Splines[i].points[0].z);

}

}

*/

}

void displaySpline()

{

glBegin(GL_LINES);

glColor3f(0, 0, 0);

for (int i = 0; i < 1000; i++)

{

glVertex3f(splineCurve[0][i], splineCurve[1][i], splineCurve[2][i]);

}

glEnd();

}

Note: splineCurve is a 2D array of floats with size[3][1000] that is supposed to hold the value of each coordinate of the spline. g_Splines is an array of spline control points.

float CatmullRom( float u, float x0, float x1, float x2, float x3 )

{

float u2 = u * u;

float u3 = u2 * u;

return ((2 * x1) +

(-x0 + x2) * u +

(2*x0 - 5*x1 + 4*x2 - x3) * u2 +

(-x0 + 3*x1 - 3*x2 + x3) * u3) * 0.5f;

}

void initSpline ()

{

for (int i = 1; i < g_iNumOfSplines; i++)

{

for (int u = 0; u < 1; u += 0.001)

{

splineCurve[0][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].x, g_Splines[i].points[i].x, g_Splines[i].points[i+1].x, g_Splines[i].points[i+2].x);

splineCurve[1][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].y, g_Splines[i].points[i].y, g_Splines[i].points[i+1].y, g_Splines[i].points[i+2].y);

splineCurve[2][u * 1000] = CatmullRom(u, g_Splines[i].points[i-1].z, g_Splines[i].points[i].z, g_Splines[i].points[i+1].z, g_Splines[i].points[i+2].z);

}

}

/*

for (int i = 0; i < g_iNumOfSplines; i++)

{

for (int k = 0; k < 4; k++)

{

glColor3f(0.5, 0.5, 0.5);

glVertex3f(g_Splines[i].points[k].x, g_Splines[i].points[k].y, g_Splines[i].points[0].z);

}

}

*/

}

void displaySpline()

{

glBegin(GL_LINES);

glColor3f(0, 0, 0);

for (int i = 0; i < 1000; i++)

{

glVertex3f(splineCurve[0][i], splineCurve[1][i], splineCurve[2][i]);

}

glEnd();

}