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SOIL库加载纹理

2016-04-13 22:21 316 查看
NeHe教程里第六课使用glaux来加载纹理位图,但是glaux 库已经弃用。新的NeHe第六课教程中推荐了SOIL库。(下载,可以在这里获取能直接使用的文件)

SOIL库是一个小型的C语言库,用来加载纹理到OpenGL。它基于stb_image 1.16。

详情:http://www.lonesock.net/soil.html

我们使用时只需要简单的把SOIL.h SOIL.lib添加到工程就可以了。

bmp文件的使用:

在InitGL()中调用LoadGlTextures()函数:

int LoadGLTextures()                                    // Load Bitmaps And Convert To Textures
{
/* load an image file directly as a new OpenGL texture */
texture[0] = SOIL_load_OGL_texture
(
"Data/NeHe.bmp",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_INVERT_Y
);

if(texture[0] == 0)
return false;

// Typical Texture Generation Using Data From The Bitmap
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

return true;                                        // Return Success
}


unsigned int SOIL_load_OGL_texture(

const char *filename,

int force_channels,

unsigned int reuse_texture_ID,

unsigned int flags);

第一个参数为文件名;

第二个说明符,SOIL_LOAD_AUTO表示使用我们磁盘载入的;

第三个表示让SOIL为我们创建一个ID;

第四个参数SOIL_FLAG_INVERT_Y允许我们做是翻转Y轴

返回值,0表示失败,其他表示OpenGL上下文句柄

效果:



实例:



/*
*      This Code Was Created By Jeff Molofee 2000
*      A HUGE Thanks To Fredric Echols For Cleaning Up
*      And Optimizing The Base Code, Making It More Flexible!
*      If You've Found This Code Useful, Please Let Me Know.
*      Visit My Site At nehe.gamedev.net
*/

#include <windows.h>        // Header File For Windows
#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 "SOIL.h"

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

GLfloat xrot;               // X Rotation ( NEW )
GLfloat yrot;               // Y Rotation ( NEW )
GLfloat zrot;               // Z Rotation ( NEW )

GLuint  texture[1];         // Storage For One Texture ( NEW )

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

int LoadGLTextures()                                    // Load Bitmaps And Convert To Textures
{
/* load an image file directly as a new OpenGL texture */
texture[0] = SOIL_load_OGL_texture
(
"Data/NeHe.bmp",
SOIL_LOAD_AUTO,
SOIL_CREATE_NEW_ID,
SOIL_FLAG_INVERT_Y
);

if(texture[0] == 0)
return false;

// Typical Texture Generation Using Data From The Bitmap
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

return true;                                        // Return Success
}

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 ( NEW )
{
return FALSE;                                   // If Texture Didn't Load Return FALSE
}

glEnable(GL_TEXTURE_2D);                            // Enable Texture Mapping ( NEW )
glShadeModel(GL_SMOOTH);                            // Enable Smooth Shading
glClearColor(0.0f, 0.0f, 0.0f, 0.5f);               // Black Background
glClearDepth(1.0f);                                 // Depth Buffer Setup
glEnable(GL_DEPTH_TEST);                            // Enables Depth Testing
glDepthFunc(GL_LEQUAL);                             // The Type Of Depth Testing To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);  // Really Nice Perspective Calculations
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
glTranslatef(0.0f,0.0f,-5.0f);

glRotatef(xrot,1.0f,0.0f,0.0f);
glRotatef(yrot,0.0f,1.0f,0.0f);
glRotatef(zrot,0.0f,0.0f,1.0f);

glBindTexture(GL_TEXTURE_2D, texture[0]);

glBegin(GL_QUADS);
// Front Face
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
// Back Face
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
// Top Face
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
// Bottom Face
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
// Right face
glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
// Left Face
glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
glEnd();

xrot+=0.3f;
yrot+=0.2f;
zrot+=0.4f;
return TRUE;                                        // Keep Going
}

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_SCREENSAVE:                 // 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("NeHe's Texture Mapping 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[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("NeHe's Texture Mapping Tutorial",640,480,16,fullscreen))
{
return 0;                       // Quit If Window Was Not Created
}
}
}
}

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