Programowanie w systemie UNIX/Cpp: Różnice pomiędzy wersjami

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Usunięta treść Dodana treść
link wewn
opengl
Linia 1: Linia 1:
=Przykłady=
Przykładowy program w [[C++]] :
Przykładowe program w [[C++]] :


=Hello world=


<source lang=cpp>
<source lang=cpp>
Linia 22: Linia 26:
./a.out
./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>

unsigned int win_w = 0;
unsigned int win_h = 0;
unsigned int mouse_x = 0;
unsigned int mouse_y = 0;

void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_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();

unsigned char pixel[3];
glReadPixels(mouse_x, mouse_y, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, pixel);
std::cout << "R: " << (int)pixel[0] << std::endl;
std::cout << "G: " << (int)pixel[1] << std::endl;
std::cout << "B: " << (int)pixel[2] << std::endl;
std::cout << std::endl;

glFlush();
glutSwapBuffers();
}

void motion(int x, int y)
{
mouse_x = x;
mouse_y = win_h - y;
glutPostRedisplay();
}

void reshape(int w, int h)
{
win_w = w;
win_h = h;
glViewport(0, 0, w, h);
}

int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);

glutInitWindowSize(640,480);
glutCreateWindow("glReadPixels()");

glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutPassiveMotionFunc(motion);
glutMainLoop();
return 0;
}

</source>

Wersja z 18:37, 6 kwi 2014

Przykłady

Przykładowe program w C++ :


Hello world

#include <iostream> 

int main () {

std::cout << "Hello, world!\n";

return 0;

}

Zapisujemy jako hello.cpp

Kompilujemy :

g++ -Wall hello.cpp

i uruchomiamy :

./a.out


OpenGl

// 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>

unsigned int win_w = 0;
unsigned int win_h = 0;
unsigned int mouse_x = 0;
unsigned int mouse_y = 0;

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_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();

    unsigned char pixel[3];
    glReadPixels(mouse_x, mouse_y, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, pixel);
    std::cout << "R: " << (int)pixel[0] << std::endl;
    std::cout << "G: " << (int)pixel[1] << std::endl;
    std::cout << "B: " << (int)pixel[2] << std::endl;
    std::cout << std::endl;

    glFlush();
    glutSwapBuffers();
}

void motion(int x, int y)
{
    mouse_x = x;
    mouse_y = win_h - y;
    glutPostRedisplay();
}

void reshape(int w, int h)
{
    win_w = w;
    win_h = h;
    glViewport(0, 0, w, h);
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);

    glutInitWindowSize(640,480);
    glutCreateWindow("glReadPixels()");

    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutPassiveMotionFunc(motion);
    glutMainLoop();
    return 0;
}