Generating texture

[romulosd]

Hello guys
I'm trying to load a PNG image to use as texture,
but when I compile the sdl window closes.
I'm sure the error is in the function of generating the png texture,
because when i don´t use this function, the sdl window does not close.
So debugging using cout i found that the cout above glTexImage2D function, shows in console, but the cout in below of glTexImage2D does not work.
how can I solve this?
Does not reading this image?

hear is the function

#include "Texture.h"
#include <iostream>
Texture::Texture() {}

 unsigned int Texture::geraTextureDePNG(const std::string& path)
{

    unsigned int _tex;
    SDL_Surface*  surface = IMG_Load(path.c_str());

    int _imgW = surface->w; //tamanhos.
    int _imgH = surface->h;

    glGenTextures(1, &_tex);  
    glBindTexture(GL_TEXTURE_2D, _tex); 
std::cout<<"texture\n"; // this show in console

    glTexImage2D(GL_TEXTURE_2D, 0, 4, surface->w, surface->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, surface->pixels);

    std::cout<<"texture2";//this cout does not showing in the console

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    SDL_FreeSurface(surface); //destrói a imagem carregada.
    return _tex;
}
Texture::~Texture()
{
    //termina o uso da textura.
    glBindTexture(GL_TEXTURE_2D, 0);

}
void Texture::TexturedCube(unsigned int _tex)
{

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
	glLoadIdentity ( );
	glPushMatrix();
	glTranslatef ( 0.0, 0.0, -5.0 );
	glRotatef ( xrot, 1.0, 0.0, 0.0 );
	glRotatef ( yrot, 0.0, 1.0, 0.0 );
	glRotatef ( zrot, 0.0, 0.0, 1.0 );

	// define qual das texturas usar
	glBindTexture ( GL_TEXTURE_2D, _tex );

	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();

	glPopMatrix();
	xrot+=0.3f;
	yrot+=0.2f;
	zrot+=0.4f;
}

[Hippogriff]

glTexImage2D(GL_TEXTURE_2D, 0, 4, surface->w, surface->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, surface->pixels);
Strange you are using "4" for the 3rd argument. I guess it ends up being GL_RGBA anyway but it's easier to read if you specify that directly.

I would check that SDL actually sees the image.

 
SDL_Surface*  surface = IMG_Load(path.c_str());

if(!surface)
    cout << "Useful Info here << endl;  

I guess make sure you have glEnable(GL_TEXTURE_2D); set up somewhere too.

[romulosd]

I tried this:

if(!surface) {
    printf("IMG_Load: %s\n", IMG_GetError());
    // handle error
}

but it does not enter the if, it means that SDL sees the image.
So what does not work?
I already put the glEnable (GL_TEXTURE_2D);
that was missing.

[10X9216C]

Your code should work. I'm almost sure your surface is null.

Test something like surface->w and surface->h. Check if its not zero. Of course, if they are zero you will see your program blow up again.
¬¬

[N36fSL3A]

An image loaded into an SDL surface is not always RGBA. It's usually something like RGB, or even BGR.

Chances are your image is NULL as myesolar said.

[romulosd]

already try this
std::cout<<surface->w;
std::cout<<surface->h;
returns me 256 and 256

[10X9216C]

Yes. As Fredbill said. You cant suppose your image have always 4 components. I'm sure you would like to have images with 3 or 4 components (often useful, but you can have 2 and even 1 component.).

PS: Your texture loader also draw rectangles? Weird....

[romulosd]

Ok already solved the problem thanks to my teacher !
Problem was that i was reading an image that was RGB and the code was reading an rgba image.
Thanks for the replies.
You guys rock!

[romulosd]

Yes my texture loader draw rectangles
because I didn´t want to create a class and a header only for that

[N36fSL3A]

romulosd wrote:

Ok already solved the problem thanks to my teacher !
Problem was that i was reading an image that was RGB and the code was reading an rgba image.

I wrote:

An image loaded into an SDL surface is not always RGBA. It's usually something like RGB, or even BGR.