first commit

CS4451/oglexamples/spinner.cpp

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+/* Rotates3D points. Changes points each time mouse is clicked (courtesy of Brooks van Horn) */
+#ifdef _WIN32
+#include <windows.h>
+#endif
+#include <GL/glut.h>
+#include <stdlib.h>
+
+void mouse( int, int, int, int );
+void display( void );
+void reshape( int, int );
+void keyboard( unsigned char, int, int );
+void Idle( void );
+void InitializeVariables( void ); /// forwarding functions
+
+int xdim, ydim; /// screen dimensions
+
+struct vPoint
+{
+	inline float &operator[] ( int index ) 
+	{
+		return element[index];
+	} 
+	float element[3]; 
+}; //
+
+const float X_STEP = 0.005; 
+const float Y_STEP = 0.020;
+const float Z_STEP = 0.025; //
+
+bool flag;                  /// flag to tell us if there is anything to draw yet/
+
+vPoint rotation; // current rotation
+
+const int MAX_DOTS = 10;   /// # of dots to generate and render/
+vPoint dots[ MAX_DOTS ];   /// the set of points to render/
+
+int main( int argc, char *argv[] )
+{
+	InitializeVariables(); /// nothing to do with OpenGL.  My function that zeroes variables and such stuff./
+
+	xdim = ( argc > 1 ) ? atoi( argv[ 1 ] ) : 500;  ydim = ( argc > 2 ) ? atoi( argv[ 2 ] ) : 500;
+
+	glutInit( &argc, argv ); //* Initialization function *//
+	glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGB ); /// Set double buffer and GRB modes/
+	glutInitWindowSize( xdim, ydim ); /// Set the screen size/
+	glutCreateWindow( "This is the title of the window.");
+	glClearColor( 0.0, 0.0, 0.0, 0.0 ); /// clear color and alpha at each pixel/
+	glShadeModel( GL_FLAT ); /// set shading mode to flat (constant color for each polygon)/
+	glutDisplayFunc( display ); /// tells OpenGL what function to call when it needs to redraw/
+	glutReshapeFunc( reshape ); /// tells OpenGL what function to call when window is reshaped/
+	glutMouseFunc( mouse ); /// tells OpenGL what function to call when a mouse button is pressed/
+	glutKeyboardFunc( keyboard ); /// tells OpenGL to call the keyboard function with current parameters/
+	glutIdleFunc( Idle );
+	glutMainLoop(); /// important call to include after the above 3/
+
+	return EXIT_SUCCESS;
+}
+
+void InitializeVariables( void ) {rotation[ 0 ] = rotation[ 1 ] = rotation[ 2 ] = 0.0;  flag = true; }
+
+void mouse( int button, int state, int x, int y )
+	/* 
+	button: GLUT_LEFT_BUTTON or GLUT_MIDDLE_BUTTON or GLUT_RIGHT_BUTTON,
+	state : state of the button: pressed (GLUT_DOWN) or not pressed (GLUT_UP),
+	x, y  : position of mouse 
+	*/
+{
+
+if ( state == GLUT_UP ) return ; /// we don't care when the mouse button is released/
+
+ for (int i = 0; i<MAX_DOTS; i++) for (int j = 0; j<3; j++) dots[i][j] = (float) rand() / (float) RAND_MAX; /// Generate dots/
+
+ flag = false; /// we now have something to display/
+
+glutPostRedisplay();} /// need to call display again so that a new thing is put on the screen/
+
+ 
+
+void keyboard( unsigned char c, int x, int y )
+//* c: ASCII character pressed (excluding shift, ctrl, alt), (x,y) = position of the mouse */
+{ 
+	if ( c == 27 ) exit( 0 );
+}  // "escape" key
+
+void Idle( void )
+{
+	rotation[0]+=X_STEP; rotation[1]+=Y_STEP; 
+	rotation[2]+=Z_STEP; glutPostRedisplay();
+}
+
+void display( void )
+{
+
+ glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+ if( flag ) 
+ {
+	glutSwapBuffers();
+	return;
+ }
+ glPushMatrix(); /// push matrix on stack/
+
+ glColor3f( 1.0, 1.0, 1.0 ); /// Here I specify a color by giving R-G-B values from 0 to 1./
+ glTranslatef( 0.0, 0.0, -3.0 ); /// move the dots so that we can see them/
+ glRotatef(rotation[0],1,0,0);  glRotatef(rotation[1],0,1,0);
+ glRotatef(rotation[2],0,0,1); /// rotate the dots/
+
+ glBegin( GL_POINTS ); 
+
+ for ( int i = 0; i < MAX_DOTS; i++ )
+	glVertex3f(dots[i][0],dots[i][1],dots[i][2]);
+
+ glEnd();
+
+ glPopMatrix(); 
+ glutSwapBuffers();
+} /// This says: "DRAW WHAT YOU'VE GOT!"/
+
+ 
+
+void reshape( int new_width, int new_height )
+{
+  xdim = new_width;  ydim = new_height;
+
+  glViewport(0,0,(GLsizei) new_width, (GLsizei) new_height ); /// This resets the viewing port/
+  glMatrixMode( GL_PROJECTION ); /// This resets the use of Matrices based upon the new view/
+  glLoadIdentity();
+  gluPerspective( 60.0, (GLfloat) xdim / (GLfloat) ydim, 0.1, 20.0 ); /// reset the viewing projection/
+  glMatrixMode( GL_MODELVIEW );
+}
+