spinningCube.c

#include<stdio.h>
#include<GL/glu.h>
#include<GL/glut.h>
#include<math.h>


GLfloat d = 0;
int a = 0;

void CustomInit(){
	glClearColor(0, 0, 0, 1);
	glEnable(GL_DEPTH_TEST);
}	


void Spin()
{
	d = d + 0.05;
	if(d > 360){
		d = 0;
	}
	glutPostRedisplay();
}


void Face(
		GLfloat A[], 
		GLfloat B[], 
		GLfloat C[],
		GLfloat D[]
	 )
{
	glBegin(GL_POLYGON);
		glVertex3fv(A);
		glVertex3fv(B);
		glVertex3fv(C);
		glVertex3fv(D);
	glEnd();
}


void Cube(
		GLfloat V0[],
		GLfloat V1[],
		GLfloat V2[],
		GLfloat V3[],
		GLfloat V4[],
		GLfloat V5[],
		GLfloat V6[],
		GLfloat V7[]
	 )
{
	glColor3f(0, 0, 1);
	Face(V0, V1, V2, V3);//Front
	glColor3f(0, 1, 0);
	Face(V4, V5, V6, V7);//Back
	glColor3f(1, 0, 0);
	Face(V0, V1, V5, V4);//Top
	glColor3f(1, 1, 0);
	Face(V2, V3, V7, V6);//Bottom
	glColor3f(0, 1, 1);
	Face(V1, V2, V6, V5);//Right
	glColor3f(1, 0, 1);
	Face(V0, V4, V7, V3);//Left
}


void Draw(){

	GLfloat V[8][3] = {
		{ -0.5,  0.5,  0.5},
		{  0.5,  0.5,  0.5},
		{  0.5, -0.5,  0.5},
		{ -0.5, -0.5,  0.5},
		{ -0.5,  0.5, -0.5},
		{  0.5,  0.5, -0.5},
		{  0.5, -0.5, -0.5},
		{ -0.5, -0.5, -0.5}
	};

	GLfloat rV[8][3], r;
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	r = d * 3.14 / 180;

	if(a == 1)
	{
		for(int i = 0; i < 8;i++){
			rV[i][0] = V[i][0];
			rV[i][1] = V[i][1] * cos(r) - V[i][2] * sin(r);
			rV[i][2] = V[i][1] * sin(r) + V[i][2] * cos(r);
		}
	}

	if( a == 2){
		for(int i = 0; i < 8; i++){
			rV[i][0] = V[i][2] * sin(r) + V[i][0] * cos(r);
			rV[i][1] = V[i][1];
			rV[i][2] = V[i][2] * cos(r) - V[i][0] * sin(r);
		}
	}

	if( a == 3){
		for(int i = 0; i < 8 ;i++){
			rV[i][0] = V[i][0] * cos(r) - V[i][1] * sin(r);
			rV[i][1] = V[i][0] * sin(r) + V[i][1] * cos(r);
			rV[i][2] = V[i][2];
		}
	}

	Cube(rV[0], rV[1], rV[2], rV[3], rV[4], rV[5], rV[6], rV[7]);

	glutSwapBuffers();
}

int main(int argc, char * argv[]){

	printf("Enter a digit::[0 -> No rotation], [1 -> X-axis], [2 -> Y-axis], [3 -> Z-axis]::");
	scanf("%d", &a);

	glutInit(&argc, argv);
	glutInitWindowSize(600, 600);
	glutInitWindowPosition(50, 150);
	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);

	glutCreateWindow("Spinning Cube with transformational matrix");
	
	CustomInit();
	glutDisplayFunc(Draw);
	glutIdleFunc(Spin);
	glutMainLoop();
	
	return 0;
}