平鋪貼圖OpenGL C ++

Question

我正在嘗試使用openGL和C ++實現tile mapping 。

我發現本教程/說明非常不錯。

當我在visual studio 2010編譯並運行代碼時，它只是打開一個窗口並顯示一個白色正方形。

也許我的文件無法正確加載。 我已經嘗試過網站使用的.raw文件以及我自己的.png文件。

    #include <GL/gl.h>
#include <GL/glut.h>
#include <windows.h>
#include <stdio.h>

GLuint texture; //the array for our texture
GLuint texture2; //the array for our second texture

int cMap[10][10] = { //our map
    {1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
    {1, 0, 1, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 1, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 1, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 1, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 1, 1, 1, 1, 1, 1, 1, 1},
    {1, 0, 0, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 0, 0, 0, 0, 0, 0, 0, 1},
    {1, 0, 0, 0, 0, 0, 0, 0, 0, 1},
    {1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
};

//function to load the RAW file

GLuint LoadTexture( const char * filename, int width, int height )
{
    GLuint texture;
    unsigned char * data;
    FILE * file;

    //The following code will read in our RAW file
    file = fopen( filename, “rb” );
    if ( file == NULL ) return 0;
    data = (unsigned char *)malloc( width * height * 3 );
    fread( data, width * height * 3, 1, file );
    fclose( file );

    glGenTextures( 1, &texture )
    glBindTexture( GL_TEXTURE_2D, texture );
    glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, 
GL_MODULATE ); //set texture environment parameters

    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, 
GL_LINEAR );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_LINEAR );

    //Here we are setting the parameter to repeat the texture 
instead of clamping the texture
    //to the edge of our shape. 
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 
GL_REPEAT );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 
GL_REPEAT );

    //Generate the texture
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, 
GL_RGB, GL_UNSIGNED_BYTE, data);
    free( data ); //free the texture
    return texture; //return whether it was successfull
}

void FreeTexture( GLuint texture )
{
  glDeleteTextures( 1, &texture ); 
}

void drawTiles (void) { //our function to draw the tiles
    for (int i = 0; i < 10; i++) //loop through the height of the map
    {
        for (int j = 0; j < 10; j++) //loop through the width of the map
        {
            if (cMap[i][j] == 0) //if the map at this position contains a 0
            {
                glBindTexture( GL_TEXTURE_2D, texture ); //bind our grass texture to our shape
            }
            else //otherwise
            {
                glBindTexture( GL_TEXTURE_2D, texture2 ); //bind our dirt texture to our shape
            }

            glPushMatrix(); //push the matrix so that our translations only affect
 this tile
                glTranslatef(j, -i, 0); //translate the tile to where it should belong

                glBegin (GL_QUADS); //begin drawing our quads
                    glTexCoord2d(0.0, 0.0);
                    glVertex3f(0.0, 0.0, 0.0); //with our vertices we have to assign a texcoord

                    glTexCoord2d(1.0, 0.0);
                    glVertex3f(1.0, 0.0, 0.0); //so that our texture has some points to draw to

                    glTexCoord2d(1.0, 1.0);
                    glVertex3f(1.0, 1.0, 0.0);

                    glTexCoord2d(0.0, 1.0);
                    glVertex3f(0.0, 1.0, 0.0);
                glEnd();
            glPopMatrix(); //pop the matrix
        } //end first loop
    } //end second loop
}

void display (void) {
    glClearColor (0.0,0.0,0.0,1.0);
    glClear (GL_COLOR_BUFFER_BIT);
    glLoadIdentity(); 
    glEnable( GL_TEXTURE_2D );
    glTranslatef(-5, 4, -20); //translate back a bit to view the map correctly

    drawTiles(); //draw our tiles
    glutSwapBuffers();
}
void reshape (int w, int h) {
    glViewport (0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    gluPerspective (60, (GLfloat)w / (GLfloat)h, 1.0, 100.0);
    glMatrixMode (GL_MODELVIEW);
}

int main (int argc, char **argv) {
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_DOUBLE);
    glutInitWindowSize (500, 500);
    glutInitWindowPosition (100, 100);
    glutCreateWindow (“A basic OpenGL Window“);
    glutDisplayFunc (display);
    glutIdleFunc (display);
    glutReshapeFunc (reshape);

    //Load our texture
    texture = LoadTexture(“texture.raw”, 256, 256);
    texture2 = LoadTexture(“texture2.raw”, 256, 256);

    glutMainLoop ();

    //Free our texture
    FreeTexture(texture);
    FreeTexture(texture2);

    return 0;
}

Answer 1

確保您的工作目錄與您的假定一致。

或使用絕對文件名。

否則， fopen()將失敗，因為它找不到文件。