Ich versuche, ein PNG-Bild als Textur zu rendern. Es wird jedoch nur ein weißes Quadrat gerendert.

Ich gebe meiner Textur eine eindeutige int-ID namens texID, lese die Pixeldaten in einen Puffer 'image' (in der .h-Datei deklariert). Ich lade meinen Pixelpuffer, mache all meine OpenGL-Sachen und binde diesen Pixelpuffer an eine Textur für OpenGL. Ich zeichne dann alles mit glDrawElements.

Außerdem initialisiere ich die Textur mit einer Größe von 32x32, wenn ihr Konstruktor aufgerufen wird. Daher bezweifle ich, dass es sich um eine Potenz von zwei Größen handelt.

Kann irgendjemand Fehler in meinem OpenGL GL_TEXTURE_2D-Setup sehen, die mir ein weißes Blockquadrat geben könnten?

 #include "Texture.h"




Texture::Texture(int width, int height, string filename)
{

    const char* fnPtr = filename.c_str(); //our image loader accepts a ptr to a char, not a string
    printf(fnPtr);
    w = width; //give our texture a width and height, the reason that we need to pass in the width and height values manually
    h = height;//UPDATE, these MUST be P.O.T.

    unsigned error = lodepng::decode(image,w,h,fnPtr);//lodepng's decode function will load the pixel data into image vector
    //display any errors with the texture
    if(error)
    {
        cout << "\ndecoder error " << error << ": " << lodepng_error_text(error) <<endl;
    }

    for(int i = 0; i<image.size(); i++)
    {
        printf("%i,", image.at(i));

    }

    printf("\nImage size is %i", image.size());

    //image now contains our pixeldata. All ready for OpenGL to do its thing

    //let's get this texture up in the video memory
    texGLInit();
}

void Texture::texGLInit()
{
    //WHERE YOU LEFT OFF: glGenTextures isn't assigning an ID to textures. it stays at zero the whole time
    //i believe this is why it's been rendering white
    glGenTextures(1, &textures);
    printf("\ntexture = %u", textures);
    glBindTexture(GL_TEXTURE_2D, textures);//evrything we're about to do is about this texture
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    //glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    //glDisable(GL_COLOR_MATERIAL);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,w,h,0, GL_RGBA, GL_UNSIGNED_BYTE, &image);
    //we COULD free the image vectors memory right about now.


}

void Texture::draw(point centerPoint, point dimensions)
{
    glEnable(GL_TEXTURE_2D);
    printf("\nDrawing block at (%f, %f)",centerPoint.x, centerPoint.y);
    glBindTexture(GL_TEXTURE_2D, textures);//bind the texture
    //create a quick vertex array for the primitive we're going to bind the texture to
    printf("TexID = %u",textures);
    GLfloat vArray[8] = 
    {
        centerPoint.x-(dimensions.x/2), centerPoint.y-(dimensions.y/2),//bottom left i0
        centerPoint.x-(dimensions.x/2), centerPoint.y+(dimensions.y/2),//top left i1
        centerPoint.x+(dimensions.x/2), centerPoint.y+(dimensions.y/2),//top right i2
        centerPoint.x+(dimensions.x/2), centerPoint.y-(dimensions.y/2)//bottom right i3
    };

    //create a quick texture array (we COULD create this on the heap rather than creating/destoying every cycle)
    GLfloat tArray[8] = 
    {
        0.0f,0.0f, //0
        0.0f,1.0f, //1
        1.0f,1.0f, //2
        1.0f,0.0f //3
    };

    //and finally.. the index array...remember, we draw in triangles....(and we'll go CW)
    GLubyte iArray[6] =
    {
        0,1,2,
        0,2,3
    };

    //Activate arrays
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    //Give openGL a pointer to our vArray and tArray
    glVertexPointer(2, GL_FLOAT, 0, &vArray[0]);
    glTexCoordPointer(2, GL_FLOAT, 0, &tArray[0]);

    //Draw it all
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_BYTE, &iArray[0]);

    //glDrawArrays(GL_TRIANGLES,0,6);

    //Disable the vertex arrays
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisable(GL_TEXTURE_2D);
    //done!

    /*glBegin(GL_QUADS);
    glTexCoord2f(0.0f,0.0f);
        glVertex2f(centerPoint.x-(dimensions.x/2), centerPoint.y-(dimensions.y/2));
    glTexCoord2f(0.0f,1.0f);
        glVertex2f(centerPoint.x-(dimensions.x/2), centerPoint.y+(dimensions.y/2));
    glTexCoord2f(1.0f,1.0f);
        glVertex2f(centerPoint.x+(dimensions.x/2), centerPoint.y+(dimensions.y/2));
    glTexCoord2f(1.0f,0.0f);
        glVertex2f(centerPoint.x+(dimensions.x/2), centerPoint.y-(dimensions.y/2));
    glEnd();*/
}



Texture::Texture(void)
{
}
Texture::~Texture(void)
{
}

Ich werde auch die Hauptklasse 'init' einbinden, in der ich vorher ein bisschen mehr OGL-Setup mache.

void init(void)
{
    printf("\n......Hello Guy. \n....\nInitilising");
    glMatrixMode(GL_PROJECTION);    
    glLoadIdentity();
    gluOrtho2D(0,XSize,0,YSize);
    glEnable(GL_TEXTURE_2D);
    myBlock = new Block(0,0,offset);
    glClearColor(0,0.4,0.7,1);


    glLineWidth(2);         // Width of the drawing line
    glMatrixMode(GL_MODELVIEW); 
    glDisable(GL_DEPTH_TEST);
    printf("\nInitialisation Complete");

}

Update: Hinzufügen der Hauptfunktion, in der ich zuerst mein OpenGL-Fenster eingerichtet habe.

int main(int argc, char** argv) 
{
  glutInit(&argc, argv);    // GLUT Initialization 
  glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE); // Initializing the Display mode
  glutInitWindowSize(800,600);  // Define the window size
  glutCreateWindow("Gem Miners");   // Create the window, with caption.
        printf("\n========== McLeanTech Systems =========\nBecoming Sentient\n...\n...\n....\nKILL\nHUMAN\nRACE \n");
  init();   // All OpenGL initialization


  //-- Callback functions ---------------------
  glutDisplayFunc(display);
  glutKeyboardFunc(mykey);
  glutSpecialFunc(processSpecialKeys);
  glutSpecialUpFunc(processSpecialUpKeys);
  //glutMouseFunc(mymouse);


  glutMainLoop();   // Loop waiting for event 
}