/* * Shows a scene (a teapot on a short cylindrical base) that is illuminated * by up to four lights plus global ambient light. The user can turn the * lights on and off. The global ambient light is a dim white. There is * a white "viewpoint" light that points from the direction of the viewer * into the scene. There is a red light, a blue light, and a green light * that rotate in circles above the teapot. (The user can turn the animation * on and off.) The locations of the colored lights are marked by spheres, * which are gray when the light is off and are colored by some emission color * when the light is on. The teapot is gray with weak specular highlights. * The base is colored with a spectrum. (The user can turn the display of * the base on and off.) The mouse can be used to rotate the scene. * Either the menu or the keyboard can be used to turn options on and off. * * This program dependes on camera.c. It must also be linked to the GL, GLU, * glut, and math libraries. For example, in Linux with the gcc compiler: * * gcc -o four-lights four-lights.c camera.c -lGL -lglut -lGLU -lm */ #include #include #include #include #include #include "camera.h" const double PI = 3.141592654; int animating = 0; // Is the animation running? int drawBase = 1; // Should the base be drawn? int ambientLight = 1; // Should global ambient light be on? int viewpointLight = 1; // Should the viewpoint light be on? int redLight = 1; // Should the red light be on? int greenLight = 1; // Should the green light be on? int blueLight = 1; // Should the blue light be on? int frameNumber = 0; // Frame number for use in animation. char message[200]; // Used for displaying a message at the bottom of the display. int width, height; // Size of the display, set in reshape(). //------------------- Drawing functions ---------------------------------------- /* Sets the positions of the colored lights and turns them on and off, depending on * the state of the redLight, greenLight, and blueLight options. Draws a small * sphere at the location of each light. */ void lights() { glColor3d(0.5,0.5,0.5); float zero[] = { 0, 0, 0, 1 }; glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, zero); if (viewpointLight) glEnable(GL_LIGHT0); else glDisable(GL_LIGHT0); if (redLight) { float red[] = { 0.5, 0, 0, 1 }; glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, red); glEnable(GL_LIGHT1); } else { glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, zero); glDisable(GL_LIGHT1); } glPushMatrix(); glRotated(-frameNumber, 0, 1, 0); glTranslated(10, 7, 0); glLightfv(GL_LIGHT1, GL_POSITION, zero); glutSolidSphere(0.5, 16, 8); glPopMatrix(); if (greenLight) { float green[] = {0, 0.5, 0, 1 }; glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, green); glEnable(GL_LIGHT2); } else { glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, zero); glDisable(GL_LIGHT2); } glPushMatrix(); glRotated((frameNumber+100)*0.8743, 0, 1, 0); glTranslated(9, 8, 0); glLightfv(GL_LIGHT2, GL_POSITION, zero); glutSolidSphere(0.5, 16, 8); glPopMatrix(); if (blueLight) { float blue[] = { 0, 0, 0.5, 1 }; glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, blue); glEnable(GL_LIGHT3); } else { glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, zero); glDisable(GL_LIGHT3); } glPushMatrix(); glRotated((frameNumber-100)*1.3057, 0, 1, 0); glTranslated(9.5, 7.5, 0); glLightfv(GL_LIGHT3, GL_POSITION, zero); glutSolidSphere(0.5, 16, 8); glPopMatrix(); glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, zero); // Turn off emission color! } // end lights() /* Fills the array with RGBA color components corresponding the given HSV color * components, where h, s, and v are in the range 0.0 to 1.0. */ void colorArrayForHue(double array[4], double h, double s, double v) { double r,g,b; double c,x; h = h*359; c = v*s; x = (h < 120)? h/60 : (h < 240)? (h-120)/60 : (h-240)/60; x = c * (1-fabs(x-1)); x += (v-c); switch ((int)(h/60)) { case 0: r = v; g = x; b = v-c; break; case 1: r = x; g = v; b = v-c; break; case 2: r = v-c; g = v; b = x; break; case 3: r = v-c; g = x; b = v; break; case 4: r = x; g = v-c; b = v; break; case 5: r = v; g = v-c; b = x; break; } array[0] = r; array[1] = g; array[2] = b; array[3] = 1; } /* Draws a cylinder with height 2 and radius 1, centered at the origin, with its axis * along the z-axis. A spectrum of hues is applied to the vertices along the edges * of the cylinder. (Since GL_COLOR_MATERIAL is enabled in this program, the colors * specified here are used as ambient and diffuse material colors for the cylinder.) */ void drawCylinder() { int i; glBegin(GL_TRIANGLE_STRIP); double rgba[4]; for (i = 0; i <= 64; i++) { double angle = 2*PI/64 * i; double x = cos(angle); double y = sin(angle); colorArrayForHue(rgba, i/64.0, 1, 0.6); glColor3dv(rgba); glNormal3d( x, y, 0 ); // Normal for both vertices at this angle. glVertex3d( x, y, 1 ); // Vertex on the top edge. glVertex3d( x, y, -1 ); // Vertex on the bottom edge. } glEnd(); glNormal3d( 0, 0, 1 ); glBegin(GL_TRIANGLE_FAN); // Draw the top, in the plane z = 1. glColor3d(1,1,1); // ambient and diffuse for center glVertex3d( 0, 0, 1); for (i = 0; i <= 64; i++) { double angle = 2*PI/64 * i; double x = cos(angle); double y = sin(angle); colorArrayForHue(rgba, i/64.0, 1, 0.6); glColor3dv(rgba); glVertex3d( x, y, 1 ); } glEnd(); glNormal3f( 0, 0, -1 ); glBegin(GL_TRIANGLE_FAN); // Draw the bottom, in the plane z = -1 glColor3d(1,1,1); // ambient and diffuse for center glVertex3d( 0, 0, -1); for (i = 64; i >= 0; i--) { double angle = 2*PI/64 * i; double x = cos(angle); double y = sin(angle); colorArrayForHue(rgba, i/64.0, 1, 0.6); glColor3dv(rgba); glVertex3d( x, y, -1 ); } glEnd(); } /* Draws the scene, with a message in the bottom 60 pixels of the window. */ void display() { glClearColor(0,0,0,0); glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); glViewport(0,60,width,height-60); // viewport for the drawing cameraApply(); lights(); float zero[] = { 0, 0, 0, 1 }; float amb[] = { 0.15, 0.15, 0.15, 1 }; float spec[] = { 0.2, 0.2, 0.2, 1 }; if (ambientLight) { glLightModelfv(GL_LIGHT_MODEL_AMBIENT, amb ); } else { glLightModelfv(GL_LIGHT_MODEL_AMBIENT, zero ); } if (drawBase) { glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, zero ); glPushMatrix(); glTranslated(0, -5, 0); glRotated(-90, 1, 0, 0); glScaled(10,10,0.5); drawCylinder(); glPopMatrix(); } glColor3d(0.7,0.7,0.7); // sets diffuse and ambient color for teapot glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, spec); glPushMatrix(); glutSolidTeapot(6); glPopMatrix(); /* Draw a message at the bottom of the window. */ glViewport(0,0,width,60); // viewport for the message glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0,width,0,60,-1,1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glDisable(GL_LIGHTING); glDisable(GL_DEPTH_TEST); glColor3f(1,1,1); glRecti(0,0,width,60); glColor3f(0,0,0); glRasterPos2f(15,20); char *m = message; snprintf(message,200,"Enabled Lights: %s%s%s%s%s", ambientLight? "Global Ambient " : "", viewpointLight? "Viewpoint " : "", redLight? "Red " : "", greenLight? "Green " : "", blueLight? "Blue" : "" ); while (*m) { glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, *m); m++; } glEnable(GL_LIGHTING); glEnable(GL_DEPTH_TEST); glutSwapBuffers(); } /* Called when the window size changes; just record the new size for use in * setting the viewports in the display method. */ void reshape(int w, int h) { width = w; height = h; } /* Initialization, including setting up a camera and configuring the four lights. */ void initGL() { glClearColor(0, 0, 0, 1); glEnable(GL_DEPTH_TEST); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_NORMALIZE); glEnable(GL_COLOR_MATERIAL); glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1); glMateriali(GL_FRONT_AND_BACK, GL_SHININESS, 32); float dim[] = { 0.5F, 0.5F, 0.5F, 1 }; glLightfv(GL_LIGHT0, GL_DIFFUSE, dim); glLightfv(GL_LIGHT0, GL_SPECULAR, dim); float red[] = { 0.5F, 0, 0, 1}; float reda[] = { 0.1F, 0, 0, 1}; glLightfv(GL_LIGHT1, GL_AMBIENT, reda); glLightfv(GL_LIGHT1, GL_DIFFUSE, red); glLightfv(GL_LIGHT1, GL_SPECULAR, red); float gr[] = { 0, 0.5F, 0, 1 }; float gra[] = { 0, 0.1F, 0, 1 }; glLightfv(GL_LIGHT2, GL_AMBIENT, gra); glLightfv(GL_LIGHT2, GL_DIFFUSE, gr); glLightfv(GL_LIGHT2, GL_SPECULAR, gr); float bl[] = {0, 0, 0.5F, 1}; float bla[] = {0, 0, 0.1F, 1}; glLightfv(GL_LIGHT3, GL_AMBIENT, bla); glLightfv(GL_LIGHT3, GL_DIFFUSE, bl); glLightfv(GL_LIGHT3, GL_SPECULAR, bl); } // --------------- support for animation ------------------------------------------ void timerFunction(int timerID) { if (animating) { frameNumber++; glutTimerFunc(30, timerFunction, 0); // Next frame in 30 milliseconds. glutPostRedisplay(); // Causes display() to be called. } } void toggleAnimation() { if ( ! animating ) { animating = 1; glutTimerFunc(30, timerFunction, 0); } else { animating = 0; } } // --------------------- Menu Keyboard handling -------------------------------- void charTyped(unsigned char ch, int x, int y) { switch (ch) { case 'a': case 'A': toggleAnimation(); break; case 'd': case 'D': drawBase = 1 - drawBase; break; case 'm': case 'M': ambientLight = 1 - ambientLight; break; case 'v': case 'V': viewpointLight = 1 - viewpointLight; break; case 'r': case 'R': redLight = 1 - redLight; break; case 'g': case 'G': greenLight = 1 - greenLight; break; case 'b': case 'B': blueLight = 1 - blueLight; break; case 27: exit(0); } glutPostRedisplay(); } void doMenu(int itemNum) { // menu handler -- change render mode. switch (itemNum) { case 1: toggleAnimation(); break; case 2: drawBase = 1 - drawBase; break; case 3: ambientLight = 1 - ambientLight; break; case 4: viewpointLight = 1 - viewpointLight; break; case 5: redLight = 1 - redLight; break; case 6: greenLight = 1 - greenLight; break; case 7: blueLight = 1 - blueLight; break; case 8: exit(0); } glutPostRedisplay(); } void createMenus() { // make a menu containing the five render modes. int menu = glutCreateMenu(doMenu); glutAddMenuEntry("Toggle Animation (A key)", 1); glutAddMenuEntry("Toggle Draw Base (D key)", 2); glutAddMenuEntry("Toggle Global Ambient Light (M key)", 3); glutAddMenuEntry("Toggle Viewpoint Light (V key)", 4); glutAddMenuEntry("Toggle Red Light (R key)", 5); glutAddMenuEntry("Toggle Green Light (G key)", 6); glutAddMenuEntry("Toggle Blue Light (B key)", 7); glutAddMenuEntry("Quit (ESC key)", 8); glutAttachMenu(GLUT_RIGHT_BUTTON); } //--------------------------------------------------------------------------- int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH); glutInitWindowSize(600,660); glutInitWindowPosition(100,100); glutCreateWindow("Left Mouse = ROTATE; Right Mouse = MENU"); initGL(); glutDisplayFunc(display); glutReshapeFunc(reshape); cameraLookAt(5,10,30, 0,0,0, 0,1,0); cameraSetScale(15); glutMouseFunc(trackballMouseFunction); glutMotionFunc(trackballMotionFunction); glutKeyboardFunc(charTyped); createMenus(); toggleAnimation(); glutMainLoop(); return 0; }