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Assignment3.cpp
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Assignment3.cpp
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/**
CS6533 Assignment 3 : Lighting and Shading
author: Zhe Wu
since: 04/27/2011
version: 1.0
base on: Assignment 2
- Projecting the shadow of rotating sphere to the ground.
Using "decal" technique.
- Add directional lighting as described in question (c).
- Implement flat shading and smooth shading.
- Add spot light and point light as described in question (d).
*/
#define WINDOWS 1 /* Set to 1 for Windows, 0 else */
#define UNIX_LINUX 0 /* Set to 1 for Unix/Linux, 0 else */
#if WINDOWS
#include <windows.h>
#include <GL/glut.h>
#endif
#if UNIX_LINUX
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#endif
#include <stdio.h>
#include <math.h>
#include <iostream>
#include <fstream>
using namespace std;
#define PI 3.1415926535897
#define sqrt3f(x,y,z) sqrt(x*x+y*y+z*z)
#define DEFAULT_SPHERE_PATH "C:\\sphere.1024"
struct point {
GLfloat x, y, z;
};
typedef point vector;
/* Points data to build the sphere*/
GLfloat** sphereData;
/* The radius of the sphere*/
GLfloat radius = 1.0;
/* VRP */
point viewer = {7,3,-10};
/* Three points on rolling track: A, B, C*/
point track[] = {{-4,1,4}, {3,1,-4},{-3,1,-3}};
/* Points to draw the green ground */
point ground[] = {{5,0,8},{5,0,-4},{-5,0,-4},{-5,0,8}};
/* Index the current rolling direction*/
int currentSegment = 0, totalSegments = 3;;
/* Current position of the sphere center*/
point centerPos = track[currentSegment];
/* Vectors of the ball rolling direction*/
point* vectors;
/* Rolling axes around which the ball rotates*/
point* rotationAxis;
/* Normals of triangles on sphere*/
point* tri_normals;
int data_count = -1,num,polygon_n;
/* Theta: the accumulated rotating angle */
/* Delta: the angle rotating each time */
GLfloat theta = 0.0, delta = 5;
/* Accumulated Matrix */
GLfloat acc_matrix[16]={1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1};
/*Shadow Matrix*/
GLfloat shadow_matrix[16]={12,0,0,0,14,0,3,-1,0,0,12,0,0,0,0,12};
/* Colors and position for shading effect*/
GLfloat light_pos[] = {-14.0 ,12.0 ,-3.0 , 1.0};
GLfloat light_dir[] = {8.0,-12.0,-1.5,0};
GLfloat global_ambient[]={1,1,1,1};
GLfloat light_ambient[]={0,0,0,1};
GLfloat light_diffuse[]={1,1,1,1};
GLfloat light_specular[]={1,1,1,1};
GLfloat green[]={0.0, 1.0, 0.0,1.0};
GLfloat golden[] = {1.0, 0.84, 0.0, 1.0};
GLfloat mat_shiness = 125.0;
void display(void);
void my_init(void);
void reshape(int w, int h);
void idle(void);
void key(unsigned char key, int x, int y);
void mouse(int btn,int state, int x,int y);
void draw_shadow(void);
void draw_sphere(void);
void init_lighting(void);
void draw_axes(void);
void init_spotlight(void);
void init_lighting(void);
/* Compute distance between two points */
float distanceAt(point p1, point p2);
/* Reset viewer to (7,3,-10) */
void setDefaultView();
//control variables
bool begin = false, rolling = false, shadow = false,wireframe = true, lighting = false, flatshade = true, spotlight = true;
/* file_in(): file input function. Modify here. */
void fileReadIn(void)
{
const int MAX_FILE_LEN = 1000;
char* filePath = new char[MAX_FILE_LEN];
cout << "Please enter sphere data file path, or press ENTER to use the sample file("
<< DEFAULT_SPHERE_PATH << ") " << endl;
cin.sync();
cin.getline(filePath,MAX_FILE_LEN);
if(strlen(filePath) == 0){
cout <<"No input file '"<< filePath <<"'. Use sample data."<<endl;
filePath = DEFAULT_SPHERE_PATH;
}
ifstream file(filePath);
if(file.fail()){
cout <<"Cannot open file "<<filePath<<endl;
exit(0);
}
//total number of triangles
file >> num;
cout <<"Total number of triangles: "<<num<<endl;
sphereData= new GLfloat*[num];
for(int i = 0; i < num ; i++)
{
int numOfPoints = 0;
file >> numOfPoints;
sphereData[i] = new GLfloat[3*numOfPoints];
for(int j=0;j<3*numOfPoints;j++ )
{
file >> sphereData[i][j];
}
}
file.close();
}
void draw_ground(){
//if lighting is on, draw ground with shade
if(lighting){
glEnable(GL_LIGHTING);
glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,green);
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT,light_ambient);
glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,light_specular);
glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,mat_shiness);
}
glColor3fv(green); // draw in green.
glBegin(GL_POLYGON);
glNormal3f(0,1,0);
glVertex3f(ground[0].x,ground[0].y,ground[0].z);
glVertex3f(ground[1].x,ground[1].y,ground[1].z);
glVertex3f(ground[2].x,ground[2].y,ground[2].z);
glVertex3f(ground[3].x,ground[3].y,ground[3].z);
glEnd();
};
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); // clear frame buffer (also called the color buffer)
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
//init directional light
//init_lighting();
gluLookAt(viewer.x,viewer.y,viewer.z, 0,0,0, 0,1,0);
//init spotlight
init_spotlight();
//draw sphere
glPushMatrix();
draw_sphere();
glPopMatrix();
//TODO what if I change the order of depth and color buffer?
//draw the ground
glDepthMask(GL_FALSE);
draw_ground();
glDepthMask(GL_TRUE);
//draw the axes
draw_axes();
//Draw shadow only if shadow is enable and the viewer is higher than the ground
if(shadow && viewer.y > 0){
glPushMatrix();
draw_shadow();
glPopMatrix();
}
//draw the ground again with z-buffer enabled
glColorMask(GL_FALSE,GL_FALSE,GL_FALSE,GL_FALSE);
draw_ground();
glColorMask(GL_TRUE,GL_TRUE,GL_TRUE,GL_TRUE);
glFlush(); // Render (draw) the object
glutSwapBuffers(); // Swap buffers in double buffering.
}
void draw_axes(){
//glLineWidth(2.0);
glDisable(GL_LIGHTING);
glColor3f(1.0,0.0,0.0);//draw in red
glBegin(GL_LINES);
glVertex3f(0,0,0);
glVertex3f(100,0,0);
glEnd();
glColor3f(1.0,0.0,1.0);//draw in magenta
glBegin(GL_LINES);
glVertex3f(0,0,0);
glVertex3f(0,100,0);
glEnd();
glColor3f(0.0,0.0,1.0);//draw in blue
glBegin(GL_LINES);
glVertex3f(0,0,0);
glVertex3f(0,0,100);
glEnd();
};
/* draw sphere by drawing triangles */
void draw_sphere(){
glTranslatef(centerPos.x,centerPos.y,centerPos.z);
//add rotation here
//Rotate the sphere around vector 8i+7k
glMultMatrixf(acc_matrix);
if(lighting){
glEnable(GL_LIGHTING);
glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,golden);
glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,golden);
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT,light_ambient);
glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,mat_shiness);
}
glColor3fv(golden); // draw in golden yellow.
for (int a = 0; a < num; a++)
{
if(wireframe){
//Do not need shading when drawing wireframe
glDisable(GL_LIGHTING);
//draw wireframe sphere
glBegin(GL_LINE_LOOP);
}else{
//draw solid sphere
glBegin(GL_TRIANGLES);
}
if(flatshade){
glNormal3f(tri_normals[a].x,tri_normals[a].y,tri_normals[a].z);
glVertex3f(sphereData[a][0], sphereData[a][1], sphereData[a][2]);
glVertex3f(sphereData[a][3], sphereData[a][4], sphereData[a][5]);
glVertex3f(sphereData[a][6], sphereData[a][7], sphereData[a][8]);
} else {
glNormal3f(sphereData[a][0], sphereData[a][1], sphereData[a][2]);
glVertex3f(sphereData[a][0], sphereData[a][1], sphereData[a][2]);
glNormal3f(sphereData[a][3], sphereData[a][4], sphereData[a][5]);
glVertex3f(sphereData[a][3], sphereData[a][4], sphereData[a][5]);
glNormal3f(sphereData[a][6], sphereData[a][7], sphereData[a][8]);
glVertex3f(sphereData[a][6], sphereData[a][7], sphereData[a][8]);
}
glEnd();
}
};
void draw_shadow(){
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(viewer.x,viewer.y,viewer.z, 0,0,0, 0,1,0);
//draw shadow on the ground
glTranslatef(centerPos.x+1,0,centerPos.z+1);
glMultMatrixf(shadow_matrix);
//glMultMatrixf(acc_matrix);
glColor4f(0.25,0.25,0.25,0.65); // draw in black.
//TODO we don't want lighting on shadow, but we can try the effect later
glDisable(GL_LIGHTING);
for (int a = 0; a < num; a++)
{
if(wireframe){
//draw wireframe shadow
glBegin(GL_LINE_LOOP);
}else{
//draw solid shadow
glBegin(GL_TRIANGLES);
}
glVertex3f(sphereData[a][0], sphereData[a][1], sphereData[a][2]);
glVertex3f(sphereData[a][3], sphereData[a][4], sphereData[a][5]);
glVertex3f(sphereData[a][6], sphereData[a][7], sphereData[a][8]);
glEnd();
}
};
vector calculateDirection(point from, point to){
vector v;
v.x = to.x - from.x;
v.y = to.y - from.y;
v.z = to.z - from.z;
//convert v to unit-length
float d = sqrt3f(v.x,v.y,v.z);
v.x = v.x/d;
v.y = v.y/d;
v.z = v.z/d;
return v;
}
vector crossProduct(vector u, vector v){
vector n;
n.x = u.y*v.z - u.z*v.y;
n.y = u.z*v.x - u.x*v.z;
n.z = u.x*v.y - u.y*v.x;
return n;
}
float calculateRadius(){
float y_max = -10000,y_min = 10000;
for (int i = 0; i < num; i++)
{
{
GLfloat y = sphereData[i][1];
y_max = (y > y_max)?y:y_max;
y_min = (y < y_min)?y:y_min;
}
{
GLfloat y = sphereData[i][4];
y_max = (y > y_max)?y:y_max;
y_min = (y < y_min)?y:y_min;
}
{
GLfloat y = sphereData[i][7];
y_max = (y > y_max)?y:y_max;
y_min = (y < y_min)?y:y_min;
}
}
return (y_max-y_min)/2;
}
vector normalize(vector v){
//convert v to unit-length
float d = sqrt3f(v.x,v.y,v.z);
v.x = v.x/d;
v.y = v.y/d;
v.z = v.z/d;
return v;
};
/* compute normals for triangles */
void calculateNormals(){
//calculate the normal of triangles
tri_normals = new point[num];
for (int a = 0; a < num; a++)
{
point p1, p2, p3;
p1.x = sphereData[a][0];
p1.y = sphereData[a][1];
p1.z = sphereData[a][2];
p2.x = sphereData[a][3];
p2.y = sphereData[a][4];
p2.z = sphereData[a][5];
p3.x = sphereData[a][6];
p3.y = sphereData[a][7];
p3.z = sphereData[a][8];
vector v1 = calculateDirection(p1,p2);
vector v2 = calculateDirection(p2,p3);
vector n = crossProduct(v1,v2);
tri_normals[a] = normalize(n);
}
};
void my_init()
{
//calculate the radius of the sphere
radius = calculateRadius();
//calculate the rolling directions
totalSegments = sizeof(track)/sizeof(point);
vectors = new point[totalSegments];
rotationAxis = new point[totalSegments];
for(int i=0;i<totalSegments - 1;i++){
vectors[i] = calculateDirection(track[i], track[i+1]);
}
//and the last point to the first one
vectors[totalSegments - 1] = calculateDirection(track[totalSegments - 1], track[0]);
//calculate the rotating axis vectors
point y_axis = {0,1,0};
for(int i=0;i<totalSegments;i++){
rotationAxis[i] = crossProduct(y_axis,vectors[i]);
}
//compute triangle normal
calculateNormals();
//clear the background color to blue
glClearColor(0.529,0.807,0.92,0);
glEnable(GL_DEPTH_TEST);
}
void init_spotlight(){
//init spot light
glEnable(GL_LIGHT1);
glLightfv(GL_LIGHT1,GL_POSITION,light_pos);
glLightfv(GL_LIGHT1,GL_SPOT_DIRECTION,light_dir);
glLightfv(GL_LIGHT1,GL_DIFFUSE,light_diffuse);
glLightfv(GL_LIGHT1,GL_SPECULAR,light_specular);
glLightfv(GL_LIGHT1,GL_AMBIENT,light_ambient);
if(spotlight){
glLightf(GL_LIGHT1,GL_SPOT_CUTOFF,20);
}else {
glLightf(GL_LIGHT1,GL_SPOT_CUTOFF,180);
}
glLightf(GL_LIGHT1,GL_SPOT_EXPONENT,5);
glLightf(GL_LIGHT1,GL_CONSTANT_ATTENUATION,2.0);
glLightf(GL_LIGHT1,GL_LINEAR_ATTENUATION,0.01);
glLightf(GL_LIGHT1,GL_QUADRATIC_ATTENUATION,0.001);
};
void init_lighting(){
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_AMBIENT,light_ambient);
glLightfv(GL_LIGHT0,GL_DIFFUSE,light_diffuse);
glLightfv(GL_LIGHT0,GL_SPECULAR,light_specular);
//global ambient light
glLightModelfv(GL_LIGHT_MODEL_AMBIENT,global_ambient);
//use flat shading as default
if(flatshade){
glShadeModel(GL_FLAT);
}else{
glShadeModel(GL_SMOOTH);
}
};
double calculateFovy(){
//distance between camera and the center of object
point obj_center = {0,radius,2};
double distance = distanceAt(viewer,obj_center);
//compute size of the whole scene
double size = sqrt3f(5.0,radius,6.0);
double radtheta, degtheta;
radtheta = 2.0 * atan2(size,distance);
degtheta = (180.0 * radtheta) / PI;
return degtheta;
}
void reshape(int w, int h)
{
int size = (w>h)?h:w;
glViewport((w-size)/2, (h-size)/2, size, size);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//calculate fovy
double fovy = calculateFovy();
gluPerspective(fovy, w/h, 1, 100);
}
int nextModel(){
int next = currentSegment + 1;
return (next == totalSegments)? 0: next;
}
float distanceAt(point p1, point p2){
float dx = p1.x - p2.x;
float dy = p1.y - p2.y;
float dz = p1.z - p2.z;
return sqrt3f(dx,dy,dz);
}
/* distance between current position and next point is greater than one between current track point and the next point*/
bool isTrespass(){
int next = nextModel();
point from = track[currentSegment];
point to = track[next];
float d1 = distanceAt(centerPos, from);
float d2 = distanceAt(to, from);
return d1 > d2;
}
void rotationMatrix(){
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glRotatef(delta,rotationAxis[currentSegment].x,rotationAxis[currentSegment].y,rotationAxis[currentSegment].z);
glMultMatrixf(acc_matrix);
glGetFloatv(GL_MODELVIEW_MATRIX,acc_matrix);
glPopMatrix();
}
void idle(void)
{
Sleep(10);
//rotate by constant speed
theta+=delta;
if(theta > 360.0)
theta -= 360.0;
//translate on direction
float offset = (radius * delta* PI)/180;
centerPos.x = centerPos.x + vectors[currentSegment].x*offset;
centerPos.y = centerPos.y + vectors[currentSegment].y*offset;
centerPos.z = centerPos.z + vectors[currentSegment].z*offset;
if(isTrespass()){
currentSegment = nextModel();
centerPos = track[currentSegment];
}
//compute accumulated rotation matrix
rotationMatrix();
/* display()*/
glutPostRedisplay();
}
void key(unsigned char key, int x, int y)
{
if(key == 'b'|| key =='B'){
begin = true;
// Start rolling
glutIdleFunc(idle);
}
if(key == 'x') viewer.x-= 1.0;
if(key == 'X') viewer.x+= 1.0;
if(key == 'y') viewer.y-= 1.0;
if(key == 'Y') viewer.y+= 1.0;
if(key == 'z') viewer.z-= 1.0;
if(key == 'Z') viewer.z+= 1.0;
}
void mouse(int button, int state, int x, int y){
if(button == GLUT_RIGHT_BUTTON && state == GLUT_UP && begin){
rolling = !rolling;
}
if(rolling){
// Stop rolling
glutIdleFunc(idle);
}else{
glutIdleFunc(NULL);
}
}
/* set to default VRP*/
void setDefaultView(){
viewer.x = 7.0;
viewer.y = 3.0;
viewer.z = -10.0;
}
/* Release program and exit*/
void quit(){
delete [] vectors;
delete [] rotationAxis;
delete [] tri_normals;
for(int i=0;i<num;i++){
delete [] sphereData[i];
}
delete [] sphereData;
exit(1);
}
/* Main menu handler:
1) Reset default view point
2) Quit
3) Switch between wireframe and solid sphere
*/
void main_menu(int index)
{
switch(index)
{
case(0):
{
setDefaultView();
break;
}
case(1):
{
quit();
break;
}
case(2):
{
wireframe = !wireframe;
break;
}
}
display();
};
/* shadow menu handler
1) Turn on shadow
2) Turn off shadow
*/
void shadow_menu(int index){
shadow = (index == 1)?false:true;
display();
};
/* shade menu handler
1) Flat shade
2) Smooth shade
*/
void shade_menu(int index){
flatshade = (index == 1)?true:false;
if(flatshade){
glShadeModel(GL_FLAT);
}else {
glShadeModel(GL_SMOOTH);
}
display();
};
/* lighting menu handler
1) Turn on lighting effect
2) Turn off lighting effect
*/
void lighting_menu(int index){
lighting = (index == 1)?false:true;
display();
};
/* spotlight menu handler
1) Spotlight
2) Point light
*/
void spotlight_menu(int index){
spotlight = (index == 1)?true:false;
display();
};
/* Add menu to mouse left button*/
void addMenu(){
int shadow = glutCreateMenu(shadow_menu);
glutAddMenuEntry("No", 1);
glutAddMenuEntry("Yes", 2);
int shade = glutCreateMenu(shade_menu);
glutAddMenuEntry("FLAT", 1);
glutAddMenuEntry("SMOOTH", 2);
int lighting = glutCreateMenu(lighting_menu);
glutAddMenuEntry("No", 1);
glutAddMenuEntry("Yes", 2);
int spotlight = glutCreateMenu(spotlight_menu);
glutAddMenuEntry("Spot light", 1);
glutAddMenuEntry("Point light", 2);
glutCreateMenu(main_menu);
glutAddMenuEntry("Default View Point", 0);
glutAddSubMenu("Enable Lighting", lighting);
glutAddMenuEntry("Quit", 1);
glutAddMenuEntry("Wire Frame", 2);
glutAddMenuEntry("Fog Options", NULL);
glutAddMenuEntry("Texture Mapping", NULL);
glutAddSubMenu("Shadow",shadow);
glutAddMenuEntry("Blending Shadow", NULL);
glutAddSubMenu("Shading", shade);
glutAddSubMenu("Lighting", spotlight);
glutAddMenuEntry("Firework", NULL);
glutAttachMenu(GLUT_LEFT_BUTTON);
}
void main(int argc, char **argv)
{
/*---- Initialize & Open Window ---*/
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); // double-buffering and RGB color
// mode.
glutInitWindowSize(500, 500);
glutInitWindowPosition(30, 30); // Graphics window position
glutCreateWindow("Assignment 2"); // Window title is "Rectangle"
fileReadIn();
addMenu();
glutDisplayFunc(display); // Register our display() function as the display
// call-back function
glutReshapeFunc(reshape); // Register our reshape() function as the reshape
// call-back function
glutMouseFunc(mouse); // for mouse
glutKeyboardFunc(key); // for keyboard
my_init(); // initialize variables
glutMainLoop(); // Enter the event loop
}