main.cpp

游戏编程精华02－含有几十个游戏编程例子

/* Copyright (C) Steven Woodcock, 2001. 
 * All rights reserved worldwide.
 *
 * This software is provided "as is" without express or implied
 * warranties. You may freely copy and compile this source into
 * applications you distribute provided that the copyright text
 * below is included in the resulting source code, for example:
 * "Portions Copyright (C) Steven Woodcock, 2001"
 */
//*********************************************************************
// Name:     main.cpp
// Purpose:  Driver routine for the Simple Flocking Game Gems 1
//           demonstration.  An OpenGL application pops up to show the 
//           user what's going on, and an output file is generated to the 
//           Windows desktop if various DEBUG options are specified 
//           (see readme.txt).
//*********************************************************************

//
// includes
//

#include <windows.h>
#include <iostream.h>
#include <time.h>
#include <mmsystem.h>

// flocking stuff

#include "CBox.h"
#include "CBoid.h"
#include "CFlock.h"

CBox   *Box1;
CFlock *Flocks[MaxFlocks];
CBoid  *Boids[MaxBoids];

// flocking debug globals

bool  gDrawAxes           = FALSE;
bool  gDrawPerceptionDist = FALSE;
bool  gDrawKeepawayDist   = FALSE;
bool  gDrawSeparationDist = FALSE;

// flocking framerate control variables

float gFrameRate         = 30.0f;
float gMilliSecsPerFrame = 1000.0f/gFrameRate;
int   gLastTime          =  0;

// flocking function prototypes

void Shutdown (void);

// GLUT stuff

#include "glut.h"
#include "mtxlib.h"

// GLUT globals

int 		gFrameNumber = 0;
vector3 	gCameraPos, gLookatPos;

const float 		   gKeyStep      = 2.0f;
const unsigned int	gWindowWidth  = 640;
const unsigned int	gWindowHeight = 480;

// GLUT function prototypes

void DisplayFunc (void);
void IdleFunc (void);
void Initialize3D (void);
void KeyboardFunc (unsigned char key, int x, int y);
void KeyboardSpecialFunc (int key, int x, int y);
void ReshapeFunc (int w, int h);
void SetPerspectiveCamera (void);
void SetOrthographicCamera (void);

/////////////////////
// Flocking Functions
/////////////////////

// main
// Makes it go.

int main (void)
{

   int i;

   // initialize the RNG

   srand ((unsigned) time (NULL));

   // build a world for our boids to flock around in

   Box1 = new CBox (50.0, 50.0, 50.0);

   // build some boids to move around in this world

   for (i = 0; i < MaxBoids; i++) {
      Boids[i] = new CBoid(i);
   }

   // build some flocks for the boids to belong to

   for (i = 0; i < MaxFlocks; i++) {
      Flocks[i] = new CFlock();
   }

   // now assign the boids to the flocks

   Flocks[0]->AddTo(Boids[0]);       // yes, I could have done this with some king
   Flocks[0]->AddTo(Boids[1]);       // of loop, but I wanted to show unequal sized flocks
   Flocks[0]->AddTo(Boids[2]);
   Flocks[0]->AddTo(Boids[3]);
   Flocks[0]->AddTo(Boids[4]);
   Flocks[0]->AddTo(Boids[5]);
   Flocks[0]->AddTo(Boids[6]);
   Flocks[0]->AddTo(Boids[7]);
   Flocks[0]->AddTo(Boids[8]);
   Flocks[0]->AddTo(Boids[9]);

   Flocks[1]->AddTo(Boids[10]);
   Flocks[1]->AddTo(Boids[11]);
   Flocks[1]->AddTo(Boids[12]);
   Flocks[1]->AddTo(Boids[13]);

   Flocks[2]->AddTo(Boids[14]);
   Flocks[2]->AddTo(Boids[15]);
   Flocks[2]->AddTo(Boids[16]);
   Flocks[2]->AddTo(Boids[17]);
   Flocks[2]->AddTo(Boids[18]);
   Flocks[2]->AddTo(Boids[19]);
   Flocks[2]->AddTo(Boids[20]);
   Flocks[2]->AddTo(Boids[21]);
   Flocks[2]->AddTo(Boids[22]);
   Flocks[2]->AddTo(Boids[23]);
   Flocks[2]->AddTo(Boids[24]);
   Flocks[2]->AddTo(Boids[25]);
   Flocks[2]->AddTo(Boids[26]);

   Flocks[3]->AddTo(Boids[27]);
   Flocks[3]->AddTo(Boids[28]);

   Flocks[4]->AddTo(Boids[29]);

#ifdef FLOCK_DEBUG
   for (i = 0; i < MaxFlocks; i++) {
      myprintf("Flock %d count = %d\n",Flocks[0]->GetCount());
   }
   myprintf("Total # of flocks = %d\n",CFlock::FlockCount);
#endif

   // initialize the GL code

   glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
   glutInitWindowPosition(200, 0);
   glutInitWindowSize(gWindowWidth, gWindowHeight);
   glutCreateWindow("SimpleFlocking App");

   glutDisplayFunc(DisplayFunc);
   glutKeyboardFunc(KeyboardFunc);
   glutSpecialFunc(KeyboardSpecialFunc);
   glutReshapeFunc(ReshapeFunc);
   glutIdleFunc(IdleFunc);
  
   Initialize3D();
  
   glutSwapBuffers();
   glutMainLoop();

   // we're done...get outta here

   return (0);
}

// Shutdown.
// Dumps out all the data about the final positions
// of the boids and then shuts down the demo.

void Shutdown (void)
{

   int i;

   // dump data about the boids at the end

   myprintf("\n\n=========\n\n");

   myprintf("Number of generations = %d\n",gFrameNumber);
   
   for (i = 0; i < MaxFlocks; i++) {
      Flocks[i]->PrintData();
   }

   myprintf("\nFinal camera postion = %f %f %f\n", gCameraPos.x,gCameraPos.y,gCameraPos.z);

   // cleanup all of our allocation pointers

   delete Box1;

   for (i = 0; i < MaxFlocks; i++) {
      delete Flocks[i];
   }

   for (i = 0; i < MaxBoids; i++) {
      delete Boids[i];
   }

   // we're all done...get outta here

   exit(0);
}

/////////////////
// GLUT Functions
/////////////////

// StringLength()
//
// Returns the string length using font "font".
//
unsigned int StringLength(void* font, const char* str) {
  int stringSize = 0;
  const char* c;

  for (c=str; *c != '\0'; c++)
    stringSize += glutBitmapWidth(font, *c);
  
  return stringSize;
}


// DisplayString()
//
// Display a string using a specific font at the location (x,y)
//   on the screen.
//
void DisplayString(int x, int y, void* font, const char* str) {
  const char* c;

  // Position the cursor for font drawing
  glRasterPos2i(x, y);

  // Draw the font letter-by-letter
  for (c=str; *c != '\0'; c++)
    glutBitmapCharacter(font, *c);
}


// DrawBox()
//
// Draw a 2D box at the specified coordinates.
//
void DrawBox(float ulx, float uly, float lrx, float lry) {

  glBegin(GL_QUADS);
  glVertex2f(ulx, uly);
  glVertex2f(ulx, lry);
  glVertex2f(lrx, lry);
  glVertex2f(lrx, uly);
  glEnd();
}

// DisplayFunc()
// Handles the display window

void DisplayFunc(void) 
{

   char infoString1[] = "Move camera with arrow keys";
   char quitString[]  = "Press <ESC> to Quit";

   int  stringSize;

   // Clear the frame buffer and Z buffer

   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
   // Set up a Perspective Projection camera

   SetPerspectiveCamera();

   // Set up current camera

   gluLookAt(gCameraPos.x, gCameraPos.y, gCameraPos.z, 
	          gLookatPos.x, gLookatPos.y, gLookatPos.z, 
	          0, 1, 0);  // Up vector

   // Draw some 3D 

   glBlendFunc(GL_ONE, GL_ZERO);

   // Draw the worldbox

   Box1->Draw();

   // Draw the boids

   for (int i = 0; i < CFlock::FlockCount; i++) {
      CFlock::ListOfFlocks[i]->Draw();
   }

   /////////////////////
   // Draw some 2D stuff
   /////////////////////

   // Set up an Orthographic Perspective camera

   SetOrthographicCamera();

   // Draw a box for info string 1

   stringSize = StringLength(GLUT_BITMAP_TIMES_ROMAN_24, infoString1);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
   glColor4ub(0x0f, 0x3f, 0xff, 0x7f);
   DrawBox(0, 0, 20+stringSize, 34);

   // Display info string 1

   glBlendFunc(GL_ONE, GL_ZERO);
   glColor4ub(0xff, 0xff, 0xff, 0x7f);
   DisplayString(10, 10, 
	   GLUT_BITMAP_TIMES_ROMAN_24, infoString1);  

   // Draw a box for the quit string

   stringSize = StringLength(GLUT_BITMAP_TIMES_ROMAN_24, quitString);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
   glColor4ub(0xff, 0x3f, 0x0f, 0x7f);
   DrawBox(gWindowWidth-20-stringSize, 0, gWindowWidth, 34);

   // Display the quit string

   glBlendFunc(GL_ONE, GL_ZERO);
   glColor4ub(0xff, 0xff, 0xff, 0x7f);
   DisplayString(gWindowWidth-10-stringSize, 10, 
	   GLUT_BITMAP_TIMES_ROMAN_24, quitString);

   // Swap frame buffers

   glutSwapBuffers();

   // Keep a frame count

   gFrameNumber++;

}

// KeyboardFunc()
// Looks for the "ESCAPE" key, by which we quit the app

void KeyboardFunc(unsigned char key, int x, int y) 
{

   switch (key) 
   {
      case 27: 
         Shutdown();
         break;
   }
}

// KeyboardSpecialFunc()
// This function handles the arrow keys to move the camera around.

void KeyboardSpecialFunc(int key, int x, int y) 
{
   switch (key) 
   {
   case GLUT_KEY_UP:
      gCameraPos.z -= gKeyStep;
      break;
   case GLUT_KEY_DOWN:
      gCameraPos.z += gKeyStep;
      break;
   case GLUT_KEY_LEFT:
      gCameraPos.x -= gKeyStep;
      break;
   case GLUT_KEY_RIGHT:
      gCameraPos.x += gKeyStep;
      break;
   case GLUT_KEY_F1:
      gCameraPos.y += gKeyStep;
      break;
   case GLUT_KEY_F2:
      gCameraPos.y -= gKeyStep;
      break;
   case GLUT_KEY_F3:
      gLookatPos.x += gKeyStep;
      break;
   case GLUT_KEY_F4:
      gLookatPos.x -= gKeyStep;
      break;
   case GLUT_KEY_F5:
      gLookatPos.y += gKeyStep;
      break;
   case GLUT_KEY_F6:
      gLookatPos.y -= gKeyStep;
      break;
   case GLUT_KEY_F7:
      gLookatPos.z += gKeyStep;
      break;
   case GLUT_KEY_F8:
      gLookatPos.z -= gKeyStep;
      break;
   case GLUT_KEY_F9:
      if (gDrawAxes == TRUE) {
         gDrawAxes = FALSE;
      } else {
         gDrawAxes = TRUE;
      }
      break;
   case GLUT_KEY_F10:
      if (gDrawPerceptionDist == TRUE) {
         gDrawPerceptionDist = FALSE;
      } else {
         gDrawPerceptionDist = TRUE;
      }
      break;
   case GLUT_KEY_F11:
      if (gDrawKeepawayDist == TRUE) {
         gDrawKeepawayDist = FALSE;
      } else {
         gDrawKeepawayDist = TRUE;
      }
      break;
   case GLUT_KEY_F12:
      if (gDrawSeparationDist == TRUE) {
         gDrawSeparationDist = FALSE;
      } else {
         gDrawSeparationDist = TRUE;
      }
      break;
   }
}

// Initialize3D()
// Finishes setting up the GLUT library.

void Initialize3D (void) 
{

   // Enable Gouraud shading

   glShadeModel(GL_SMOOTH);

   // Set clear color and alpha

   glClearColor(0.1f, 0.2f, 0.2f, 0.2f);

   // Enable blending of source pixel data with frame buffer

   glEnable(GL_BLEND);

   // Render front faces filled

   glFrontFace(GL_CCW);
   glPolygonMode(GL_FRONT, GL_FILL);

   // Initialize camera and lookat positions

   gCameraPos = vector3(0.0f, 0.0f, Box1->GetBoxLength() * 2.0f);
   gLookatPos = vector3(0.0f, 0.0f, 0.0f);

}

// IdleFunc()
// Idle function for between frames

void IdleFunc(void) 
{

   int i;

   // Call the display routine next time through the main loop  

   glutPostRedisplay();

   // Test:  Time to update the boids?

   if ((timeGetTime() - gLastTime) >= gMilliSecsPerFrame) {

      // yes--update the boids

      for (i = 0; i < CFlock::FlockCount; i++) {
         CFlock::ListOfFlocks[i]->Update();
      }

      // save the current time

      gLastTime = timeGetTime();
   }
}

// ReshapeFunc()
// This function is called when the user changes the window size.

void ReshapeFunc(int w, int h) 
{

  // Modify the viewport for the new window settings

  glViewport (0, 0, w, h);

}

// SetPerspectiveCamera()
// Sets up a perspective (3D) projection

void SetPerspectiveCamera(void) 
{
  // Enable Z buffer

  glEnable(GL_DEPTH_TEST);

  // Set the projection matrix
  // Two ways shown here-- with the OpenGL routine or the mtxlib

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

#if 0
  glFrustum (-1.6, 1.6, -1.6, 1.6, 4, 512);
#else
  matrix44 perspMatrix = FrustumMatrix44(-1.6, 1.6, -1.6, 1.6, 4, 512);
  glLoadMatrixf((float*)&perspMatrix);
#endif

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

#if 1
  // Turn backface culling off
  glDisable(GL_CULL_FACE);
#else
  // Turn backface culling on
  glEnable(GL_CULL_FACE);
  glCullFace(GL_BACK);
#endif

}

// SetOrthographicCamera()
// Sets up an orthographic (2D) projection

void SetOrthographicCamera(void) 
{

  // Disable Z buffer

  glDisable(GL_DEPTH_TEST);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(0, 640, 0, 320, -1, 1);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  // Disable backface culling

  glDisable(GL_CULL_FACE);

}