Solar System - Transformations

Tue Mar 15, 2011 11:00 pm

Solar System - Transformations example :

Code:: #include "windows.h" #include <gl\glut.h> #define sunRaduis 0.4 #define earthRaduis 0.06 #define moonRaduis 0.016 GLfloat rotationSpeed = 0.1; GLfloat daysInYear = 365; GLfloat year = 0.0; //degrees GLfloat day = 0.0; GLfloat moonAroundEarth = 0.0; GLfloat moonItsSelf = 0.0; GLfloat earthOrbitRadius = 1.0; GLfloat moonOrbitRadius = 0.1; GLfloat moonAroundEarthRate = 2 * rotationSpeed; GLfloat moonRotationItselfRate = 5.0 * rotationSpeed; GLfloat dayRate = 5.0 * rotationSpeed; GLfloat yearRate = daysInYear / 360.0 * dayRate * rotationSpeed; void drawSolarSystem(void); void Initialization(void); void displayFunc(void); void reshapeFunc(int x, int y); void idleFunc(void); int main(int argc, char* argv[]) { // Initialization for glut glutInit(&argc, argv); // set the buffer mode ( double and colors (RGB) glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); // set the window frame size glutInitWindowSize(700,700); glutCreateWindow("Solar system"); Initialization(); // reshape call back function reference setting. glutReshapeFunc(reshapeFunc); // display call back function reference setting glutDisplayFunc(displayFunc); // idle callback function reference setting ( used in animation ) glutIdleFunc(idleFunc); // enters the GLUT event processing loop glutMainLoop(); return 0; } void drawSolarSystem(void) { glPushMatrix(); /* glPushMatrix() pushes the current matrix stack down by one, duplicating the current matrix. That is, after a glPushMatrix call, the matrix on top of the stack is identical to the one below it. */ gluLookAt( 0.0,0.0,-4.0, 0.0,0.0,1.0, 0.0,-3.0,0.0); //gluLookAt //creates a viewing matrix derived from an eye point, a reference point indicating the //center of the scene, and an UP vector // Color of the sun. glColor3f(1.0,0.8,0.3); // Drawing the sun. glutSolidSphere(sunRaduis,50,50); glPushMatrix(); glRotatef(year,0.0,1.0,0.0); //rotation for earth glTranslatef(earthOrbitRadius,0.0,0.0); // translation for earth. glRotatef(-year,0.0,1.0,0.0); glPushMatrix(); glRotatef(day,0.25,1.0,0.0); glColor3f(0.4,0.6,0.3); //Drawing the earth glutSolidSphere(earthRaduis,10,10); glPopMatrix(); // rotation for moon. glRotatef(moonAroundEarth,0.0,1.0,0.0); // translation for moon. glTranslatef(moonOrbitRadius,0.0,0.0); // around earth rotation. glRotatef(-moonAroundEarth,0.0,1.0,0.0); // moon rotation about it self. glRotatef(moonItsSelf,0.0,1.0,0.0); glColor3f(0.3,0.3,0.5); // draw the moon glutSolidSphere(moonRaduis,8,8); glPopMatrix(); glPopMatrix(); } void Initialization(void) { // background color glClearColor(0.0,0.0,0.0,0.0); glClearDepth(10.0); // GL_MODELVIEW :Applies subsequent matrix operations to the modelview matrix stack. /* The modelview matrix is for transformation of geometry from model to view space (therefore the camera/view transform most correctly goes in the modelview matrix). */ glMatrixMode(GL_MODELVIEW); // replace the current matrix with the identity matrix glLoadIdentity(); } void displayFunc(void) { glClear(GL_COLOR_BUFFER_BIT); drawSolarSystem(); // flush to screen. glFlush(); // swap buffers , yes we need this ( double buffering used!) glutSwapBuffers(); } void reshapeFunc(int x, int y) { if (y == 0 || x==0) return; glLoadIdentity(); gluPerspective(40.0,(GLdouble)x/(GLdouble)y,0.5,20.0); glMatrixMode(GL_MODELVIEW); glViewport(0,0,x,y); displayFunc(); } void idleFunc(void) { // idle event call back in animation , here we increase the values and redisply . day += dayRate; year += yearRate; moonItsSelf += moonRotationItselfRate; moonAroundEarth += moonAroundEarthRate; displayFunc(); }

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: sun system transformation; sun-system.GIF (2.84 KiB) Viewed 16605 times