gl_util.h

#ifndef _GL_UTIL_H
#define _GL_UTIL_H

#include <GL/glut.h>
#include <GL/glu.h>
#include <cmath>

#define RADPERDEG 0.0174533

int NoColor = false;



void drawArrow(float x1, float y1, float z1, float x2, float y2,
    float z2, float D) {
    float x = x2 - x1;
    float y = y2 - y1;
    float z = z2 - z1;
    float L = sqrt(x * x + y * y + z * z);

    GLUquadricObj *quadObj;

    glPushMatrix();

    glTranslated(x1, y1, z1);

    if ((x != 0.) || (y != 0.)) {
        glRotated(atan2(y, x) / RADPERDEG, 0., 0., 1.);
        glRotated(atan2(sqrt(x * x + y * y), z) / RADPERDEG, 0., 1., 0.);
    }
    else if (z < 0) {
        glRotated(180, 1., 0., 0.);
    }

    glTranslatef(0, 0, L - 4 * D);

    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluCylinder(quadObj, 2 * D, 0.0, 4 * D, 32, 4);
    gluDeleteQuadric(quadObj);

    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluDisk(quadObj, 0.0, 2 * D, 32, 4);
    gluDeleteQuadric(quadObj);

    glTranslatef(0, 0, -L + 4 * D);

    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluCylinder(quadObj, D, D, L - 4 * D, 32, 4);
    gluDeleteQuadric(quadObj);

    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluDisk(quadObj, 0.0, D, 32, 4);
    gluDeleteQuadric(quadObj);

    glPopMatrix();
}

void drawCircle(float r) {
    glPushMatrix();
    GLUquadricObj *quadObj;
    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_SILHOUETTE);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluDisk(quadObj, 0.0, r, 32, 4);
    gluDeleteQuadric(quadObj);
    glPopMatrix();
}

void drawCylinder(float h, float r) {
    glPushMatrix();
    GLUquadricObj *quadObj;
    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluCylinder(quadObj, r, r, h, 32, 4);
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluDisk(quadObj, 0.0, r, 32, 4);
    glTranslatef(0, 0, h);
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluDisk(quadObj, 0.0, r, 32, 4);
    gluDeleteQuadric(quadObj);
    glPopMatrix();
}

void drawCone(float h, float r0, float r1) {
    glPushMatrix();
    GLUquadricObj *quadObj;
    quadObj = gluNewQuadric();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    gluCylinder(quadObj, r0, r1, h, 32, 4);
    gluDeleteQuadric(quadObj);
    glPopMatrix();
}

void drawSphere(float r, float slices , float stacks) {
    GLUquadricObj *quadObj;
    quadObj = gluNewQuadric();
    gluSphere(quadObj, r, slices, stacks);
    gluDeleteQuadric(quadObj);
}


void draw_axes_arrow(float width, float height, float depth, float r)
{
    glColor3f(1, 0, 0);
    drawArrow(-width / 2, 0, 0, width / 2, 0, 0, r);
    glColor3f(0, 1, 0);
    drawArrow(0, -height / 2, 0, 0, height / 2, 0, r);
    glColor3f(0, 0, 1);
    drawArrow(0, 0, -depth / 2, 0, 0, depth / 2, r);
}


void draw_axes(float width, float height, float depth)
{
    glColor3f(1, 0, 0);
    glBegin(GL_LINES);
    glVertex3f(-width / 2, 0, 0);
    glVertex3f(width / 2, 0, 0);
    glEnd();
    glColor3f(0, 0, 1);
    glBegin(GL_LINES);
    glVertex3f(0, -height / 2, 0);
    glVertex3f(0, height / 2, 0);
    glEnd();
    glColor3f(0, 1, 0);
    glBegin(GL_LINES);
    glVertex3f(0, 0, -depth / 2);
    glVertex3f(0, 0, depth / 2);
    glEnd();
}


void draw_axes_positive(float width, float height, float depth)
{
    glColor3f(1, 0, 0);
    glBegin(GL_LINES);
    glVertex3f(0, 0, 0);
    glVertex3f(width, 0, 0);
    glEnd();
    glColor3f(0, 0, 1);
    glBegin(GL_LINES);
    glVertex3f(0, 0, 0);
    glVertex3f(0, height, 0);
    glEnd();
    glColor3f(0, 1, 0);
    glBegin(GL_LINES);
    glVertex3f(0, 0, 0);
    glVertex3f(0, 0, depth);
    glEnd();
}

void drawCube(float dx, float dy, float dz) {
    glPushMatrix();
    glTranslatef(-dx / 2, -dy / 2, -dz / 2);

    glBegin(GL_QUADS);
    // back face
    glNormal3f(0, 0, -1);
    glVertex3f(0, 0, 0);
    glVertex3f(0, dy, 0);
    glVertex3f(dx, dy, 0);
    glVertex3f(dx, 0, 0);

    // flront face
    glNormal3f(0, 0, 1);
    glVertex3f(0, 0, dz);
    glVertex3f(0, dy, dz);
    glVertex3f(dx, dy, dz);
    glVertex3f(dx, 0, dz);

    // bottom face  (z = 1.0f)
    glNormal3f(0, -1, 0);
    glVertex3f(0, 0, 0);
    glVertex3f(0, 0, dz);
    glVertex3f(dx, 0, dz);
    glVertex3f(dx, 0, 0);

    // top face (z = -1.0f)
    glNormal3f(0, 1, 0);
    glVertex3f(0, dy, 0);
    glVertex3f(0, dy, dz);
    glVertex3f(dx, dy, dz);
    glVertex3f(dx, dy, 0);

    // Left face (x = -1.0f)
    glNormal3f(-1, 0, 0);
    glVertex3f(0, 0, 0);
    glVertex3f(0, 0, dz);
    glVertex3f(0, dy, dz);
    glVertex3f(0, dy, 0);

    // // Right face (x = 1.0f)
    glNormal3f(1, 0, 0);
    glVertex3f(dx, 0, 0);
    glVertex3f(dx, 0, dz);
    glVertex3f(dx, dy, dz);
    glVertex3f(dx, dy, 0);

    glEnd();  // End of drawing color-cube
    glPopMatrix();
}

void renderString(float x, float y, const char* string, float r = 1, float g = 1, float b = 1)
{  
  glColor3f(r, g, b); 
  glRasterPos2f(x, y);
  glutBitmapString(GLUT_BITMAP_9_BY_15, (const unsigned char*)string);
}


#endif