movement repeat in 2d game by opengl - c

Question

When the red car is moving, it is repeated with every movement and at every chance has repeated, I had searched but not found a solution, so what is the solution to the problem?
#include <GL\glut.h>
#define drawW 400
#define drawH 300
void reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
float ratio = (float)width / height;
if (width > height)
{
glOrtho(-drawW * ratio, drawW * ratio, -drawH, drawH, -1, 1);
}
else
{
glOrtho(-drawW, drawW, -drawH / ratio, drawH / ratio, -1, 1);
}
glClear(GL_DEPTH_BUFFER_BIT);
glClearColor(0.21, 0.22, 0.18, 1);
}
void car() {
//drawing the movement car
glTranslated(0, -100, 0);
glBegin(GL_POLYGON);
glColor3f(0.73, 0.63, 0.56);
glVertex2f(50, 50);
glVertex2f(0, 100);
glVertex2f(-50, 50);
glVertex2f(-50, -100);
glVertex2f(50, -100);
glEnd();
//drawing the 1st wheel in the 1st quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(75, 25);
glVertex2f(50, 25);
glVertex2f(50, 0);
glVertex2f(75, 0);
glEnd();
//drawing the 2nd wheel in the 2nd quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(-50, 25);
glVertex2f(-75, 25);
glVertex2f(-75, 0);
glVertex2f(-50, 0);
glEnd();
//drawing the 3rd wheel in the 3rd quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(-50, -50);
glVertex2f(-75, -50);
glVertex2f(-75, -75);
glVertex2f(-50, -75);
glEnd();
//drawing the 4th wheel in the 4th quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(75, -50);
glVertex2f(50, -50);
glVertex2f(50, -75);
glVertex2f(75, -75);
glEnd();
glFlush();
}
void display()
{
glClear(GL_COLOR_BUFFER_BIT);
//drawing the green car in the 1st quarter
glBegin(GL_POLYGON);
glColor3f(0.28, 0.64, 0.47);
glVertex2i(350, 300);
glVertex2i(300, 300);
glVertex2i(300, 150);
glVertex2i(325, 125);
glVertex2i(350, 150);
glEnd();
//drawing the 1st wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(300, 275.0);
glVertex2i(283, 275);
glVertex2i(283, 250);
glVertex2i(300, 250.0);
glEnd();
//drawing the 2nd wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(300, 200.0);
glVertex2i(283, 200);
glVertex2i(283, 175);
glVertex2i(300, 175.0);
glEnd();
//drawing the 3rd wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(365, 200);
glVertex2i(350, 200);
glVertex2i(350, 175);
glVertex2i(365, 175);
glEnd();
//drawing the 4th wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(365, 275);
glVertex2i(350, 275);
glVertex2i(350, 250);
glVertex2i(365, 250);
glEnd();
glFlush();
//drawing the purple car
glBegin(GL_POLYGON);
glColor3f(0.48, 0.48, 0.64);
glVertex2i(-350, 300);
glVertex2i(-300, 300);
glVertex2i(-300, 150);
glVertex2i(-325, 125);
glVertex2i(-350, 150);
glEnd();
//drawing the 1st wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(-300, 275.0);
glVertex2i(-283, 275);
glVertex2i(-283, 250);
glVertex2i(-300, 250.0);
glEnd();
//drawing the 2nd wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(-300, 200.0);
glVertex2i(-283, 200);
glVertex2i(-283, 175);
glVertex2i(-300, 175.0);
glEnd();
//drawing the 3rd wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(-365, 200);
glVertex2i(-350, 200);
glVertex2i(-350, 175);
glVertex2i(-365, 175);
glEnd();
//drawing the 4th wheel of the car
glBegin(GL_POLYGON);
glColor3f(0, 0, 0.0);
glVertex2i(-365, 275);
glVertex2i(-350, 275);
glVertex2i(-350, 250);
glVertex2i(-365, 250);
glEnd();
//the break
glBegin(GL_POLYGON);
glColor3f(0.0, 0, 0.0);
glVertex2i(-300, 100);
glVertex2i(-300, 75);
glVertex2i(-150, 100);
glVertex2i(-150, 75);
glEnd();
//drawing the line in the middle of the road
glBegin(GL_POLYGON);
glColor3f(30, 30, 0);
glVertex2f(20, 200);
glVertex2f(-20, 200);
glVertex2f(-20, 50);
glVertex2f(20, 50);
glEnd();
//drawing the red object of the car
glTranslated(0, -100, 0);
glBegin(GL_POLYGON);
glColor3f(0.91, 0.07, 0.09);
glVertex2f(50, 50);
glVertex2f(0, 100);
glVertex2f(-50, 50);
glVertex2f(-50, -100);
glVertex2f(50, -100);
glEnd();
//drawing the 1st wheel in the 1st quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(75, 25);
glVertex2f(50, 25);
glVertex2f(50, 0);
glVertex2f(75, 0);
glEnd();
//drawing the 2nd wheel in the 2nd quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(-50, 25);
glVertex2f(-75, 25);
glVertex2f(-75, 0);
glVertex2f(-50, 0);
glEnd();
//drawing the 3rd wheel in the 3rd quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(-50, -50);
glVertex2f(-75, -50);
glVertex2f(-75, -75);
glVertex2f(-50, -75);
glEnd();
//drawing the 4th wheel in the 4th quarter
glBegin(GL_POLYGON);
glColor3f(0, 0.0, 0);
glVertex2f(75, -50);
glVertex2f(50, -50);
glVertex2f(50, -75);
glVertex2f(75, -75);
glEnd();
glFlush();
}
void processNormalKeys(unsigned char key, int x, int y)
{
switch (key)
{
case 'd':
case 'D':
glTranslated(200, 100, 0);
car();
glutPostRedisplay;
break;
case 'a':
case 'A':
glTranslated(-200, 100, 0);
car();
break;
}
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitWindowSize(1000, 600);
glutCreateWindow("Speedy Car Race");
glutSwapBuffers;
glutDisplayFunc(car);
glutPostRedisplay();
glutDisplayFunc(display);
glutKeyboardFunc(processNormalKeys);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}
I try adding glutSwapBuffer(), glutPostRedisplay(), glClear(GL_COLOR_BUFFER_BIT)
but not of them working?

Answer 1

This line DOES NOT call glutPostRedisplay:
glutPostRedisplay;
Therefore your keyboard events do not trigger the display() function, glClear isn't called, and the buffer isn't cleared.
To actually call glutPostRedisplay, you must put parentheses after the function name:
glutPostRedisplay();