本例子參考於網絡，並進行了一些修改，使用glut+vs2008來實現。
在鼠標點擊處重新畫一個旋轉的紅色立方體！
參考代碼如下：
C++ Code
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#include
<GL/glut.h> #include <GL/glu.h> #include <GL/gl.h> #include <vector> using namespace std; #define HEIGHT 480 #define WIDTH 640 typedef struct Point3D { double objx; double objy; double objz; }POINT_3D, *PPOINT_3D; double objx = 0 , objy = 0 , objz = 0 ; double objnx = 0 , objny = 0 , objnz = 0 ; double objfx = 0 , objfy = 0 , objfz = 0 ; double angle = 0 . 0 ; vector<POINT_3D> vec3dPoint; vector<POINT_3D>::iterator it; #pragma comment(linker, "/subsystem:\" windows\ " /entry:\" mainCRTStartup\ "" ) /*THE FUNCTION TO DRAW THE STUFF ON THE SCREEN*/ void display( ) { glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT ); //The big green floor like polygon glBegin( GL_POLYGON ); glColor3f( 0 , 1 , 0 ); glVertex3f( - 100 , 0 , 100 ); glVertex3f( - 100 , 0 , - 100 ); glVertex3f( 100 , 0 , - 100 ); glVertex3f( 100 , 0 , 100 ); glEnd( ); for (it = vec3dPoint.begin(); it != vec3dPoint.end(); it++) { //The red cube to be drawn at clicked position glPushMatrix( ); glColor3f( 1 , 0 , 0 ); glTranslatef( it->objx,it->objy,it->objz ); glRotatef(angle, 1 . 0 , 1 . 0 , 1 . 0 ); angle++; if (angle > 360 ) { angle = 0 . 0 ; } glutSolidCube( 10 ); glPopMatrix( ); } glFlush( ); glutSwapBuffers( ); } void mouse( int button, int state, int x, int y) { double modelview[ 16 ], projection[ 16 ]; int viewport[ 4 ]; float z = 1 ; /*Read the projection, modelview and viewport matrices using the glGet functions.*/ glGetDoublev( GL_PROJECTION_MATRIX, projection ); glGetDoublev( GL_MODELVIEW_MATRIX, modelview ); glGetIntegerv( GL_VIEWPORT, viewport ); //Read the window z value from the z-buffer glReadPixels( x, viewport[ 3 ]-y, 1 , 1 , GL_DEPTH_COMPONENT, GL_FLOAT, &z ); //Use the gluUnProject to get the world co-ordinates of //the point the user clicked and save in objx, objy, objz. gluUnProject( x, viewport[ 3 ]-y, 0.0 , modelview, projection, viewport, &objnx, &objny, &objnz ); gluUnProject( x, viewport[ 3 ]-y, z, modelview, projection, viewport, &objx, &objy, &objz ); gluUnProject( x, viewport[ 3 ]-y, 1 . 0 , modelview, projection, viewport, &objfx, &objfy, &objfz ); POINT_3D objxyz; objxyz.objx = objx; objxyz.objy = objy; objxyz.objz = objz; vec3dPoint.push_back(objxyz); } void initVector() { vec3dPoint.clear(); POINT_3D objxyz; objxyz.objx = objx; objxyz.objy = objy; objxyz.objz = objz; vec3dPoint.push_back(objxyz); } void init( int width, int height ) { glViewport( 0 , 0 , width, height ); glMatrixMode( GL_PROJECTION ); glLoadIdentity( ); gluPerspective( 45 , 1 . 33 , 0 . 1 , 400 ); glMatrixMode( GL_MODELVIEW ); glLoadIdentity( ); gluLookAt( 0 , 100 , 200 , 0 , 0 , 0 , 0 , 1 , 0 ); } int main( int argc, char **argv ) { glutInit( &argc, argv ); //The most important part specify the things your //glut window should provide glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH ); glutInitWindowSize( 640 , 480 ); glutCreateWindow( "gluUnProject Demo" ); glClearColor( 0 , 0 , 0 , 0 ); //enable z buffer glEnable( GL_DEPTH_TEST ); //set the value in z-buffer as 1.0 glClearDepth( 1 . 0 ); initVector(); init( 640 , 480 ); glutDisplayFunc( display ); glutReshapeFunc( init ); glutIdleFunc( display ); glutMouseFunc( mouse ); glutMainLoop( ); } |