Cppcheck report - openGPMP: ../../modules/complex/openGL_example00.c

// C program to demonstrate
// drawing a circle using
// OpenGL
#include <GL/glut.h>
#include <math.h>
#include <stdio.h>
#define pi 3.142857

// function to initialize
void myInit(void) {
    // making background color black as first
    // 3 arguments all are 0.0
    glClearColor(0.0, 0.0, 0.0, 1.0);

    // making picture color green (in RGB mode), as middle argument
    // is 1.0
    glColor3f(0.0, 1.0, 0.0);

    // breadth of picture boundary is 1 pixel
    glPointSize(1.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    // setting window dimension in X- and Y- direction
    gluOrtho2D(-780, 780, -420, 420);
}

void display(void) {
    glClear(GL_COLOR_BUFFER_BIT);
    glBegin(GL_POINTS);
    float x, y, i;
<--- The scope of the variable 'x' can be reduced. [+]
The scope of the variable 'x' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.
<--- The scope of the variable 'y' can be reduced. [+]
The scope of the variable 'y' can be reduced. Warning: Be careful when fixing this message, especially when there are inner loops. Here is an example where cppcheck will write that the scope for 'i' can be reduced:
void f(int x)
{
    int i = 0;
    if (x) {
        // it's safe to move 'int i = 0;' here
        for (int n = 0; n < 10; ++n) {
            // it is possible but not safe to move 'int i = 0;' here
            do_something(&i);
        }
    }
}
When you see this message it is always safe to reduce the variable scope 1 level.

    // iterate y up to 2*pi, i.e., 360 degree
    // with small increment in angle as
    // glVertex2i just draws a point on specified co-ordinate
    for (i = 0; i < (2 * pi); i += 0.001) {
        // let 200 is radius of circle and as,
        // circle is defined as x=r*cos(i) and y=r*sin(i)
        x = 200 * cos(i);
        y = 200 * sin(i);

        glVertex2i(x, y);
    }
    glEnd();
    glFlush();
}

int main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);

    // giving window size in X- and Y- direction
    glutInitWindowSize(1366, 768);
    glutInitWindowPosition(0, 0);

    // Giving name to window
    glutCreateWindow("Circle Drawing");
    myInit();

    glutDisplayFunc(display);
    glutMainLoop();
}