I''ve been working on this project for a while and have recently encountered a few problems. I decided to implement object selection. I''ve only just implemented a very basic picking system, but un doing so I redesigned the structure of my code. The problem that has now come up is that you can only view the scene when you''re moving around, using the cursor keys, but as soon as you stop moving the objects all disappear. I don''t know if I''m missing something really stupid, which is probably the case, or if there is something drastically wrong. I''ve included some of my code below. I''d really appreciate any help or notes from anyone. Cheers Mike void orient(float ang) { lx = sin(ang); lz = -cos(ang); glLoadIdentity(); gluLookAt(jx, jy, jz, jx + lx,jy + ly,jz + lz, 0.0f,1.0f,0.0f); } void moveFlat(int i) { jx = jx + i*(lx)*0.1; jz = jz + i*(lz)*0.1; glLoadIdentity(); gluLookAt(jx, jy, jz, jx + lx,jy + ly,jz + lz, 0.0f,1.0f,0.0f); } void moveVertically(int i) { jy = jy + i*(0.1); glLoadIdentity(); gluLookAt(jx, jy, jz, jx + lx,jy + ly,jz + lz, 0.0f,1.0f,0.0f); } void renderScene() { //gets data from db then decides what to draw //works 100% drawGO(); drawDO(); } void setupLight() { glLightModelfv(GL_LIGHT_MODEL_AMBIENT, GlobalLightAmbient) ; glLightModelf(GL_LIGHT_MODEL_LOCAL_VIEWER, 1.0) ; glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient); // Setup The Ambient Light glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse); // Setup The Diffuse Light glLightfv(GL_LIGHT1, GL_POSITION,LightPosition); // Position The Light glEnable(GL_LIGHT1); // Enable Light One glEnable(GL_LIGHTING); } void setupCamera(int c_pickmode,int c_x,int c_y) { GLint viewport[4]; glMatrixMode(GL_PROJECTION); glLoadIdentity(); if (c_pickmode == TRUE) { glGetIntegerv(GL_VIEWPORT,viewport); // Get the viewport bounds gluPickMatrix(c_x,viewport[3]-c_y,3.0,3.0,viewport); } gluPerspective(70.0, // Field of view 1.0, // aspect ratio 0.1,1000.0); glLightfv(GL_LIGHT0, GL_AMBIENT, GlobalLightAmbient); glMatrixMode(GL_MODELVIEW); if (deltaMove) { moveFlat(deltaMove); } if (deltaAngle) { angle += deltaAngle; orient(angle); } if (deltaVert) { moveVertically(deltaVert); } } void CreateEnvironment(void) { glClearColor(0.0f, 0.0f, 0.7f, 0.5f); //Background glEnable(GL_DEPTH_TEST) ; glEnable(GL_NORMALIZE) ; glShadeModel(GL_SMOOTH) ; glDisable(GL_CULL_FACE) ; } void display() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); setupCamera(FALSE,0,0); setupLight(); renderScene(); glPopMatrix(); glutSwapBuffers(); } void HandleIdle(void) { glutPostRedisplay(); } void HandleVisibility(int visible) { if (visible == GLUT_VISIBLE) glutIdleFunc(HandleIdle); else glutIdleFunc(NULL); } void pressKey(int key, int x, int y) { switch (key) { case GLUT_KEY_LEFT : deltaAngle = -0.01f;break; case GLUT_KEY_RIGHT : deltaAngle = 0.01f;break; case GLUT_KEY_UP : deltaMove = 1;break; case GLUT_KEY_DOWN : deltaMove = -1;break; case GLUT_KEY_PAGE_UP : deltaVert = 1;break; case GLUT_KEY_PAGE_DOWN: deltaVert = -1;break; } } void releaseKey(int key, int x, int y) { switch (key) { case GLUT_KEY_LEFT : case GLUT_KEY_RIGHT : deltaAngle = 0.0f;break; case GLUT_KEY_UP : case GLUT_KEY_DOWN : deltaMove = 0;break; case GLUT_KEY_PAGE_UP : case GLUT_KEY_PAGE_DOWN : deltaVert = 0;break; } } void processNormalKeys(unsigned char key, int x, int y) { if (key == 27) exit(0); } void mouse(int button, int state, int x, int y) { int maxselect = 100,nhits = 0; GLuint selectlist[100]; if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) { glSelectBuffer(maxselect,selectlist); glRenderMode(GL_SELECT); glInitNames(); glPushName(0); glPushMatrix(); setupCamera(TRUE,x,y); renderScene(); glPopMatrix(); nhits = glRenderMode(GL_RENDER); if (nhits < 0){ } if (nhits > 0) { /* Process the hits */ ShowWindow(aboutwin,SW_SHOW); } } } int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA); glutInitWindowPosition(100,100); glutInitWindowSize(640,360); glutCreateWindow("PIT Version 1.0"); glutDisplayFunc(display); glutVisibilityFunc(HandleVisibility); glutIgnoreKeyRepeat(1); glutKeyboardFunc(processNormalKeys); glutSpecialFunc(pressKey); glutSpecialUpFunc(releaseKey); glutMouseFunc(mouse); CreateEnvironment();