Cg Programs

// gasket2.cpp : main project file. #include "stdafx.h"

/* recursive subdivision of triangle to form Sierpinski gasket */ /* number of recursive steps given on command line */

#include <windows.h> #include <math.h> #include <GL/glut.h>

/* initial triangle */

GLfloat v[3][2]={{-1.0, -0.58}, {1.0, -0.58}, {0.0, 1.15}};

int n;

void triangle( GLfloat *a, GLfloat *b, GLfloat *c)

/* specify one triangle */ { glVertex2fv(a); glVertex2fv(b); glVertex2fv(c); }

void divide_triangle(GLfloat *a, GLfloat *b, GLfloat *c, int m) {

/* triangle subdivision using vertex numbers */

GLfloat v0[2], v1[2], v2[2]; int j; if(m>0) { for(j=0; j<2; j++) v0[j]=(a[j]+b[j])/2; for(j=0; j<2; j++) v1[j]=(a[j]+c[j])/2; for(j=0; j<2; j++) v2[j]=(b[j]+c[j])/2;

divide_triangle(a, v0, v1, m-1); divide_triangle(c, v1, v2, m-1); divide_triangle(b, v2, v0, m-1); } else triangle(a,b,c); /* draw triangle at end of recursion */ }

void display() { glClear(GL_COLOR_BUFFER_BIT);

glBegin(GL_TRIANGLES); divide_triangle(v[0], v[1], v[2], n); glEnd(); glFlush(); }

void myinit() { glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(-2.0, 2.0, -2.0, 2.0); glMatrixMode(GL_MODELVIEW); glClearColor (1.0, 1.0, 1.0, 1.0); glColor3f(0.0,0.0,0.0); }

int main(int argc, char **argv) { // n=atoi(argv[1]); /* or set number of subdivision steps here */ n=4; glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500, 500); glutCreateWindow("Sierpinski Gasket"); glutDisplayFunc(display);

myinit(); glutMainLoop(); } // triangle.cpp : main project file.

#include "stdafx.h"

/* * OpenGLSamples Examples * VC++ users should create a Win32 Console project and link * the program with glut32.lib, glu32.lib, opengl32.lib * */

#include <stdio.h> #include <windows.h> #include <GL/gl.h> #include <GL/glut.h> using namespace System; // Standard header for MS Windows applications // Open Graphics Library (OpenGL) header // The GL Utility Toolkit (GLUT) Header

#define KEY_ESCAPE 27

typedef struct { int width; int height;

char* title;

float field_of_view_angle; float z_near; float z_far; } glutWindow;

glutWindow win;

void display() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); Depth Buffer glLoadIdentity(); glTranslatef(0.0f,0.0f,-3.0f); // Clear Screen and

/* * Triangle code starts here * 3 vertices, 3 colors. */ glBegin(GL_TRIANGLES); glColor3f(0.0f,0.0f,1.0f); glVertex3f( 0.0f, 1.0f, 0.0f); glColor3f(0.0f,1.0f,0.0f); glVertex3f(-1.0f,-1.0f, 0.0f); glColor3f(1.0f,0.0f,0.0f);

glVertex3f( 1.0f,-1.0f, 0.0f); glEnd();

glutSwapBuffers(); }

void initialize () { glMatrixMode(GL_PROJECTION); // select projection matrix glViewport(0, 0, win.width, win.height); // set the viewport glMatrixMode(GL_PROJECTION); // set matrix mode glLoadIdentity(); // reset projection matrix GLfloat aspect = (GLfloat) win.width / win.height; gluPerspective(win.field_of_view_angle, aspect, win.z_near, win.z_far); perspective projection matrix glMatrixMode(GL_MODELVIEW); // specify which matrix is the current matrix glShadeModel( GL_SMOOTH ); glClearDepth( 1.0f ); // specify the clear value for the depth buffer glEnable( GL_DEPTH_TEST ); glDepthFunc( GL_LEQUAL ); glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST ); // specify implementation-specific hints // set up a

glClearColor(0.0, 0.0, 0.0, 1.0); // specify clear values for the color buffers

}

void keyboard ( unsigned char key, int mousePositionX, int mousePositionY ) { switch ( key ) { case KEY_ESCAPE: exit ( 0 ); break;

default: break; } }

int main(int argc, char **argv) { // set window values win.width = 640; win.height = 480; win.title = "OpenGL/GLUT Example. Visit http://openglsamples.sf.net "; win.field_of_view_angle = 45; win.z_near = 1.0f;

win.z_far = 500.0f;

// initialize and run program glutInit(&argc, argv); // GLUT initialization

glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH ); // Display Mode glutInitWindowSize(win.width,win.height); size glutCreateWindow(win.title); create Window glutDisplayFunc(display); // register Display Function glutIdleFunc( display ); register Idle Function glutKeyboardFunc( keyboard ); register Keyboard Handler initialize(); glutMainLoop(); // run GLUT mainloop return 0; } // gasket.cpp : main project file. // // // set window

//

#include "stdafx.h" #include <stdio.h> #include <windows.h> #include <GL/gl.h> #include <GL/glut.h> using namespace System; // Standard header for MS Windows applications // Open Graphics Library (OpenGL) header

void myinit() { // attributes glClearColor(1.0,1.0,1.0,1.0); glColor3f(1.0,0.0,0.0); //red //white background

// setup viewing glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0,50.0,0.0,50.0); // (GLdouble L,R,B,T) glMatrixMode(GL_MODELVIEW); }

void display() { // GLfloat verticies[3][3] = {{0.0,0.0,0.0}, {25.0,50.0,0.0}, {50.0,0.0,0.0}}; GLfloat verticies[3][2] = {{0.0,0.0}, {25.0,50.0}, {50.0,0.0}};

//

GLfloat p[3] = {7.5,0.0,0.0}; GLfloat p[2] = {7.5,0.0};

// arbitrary point inside triangle

int j,k; int rand(); glClear(GL_COLOR_BUFFER_BIT); // clear the window

glBegin(GL_POINTS);

for(k=0; k<25000; k++) { j = rand()%3; // pick vertex at random

p[0] = (p[0] + verticies[j][0])/2.0; p[1] = (p[1] + verticies[j][1])/2.0;

// plot point // glVertex3fv(p); glVertex2fv(p);

} glEnd(); glFlush(); }

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

glutInitWindowSize(500,500); glutInitWindowPosition(0,0); glutCreateWindow("OpenGL Example"); glutDisplayFunc(display); myinit(); attributes // initialization function to set openGL state variables dealing with viewing and

// - parameters that we prefer to set once, independently of the display function glutMainLoop();

}