Programowanie w systemie UNIX/Cpp: Różnice pomiędzy wersjami

(→‎OpenGl: nowy kod)
./a.out
 
 
==OpenGl ==
 
 
<source lang = cpp>
 
// http://stackoverflow.com/questions/8000921/how-to-get-color-from-the-pixel-opengl
// g++ r.cpp -lGL -lGLU -lglut -Wall
// ./a.out
 
#include <GL/glut.h>
#include <iostream>
 
using namespace std;
 
void display()
{
glClear(GL_COLOR_BUFFER_BIT);
 
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-10, 10, -10, 10, -1, 1);
 
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
 
glPushMatrix();
glScalef(5,5,5);
glBegin(GL_TRIANGLES);
glColor3ub(255,0,0);
glVertex2f(-1,-1);
glColor3ub(0,255,0);
glVertex2f(1,-1);
glColor3ub(0,0,255);
glVertex2f(1,1);
glEnd();
glPopMatrix();
 
glutSwapBuffers();
}
 
void motion(int x, int y)
{
y = glutGet( GLUT_WINDOW_HEIGHT ) - y;
 
unsigned char pixel[4];
glReadPixels(x, y, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, pixel);
cout << "R: " << (int)pixel[0] << endl;
cout << "G: " << (int)pixel[1] << endl;
cout << "B: " << (int)pixel[2] << endl;
cout << endl;
}
 
int main(int argc, char **argv)
{
glutInitWindowSize(640,480);
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
glutCreateWindow("glReadPixels()");
 
glutDisplayFunc(display);
glutPassiveMotionFunc(motion);
glutMainLoop();
return 0;
}
 
</source>
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