Nehe_006 _ How to map

This section describes how to paste a BMP image of a specific format to a 3D image surface. The demo in this lesson is a rectangle.

There are many formats for BMP images. You need to write a function to read BMP images.

Note that the Glaux library is used, and then the replacement function provided by nehe is used. This program is successfully debugged under vs2008.

Save the required image to the data directory of the same level.

#include<windows.h>//vs2008,windows.h has glaut.h
#include<tchar.h>
//#include <stdio.h>//fopen
#include <gl\gl.h>
#include <gl\glu.h>
#pragma comment(lib,"opengl32.lib")
#pragma comment(lib,"glu32.lib")

HGLRC           hRC=NULL;           // Permanent Rendering Context
HDC             hDC=NULL;           // Private GDI Device 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=FALSE;           // no 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

bool NeHeLoadBitmap(LPTSTR szFileName, GLuint &texid)   // Creates Texture From A Bitmap File
{
    HBITMAP hBMP;                           // Handle Of The Bitmap
    BITMAP    BMP;                           // Bitmap Structure
    glGenTextures(1, &texid);               // Create The Texture
    hBMP=(HBITMAP)LoadImage(GetModuleHandle(NULL), szFileName, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE );

if (!hBMP)                               // Does The Bitmap Exist?
return FALSE;                       // If Not Return False
    GetObject(hBMP, sizeof(BMP), &BMP);       // Get The Object
// hBMP:        Handle To Graphics Object
// sizeof(BMP): Size Of Buffer For Object Information
// &BMP:        Buffer For Object Information
    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);   // Pixel Storage Mode (Word Alignment / 4 Bytes)
// Typical Texture Generation Using Data From The Bitmap
    glBindTexture(GL_TEXTURE_2D, texid);   // Bind To The Texture ID
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);    // Linear Min Filter
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);    // Linear Mag Filter
    glTexImage2D(GL_TEXTURE_2D, 0, 3, BMP.bmWidth, BMP.bmHeight, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, BMP.bmBits);
    DeleteObject(hBMP);                       // Delete The Object
return TRUE;                           // Loading Was Successful
}
/*
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");
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
}//end of LoadBMP

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/NeHe.bmp"))
{
Status=TRUE;
glGenTextures(1, &texture[0]);   // Create The Texture
// Typical Texture Generation Using Data From The Bitmap
glBindTexture(GL_TEXTURE_2D, texture[0]);
// Generate The Texture
glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);    // Linear Filtering
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);    // Linear Filtering
}
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
}//end of LoadGLTextures
*/

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
}//end of ReSizeGLScene

int InitGL(GLvoid)   // All Setup For OpenGL Goes Here
{
//if (!LoadGLTextures())           // Jump To Texture Loading Routine ( NEW )
if (!NeHeLoadBitmap(_T("Data/NeHe.bmp"), texture[0]))   // Load The Bitmap
    {
return FALSE;           // If Texture Didn't Load Return FALSE ( NEW )
    }
    glEnable(GL_TEXTURE_2D);       // Enable Texture Mapping ( NEW )

    glShadeModel(GL_SMOOTH);       // Enables Smooth Shading
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);   // Black Background
    glClearDepth(1.0f);           // Depth Buffer Setup
    glEnable(GL_DEPTH_TEST);       // Enables Depth Testing
    glDepthFunc(GL_LEQUAL);           // The Type Of Depth Test To Do
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);// Really Nice Perspective Calculations

return TRUE;   // Initialization Went OK
}//end of InitGL

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 Current Modelview Matrix

//
//TODO:the code of openGL
//
    glTranslatef(0.0f,0.0f,-5.0f);   // Move Left 1.5 Units And Into The Screen 6.0

    glRotatef(xrot,1.0f,0.0f,0.0f);       // Rotate On The X Axis
    glRotatef(yrot,0.0f,1.0f,0.0f);       // Rotate On The Y Axis
    glRotatef(zrot,0.0f,0.0f,1.0f);       // Rotate On The Z Axis

    glBindTexture(GL_TEXTURE_2D, texture[0]);    // Select Our Texture

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

    xrot+=2.0f;   // X Axis Rotation
    yrot+=2.0f;   // Y Axis Rotation
    zrot+=2.0f;   // Z Axis Rotation

if(xrot>=360.0f)xrot-=360.0f;
if(yrot>=360.0f)yrot-=360.0f;
if(zrot>=360.0f)zrot-=360.0f;

return TRUE;       // Keep Going
}

GLvoid KillGLWindow(GLvoid)           // Properly Kill The Window
{

}

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