Reaper
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Joined: Jun 2004
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O.P. C++ Help
I'm doing a bit of coding with C++ and OpenGL.
I'm using cubic bezier curves. I having a some trouble. Instead of using lines to draw the curves, I want to use cubes. I've managed to changed it but when I draw 1 curve, it shows many cubes spaced out.
How can I get the cubes to stay together?
code: /* Draw x , y and z axis */
#include <stdlib.h>
#include <glut.h> //OpenGL library
GLfloat Ax,Bx,Cx,Dx,Ay,By,Cy,Dy,Az,Bz,Cz,Dz,x1,k,l,x2,y2,z2,t,p,constx1,consty1,constz1;
int i;
/* define a draw routine to draw the x,y and z axis */
void drawaxis(void) /*x,y,z*/
{
// x coordinates to draw the x axis
GLdouble x1[3] = {-100.0, 0.0, 0.0}; // define coordinates as an array
GLdouble x2[3] = {50.0, 0.0, 0.0}; //GLdouble opengl varaible for storing doubles
// y coordinates to draw the y axis
GLdouble y1[3] = {0.0, -100.0, 0.0};
GLdouble y2[3] = {0.0, 50.0, 0.0};
// z coordinates to draw the z axis
GLdouble z1[3] = {0.0, 0.0, -100.0};
GLdouble z2[3] = {0.0, 0.0, 50.0};
glBegin(GL_LINES);
glColor3f(1.0, 0.0, 0.0); //give different color to the three axis, red for x axis
glVertex3dv(x1);
glVertex3dv(x2);
glColor3f(0.0, 1.0, 0.0); //give green color to y axis
glVertex3dv(y1);
glVertex3dv(y2);
glColor3f(1.0, 1.0, 1.0); //give white color to z axis
glVertex3dv(z1);
glVertex3dv(z2);
glEnd();
}
// define the Bezier routine here
void DrawBezier(float firstx1,float firsty1,float firstz1,float lastx2,float lasty2,float lastz2,float conx1, float cony1,float conz1,float conx2,float cony2,float conz2)
{
Ax =lastx2 -firstx1-3*conx2+3*conx1;
Bx = 3*firstx1 -6*conx1 +3*conx2;
Cx=-3*firstx1+3*conx1;
Dx=firstx1;
Ay =lasty2 -firsty1-3*cony2+3*cony1;
By = 3*firsty1 -6*cony1 +3*cony2;
Cy=-3*firsty1+3*cony1;
Dy=firsty1;
Az =lastz2 -firstz1-3*conz2+3*conz1;
Bz = 3*firstz1 -6*conz1 +3*conz2;
Cz=-3*firstz1+3*conz1;
Dz=firstz1;
// now draw the curve
for (t=0.0;t<=1.0 ; t=t+0.05)
{
x1=Ax*t*t*t +Bx*t*t + Cx*t + Dx;
k =Ay*t*t*t +By*t*t + Cy*t + Dy;
l =Az*t*t*t +Bz*t*t + Cz*t + Dz;
p=t+0.05;
x2=Ax*p*p*p +Bx*p*p + Cx*p + Dx;
y2=Ay*p*p*p +By*p*p + Cy*p + Dy;
z2=Az*p*p*p +Bz*p*p + Cz*p + Dz;
glLineWidth(5);
glTranslatef(x1,k,l);
glutSolidCube(1);
}
}
/* reshape callback function executed when window is moved or resized */
void reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(50.0,1.0,15.0,350.0); //Perspective
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
/* display routine this where the drawing takes place */
void display(void)
{
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); /* clear window */
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(50.0, 20.0, 50.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); //position of the eye
drawaxis(); // draw the coordinate axis
//draw Bezier curve here notice use of z coordinates in the control points
//DrawBezier(-5,10,10,5,10,10,1.5,10,10,3.5,10,10); //first arc
//DrawBezier(-10,13,10,0,10,10,-2.5,10.5,10,-7.5,12.5,10); //second arc
//DrawBezier(0,0,0,1,0,0,0.25,0,0,0.75,0,0);
DrawBezier(5,0,0,10,2,0,6.25,0.5,0,8.25,1.5,0);
//DrawBezier(10,2,0,15,4,0,11.25,2.5,0,13.75,3.5,0);
//DrawBezier(0,0,0,0,0,0,0,0,0,0,0,0);
glutSwapBuffers();
glFlush();
}
/* graphics initialisation */
void init(void)
{
glClearColor (0.0, 0.0, 0.0, 0.0); /* window will be cleared to black */
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE); // Enable back culling
glCullFace(GL_BACK); // Cull back faces
}
int main(int argc, char** argv)
{
/* window management code ... */
/* initialises GLUT and processes any command line arguments */
glutInit(&argc, argv);
/* use single-buffered window and RGBA colour model */
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
/* enable the depth test */
glEnable(GL_DEPTH_TEST);
/* window width = 600 pixels, height = 600 pixels */
glutInitWindowSize (600, 600);
/* window upper left corner at (0, 0) */
glutInitWindowPosition (0, 0);
/* creates an OpenGL window with command argument in its title bar */
glutCreateWindow ("Opening Window");
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}
(You need OpenGL installed to be able to run this)
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