// This is a simple introductory program; its main window contains a static
// picture of a tetrahedron, whose top vertex is white and whose bottom
// vertices are red, green and blue. The program illustrates viewing by
// defining an object at a convenient location, then transforming it so that
// it lies within the view volume. This is a lousy way to do things (it's
// easier to use gluLookAt()), but it's nice to see how viewing is done at
// a very low level.
#ifdef __APPLE_CC__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
// Clears the window and draws the tetrahedron. The tetrahedron is easily
// specified with a triangle strip, though the specification really isn't very
// easy to read.
void display() {
glClear(GL_COLOR_BUFFER_BIT);
// Draw a white grid "floor" for the tetrahedron to sit on.
glColor3f(1.0, 1.0, 1.0);
glBegin(GL_LINES);
for (GLfloat i = -2.5; i <= 2.5; i += 0.25) {
glVertex3f(i, 0, 2.5); glVertex3f(i, 0, -2.5);
glVertex3f(2.5, 0, i); glVertex3f(-2.5, 0, i);
}
glEnd();
// Draw the tetrahedron. It is a four sided figure, so when defining it
// with a triangle strip we have to repeat the last two vertices.
glBegin(GL_TRIANGLE_STRIP);
glColor3f(1, 1, 1); glVertex3f(0, 2, 0);
glColor3f(1, 0, 0); glVertex3f(-1, 0, 1);
glColor3f(0, 1, 0); glVertex3f(1, 0, 1);
glColor3f(0, 0, 1); glVertex3f(0, 0, -1.4);
glColor3f(1, 1, 1); glVertex3f(0, 2, 0);
glColor3f(1, 0, 0); glVertex3f(-1, 0, 1);
glEnd();
glFlush();
}
// Sets up global attributes like clear color and drawing color, enables and
// initializes any needed modes (in this case we want backfaces culled), and
// sets up the desired projection and modelview matrices. It is cleaner to
// define these operations in a function separate from main().
void init() {
// Set the current clear color to sky blue and the current drawing color to
// white.
glClearColor(0.1, 0.39, 0.88, 1.0);
glColor3f(1.0, 1.0, 1.0);
// Tell the rendering engine not to draw backfaces. Without this code,
// all four faces of the tetrahedron would be drawn and it is possible
// that faces farther away could be drawn after nearer to the viewer.
// Since there is only one closed polyhedron in the whole scene,
// eliminating the drawing of backfaces gives us the realism we need.
// THIS DOES NOT WORK IN GENERAL.
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
// Set the camera lens so that we have a perspective viewing volume whose
// horizontal bounds at the near clipping plane are -2..2 and vertical
// bounds are -1.5..1.5. The near clipping plane is 1 unit from the camera
// and the far clipping plane is 40 units away.
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-2, 2, -1.5, 1.5, 1, 40);
// Set up transforms so that the tetrahedron which is defined right at
// the origin will be rotated and moved into the view volume. First we
// rotate 70 degrees around y so we can see a lot of the left side.
// Then we rotate 50 degrees around x to "drop" the top of the pyramid
// down a bit. Then we move the object back 3 units "into the screen".
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0, 0, -3);
glRotatef(50, 1, 0, 0);
glRotatef(70, 0, 1, 0);
}
// Initializes GLUT, the display mode, and main window; registers callbacks;
// does application initialization; enters the main event loop.
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition(80, 80);
glutInitWindowSize(800, 600);
glutCreateWindow("A Simple Tetrahedron");
glutDisplayFunc(display);
init();
glutMainLoop();
}
Torus
Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!
OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name;
cout << "Enter name:";
getline (cin, name);
cout << "Hello " << name;
return 0;
}
C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) {
//code
}
else {
//code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression){
case value1:
// code
break; // optional
case value2:
// code
break; // optional
......
default:
code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while (condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
// code
}