[译]GLUT教程 - 整合代码5

Lighthouse3d.com >> GLUT Tutorial >> Extras >> The Code So Far V

 

该代码与位图字体的代码类似.区别是用了笔划字体来显示每个雪人上的数字,然后雪人是用正交投影来显示,还有一段用位图字体显示的文本.后面包含了每秒帧数的文本不受镜头移动的影响,它一直停留在屏幕的相同位置.

字体菜单也改成了用笔划字体代替位图字体.

#include <stdio.h>

#include <stdlib.h>

#include <math.h>



#ifdef __APPLE__

#include <GLUT/glut.h>

#else

#include <GL/glut.h>

#endif



// angle of rotation for the camera direction

float angle = 0.0f;



// actual vector representing the camera's direction

float lx=0.0f,lz=-1.0f;



// XZ position of the camera

float x=0.0f, z=5.0f;



// the key states. These variables will be zero

//when no key is being presses

float deltaAngle = 0.0f;

float deltaMove = 0;

int xOrigin = -1;



// Constant definitions for Menus

#define RED 1

#define GREEN 2

#define BLUE 3

#define ORANGE 4



#define FILL 1

#define LINE 2



// Pop up menu identifiers

int fillMenu, fontMenu, mainMenu, colorMenu;



// color for the nose

float red = 1.0f, blue=0.5f, green=0.5f;



// scale of snowman

float scale = 1.0f;



// menu status

int menuFlag = 0;



// default font

void *font = GLUT_STROKE_ROMAN;



// width and height of the window

int h,w;



// variables to compute frames per second

int frame;

long time, timebase;

char s[50];



void changeSize(int ww, int hh) {



    h = hh;

    w = ww;

    // Prevent a divide by zero, when window is too short

    // (you cant make a window of zero width).

    if (h == 0)

        h = 1;



    float ratio =  w * 1.0 / h;



    // Use the Projection Matrix

    glMatrixMode(GL_PROJECTION);



    // Reset Matrix

    glLoadIdentity();



    // Set the viewport to be the entire window

    glViewport(0, 0, w, h);



    // Set the correct perspective.

    gluPerspective(45.0f, ratio, 0.1f, 100.0f);



    // Get Back to the Modelview

    glMatrixMode(GL_MODELVIEW);

}



void drawSnowMan() {



    glScalef(scale, scale, scale);

    glColor3f(1.0f, 1.0f, 1.0f);



// Draw Body

    glTranslatef(0.0f ,0.75f, 0.0f);

    glutSolidSphere(0.75f,20,20);



// Draw Head

    glTranslatef(0.0f, 1.0f, 0.0f);

    glutSolidSphere(0.25f,20,20);



// Draw Eyes

    glPushMatrix();

    glColor3f(0.0f,0.0f,0.0f);

    glTranslatef(0.05f, 0.10f, 0.18f);

    glutSolidSphere(0.05f,10,10);

    glTranslatef(-0.1f, 0.0f, 0.0f);

    glutSolidSphere(0.05f,10,10);

    glPopMatrix();



// Draw Nose

    glColor3f(red, green, blue);

    glRotatef(0.0f,1.0f, 0.0f, 0.0f);

    glutSolidCone(0.08f,0.5f,10,2);



    glColor3f(1.0f, 1.0f, 1.0f);



}



void renderBitmapString(

        float x,

        float y,

        float z,

        void *font,

        char *string) {



    char *c;

    glRasterPos3f(x, y,z);

    for (c=string; *c != '\0'; c++) {

        glutBitmapCharacter(font, *c);

    }

}



void renderStrokeFontString(

        float x,

        float y,

        float z,

        void *font,

        char *string) {  



    char *c;

    glPushMatrix();

    glTranslatef(x, y,z);

    glScalef(0.002f, 0.002f, 0.002f);

    for (c=string; *c != '\0'; c++) {

        glutStrokeCharacter(font, *c);

    }

    glPopMatrix();

}



void restorePerspectiveProjection() {



    glMatrixMode(GL_PROJECTION);

    // restore previous projection matrix

    glPopMatrix();



    // get back to modelview mode

    glMatrixMode(GL_MODELVIEW);

}



void setOrthographicProjection() {



    // switch to projection mode

    glMatrixMode(GL_PROJECTION);



    // save previous matrix which contains the

    //settings for the perspective projection

    glPushMatrix();



    // reset matrix

    glLoadIdentity();



    // set a 2D orthographic projection

    gluOrtho2D(0, w, h, 0);



    // switch back to modelview mode

    glMatrixMode(GL_MODELVIEW);

}



void computePos(float deltaMove) {



    x += deltaMove * lx * 0.1f;

    z += deltaMove * lz * 0.1f;

}



void renderScene(void) {



    if (deltaMove)

        computePos(deltaMove);



    // Clear Color and Depth Buffers

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);



    // Reset transformations

    glLoadIdentity();

    // Set the camera

    gluLookAt(    x, 1.0f, z,

            x+lx, 1.0f,  z+lz,

            0.0f, 1.0f,  0.0f);



// Draw ground



    glColor3f(0.9f, 0.9f, 0.9f);

    glBegin(GL_QUADS);

        glVertex3f(-100.0f, 0.0f, -100.0f);

        glVertex3f(-100.0f, 0.0f,  100.0f);

        glVertex3f( 100.0f, 0.0f,  100.0f);

        glVertex3f( 100.0f, 0.0f, -100.0f);

    glEnd();



// Draw 36 SnowMen

    char number[3];

    for(int i = -3; i < 3; i++)

        for(int j=-3; j < 3; j++) {

            glPushMatrix();

            glTranslatef(i*10.0f, 0.0f, j * 10.0f);

            drawSnowMan();

            sprintf(number,"%d",(i+3)*6+(j+3));

            renderStrokeFontString(0.0f, 0.5f, 0.0f, (void *)font ,number);

            glPopMatrix();

        }



    // Code to compute frames per second

    frame++;



    time=glutGet(GLUT_ELAPSED_TIME);

    if (time - timebase > 1000) {

        sprintf(s,"Lighthouse3D - FPS:%4.2f",

            frame*1000.0/(time-timebase));

        timebase = time;

        frame = 0;

    }



        // Code to display a string (fps) with bitmap fonts

    setOrthographicProjection();



    glPushMatrix();

    glLoadIdentity();

    renderBitmapString(5,30,0,GLUT_BITMAP_HELVETICA_18,s);

    glPopMatrix();



    restorePerspectiveProjection();



    glutSwapBuffers();

}



// -----------------------------------

//             KEYBOARD

// -----------------------------------



void processNormalKeys(unsigned char key, int xx, int yy) {



    switch (key) {

        case 27:

            glutDestroyMenu(mainMenu);

            glutDestroyMenu(fillMenu);

            glutDestroyMenu(colorMenu);

            glutDestroyMenu(fontMenu);

            exit(0);

            break;

    }

}



void pressKey(int key, int xx, int yy) {



    switch (key) {

        case GLUT_KEY_UP : deltaMove = 0.5f; break;

        case GLUT_KEY_DOWN : deltaMove = -0.5f; break;

    }

}



void releaseKey(int key, int x, int y) {



    switch (key) {

        case GLUT_KEY_UP :

        case GLUT_KEY_DOWN : deltaMove = 0;break;

    }

}



// -----------------------------------

//             MOUSE

// -----------------------------------



void mouseMove(int x, int y) {



    // this will only be true when the left button is down

    if (xOrigin >= 0) {



        // update deltaAngle

        deltaAngle = (x - xOrigin) * 0.001f;



        // update camera's direction

        lx = sin(angle + deltaAngle);

        lz = -cos(angle + deltaAngle);

    }

}



void mouseButton(int button, int state, int x, int y) {



    // only start motion if the left button is pressed

    if (button == GLUT_LEFT_BUTTON) {



        // when the button is released

        if (state == GLUT_UP) {

            angle += deltaAngle;

            xOrigin = -1;

        }

        else  {// state = GLUT_DOWN

            xOrigin = x;

        }

    }

}



// -----------------------------------

//             MENUS

// -----------------------------------



void processMenuStatus(int status, int x, int y) {



    if (status == GLUT_MENU_IN_USE)

        menuFlag = 1;

    else

        menuFlag = 0;

}



void processMainMenu(int option) {



    // nothing to do in here

    // all actions are for submenus

}



void processFillMenu(int option) {



    switch (option) {



        case FILL: glPolygonMode(GL_FRONT, GL_FILL); break;

        case LINE: glPolygonMode(GL_FRONT, GL_LINE); break;

    }

}



void processFontMenu(int option) {



    switch (option) {

        case 1: font = GLUT_STROKE_ROMAN;

            break;

        case 2: font = GLUT_STROKE_MONO_ROMAN;

            break;

    }

}



void processColorMenu(int option) {



    switch (option) {

        case RED :

            red = 1.0f;

            green = 0.0f;

            blue = 0.0f; break;

        case GREEN :

            red = 0.0f;

            green = 1.0f;

            blue = 0.0f; break;

        case BLUE :

            red = 0.0f;

            green = 0.0f;

            blue = 1.0f; break;

        case ORANGE :

            red = 1.0f;

            green = 0.5f;

            blue = 0.5f; break;

    }

}



void createPopupMenus() {



    fontMenu = glutCreateMenu(processFontMenu);



        glutAddMenuEntry("STROKE_ROMAN",1 );

        glutAddMenuEntry("STROKE_MONO_ROMAN",2 );

    fillMenu = glutCreateMenu(processFillMenu);



    glutAddMenuEntry("Fill",FILL);

    glutAddMenuEntry("Line",LINE);



    colorMenu = glutCreateMenu(processColorMenu);

    glutAddMenuEntry("Red",RED);

    glutAddMenuEntry("Blue",BLUE);

    glutAddMenuEntry("Green",GREEN);

    glutAddMenuEntry("Orange",ORANGE);



    mainMenu = glutCreateMenu(processMainMenu);



    glutAddSubMenu("Polygon Mode", fillMenu);

    glutAddSubMenu("Color", colorMenu);

    glutAddSubMenu("Font",fontMenu);

    // attach the menu to the right button

    glutAttachMenu(GLUT_RIGHT_BUTTON);



    // this will allow us to know if the menu is active

    glutMenuStatusFunc(processMenuStatus);

}



// -----------------------------------

//             MAIN

// -----------------------------------



int main(int argc, char **argv) {



    // init GLUT and create window

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);

    glutInitWindowPosition(100,100);

    glutInitWindowSize(320,320);

    glutCreateWindow("Lighthouse3D - GLUT Tutorial");



    // register callbacks

    glutDisplayFunc(renderScene);

    glutReshapeFunc(changeSize);

    glutIdleFunc(renderScene);



    glutIgnoreKeyRepeat(1);

    glutKeyboardFunc(processNormalKeys);

    glutSpecialFunc(pressKey);

    glutSpecialUpFunc(releaseKey);



    // here are the two new functions

    glutMouseFunc(mouseButton);

    glutMotionFunc(mouseMove);



    // OpenGL init

    glEnable(GL_DEPTH_TEST);

    glEnable(GL_CULL_FACE);



    // init Menus

    createPopupMenus();



    // enter GLUT event processing cycle

    glutMainLoop();

    

    return 1;

}