teapot_triangle.cpp

#include <iostream>
#include <GL/gl.h>
#include <GL/glut.h>
#include <GL/glu.h>

bool fullscreen = false;
int windowX, windowY, windowWidth, windowHeight, cursor;

float angle = 0;
float color = 0;
bool colorMode = true;

void setup() {
	glMatrixMode(GL_PROJECTION);
	glClearColor(0, 0, 0, 0);
}

void reshape(int w, int h) {
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   if (w <= h)
      glOrtho(-1.0, 1.0, -1.0*(GLfloat)h/(GLfloat)w,
               1.0*(GLfloat)h/(GLfloat)w, -1.0, 1.0);

   else
      glOrtho(-1.0*(GLfloat)w/(GLfloat)h,
               1.0*(GLfloat)w/(GLfloat)h, -1.0, 1.0, -1.0, 1.0);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

void keyPressed(unsigned char key, int x, int y) {
	if (key == 'f' || (fullscreen && key == 27)) {
		fullscreen = !fullscreen;
		if (fullscreen) {
			windowX = glutGet(GLUT_WINDOW_X);
			windowY = glutGet(GLUT_WINDOW_Y);
			windowWidth = glutGet(GLUT_WINDOW_WIDTH);
			windowHeight = glutGet(GLUT_WINDOW_HEIGHT);
			glutFullScreen();
			glutSetCursor(GLUT_CURSOR_NONE);
		} else {
			glutPositionWindow(windowX, windowY);
			glutReshapeWindow(windowWidth, windowHeight);
			glutSetCursor(GLUT_CURSOR_INHERIT);
		}
	}
}

void animate(int value) {
	angle += 7;
	if (colorMode)
		color += 0.01;
	else
		color -= 0.01;
	if (color > 1) {
		colorMode = false;
	} else if (color < 0) {
		colorMode = true;
	}
	glutPostRedisplay();
	glutTimerFunc(25, animate, 0);
}

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

	glRotatef(0.5 * angle, 0, 0, 1);
	glRotatef(-0.2 * angle, 1, 1, 0);

	glTranslatef(-0.5, 0, 0);
	glRotatef(angle, 0, 0, 1);
	glRotatef(-0.2 * angle, 1, 0, 0);
	glRotatef(0.4 * angle, 0, 1, 0);
	glBegin(GL_TRIANGLES);
		glColor3f(1, 0, 0);
		glVertex2f(0, 0.5); // vertex 1
		glColor3f(0, 1, 0);
		glVertex2f(-0.5f, -0.25f); // vertex 2
		glColor3f(0, 0, 1);
		glVertex2f(0.5f, -0.25f); // vertex 3
	glEnd();
	glRotatef(-0.4 * angle, 0, 1, 0);
	glRotatef(0.2 * angle, 1, 0, 0);
	glRotatef(-angle, 0, 0, 1);
	glTranslatef(0.5, 0, 0);

	glTranslatef(0.5, 0, 0);
	glRotatef(-angle, 0, 0, 1);
	glColor3f(color, 1 - color, 0.5 + 0.5*color);
	glutWireTeapot(0.25);
	glRotatef(angle, 0, 0, 1);
	glTranslatef(-0.5, 0, 0);
	
	glLoadIdentity();

	glutSwapBuffers();
}

int main(int argc, char *argv[]) {
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
	glutInitWindowSize(800, 800);
	glutCreateWindow("TeapotTriangle");

	setup();
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyPressed);
	glutTimerFunc(1, animate, 0);
	glutDisplayFunc(display);
	glutMainLoop();

	return 0;
}