Drawing a triangle with colors

Mon Mar 14, 2011 1:06 pm

Code:: #include <cstdlib> #include <GL/glut.h> #include <GL/glut.h> void displayFunc(void) { // Clear the current buffer before drawing . glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); // Draw polygon glBegin(GL_POLYGON); { // change color glColor3f(0.0,1.0,0.0); // set point glVertex3f(-0.4,-0.5,-3.0); // change color glColor3f(1.0,0.0,0.0); // set point glVertex3f(0.6,-0.5,-3.0); // change color glColor3f(0.0,0.0,1.0); // set point glVertex3f(0.7,0.5,-3.0); } glEnd(); // Flush the buffer glFlush(); } void reshapeFunc(int x, int y) { if (y == 0 || x == 0) return; //New projection matrix. glMatrixMode(GL_PROJECTION); //Load Identity matrix. glLoadIdentity(); //Angle of view:40 degrees //Near clipping plane distance: 0.5 //Far clipping plane distance: 20.0 gluPerspective(40.0,(GLdouble)x/(GLdouble)y,0.5,20.0); glMatrixMode(GL_MODELVIEW); //Use all window size for rendering glViewport(0,0,x,y); } int main(int argc, char *argv[]) { //Initialization to GLUT glutInit(&argc, argv); // Single Buffer // Use RGB Colors glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // Set the width and height of windows glutInitWindowSize(400,400); // Create the window / with title = codemiles openGL glutCreateWindow("codemiles openGL"); glClearColor(0.0,0.0,0.0,0.0); //Set the function used for display call back . glutDisplayFunc(displayFunc); //Set the function used for reshape call back . glutReshapeFunc(reshapeFunc); //start glut map glutMainLoop(); return 0; }

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