OpenGL入门笔记（十一）

每个3D世界基本上可以看作是sector(区段)的集合。一个sector(区段)可以是一个房间、一个立方体、或者任意一个闭合的区间。在程序内部直接存储数据会让程序显得太过死板和无趣。从磁盘上载入世界资料，会给我们带来更多的弹性，可以让我们体验不同的世界，而不用被迫重新编译程序。另一个好处就是用户可以切换世界资料并修改它们而无需知道程序如何读入输出这些资料的。

数据文件中每个三角形都以如下形式声明:

X1 Y1 Z1 U1 V1

X2 Y2 Z2 U2 V2

X3 Y3 Z3 U3 V3



坐标数据文件

NUMPOLLIES 36

// Floor 1
-3.0 0.0 -3.0 0.0 6.0
-3.0 0.0 3.0 0.0 0.0
3.0 0.0 3.0 6.0 0.0

-3.0 0.0 -3.0 0.0 6.0
3.0 0.0 -3.0 6.0 6.0
3.0 0.0 3.0 6.0 0.0

// Ceiling 1
-3.0 1.0 -3.0 0.0 6.0
-3.0 1.0 3.0 0.0 0.0
3.0 1.0 3.0 6.0 0.0
-3.0 1.0 -3.0 0.0 6.0
3.0 1.0 -3.0 6.0 6.0
3.0 1.0 3.0 6.0 0.0

// A1

-2.0 1.0 -2.0 0.0 1.0
-2.0 0.0 -2.0 0.0 0.0
-0.5 0.0 -2.0 1.5 0.0
-2.0 1.0 -2.0 0.0 1.0
-0.5 1.0 -2.0 1.5 1.0
-0.5 0.0 -2.0 1.5 0.0

// A2

2.0 1.0 -2.0 2.0 1.0
2.0 0.0 -2.0 2.0 0.0
0.5 0.0 -2.0 0.5 0.0
2.0 1.0 -2.0 2.0 1.0
0.5 1.0 -2.0 0.5 1.0
0.5 0.0 -2.0 0.5 0.0

// B1

-2.0 1.0 2.0 2.0 1.0
-2.0 0.0 2.0 2.0 0.0
-0.5 0.0 2.0 0.5 0.0
-2.0 1.0 2.0 2.0 1.0
-0.5 1.0 2.0 0.5 1.0
-0.5 0.0 2.0 0.5 0.0

// B2

2.0 1.0 2.0 2.0 1.0
2.0 0.0 2.0 2.0 0.0
0.5 0.0 2.0 0.5 0.0
2.0 1.0 2.0 2.0 1.0
0.5 1.0 2.0 0.5 1.0
0.5 0.0 2.0 0.5 0.0

// C1

-2.0 1.0 -2.0 0.0 1.0
-2.0 0.0 -2.0 0.0 0.0
-2.0 0.0 -0.5 1.5 0.0
-2.0 1.0 -2.0 0.0 1.0
-2.0 1.0 -0.5 1.5 1.0
-2.0 0.0 -0.5 1.5 0.0

// C2

-2.0 1.0 2.0 2.0 1.0
-2.0 0.0 2.0 2.0 0.0
-2.0 0.0 0.5 0.5 0.0
-2.0 1.0 2.0 2.0 1.0
-2.0 1.0 0.5 0.5 1.0
-2.0 0.0 0.5 0.5 0.0

// D1

2.0 1.0 -2.0 0.0 1.0
2.0 0.0 -2.0 0.0 0.0
2.0 0.0 -0.5 1.5 0.0
2.0 1.0 -2.0 0.0 1.0
2.0 1.0 -0.5 1.5 1.0
2.0 0.0 -0.5 1.5 0.0

// D2

2.0 1.0 2.0 2.0 1.0
2.0 0.0 2.0 2.0 0.0
2.0 0.0 0.5 0.5 0.0
2.0 1.0 2.0 2.0 1.0
2.0 1.0 0.5 0.5 1.0
2.0 0.0 0.5 0.5 0.0

// Upper hallway - L
-0.5 1.0 -3.0 0.0 1.0
-0.5 0.0 -3.0 0.0 0.0
-0.5 0.0 -2.0 1.0 0.0
-0.5 1.0 -3.0 0.0 1.0
-0.5 1.0 -2.0 1.0 1.0
-0.5 0.0 -2.0 1.0 0.0

// Upper hallway - R
0.5 1.0 -3.0 0.0 1.0
0.5 0.0 -3.0 0.0 0.0
0.5 0.0 -2.0 1.0 0.0
0.5 1.0 -3.0 0.0 1.0
0.5 1.0 -2.0 1.0 1.0
0.5 0.0 -2.0 1.0 0.0

// Lower hallway - L
-0.5 1.0 3.0 0.0 1.0
-0.5 0.0 3.0 0.0 0.0
-0.5 0.0 2.0 1.0 0.0
-0.5 1.0 3.0 0.0 1.0
-0.5 1.0 2.0 1.0 1.0
-0.5 0.0 2.0 1.0 0.0

// Lower hallway - R
0.5 1.0 3.0 0.0 1.0
0.5 0.0 3.0 0.0 0.0
0.5 0.0 2.0 1.0 0.0
0.5 1.0 3.0 0.0 1.0
0.5 1.0 2.0 1.0 1.0
0.5 0.0 2.0 1.0 0.0

// Left hallway - Lw

-3.0 1.0 0.5 1.0 1.0
-3.0 0.0 0.5 1.0 0.0
-2.0 0.0 0.5 0.0 0.0
-3.0 1.0 0.5 1.0 1.0
-2.0 1.0 0.5 0.0 1.0
-2.0 0.0 0.5 0.0 0.0

// Left hallway - Hi

-3.0 1.0 -0.5 1.0 1.0
-3.0 0.0 -0.5 1.0 0.0
-2.0 0.0 -0.5 0.0 0.0
-3.0 1.0 -0.5 1.0 1.0
-2.0 1.0 -0.5 0.0 1.0
-2.0 0.0 -0.5 0.0 0.0

// Right hallway - Lw

3.0 1.0 0.5 1.0 1.0
3.0 0.0 0.5 1.0 0.0
2.0 0.0 0.5 0.0 0.0
3.0 1.0 0.5 1.0 1.0
2.0 1.0 0.5 0.0 1.0
2.0 0.0 0.5 0.0 0.0

// Right hallway - Hi

3.0 1.0 -0.5 1.0 1.0
3.0 0.0 -0.5 1.0 0.0
2.0 0.0 -0.5 0.0 0.0
3.0 1.0 -0.5 1.0 1.0
2.0 1.0 -0.5 0.0 1.0
2.0 0.0 -0.5 0.0 0.0

到目前为止，我们所作过的都是些简单的旋转和平移。但我们的镜头始终位于原点(0，0，0)处。任何一个不错的3D引擎都会允许用户在这个世界中游走和遍 历，我们的这个也一样。实现这个功能的一种途径是直接移动镜头并绘制以镜头为中心的3D环境。这样做会很慢并且不易用代码实现。我们的解决方法如下：

1）根据用户的指令旋转并变换镜头位置。

2）围绕原点，以与镜头相反的旋转方向来旋转世界。(让人产生镜头旋转的错觉)

3）以与镜头平移方式相反的方式来平移世界(让人产生镜头移动的错觉)。

实现很简单。当左右方向键按下后，旋转变量yrot相应增加或减少。当前后方向键按下后，我们使用sine和cosine函数重新生成镜头位置。Piover180是一个很简单的折算因子用来折算度和弧度。

walkbias基本上就是当人行走时头部产生上下摆动的幅度。我们使用简单的sine正弦波来调节镜头的Y轴位置。如果不添加这个而只是前后移动的话，程序看起来就没这么棒了。



demo10

#include <windows.h> // Header File For Windows
#include <math.h> // Math Library Header File
#include <stdio.h> // Header File For Standard Input/Output
#include <gl/gl.h> // Header File For The OpenGL32 Library
#include <gl/glu.h> // Header File For The GLu32 Library
#include <gl/glaux.h> // Header File For The Glaux Library

HDC hDC=NULL; // Private GDI Device Context
HGLRC hRC=NULL; // Permanent Rendering Context
HWND hWnd=NULL; // Holds Our Window Handle
HINSTANCE hInstance; // Holds The Instance Of The Application

bool keys[256]; // Array Used For The Keyboard Routine
bool active=TRUE; // Window Active Flag Set To TRUE By Default
bool fullscreen=TRUE; // Fullscreen Flag Set To Fullscreen Mode By Default
bool blend; // Blending ON/OFF
bool bp; // B Pressed?
bool fp; // F Pressed?

const float piover180 = 0.0174532925f;
float heading;
float xpos;
float zpos;

GLfloat yrot; // Y Rotation
GLfloat walkbias = 0;
GLfloat walkbiasangle = 0;
GLfloat lookupdown = 0.0f;
GLfloat z=0.0f; // Depth Into The Screen

GLuint filter; // Which Filter To Use
GLuint texture[3]; // Storage For 3 Textures

typedef struct tagVERTEX
{
float x, y, z;//3D坐标
float u, v;//纹理坐标
} VERTEX;

typedef struct tagTRIANGLE
{//Triangle三角形结构
VERTEX vertex[3];
} TRIANGLE;

typedef struct tagSECTOR
{
int numtriangles;// Sector中的三角形个数
TRIANGLE* triangle;// 指向三角数组的指针
} SECTOR;

SECTOR sector1; // Our Model Goes Here:

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc

void readstr(FILE *f,char *string)
{// 读入一个字符串
do
{
fgets(string, 255, f);
} while ((string[0] == '/') || (string[0] == '/n'));
return;
}

void SetupWorld()
{// 设置我们的世界
float x, y, z, u, v;
int numtriangles;
FILE *filein;
char oneline[255];
filein = fopen("data/world.txt", "rt"); // File To Load World Data From

readstr(filein,oneline);
sscanf(oneline, "NUMPOLLIES %d/n", &numtriangles);

sector1.triangle = new TRIANGLE[numtriangles];
sector1.numtriangles = numtriangles;
for (int loop = 0; loop < numtriangles; loop++)
{
for (int vert = 0; vert < 3; vert++)
{
readstr(filein,oneline);
sscanf(oneline, "%f %f %f %f %f", &x, &y, &z, &u, &v);
sector1.triangle[loop].vertex[vert].x = x;
sector1.triangle[loop].vertex[vert].y = y;
sector1.triangle[loop].vertex[vert].z = z;
sector1.triangle[loop].vertex[vert].u = u;
sector1.triangle[loop].vertex[vert].v = v;
}
}
fclose(filein);
return;
}

AUX_RGBImageRec *LoadBMP(char *Filename) // Loads A Bitmap Image
{
FILE *File=NULL; // File Handle

if (!Filename) // Make Sure A Filename Was Given
{
return NULL; // If Not Return NULL
}

File=fopen(Filename,"r"); // Check To See If The File Exists

if (File) // Does The File Exist?
{
fclose(File); // Close The Handle
return auxDIBImageLoad(Filename); // Load The Bitmap And Return A Pointer
}
return NULL; // If Load Failed Return NULL
}

int LoadGLTextures() // Load Bitmaps And Convert To Textures
{
int Status=FALSE; // Status Indicator

AUX_RGBImageRec *TextureImage[1]; // Create Storage Space For The Texture

memset(TextureImage,0,sizeof(void *)*1); // Set The Pointer To NULL

// Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
if (TextureImage[0]=LoadBMP("Data/Mud.bmp"))
{
Status=TRUE; // Set The Status To TRUE

glGenTextures(3, &texture[0]); // Create Three Textures

// Create Nearest Filtered Texture
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);

// Create Linear Filtered Texture
glBindTexture(GL_TEXTURE_2D, texture[1]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);

// Create MipMapped Texture
glBindTexture(GL_TEXTURE_2D, texture[2]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
gluBuild2DMipmaps(GL_TEXTURE_2D, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);
}
if (TextureImage[0]) // If Texture Exists
{
if (TextureImage[0]->data) // If Texture Image Exists
{
free(TextureImage[0]->data); // Free The Texture Image Memory
}

free(TextureImage[0]); // Free The Image Structure
}

return Status; // Return The Status
}

GLvoid ReSizeGLScene(GLsizei width, GLsizei height) // Resize And Initialize The GL Window
{
if (height==0) // Prevent A Divide By Zero By
{
height=1; // Making Height Equal One
}

glViewport(0,0,width,height); // Reset The Current Viewport

glMatrixMode(GL_PROJECTION); // Select The Projection Matrix
glLoadIdentity(); // Reset The Projection Matrix

// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix
glLoadIdentity(); // Reset The Modelview Matrix
}

int InitGL(GLvoid) // All Setup For OpenGL Goes Here
{
if (!LoadGLTextures()) // Jump To Texture Loading Routine
{
return FALSE; // If Texture Didn't Load Return FALSE
}

glEnable(GL_TEXTURE_2D); // Enable Texture Mapping
glBlendFunc(GL_SRC_ALPHA,GL_ONE); // Set The Blending Function For Translucency
glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations

SetupWorld();//建立世界

return TRUE; // Initialization Went OK
}

int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The View

GLfloat x_m, y_m, z_m, u_m, v_m;
GLfloat xtrans = -xpos;
GLfloat ztrans = -zpos;
GLfloat ytrans = -walkbias-0.25f;
GLfloat sceneroty = 360.0f - yrot;

int numtriangles;

glRotatef(lookupdown,1.0f,0,0);
glRotatef(sceneroty,0,1.0f,0);

glTranslatef(xtrans, ytrans, ztrans);
glBindTexture(GL_TEXTURE_2D, texture[filter]);

numtriangles = sector1.numtriangles;

// Process Each Triangle
for (int loop_m = 0; loop_m < numtriangles; loop_m++)
{
glBegin(GL_TRIANGLES);
glNormal3f( 0.0f, 0.0f, 1.0f);
x_m = sector1.triangle[loop_m].vertex[0].x;
y_m = sector1.triangle[loop_m].vertex[0].y;
z_m = sector1.triangle[loop_m].vertex[0].z;
u_m = sector1.triangle[loop_m].vertex[0].u;
v_m = sector1.triangle[loop_m].vertex[0].v;
glTexCoord2f(u_m,v_m); glVertex3f(x_m,y_m,z_m);

x_m = sector1.triangle[loop_m].vertex[1].x;
y_m = sector1.triangle[loop_m].vertex[1].y;
z_m = sector1.triangle[loop_m].vertex[1].z;
u_m = sector1.triangle[loop_m].vertex[1].u;
v_m = sector1.triangle[loop_m].vertex[1].v;
glTexCoord2f(u_m,v_m); glVertex3f(x_m,y_m,z_m);

x_m = sector1.triangle[loop_m].vertex[2].x;
y_m = sector1.triangle[loop_m].vertex[2].y;
z_m = sector1.triangle[loop_m].vertex[2].z;
u_m = sector1.triangle[loop_m].vertex[2].u;
v_m = sector1.triangle[loop_m].vertex[2].v;
glTexCoord2f(u_m,v_m); glVertex3f(x_m,y_m,z_m);
glEnd();
}
return TRUE; // Everything Went OK
}

GLvoid KillGLWindow(GLvoid) // Properly Kill The Window
{
if (fullscreen) // Are We In Fullscreen Mode?
{
ChangeDisplaySettings(NULL,0); // If So Switch Back To The Desktop
ShowCursor(TRUE); // Show Mouse Pointer
}

if (hRC) // Do We Have A Rendering Context?
{
if (!wglMakeCurrent(NULL,NULL)) // Are We Able To Release The DC And RC Contexts?
{
MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}

if (!wglDeleteContext(hRC)) // Are We Able To Delete The RC?
{
MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}
hRC=NULL; // Set RC To NULL
}

if (hDC && !ReleaseDC(hWnd,hDC)) // Are We Able To Release The DC
{
MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hDC=NULL; // Set DC To NULL
}

if (hWnd && !DestroyWindow(hWnd)) // Are We Able To Destroy The Window?
{
MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hWnd=NULL; // Set hWnd To NULL
}

if (!UnregisterClass("OpenGL",hInstance)) // Are We Able To Unregister Class
{
MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hInstance=NULL; // Set hInstance To NULL
}
}

/* This Code Creates Our OpenGL Window. Parameters Are: *
* title - Title To Appear At The Top Of The Window *
* width - Width Of The GL Window Or Fullscreen Mode *
* height - Height Of The GL Window Or Fullscreen Mode *
* bits - Number Of Bits To Use For Color (8/16/24/32) *
* fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE) */

BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
GLuint PixelFormat; // Holds The Results After Searching For A Match
WNDCLASS wc; // Windows Class Structure
DWORD dwExStyle; // Window Extended Style
DWORD dwStyle; // Window Style
RECT WindowRect; // Grabs Rectangle Upper Left / Lower Right Values
WindowRect.left=(long)0; // Set Left Value To 0
WindowRect.right=(long)width; // Set Right Value To Requested Width
WindowRect.top=(long)0; // Set Top Value To 0
WindowRect.bottom=(long)height; // Set Bottom Value To Requested Height

fullscreen=fullscreenflag; // Set The Global Fullscreen Flag

hInstance = GetModuleHandle(NULL); // Grab An Instance For Our Window
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window.
wc.lpfnWndProc = (WNDPROC) WndProc; // WndProc Handles Messages
wc.cbClsExtra = 0; // No Extra Window Data
wc.cbWndExtra = 0; // No Extra Window Data
wc.hInstance = hInstance; // Set The Instance
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon
wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer
wc.hbrBackground = NULL; // No Background Required For GL
wc.lpszMenuName = NULL; // We Don't Want A Menu
wc.lpszClassName = "OpenGL"; // Set The Class Name

if (!RegisterClass(&wc)) // Attempt To Register The Window Class
{
MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (fullscreen) // Attempt Fullscreen Mode?
{
DEVMODE dmScreenSettings; // Device Mode
memset(&dmScreenSettings,0,sizeof(dmScreenSettings)); // Makes Sure Memory's Cleared
dmScreenSettings.dmSize=sizeof(dmScreenSettings); // Size Of The Devmode Structure
dmScreenSettings.dmPelsWidth = width; // Selected Screen Width
dmScreenSettings.dmPelsHeight = height; // Selected Screen Height
dmScreenSettings.dmBitsPerPel = bits; // Selected Bits Per Pixel
dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

// Try To Set Selected Mode And Get Results. NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar.
if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL)
{
// If The Mode Fails, Offer Two Options. Quit Or Use Windowed Mode.
if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By/nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen=FALSE; // Windowed Mode Selected. Fullscreen = FALSE
}
else
{
// Pop Up A Message Box Letting User Know The Program Is Closing.
MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
return FALSE; // Return FALSE
}
}
}

if (fullscreen) // Are We Still In Fullscreen Mode?
{
dwExStyle=WS_EX_APPWINDOW; // Window Extended Style
dwStyle=WS_POPUP; // Windows Style
ShowCursor(FALSE); // Hide Mouse Pointer
}
else
{
dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style
dwStyle=WS_OVERLAPPEDWINDOW; // Windows Style
}

AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust Window To True Requested Size

// Create The Window
if (!(hWnd=CreateWindowEx( dwExStyle, // Extended Style For The Window
"OpenGL", // Class Name
title, // Window Title
dwStyle | // Defined Window Style
WS_CLIPSIBLINGS | // Required Window Style
WS_CLIPCHILDREN, // Required Window Style
0, 0, // Window Position
WindowRect.right-WindowRect.left, // Calculate Window Width
WindowRect.bottom-WindowRect.top, // Calculate Window Height
NULL, // No Parent Window
NULL, // No Menu
hInstance, // Instance
NULL))) // Dont Pass Anything To WM_CREATE
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

static PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be
{
sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
1, // Version Number
PFD_DRAW_TO_WINDOW | // Format Must Support Window
PFD_SUPPORT_OPENGL | // Format Must Support OpenGL
PFD_DOUBLEBUFFER, // Must Support Double Buffering
PFD_TYPE_RGBA, // Request An RGBA Format
bits, // Select Our Color Depth
0, 0, 0, 0, 0, 0, // Color Bits Ignored
0, // No Alpha Buffer
0, // Shift Bit Ignored
0, // No Accumulation Buffer
0, 0, 0, 0, // Accumulation Bits Ignored
16, // 16Bit Z-Buffer (Depth Buffer)
0, // No Stencil Buffer
0, // No Auxiliary Buffer
PFD_MAIN_PLANE, // Main Drawing Layer
0, // Reserved
0, 0, 0 // Layer Masks Ignored
};

if (!(hDC=GetDC(hWnd))) // Did We Get A Device Context?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))) // Did Windows Find A Matching Pixel Format?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if(!SetPixelFormat(hDC,PixelFormat,&pfd)) // Are We Able To Set The Pixel Format?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if (!(hRC=wglCreateContext(hDC))) // Are We Able To Get A Rendering Context?
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

if(!wglMakeCurrent(hDC,hRC)) // Try To Activate The Rendering Context
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

ShowWindow(hWnd,SW_SHOW); // Show The Window
SetForegroundWindow(hWnd); // Slightly Higher Priority
SetFocus(hWnd); // Sets Keyboard Focus To The Window
ReSizeGLScene(width, height); // Set Up Our Perspective GL Screen

if (!InitGL()) // Initialize Our Newly Created GL Window
{
KillGLWindow(); // Reset The Display
MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE; // Return FALSE
}

return TRUE; // Success
}

LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window
UINT uMsg, // Message For This Window
WPARAM wParam, // Additional Message Information
LPARAM lParam) // Additional Message Information
{
switch (uMsg) // Check For Windows Messages
{
case WM_ACTIVATE: // Watch For Window Activate Message
{
if (!HIWORD(wParam)) // Check Minimization State
{
active=TRUE; // Program Is Active
}
else
{
active=FALSE; // Program Is No Longer Active
}

return 0; // Return To The Message Loop
}

case WM_SYSCOMMAND: // Intercept System Commands
{
switch (wParam) // Check System Calls
{
case SC_SCREENS***E: // Screensaver Trying To Start?
case SC_MONITORPOWER: // Monitor Trying To Enter Powersave?
return 0; // Prevent From Happening
}
break; // Exit
}

case WM_CLOSE: // Did We Receive A Close Message?
{
PostQuitMessage(0); // Send A Quit Message
return 0; // Jump Back
}

case WM_KEYDOWN: // Is A Key Being Held Down?
{
keys[wParam] = TRUE; // If So, Mark It As TRUE
return 0; // Jump Back
}

case WM_KEYUP: // Has A Key Been Released?
{
keys[wParam] = FALSE; // If So, Mark It As FALSE
return 0; // Jump Back
}

case WM_SIZE: // Resize The OpenGL Window
{
ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height
return 0; // Jump Back
}
}

// Pass All Unhandled Messages To DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain( HINSTANCE hInstance, // Instance
HINSTANCE hPrevInstance, // Previous Instance
LPSTR lpCmdLine, // Command Line Parameters
int nCmdShow) // Window Show State
{
MSG msg; // Windows Message Structure
BOOL done=FALSE; // Bool Variable To Exit Loop

// Ask The User Which Screen Mode They Prefer
if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen=FALSE; // Windowed Mode
}

// Create Our OpenGL Window
if (!CreateGLWindow("Lionel Brits & NeHe's 3D World Tutorial",640,480,16,fullscreen))
{
return 0; // Quit If Window Was Not Created
}

while(!done) // Loop That Runs While done=FALSE
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting?
{
if (msg.message==WM_QUIT) // Have We Received A Quit Message?
{
done=TRUE; // If So done=TRUE
}
else // If Not, Deal With Window Messages
{
TranslateMessage(&msg); // Translate The Message
DispatchMessage(&msg); // Dispatch The Message
}
}
else // If There Are No Messages
{
// Draw The Scene. Watch For ESC Key And Quit Messages From DrawGLScene()
if ((active && !DrawGLScene()) || keys[VK_ESCAPE]) // Active? Was There A Quit Received?
{
done=TRUE; // ESC or DrawGLScene Signalled A Quit
}
else // Not Time To Quit, Update Screen
{
SwapBuffers(hDC); // Swap Buffers (Double Buffering)
if (keys['B'] && !bp)
{
bp=TRUE;
blend=!blend;
if (!blend)
{
glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
}
else
{
glEnable(GL_BLEND);
glDisable(GL_DEPTH_TEST);
}
}
if (!keys['B'])
{
bp=FALSE;
}

if (keys['F'] && !fp)
{
fp=TRUE;
filter+=1;
if (filter>2)
{
filter=0;
}
}
if (!keys['F'])
{
fp=FALSE;
}

if (keys[VK_PRIOR])
{
z-=0.02f;
}

if (keys[VK_NEXT])
{
z+=0.02f;
}

if (keys[VK_UP])
{

xpos -= (float)sin(heading*piover180) * 0.05f;
zpos -= (float)cos(heading*piover180) * 0.05f;
if (walkbiasangle >= 359.0f)
{
walkbiasangle = 0.0f;
}
else
{
walkbiasangle+= 10;
}
walkbias = (float)sin(walkbiasangle * piover180)/20.0f;
}

if (keys[VK_DOWN])
{
xpos += (float)sin(heading*piover180) * 0.05f;
zpos += (float)cos(heading*piover180) * 0.05f;
if (walkbiasangle <= 1.0f)
{
walkbiasangle = 359.0f;
}
else
{
walkbiasangle-= 10;
}
walkbias = (float)sin(walkbiasangle * piover180)/20.0f;
}

if (keys[VK_RIGHT])
{
heading -= 1.0f;
yrot = heading;
}

if (keys[VK_LEFT])
{
heading += 1.0f;
yrot = heading;
}

if (keys[VK_PRIOR])
{
lookupdown-= 1.0f;
}

if (keys[VK_NEXT])
{
lookupdown+= 1.0f;
}

if (keys[VK_F1]) // Is F1 Being Pressed?
{
keys[VK_F1]=FALSE; // If So Make Key FALSE
KillGLWindow(); // Kill Our Current Window
fullscreen=!fullscreen; // Toggle Fullscreen / Windowed Mode
// Recreate Our OpenGL Window
if (!CreateGLWindow("Lionel Brits & NeHe's 3D World Tutorial",640,480,16,fullscreen))
{
return 0; // Quit If Window Was Not Created
}
}
}
}
}

// Shutdown
KillGLWindow(); // Kill The Window
return (msg.wParam); // Exit The Program
}