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Earth.cpp
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Earth.cpp
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// earth-simulation by Ohad Eder Pressman, 2001
// ohad@visual-i.com / ohad.visual-i.com
#define PI 3.14159265
#include <stdio.h>
#include <math.h>
#include <string.h>
#include "glut/glut.h"
#include "GLTexture.h"
#include "gltexfont/gltexfont.h"
#include "countries/countries.h"
// menu
enum MenuCommands {
MENU_TEXTURE = 0,
MENU_WIREFRAME,
MENU_LINEWIDTH,
MENU_COUNTRY_NAMES,
MENU_COAST,
MENU_ISLAND,
MENU_LAKE,
MENU_RIVER,
MENU_NATION,
MENU_USSTATE,
MENU_EXIT
};
// defines
#define PI 3.14159265
#define EARTH_LON_RES 60 // Longitude Resolution (x)
#define EARTH_LAT_RES 60 // Latitude Resolution (y)
#define EARTH_RADIUS 6378 // in kilometers
#define WORLD_SCALE 0.01f // scale of all the world
#define MIN_SCALE 0.5f // how much can we zoom out
#define MAX_SCALE 1.9f // and in
// structures
struct Vector {
GLfloat x, y, z;
};
struct Mapping {
GLfloat u, v;
};
// vector-file
struct VxpFeature {
int nVerts;
Vector *pVerts;
};
struct Vxp {
int nFeatures;
VxpFeature *pFeatures;
};
// variables
CGLTexture earthTexture;
Vector vertices[EARTH_LON_RES+1][EARTH_LAT_RES+1];
Mapping mapping[EARTH_LON_RES+1][EARTH_LAT_RES+1];
Vector country_names_pos[NUM_COUNTRIES];
int mouseX, mouseY;
int mouseButtonDown = 0, isCtrlDown = 0;
float rotX = 140, rotY = 0;
float autoRotX = 0, autoRotY = 0;
float scaleAll = 1;
int drawWireframe = 1;
int drawTexture = 1;
int showCountries = 1;
int lineWidth = 1;
int showVxp[6] = {0,0,0,0,0,0};
Vxp *vxp_data[6];
// forward
void LonLat2Point(float lon, float lat, Vector *pos);
// functions
// read binary-vector-data files (not a commercial format)
Vxp *load_bdv(char *pFileName)
{
Vxp *vxp = new Vxp;
FILE *f;
// read file
f = fopen(pFileName, "rb");
// read number of features
fread(&vxp->nFeatures, 4, 1, f);
// allocate features
vxp->pFeatures = new VxpFeature[vxp->nFeatures];
// start reading features
for (int i=0; i< vxp->nFeatures; i++) {
// read number of vertices
fread(&vxp->pFeatures[i].nVerts, 4, 1, f);
// allocate vertices
vxp->pFeatures[i].pVerts = new Vector[ vxp->pFeatures[i].nVerts ];
// scan vertices
for (int j=0; j<vxp->pFeatures[i].nVerts; j++) {
float lonlat[2];
fread(lonlat, 8, 1, f);
// project on sphere
LonLat2Point(lonlat[1], lonlat[0], &vxp->pFeatures[i].pVerts[j]);
}
}
fclose(f);
return vxp;
}
void Resize( GLsizei iWidth, GLsizei iHeight )
{
glViewport (0,0,iWidth,iHeight);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
gluPerspective(65.0,(GLfloat)iWidth/(GLfloat)iHeight, 0.1, 120.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void Idle()
{
glutPostRedisplay();
}
void Init()
{
earthTexture.LoadTGA("images/earth.tga");
// generate our sphere
for (int x=0; x<=EARTH_LON_RES; x++) {
for (int y=0; y<=EARTH_LAT_RES; y++) {
// angle around y-axis (which is x-value)
float angX, angY;
angX = (x * 360.f / EARTH_LON_RES) * PI / 180.f;
angY = (-90.f + (y * 180.f / EARTH_LAT_RES)) * PI / 180.f;
vertices[x][y].x = fabsf(cosf(angY)) * EARTH_RADIUS * sinf(angX);
vertices[x][y].y = EARTH_RADIUS * sinf(angY);
vertices[x][y].z = fabsf(cosf(angY)) * EARTH_RADIUS * cosf(angX);
mapping[x][y].u = (float)x / EARTH_LON_RES;
mapping[x][y].v = (float)y / EARTH_LAT_RES;
}
}
// load bvd files
vxp_data[0] = load_bdv("vector data/coast.bvd");
vxp_data[1] = load_bdv("vector data/island.bvd");
vxp_data[2] = load_bdv("vector data/lake.bvd");
vxp_data[3] = load_bdv("vector data/river.bvd");
vxp_data[4] = load_bdv("vector data/nation.bvd");
vxp_data[5] = load_bdv("vector data/state.bvd");
}
void DrawEarth()
{
if (drawTexture) {
glEnable(GL_TEXTURE_2D);
earthTexture.Use();
}
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glColor3f(1,1,1);
int x, y;
for (y=0; y<EARTH_LAT_RES; y++) {
glBegin(GL_QUAD_STRIP);
for (x=0; x<EARTH_LON_RES; x++) {
glTexCoord2fv((float*)&mapping[x][y]);
glVertex3fv((float*)&vertices[x][y]);
glTexCoord2fv((float*)&mapping[x][y+1]);
glVertex3fv((float*)&vertices[x][y+1]);
glTexCoord2fv((float*)&mapping[x+1][y]);
glVertex3fv((float*)&vertices[x+1][y]);
glTexCoord2fv((float*)&mapping[x+1][y+1]);
glVertex3fv((float*)&vertices[x+1][y+1]);
}
glEnd();
}
if (drawWireframe) {
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glLineWidth(lineWidth);
for (y=0; y<=EARTH_LAT_RES; y++) {
glBegin(GL_LINE_STRIP);
for (x=0; x<=EARTH_LON_RES; x++) {
glColor4f(0,0,0,0.2f);
glVertex3fv((float*)&vertices[x][y]);
}
glEnd();
}
for (x=0; x<=EARTH_LON_RES; x++) {
glBegin(GL_LINE_STRIP);
for (y=0; y<=EARTH_LAT_RES; y++) {
glColor4f(0,0,0,0.2f);
glVertex3fv((float*)&vertices[x][y]);
}
glEnd();
}
glDisable(GL_BLEND);
}
glDisable(GL_TEXTURE_2D);
}
void DrawVxp(Vxp *vxp)
{
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
for (int i=0; i<vxp->nFeatures; i++) {
glBegin(GL_LINE_STRIP);
if (drawTexture) {
glColor4f(1,1,1,0.5f);
} else {
glColor4f(0,0,0,0.5f);
}
// run over all vertices in this feature
for (int j=0; j<vxp->pFeatures[i].nVerts; j++) {
glVertex3fv((float*)&vxp->pFeatures[i].pVerts[j]);
}
glEnd();
}
glDisable(GL_BLEND);
}
void LonLat2Point(float lon, float lat, Vector *pos)
{
// lon -90..90
// lat -180..180
float angX, angY;
angX = (180.f+lat) * PI / 180.f;
angY = lon * PI / 180.f;
pos->x = fabsf(cosf(angY)) * EARTH_RADIUS * sinf(angX);
pos->y = EARTH_RADIUS * sinf(angY);
pos->z = fabsf(cosf(angY)) * EARTH_RADIUS * cosf(angX);
}
void DrawScene()
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
static float time = 0;
time += 0.1;
// if the mouse-button is not down, auto-rotate
if (!mouseButtonDown) {
rotX += autoRotX*scaleAll*0.1f;
rotY += autoRotY*scaleAll*0.1f;
}
glTranslatef(0,0,-125);
glScalef(WORLD_SCALE, WORLD_SCALE, WORLD_SCALE);
glScalef(scaleAll, scaleAll, scaleAll);
glRotatef(rotY, 1,0,0);
glRotatef(rotX, 0,1,0);
GLdouble modelview_matrix[16];
glGetDoublev(GL_MODELVIEW_MATRIX, modelview_matrix);
DrawEarth();
glPopMatrix();
}
void MouseButton(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON) {
if (state == GLUT_DOWN) {
mouseX = x;
mouseY = y;
mouseButtonDown = 1;
isCtrlDown = glutGetModifiers() & GLUT_ACTIVE_CTRL;
} else {
mouseButtonDown = 0;
}
}
}
void MouseMotion(int x, int y)
{
int deltX, deltY;
// calculate mouse movement since click
deltX = x - mouseX;
deltY = y - mouseY;
// store new mouse position
mouseX = x;
mouseY = y;
if (mouseButtonDown) {
// is Cotrl Down ?
if (isCtrlDown) {
// scale
float addition;
addition = ((deltX+deltY) / 200.f);
if (addition < 0 && scaleAll+addition > MIN_SCALE) {
scaleAll += addition;
}
if (addition > 0 && scaleAll+addition < MAX_SCALE) {
scaleAll += addition;
}
} else {
// rotate
rotX += deltX*0.25f/scaleAll;
rotY += deltY*0.25f/scaleAll;
// save values for auto rotation
autoRotX = deltX*0.25f;
autoRotY = deltY*0.25f;
}
glutPostRedisplay();
}
}
void SelectFromMenu(int idCommand)
{
switch (idCommand) {
case MENU_WIREFRAME:
drawWireframe = !drawWireframe;
break;
case MENU_TEXTURE:
drawTexture = !drawTexture;
break;
case MENU_LINEWIDTH:
if (lineWidth == 1) {
lineWidth = 2;
} else {
lineWidth = 1;
}
break;
case MENU_COUNTRY_NAMES:
showCountries = !showCountries;
break;
case MENU_COAST:
case MENU_ISLAND:
case MENU_LAKE:
case MENU_NATION:
case MENU_RIVER:
case MENU_USSTATE:
showVxp[idCommand-MENU_COAST] = !showVxp[idCommand-MENU_COAST];
break;
case MENU_EXIT:
exit(0);
break;
}
glutPostRedisplay();
}
void Keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 't':
SelectFromMenu(MENU_TEXTURE);
break;
case 'w':
SelectFromMenu(MENU_WIREFRAME);
break;
case 'l':
SelectFromMenu(MENU_LINEWIDTH);
break;
case 27: // escape
SelectFromMenu(MENU_EXIT);
break;
}
}
void main(int argc, char **argv)
{
GLsizei iWidth = 640.0;
GLsizei iHeight = 480.0;
glutInit(&argc, argv);
glutInitWindowPosition( 0, 0);
glutInitWindowSize(iWidth, iHeight);
glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
glutCreateWindow( "Earth Simulation" );
glutAttachMenu(GLUT_RIGHT_BUTTON);
glutDisplayFunc(DrawScene );
glutIdleFunc(Idle );
glutReshapeFunc(Resize );
glutMouseFunc(MouseButton);
glutMotionFunc(MouseMotion);
glutKeyboardFunc(Keyboard);
Init();
glClearColor(0.13f, 0.34f, 0.83f,0); // blue
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
Resize(iWidth, iHeight);
glutMainLoop();
}