//---------------------------------------------------------------------
// Ukazkovy priklad cislo 34
// Autor: Pavel Tisnovsky
//
// Tento priklad svym ovladanim navazuje na priklad cislo 28 a jeho
// pokracovani.
// Nove je pridana funkce pro zmenu prikazu vykreslovani:
// krome klasickeho vykreslovani (glBegin, glEnd) lze pouzit i funkce
// glArrayElement(), glDrawArrays() a glDrawElements().
// Jsou pridany take ctyri klavesove zkratky - viz nize.
//
// Program lze ovladat kombinaci mysi a klavesnice. Pomoci leveho
// tlacitka mysi se aplikuje nektera operace, prave tlacitko mysi slouzi
// k zobrazeni kontextoveho menu. Zakladni udaje o scene se vypisuji
// primo do okna aplikace.
//
// Funkce klaves v tomto programu:
// ESC - ukonceni aplikace
// 'q' - ukonceni aplikace
// 'r' - rezim rotace objektu
// 't' - rezim posunu objektu dale/blize ke kamere
// 'z' - rezim posunu blizke orezavaci roviny
// 'x' - rezim posunu vzdalene orezavaci roviny
// 'f' - prepnuti do rezimu full-screen
// 'w' - prepnuti zpet do okna
// 'e' - povoleni testu pameti hloubky
// 'd' - zakazani testu pameti hloubky
// '[' - povoleni orezavani
// ']' - zakaz orezavani
// '.' - zmenseni zorneho uhlu
// ',' - zvetseni zorneho uhlu
// '>' - rychlejsi zmenseni zorneho uhlu
// '<' - rychlejsi zvetseni zorneho uhlu
// '0'-'9' - zmena rezimu vykreslovani prednich a zadnich stran polygonu
// F1 - normalni vykreslovani (glBegin() a glEnd())
// F2 - vykreslovani pomoci funkce glArrayElement()
// F3 - vykreslovani pomoci funkce glDrawArrays()
// F4 - vykreslovani pomoci funkce glDrawElements()
//---------------------------------------------------------------------
#include <GL/glut.h> // hlavickovy soubor funkci GLUTu a OpenGL
#include <stdio.h>
#include <stdlib.h>
enum { // operace, ktere se mohou provadet s mysi:
ROTATE, // rotace objektu
TRANSLATE, // posun objektu
NEAR_PLANE, // zmena blizsi orezavaci roviny
FAR_PLANE // zmena vzdalenejsi orezavaci roviny
} operation=ROTATE;
enum { // prikazy z kontextoveho menu:
COMMAND_ROTATE, // rotace objektu
COMMAND_TRANSLATE, // posun objektu
COMMAND_NEAR_PLANE, // zmena blizsi orezavaci roviny
COMMAND_FAR_PLANE, // zmena vzdalenejsi orezavaci roviny
COMMAND_FRONT_FACE_DISABLE, // zakazani zobrazovani prednich sten polygonu
COMMAND_FRONT_FACE_ENABLE, // povoleni zobrazovani prednich sten polygonu
COMMAND_FRONT_FACE_POINTS, // predni steny polygonu vykreslovat jako body ve vrcholech
COMMAND_FRONT_FACE_LINES, // predni steny polygonu vykreslovat jako usecky na hranach
COMMAND_FRONT_FACE_POLYGONS, // predni steny polygonu vykreslovat vyplnene
COMMAND_BACK_FACE_DISABLE, // zakazani zobrazovani zadnich sten polygonu
COMMAND_BACK_FACE_ENABLE, // povoleni zobrazovani zadnich sten polygonu
COMMAND_BACK_FACE_POINTS, // zadni steny polygonu vykreslovat jako body ve vrcholech
COMMAND_BACK_FACE_LINES, // zadni steny polygonu vykreslovat jako usecky na hranach
COMMAND_BACK_FACE_POLYGONS, // zadni steny polygonu vykreslovat vyplnene
COMMAND_ENABLE_DEPTH_TEST, // povoleni Z-bufferu
COMMAND_DISABLE_DEPTH_TEST, // zakazani Z-bufferu
COMMAND_DEPTH_FUNC_NEVER, // |
COMMAND_DEPTH_FUNC_LESS, // |
COMMAND_DEPTH_FUNC_LEQUAL, // | nastaveni funkci, ktere se budou provadet mezi hodnotou
COMMAND_DEPTH_FUNC_EQUAL, // | zapsanou v Z-bufferu a hodnotou prave vykreslovaneho
COMMAND_DEPTH_FUNC_GEQUAL, // | fragmentu
COMMAND_DEPTH_FUNC_GREATER, // |
COMMAND_DEPTH_FUNC_NOTEQUAL, // |
COMMAND_DEPTH_FUNC_ALWAYS, // |
COMMAND_FULL_SCREEN, // prepnuti do rezimu okna pres celou obrazovku
COMMAND_WINDOW, // prepnuti do rezimu normalniho okna
COMMAND_CLIP_PLANE_ENABLE, // povoleni pridavne orezavaci roviny
COMMAND_CLIP_PLANE_DISABLE, // zakazani pridavne orezavaci roviny
COMMAND_CLIP_PLANE_XY, // |
COMMAND_CLIP_PLANE_XZ, // |
COMMAND_CLIP_PLANE_YZ, // | nastaveni orientace pridavne orezavaci roviny
COMMAND_CLIP_PLANE_POSITIVE_DIRECTION, // |
COMMAND_CLIP_PLANE_NEGATIVE_DIRECTION, // |
COMMAND_CLIP_PLANE_DIST_0, // --
COMMAND_CLIP_PLANE_DIST_1, // |
COMMAND_CLIP_PLANE_DIST_2, // |
COMMAND_CLIP_PLANE_DIST_3, // | nastaveni vzdalenosti pridavne orezavaci roviny
COMMAND_CLIP_PLANE_DIST_4, // |
COMMAND_CLIP_PLANE_DIST_5, // |
COMMAND_DRAW_MODE_NORMAL, // vykreslovani pres funkce glBegin() a glEnd()
COMMAND_DRAW_MODE_ARRAY_ELEMENT, // vykreslovani pres funkci glArrayElement()
COMMAND_DRAW_MODE_DRAW_ARRAYS, // vykreslovani pres funkci glDrawArrays()
COMMAND_DRAW_MODE_DRAW_ELEMENTS, // vykreslovani pres funkci glDrawElements()
COMMAND_QUIT, // ukonceni aplikace
COMMAND_NONE
} command;
int xnew=0, ynew=0, znew=0; // soucasna pozice mysi, ze ktere se pocitaji rotace a posuvy
int xold=0, yold=0, zold=0; // minula pozice mysi, ze ktere se pocitaji rotace a posuvy
int xx, yy, zz; // bod, ve kterem se nachazi kurzor mysi
int np_old=1, np_new=1, npp=1; // priznaky blizke orezavaci roviny
int fp_old=900, fp_new=900, fpp=900; // priznaky vzdalene orezavaci roviny
float fov=70.0; // hodnota zorneho uhlu - field of view
float nearPlane=0.1; // blizsi orezavaci rovina
float farPlane=90.0; // vzdalenejsi orezavaci rovina
int windowWidth; // sirka okna
int windowHeight; // vyska okna
int depthBufferEnabled=1; // priznak, zda je povolena pamet hloubky
int frontFaceEnabled=1; // priznak viditelnosti prednich sten
int backFaceEnabled=1; // priznak viditelnosti zadnich sten
int clipPlaneNormal=COMMAND_CLIP_PLANE_XY; // normala orezavaci roviny
int clipPlaneDirection=COMMAND_CLIP_PLANE_POSITIVE_DIRECTION;// orientace normaly
int clipPlaneDistance=COMMAND_CLIP_PLANE_DIST_0;// vzdalenost orezavaci roviny od pocatku
int drawMode=COMMAND_DRAW_MODE_NORMAL; // zpusob vykreslovani
//---------------------------------------------------------------------
// Funkce, ktera je zavolana pri vyberu prikazu z kontextoveho menu
//---------------------------------------------------------------------
void onMenu(int command)
{
switch (command) { // rozeskok podle vybraneho prikazu
case COMMAND_ROTATE: operation=ROTATE; break;
case COMMAND_TRANSLATE: operation=TRANSLATE; break;
case COMMAND_NEAR_PLANE: operation=NEAR_PLANE; break;
case COMMAND_FAR_PLANE: operation=FAR_PLANE; break;
case COMMAND_FRONT_FACE_DISABLE: glCullFace(GL_FRONT); glEnable(GL_CULL_FACE); glutPostRedisplay(); break;
case COMMAND_FRONT_FACE_ENABLE: glDisable(GL_CULL_FACE); glutPostRedisplay(); break;
case COMMAND_FRONT_FACE_POINTS: glPolygonMode(GL_FRONT, GL_POINT); glutPostRedisplay(); break;
case COMMAND_FRONT_FACE_LINES: glPolygonMode(GL_FRONT, GL_LINE); glutPostRedisplay(); break;
case COMMAND_FRONT_FACE_POLYGONS: glPolygonMode(GL_FRONT, GL_FILL); glutPostRedisplay(); break;
case COMMAND_BACK_FACE_DISABLE: glCullFace(GL_BACK); glEnable(GL_CULL_FACE); glutPostRedisplay(); break;
case COMMAND_BACK_FACE_ENABLE: glDisable(GL_CULL_FACE); glutPostRedisplay(); break;
case COMMAND_BACK_FACE_POINTS: glPolygonMode(GL_BACK, GL_POINT); glutPostRedisplay(); break;
case COMMAND_BACK_FACE_LINES: glPolygonMode(GL_BACK, GL_LINE); glutPostRedisplay(); break;
case COMMAND_BACK_FACE_POLYGONS: glutPostRedisplay(); glPolygonMode(GL_BACK, GL_FILL); break;
case COMMAND_ENABLE_DEPTH_TEST: depthBufferEnabled=1; glEnable(GL_DEPTH_TEST); glutPostRedisplay(); break;
case COMMAND_DISABLE_DEPTH_TEST: depthBufferEnabled=0; glDisable(GL_DEPTH_TEST); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_NEVER: glDepthFunc(GL_NEVER); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_LESS: glDepthFunc(GL_LESS); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_LEQUAL: glDepthFunc(GL_LEQUAL); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_EQUAL: glDepthFunc(GL_EQUAL); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_GEQUAL: glDepthFunc(GL_GEQUAL); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_GREATER: glDepthFunc(GL_GREATER); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_NOTEQUAL: glDepthFunc(GL_NOTEQUAL); glutPostRedisplay(); break;
case COMMAND_DEPTH_FUNC_ALWAYS: glDepthFunc(GL_ALWAYS); glutPostRedisplay(); break;
case COMMAND_FULL_SCREEN: glutFullScreen(); break;
case COMMAND_WINDOW: glutReshapeWindow(500, 500); break;
case COMMAND_CLIP_PLANE_ENABLE: glEnable(GL_CLIP_PLANE0); glutPostRedisplay(); break;
case COMMAND_CLIP_PLANE_DISABLE: glDisable(GL_CLIP_PLANE0); glutPostRedisplay(); break;
case COMMAND_CLIP_PLANE_XY:
case COMMAND_CLIP_PLANE_XZ:
case COMMAND_CLIP_PLANE_YZ: clipPlaneNormal=command; glutPostRedisplay(); break;
case COMMAND_CLIP_PLANE_POSITIVE_DIRECTION:
case COMMAND_CLIP_PLANE_NEGATIVE_DIRECTION: clipPlaneDirection=command; glutPostRedisplay(); break;
case COMMAND_CLIP_PLANE_DIST_0:
case COMMAND_CLIP_PLANE_DIST_1:
case COMMAND_CLIP_PLANE_DIST_2:
case COMMAND_CLIP_PLANE_DIST_3:
case COMMAND_CLIP_PLANE_DIST_4:
case COMMAND_CLIP_PLANE_DIST_5:
clipPlaneDistance=command; glutPostRedisplay(); break;
case COMMAND_DRAW_MODE_NORMAL:
case COMMAND_DRAW_MODE_ARRAY_ELEMENT:
case COMMAND_DRAW_MODE_DRAW_ELEMENTS:
case COMMAND_DRAW_MODE_DRAW_ARRAYS:
drawMode=command; glutPostRedisplay(); break;
case COMMAND_QUIT: exit(0); break;
case COMMAND_NONE: break;
}
}
//---------------------------------------------------------------------
// Funkce pro inicializaci vykreslovani
//---------------------------------------------------------------------
void onInit(void)
{
GLdouble equation[]={0.0, 1.0, 0.0, 0.0};
int menu; // identifikatory jednotlivych menu a submenu
int menuMode;
int menuDrawMode;
int menuDepth;
int menuDFunc;
int menuFrontFace;
int menuBackFace;
int menuClipping, menuClipNormal, menuClipDirection, menuClipDistance;
int menuQuit;
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // barva pozadi obrazku
glClearDepth(1.0f); // implicitni hloubka ulozena v pameti hloubky
glEnable(GL_DEPTH_TEST); // povoleni funkce pro testovani hodnot v pameti hloubky
glDepthFunc(GL_LESS); // funkce pro testovani fragmentu
glShadeModel(GL_SMOOTH); // nastaveni stinovaciho rezimu
glPolygonMode(GL_FRONT, GL_FILL); // nastaveni rezimu vykresleni modelu
glPolygonMode(GL_BACK, GL_FILL); // jak pro predni tak pro zadni steny
glPointSize(3.0f); // body zobrazovat s prumerem 3 pixely
glEnable(GL_POINT_SMOOTH); // povoleni antialiasingu bodu
glLineWidth(1.0f); // usecky zobrazovat siroke 1 pixel
glEnable(GL_LINE_SMOOTH); // povoleni antialiasingu usecek
glDisable(GL_CULL_FACE); // zadne hrany ani steny se nebudou odstranovat
glClipPlane(GL_CLIP_PLANE0, equation);
menuMode=glutCreateMenu(onMenu); // vytvoreni kontextoveho menu a jeho submenu
glutSetMenu(menuMode);
glutAddMenuEntry("Rotate object\tR", COMMAND_ROTATE);
glutAddMenuEntry("Translate object\tT", COMMAND_TRANSLATE);
glutAddMenuEntry("Translate near clipping plane\tZ", COMMAND_NEAR_PLANE);
glutAddMenuEntry("Translate far clipping plane\tX", COMMAND_FAR_PLANE);
menuDrawMode=glutCreateMenu(onMenu);
glutSetMenu(menuDrawMode);
glutAddMenuEntry("Normal\tF1", COMMAND_DRAW_MODE_NORMAL);
glutAddMenuEntry("ArrayElement\tF2", COMMAND_DRAW_MODE_ARRAY_ELEMENT);
glutAddMenuEntry("DrawArrays\tF3", COMMAND_DRAW_MODE_DRAW_ARRAYS);
glutAddMenuEntry("DrawElements\tF4", COMMAND_DRAW_MODE_DRAW_ELEMENTS);
menuDepth=glutCreateMenu(onMenu);
glutSetMenu(menuDepth);
glutAddMenuEntry("Enable depth test\tE", COMMAND_ENABLE_DEPTH_TEST);
glutAddMenuEntry("Disable depth test\tD", COMMAND_DISABLE_DEPTH_TEST);
menuDFunc=glutCreateMenu(onMenu);
glutSetMenu(menuDFunc);
glutAddMenuEntry("Never", COMMAND_DEPTH_FUNC_NEVER);
glutAddMenuEntry("Less", COMMAND_DEPTH_FUNC_LESS);
glutAddMenuEntry("Less or Equal", COMMAND_DEPTH_FUNC_LEQUAL);
glutAddMenuEntry("Equal", COMMAND_DEPTH_FUNC_EQUAL);
glutAddMenuEntry("Greater or Equal", COMMAND_DEPTH_FUNC_GEQUAL);
glutAddMenuEntry("Greater", COMMAND_DEPTH_FUNC_GREATER);
glutAddMenuEntry("Not Equal", COMMAND_DEPTH_FUNC_NOTEQUAL);
glutAddMenuEntry("Always", COMMAND_DEPTH_FUNC_ALWAYS);
menuFrontFace=glutCreateMenu(onMenu);
glutSetMenu(menuFrontFace);
glutAddMenuEntry("Disable\t1", COMMAND_FRONT_FACE_DISABLE);
glutAddMenuEntry("Enable\t2", COMMAND_FRONT_FACE_ENABLE);
glutAddMenuEntry("Points\t3", COMMAND_FRONT_FACE_POINTS);
glutAddMenuEntry("Lines\t4", COMMAND_FRONT_FACE_LINES);
glutAddMenuEntry("Polygons\t5", COMMAND_FRONT_FACE_POLYGONS);
menuBackFace=glutCreateMenu(onMenu);
glutSetMenu(menuBackFace);
glutAddMenuEntry("Disable\t6", COMMAND_BACK_FACE_DISABLE);
glutAddMenuEntry("Enable\t7", COMMAND_BACK_FACE_ENABLE);
glutAddMenuEntry("Points\t8", COMMAND_BACK_FACE_POINTS);
glutAddMenuEntry("Lines\t9", COMMAND_BACK_FACE_LINES);
glutAddMenuEntry("Polygons\t0", COMMAND_BACK_FACE_POLYGONS);
menuClipNormal=glutCreateMenu(onMenu);
glutSetMenu(menuClipNormal);
glutAddMenuEntry("x-axis", COMMAND_CLIP_PLANE_YZ);
glutAddMenuEntry("y-axis", COMMAND_CLIP_PLANE_XZ);
glutAddMenuEntry("z-axis", COMMAND_CLIP_PLANE_XY);
menuClipDirection=glutCreateMenu(onMenu);
glutSetMenu(menuClipDirection);
glutAddMenuEntry("Positive", COMMAND_CLIP_PLANE_POSITIVE_DIRECTION);
glutAddMenuEntry("Negative", COMMAND_CLIP_PLANE_NEGATIVE_DIRECTION);
menuClipDistance=glutCreateMenu(onMenu);
glutSetMenu(menuClipDistance);
glutAddMenuEntry("0", COMMAND_CLIP_PLANE_DIST_0);
glutAddMenuEntry("1", COMMAND_CLIP_PLANE_DIST_1);
glutAddMenuEntry("2", COMMAND_CLIP_PLANE_DIST_2);
glutAddMenuEntry("3", COMMAND_CLIP_PLANE_DIST_3);
glutAddMenuEntry("4", COMMAND_CLIP_PLANE_DIST_4);
menuClipping=glutCreateMenu(onMenu);
glutSetMenu(menuClipping);
glutAddMenuEntry("Enable clipping", COMMAND_CLIP_PLANE_ENABLE);
glutAddMenuEntry("Disable clipping", COMMAND_CLIP_PLANE_DISABLE);
glutAddSubMenu("Normal", menuClipNormal);
glutAddSubMenu("Normal' direction", menuClipDirection);
glutAddSubMenu("Distance", menuClipDistance);
menuQuit=glutCreateMenu(onMenu);
glutSetMenu(menuQuit);
glutAddMenuEntry("Yes\tQ", COMMAND_QUIT);
glutAddMenuEntry("No", COMMAND_NONE);
menu=glutCreateMenu(onMenu);
glutAddSubMenu("Mode", menuMode);
glutAddSubMenu("Draw mode", menuDrawMode);
glutAddSubMenu("Front faces", menuFrontFace);
glutAddSubMenu("Back faces", menuBackFace);
glutAddSubMenu("Depth test", menuDepth);
glutAddSubMenu("Depth function", menuDFunc);
glutAddSubMenu("Clipping", menuClipping);
glutAddMenuEntry("Full screen\tF", COMMAND_FULL_SCREEN);
glutAddMenuEntry("Window\tW", COMMAND_WINDOW);
glutAddSubMenu("Quit", menuQuit);
glutAttachMenu(GLUT_RIGHT_BUTTON); // menu je navazano na prave tlacitko mysi
}
//---------------------------------------------------------------------
// Nastaveni souradneho systemu v zavislosti na velikosti okna
//---------------------------------------------------------------------
void onResize(int w, int h) // argumenty w a h reprezentuji novou velikost okna
{
glViewport(0, 0, w, h); // viditelna oblast pres cele okno
windowWidth=w; // zapamatovat si velikost okna
windowHeight=h;
}
//---------------------------------------------------------------------
// Nastaveni perspektivni projekce
//---------------------------------------------------------------------
void setPerspectiveProjection(void)
{
glMatrixMode(GL_PROJECTION); // zacatek modifikace projekcni matice
glLoadIdentity(); // vymazani projekcni matice (=identita)
gluPerspective(fov, (double)windowWidth/(double)windowHeight, nearPlane, farPlane);// nastaveni perspektivni kamery
glMatrixMode(GL_MODELVIEW); // bude se menit modelova matice
glLoadIdentity(); // nahrat jednotkovou matici
}
//---------------------------------------------------------------------
// Nastaveni ortogonalni projekce
//---------------------------------------------------------------------
void setOrthogonalProjection(void)
{
glMatrixMode(GL_PROJECTION); // zacatek modifikace projekcni matice
glLoadIdentity(); // vymazani projekcni matice (=identita)
glOrtho(0, windowWidth, 0, windowHeight, -1, 1);
glMatrixMode(GL_MODELVIEW); // bude se menit modelova matice
glLoadIdentity(); // nahrat jednotkovou matici
}
//---------------------------------------------------------------------
// Funkce pro nastaveni orezavaci roviny
//---------------------------------------------------------------------
void setClipPlane(void)
{
GLdouble dir=1.0; // je bud -1 nebo 1 podle orientace normaly
GLdouble equation[]={0.0f, 0.0f, 0.0f, 0.0f};// parametry A, B, C, D ze vztahu Ax+By+Cz+D=0
if (clipPlaneDirection==COMMAND_CLIP_PLANE_NEGATIVE_DIRECTION)
dir=-1.0; // podle vyberu z menu se muze zmenit orientace normaly
switch (clipPlaneNormal) { // zmena smeru normaly
case COMMAND_CLIP_PLANE_XY: equation[2]=dir; break;
case COMMAND_CLIP_PLANE_XZ: equation[1]=dir; break;
case COMMAND_CLIP_PLANE_YZ: equation[0]=dir; break;
}
equation[3]=clipPlaneDistance-COMMAND_CLIP_PLANE_DIST_0;// vzdalenost orezavaci roviny
glClipPlane(GL_CLIP_PLANE0, equation); // nastaveni orezavaci roviny
}
//---------------------------------------------------------------------
// Vypsani retezce do okna na pozici [x,y]
//---------------------------------------------------------------------
void printString(int x, int y, char *text)
{
glRasterPos2i(x, y); // pozice prvniho znaku retezce
for (; *text; text++) // pruchod retezcem
glutBitmapCharacter(GLUT_BITMAP_9_BY_15, *text);// vykresleni jednoho znaku
}
//--------------------------------------------------------------------
// Vypsani informaci o nastavenych parametrech
//--------------------------------------------------------------------
void drawInfoText(void)
{
char str[100];
char *dm[]={"normal", "glArrayElement", "glDrawArrays", "glDrawElements"};
int ce=glIsEnabled(GL_CLIP_PLANE0);
glDisable(GL_CLIP_PLANE0); // text by se mel vypsat vzdy, proto vypneme orezavani
glColor3f(1.0,1.0,1.0);
sprintf(str, "Rotation x: %d", xnew);
printString(10, 100, str); // vypsat rotaci ve smeru osy x
sprintf(str, "Rotation y: %d", ynew);
printString(10, 85, str); // vypsat rotaci ve smeru osy y
sprintf(str, "Translation: %d", znew);
printString(10, 70, str); // vypsat posun objektu od kamery
sprintf(str, "Near plane: %5.2f", nearPlane);
printString(10, 55, str); // vzdalenost blizke orezavaci roviny
sprintf(str, "Far plane: %5.2f", farPlane);
printString(10, 40, str); // vzdalenost vzdalene orezavaci roviny
sprintf(str, "Field of view: %5.2f", fov);
printString(10, 25, str); // zorny uhel kamery
sprintf(str, "Clip plane: %s", ce ? "enabled":"disabled");
printString(10, 10, str); // povoleni ci zakazani orezavaci roviny
sprintf(str, "Draw mode: %s", dm[drawMode-COMMAND_DRAW_MODE_NORMAL]);
printString(250, 100, str);
if (ce) glEnable(GL_CLIP_PLANE0); // opetovne zapnuti orezavani
}
//--------------------------------------------------------------------
// Vykresleni objektu
//--------------------------------------------------------------------
void drawObjectNormal(void)
{
glBegin(GL_QUADS); // vykresleni otevrene krychle - sten domecku
glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(-5.0f, -5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(-5.0f, -5.0f, 5.0f);
glColor3f(0.0f, 1.0f, 1.0f); glVertex3f( 5.0f, -5.0f, 5.0f);
glColor3f(1.0f, 0.0f, 0.0f); glVertex3f( 5.0f, -5.0f, -5.0f);
glColor3f(1.0f, 0.0f, 1.0f); glVertex3f(-5.0f, 5.0f, -5.0f);
glColor3f(1.0f, 1.0f, 0.0f); glVertex3f(-5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 1.0f, 1.0f); glVertex3f( 5.0f, 5.0f, 5.0f);
glColor3f(0.0f, 0.0f, 1.0f); glVertex3f( 5.0f, 5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(-5.0f, -5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 1.0f); glVertex3f(-5.0f, -5.0f, 5.0f);
glColor3f(1.0f, 0.0f, 0.0f); glVertex3f(-5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 0.0f, 1.0f); glVertex3f(-5.0f, 5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f( 5.0f, -5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 1.0f); glVertex3f( 5.0f, -5.0f, 5.0f);
glColor3f(1.0f, 0.0f, 0.0f); glVertex3f( 5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 0.0f, 1.0f); glVertex3f( 5.0f, 5.0f, -5.0f);
glEnd();
glBegin(GL_TRIANGLES); // vykresleni strechy domecku z trojuhelniku
glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(-5.0f, 5.0f, -5.0f);
glColor3f(0.0f, 1.0f, 1.0f); glVertex3f( 5.0f, 5.0f, -5.0f);
glColor3f(1.0f, 1.0f, 1.0f); glVertex3f( 0.0f, 11.0f, 0.0f);
glColor3f(1.0f, 0.0f, 0.0f); glVertex3f( 5.0f, 5.0f, -5.0f);
glColor3f(1.0f, 1.0f, 0.0f); glVertex3f( 5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 1.0f, 1.0f); glVertex3f( 0.0f, 11.0f, 0.0f);
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f( 5.0f, 5.0f, 5.0f);
glColor3f(0.0f, 1.0f, 1.0f); glVertex3f(-5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 1.0f, 1.0f); glVertex3f( 0.0f, 11.0f, 0.0f);
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(-5.0f, 5.0f, 5.0f);
glColor3f(1.0f, 1.0f, 0.0f); glVertex3f(-5.0f, 5.0f, -5.0f);
glColor3f(1.0f, 1.0f, 1.0f); glVertex3f( 0.0f, 11.0f, 0.0f);
glEnd();
}
static GLint vertices[]={-5,-5,-5, // pole pozic vrcholu
-5,-5, 5,
5,-5, 5,
5,-5,-5,
-5, 5,-5,
-5, 5, 5,
5, 5, 5,
5, 5,-5,
-5,-5,-5,
-5,-5, 5,
-5, 5, 5,
-5, 5,-5,
5,-5,-5,
5,-5, 5,
5, 5, 5,
5, 5,-5};
static GLfloat colors[]={ 0.0f, 0.0f, 1.0f,// pole barev vrcholu
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f,
1.0f, 1.0f, 1.0f,
0.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 1.0f};
static GLubyte indexes[]={0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
//--------------------------------------------------------------------
// vykresleni sceny pomoci funkce glArrayElement()
// pro jednoduchost se vykresluje pouze otevrena krychle
//--------------------------------------------------------------------
void drawArrayElement(void)
{
int i;
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3, GL_FLOAT, 0, colors);
glVertexPointer(3, GL_INT, 0, vertices);
glBegin(GL_QUADS);
for (i=0; i<16; i++) // vykreslit vsechny vrcholy
glArrayElement(i);
glEnd();
}
//--------------------------------------------------------------------
// vykresleni sceny pomoci funkce glDrawArrays()
// pro jednoduchost se vykresluje pouze otevrena krychle
//--------------------------------------------------------------------
void drawArrays(void)
{
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3, GL_FLOAT, 0, colors);
glVertexPointer(3, GL_INT, 0, vertices);
glDrawArrays(GL_QUADS, 0, 16);
}
//--------------------------------------------------------------------
// vykresleni sceny pomoci funkce glDrawElements()
// pro jednoduchost se vykresluje pouze otevrena krychle
// V teto funkci by bylo mozne provest takove zjednoduseni, ze by
// se vrcholy v poli vrcholu a barev neopakovaly a indexy v poli
// 'indexes' by se samozrejme musely zmenit.
//--------------------------------------------------------------------
void drawElements(void)
{
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glColorPointer(3, GL_FLOAT, 0, colors);
glVertexPointer(3, GL_INT, 0, vertices);
glDrawElements(GL_QUADS, 16, GL_UNSIGNED_BYTE, indexes);
}
//--------------------------------------------------------------------
// Tato funkce je volana pri kazdem prekresleni okna
//--------------------------------------------------------------------
void onDisplay(void)
{
if (depthBufferEnabled) // podle povoleni pameti hloubky
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);// vymazani barvoveho bufferu i pameti hloubky
else
glClear(GL_COLOR_BUFFER_BIT); // vymazani vsech bitovych rovin barvoveho bufferu
setOrthogonalProjection(); // ortogonalni rezim pro kresleni 2D obrazku
drawInfoText(); // vypsat informace o nastaveni
setPerspectiveProjection(); // nastaveni perspektivni kamery
glTranslatef(0.0f, 0.0f, -50.0f); // posun objektu dale od kamery
glTranslatef(0.0f, 0.0f, znew); // priblizeni ci vzdaleni objektu podle pohybu kurzoru mysi
glRotatef(ynew, 1.0f, 0.0f, 0.0f); // rotace objektu podle pohybu kurzoru mysi
glRotatef(xnew, 0.0f, 1.0f, 0.0f);
setClipPlane(); // nastaveni orezavaci roviny
switch (drawMode) { // vykresleni objektu ve scene
case COMMAND_DRAW_MODE_NORMAL:
drawObjectNormal();
break;
case COMMAND_DRAW_MODE_ARRAY_ELEMENT:
drawArrayElement();
break;
case COMMAND_DRAW_MODE_DRAW_ARRAYS:
drawArrays();
break;
case COMMAND_DRAW_MODE_DRAW_ELEMENTS:
drawElements();
break;
default:
break;
}
glFlush(); // provedeni a vykresleni vsech zmen
glutSwapBuffers(); // a prohozeni predniho a zadniho bufferu
}
//---------------------------------------------------------------------
// Tato funkce je volana pri stlaceni ASCII klavesy
//---------------------------------------------------------------------
void onKeyboard(unsigned char key, int x, int y)
{
if (key>='A' && key<='Z') // uprava velkych pismen na mala
key+='a'-'A'; // pro zjednoduseni prikazu switch
switch (key) {
case 27: exit(0); break; // ukonceni aplikace
case 'q': exit(0); break; // ukonceni aplikace
case 'f': onMenu(COMMAND_FULL_SCREEN); break; // prepnuti do full-screen rezimu
case 'w': onMenu(COMMAND_WINDOW); break; // prepnuti zpet do okna
case 'e': onMenu(COMMAND_ENABLE_DEPTH_TEST); break; // povoleni funkce pameti hloubky
case 'd': onMenu(COMMAND_DISABLE_DEPTH_TEST); break; // zakazani funkce pameti hloubky
case 'r': onMenu(COMMAND_ROTATE); break; // rezim rotace objektu
case 't': onMenu(COMMAND_TRANSLATE); break; // rezim posunu objektu
case 'z': onMenu(COMMAND_NEAR_PLANE); break; // rezim posunu blizke orezavaci roviny
case 'x': onMenu(COMMAND_FAR_PLANE); break; // rezim posunu vzdalene orezavaci roviny
case '[': onMenu(COMMAND_CLIP_PLANE_ENABLE); break; // povoleni orezavani
case ']': onMenu(COMMAND_CLIP_PLANE_DISABLE); break; // zakaz orezavani
case '.': fov--; glutPostRedisplay(); break; // zmenseni zorneho uhlu
case ',': fov++; glutPostRedisplay(); break; // zvetseni zorneho uhlu
case '>': fov-=5; glutPostRedisplay(); break; // rychlejsi zmenseni zorneho uhlu
case '<': fov+=5; glutPostRedisplay(); break; // rychlejsi zvetseni zorneho uhlu
case '1': onMenu(COMMAND_FRONT_FACE_DISABLE); break; // zakaz vykresleni prednich sten
case '2': onMenu(COMMAND_FRONT_FACE_ENABLE); break; // povoleni vykresleni prednich sten
case '3': onMenu(COMMAND_FRONT_FACE_POINTS); break; // predni steny se vykresli jako body
case '4': onMenu(COMMAND_FRONT_FACE_LINES); break; // predni steny se vykresli jako usecky
case '5': onMenu(COMMAND_FRONT_FACE_POLYGONS);break; // predni steny se vykresli jako polygony
case '6': onMenu(COMMAND_BACK_FACE_DISABLE); break; // zakaz vykresleni zadnich sten
case '7': onMenu(COMMAND_BACK_FACE_ENABLE); break; // povoleni vykresleni zadnich sten
case '8': onMenu(COMMAND_BACK_FACE_POINTS); break; // zadni steny se vykresli jako body
case '9': onMenu(COMMAND_BACK_FACE_LINES); break; // zadni steny se vykresli jako usecky
case '0': onMenu(COMMAND_BACK_FACE_POLYGONS); break; // zadni steny se vykresli jako polygony
default: break;
}
}
//---------------------------------------------------------------------
// Tato funkce je zavolana pri stlaceni klavesy, ktera nema ASCII kod
//---------------------------------------------------------------------
void onSpecialKey(int key, int x, int y)
{
switch (key) {
case GLUT_KEY_F1: onMenu(COMMAND_DRAW_MODE_NORMAL); break;
case GLUT_KEY_F2: onMenu(COMMAND_DRAW_MODE_ARRAY_ELEMENT); break;
case GLUT_KEY_F3: onMenu(COMMAND_DRAW_MODE_DRAW_ARRAYS); break;
case GLUT_KEY_F4: onMenu(COMMAND_DRAW_MODE_DRAW_ELEMENTS); break;
default: break;
}
}
//---------------------------------------------------------------------
// Tato funkce je volana pri stisku ci pusteni tlacitka mysi
//---------------------------------------------------------------------
void onMouseButton(int button, int state, int x, int y)
{
if (button==GLUT_LEFT_BUTTON) { // pri zmene stavu leveho tlacitka
switch (operation) {
case ROTATE: // rotace objektu
if (state==GLUT_DOWN) { // pri stlaceni tlacitka
xx=x; // zapamatovat pozici kurzoru mysi
yy=y;
}
else { // pri pusteni tlacitka
xold=xnew; // zapamatovat novy pocatek
yold=ynew;
}
glutPostRedisplay(); // prekresleni sceny
break;
case TRANSLATE: // posun objektu
if (state==GLUT_DOWN) zz=y; // pri stlaceni tlacitka zapamatovat polohu kurzoru mysi
else zold=znew; // pri pusteni tlacitka zapamatovat novy pocatek
glutPostRedisplay(); // prekresleni sceny
break;
case NEAR_PLANE: // zmena polohy blizke orezavaci roviny
if (state==GLUT_DOWN) npp=y; // pri stlaceni tlacitka zapamatovat polohu kurzoru mysi
else np_old=np_new;
break;
case FAR_PLANE: // zmena polohy vzdalene orezavaci roviny
if (state==GLUT_DOWN) fpp=y; // pri stlaceni tlacitka zapamatovat polohu kurzoru mysi
else fp_old=fp_new;
break;
default:
break;
}
}
}
//---------------------------------------------------------------------
// Tato funkce je volana pri pohybu mysi se stlacenym tlacitkem.
// To, ktere tlacitko je stlaceno si musime predem zaznamenat do
// globalni promenne stav ve funkci onMouseButton()
//---------------------------------------------------------------------
void onMouseMotion(int x, int y)
{
switch (operation) {
case ROTATE: // stav rotace objektu
xnew=xold+x-xx; // vypocitat novou pozici
ynew=yold+y-yy;
glutPostRedisplay(); // a prekreslit scenu
break;
case TRANSLATE: // stav priblizeni/oddaleni objektu
znew=zold+y-zz; // vypocitat novou pozici
glutPostRedisplay(); // a prekreslit scenu
break;
case NEAR_PLANE: // priblizeni/vzdaleni blizke orezavaci roviny
np_new=np_old+y-npp;
nearPlane=np_new/100.0;
onResize(windowWidth, windowHeight);// zmena projekcni matice
glutPostRedisplay(); // a prekreslit scenu
break;
case FAR_PLANE: // priblizeni/vzdaleni vzdalene orezavaci roviny
fp_new=fp_old+y-fpp;
farPlane=fp_new/10.0;
onResize(windowWidth, windowHeight);// zmena projekcni matice
glutPostRedisplay(); // a prekreslit scenu
break;
}
}
//---------------------------------------------------------------------
// Hlavni funkce konzolove aplikace
//---------------------------------------------------------------------
int main(int argc, char **argv)
{
glutInit(&argc, argv); // inicializace knihovny GLUT
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);// nastaveni dvou barvovych bufferu a pameti hloubky
glutInitWindowPosition(30, 30); // pocatecni pozice leveho horniho rohu okna
glutInitWindowSize(500, 500); // pocatecni velikost okna
glutCreateWindow("Priklad na OpenGL cislo 34");// vytvoreni okna pro kresleni
glutDisplayFunc(onDisplay); // registrace funkce volane pri prekreslovani okna
glutReshapeFunc(onResize); // registrace funkce volane pri zmene velikosti okna
glutKeyboardFunc(onKeyboard); // registrace funkce volane pri stlaceni klavesy
glutSpecialFunc(onSpecialKey); // registrace funkce volane pri stlaceni non-ASCII klavesy
glutMouseFunc(onMouseButton); // registrace funkce volane pri stlaceni ci pusteni tlacitka
glutMotionFunc(onMouseMotion); // registrace funkce volane pri pohybu mysi se stlacenym tlacitkem
onInit(); // inicializace vykreslovani
glutMainLoop(); // nekonecna smycka, kde se volaji zaregistrovane funkce
return 0; // navratova hodnota vracena operacnimu systemu
}
//---------------------------------------------------------------------
// Konec zdrojoveho souboru
//---------------------------------------------------------------------