Set line colors in OpenGL 3+ - c++

Question

how can I set the color for the lines I draw using openGL3 ?
the rendering function I'm using is the following
void renderVertex(std::vector<doubleVertex> &Poly, int32_t iniBound, int32_t endBound, int32_t Type){
for (int32_t i = iniBound; i < endBound; i++) {
GLfloat *ptr_polygonVertices;
ptr_polygonVertices = createPolygonVertices(Poly[i]);
// render OpenGL here
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(2, GL_FLOAT, 0, ptr_polygonVertices);
glDrawArrays(Type, 0, Poly[i].x.size() - 1);
glDisableClientState(GL_VERTEX_ARRAY);
delete[] ptr_polygonVertices;
}
}
Inside this loop
while (!glfwWindowShouldClose(window)) {
glClear(GL_COLOR_BUFFER_BIT);
renderVertex(Poly, 0, nBound, GL_LINE_LOOP);
// Swap front and back buffers
glfwSwapBuffers(window);
// Poll for and process events
glfwPollEvents();
}
If necessary, the complete code is the listed here:
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <math.h>
#include <stdlib.h>
#include "Globals.h"
GLfloat* createPolygonVertices(doubleVertex &Poly);
doubleVertex createCircle(double x, double y, double radius, int numberOfSides);
void windowInit(GLFWwindow *window);
void renderVertex(std::vector<doubleVertex> &Poly, int32_t iniBound, int32_t endBound, int32_t Type);
int main(void)
{
GLFWwindow *window;
// Initialize the library
if (!glfwInit())
exit(0);
// Create a windowed mode window and its OpenGL context
window = glfwCreateWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Polygon Linear Infill", NULL, NULL);
windowInit(window);
////////////////////////////////////// Polygon Example //////////////////////////////////////////
std::vector<doubleVertex> Poly{
{
{ 0, 23.37, 50.24, 31.26, 34.57, 1.46, 4.69, 0 },
{ 0, 11.91, 0, -21.39, -32.22, -26.31, -13.17, 0 }
},
{
{ 42.19, 35.69, 29.76, 34.46, 42.19 },
{ -4.26, 2.34, -5.2, -11.87, -4.26 }
},
{
{ 23.57, 26.29, 11.94, 23.57 },
{ -26.73, -17.39, -18.38, -26.73 }
}
};
double x = 14.97, y = -5.28, r = 7.33;
Poly.push_back(createCircle(x, y, r, 37));
uint32_t i, nBound = Poly.size();
while (!glfwWindowShouldClose(window)) {
glClear(GL_COLOR_BUFFER_BIT);
renderVertex(Poly, 0, nBound, GL_LINE_LOOP);
// Swap front and back buffers
glfwSwapBuffers(window);
// Poll for and process events
glfwPollEvents();
}
glfwTerminate();
return 0;
}
GLfloat* createPolygonVertices(doubleVertex &Poly){
int32_t j, n_Vertex, cnt_polygonVertices=0;
n_Vertex = Poly.x.size();
GLfloat *polygonVertices;
polygonVertices = new GLfloat[(n_Vertex-1) * 2];
for (j = 0; j < n_Vertex-1; j++) {
polygonVertices[cnt_polygonVertices] = Poly.x[j];
cnt_polygonVertices++;
polygonVertices[cnt_polygonVertices] = Poly.y[j];
cnt_polygonVertices++;
}
return polygonVertices;
}
doubleVertex createCircle(double x, double y, double radius, int numberOfSides){
int numberOfVertices = numberOfSides + 2;
double twicePi = 2.0f * M_PI;
doubleVertex Poly;
for (int i = 0; i < numberOfVertices; i++)
{
Poly.x.push_back(x + (radius * cos(i * twicePi / numberOfSides)));
Poly.y.push_back(y + (radius * sin(i * twicePi / numberOfSides)));
}
return Poly;
}
void windowInit(GLFWwindow *window){
if (!window) {
glfwTerminate();
exit(0);
}
// Make the window's context current
glfwMakeContextCurrent(window);
glViewport(0.0f, 0.0f, SCREEN_WIDTH, SCREEN_HEIGHT); // specifies the part of the window to which OpenGL will draw (in pixels), convert from normalised to pixels
glMatrixMode(GL_PROJECTION); // projection matrix defines the properties of the camera that views the objects in the world coordinate frame. Here you typically set the zoom factor, aspect ratio and the near and far clipping planes
glLoadIdentity(); // replace the current matrix with the identity matrix and starts us a fresh because matrix transforms such as glOrpho and glRotate cumulate, basically puts us at (0, 0, 0)
glOrtho(0, 51, -33, 12, 0, 1); // essentially set coordinate system
glMatrixMode(GL_MODELVIEW); // (default matrix mode) modelview matrix defines how your objects are transformed (meaning translation, rotation and scaling) in your world
glLoadIdentity(); // same as above comment
}
void renderVertex(std::vector<doubleVertex> &Poly, int32_t iniBound, int32_t endBound, int32_t Type){
for (int32_t i = iniBound; i < endBound; i++) {
GLfloat *ptr_polygonVertices;
ptr_polygonVertices = createPolygonVertices(Poly[i]);
// render OpenGL here
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(2, GL_FLOAT, 0, ptr_polygonVertices);
glDrawArrays(Type, 0, Poly[i].x.size() - 1);
glDisableClientState(GL_VERTEX_ARRAY);
delete[] ptr_polygonVertices;
}
}
Thanks in advance!