Bug in Windows 7/10/?'s OpenGL 1.1 drivers? Wrong texture is used in the following ex

[tommyg]

Hello!

I’ve already posted this on stackoverflow a month ago, but got no response except a couple of upvotes. I don’t seem to be allowed to link to it yet…

Basically, what happens is that even though i’ve bound a new texture, and gdebugger can see that this is the case, the previously bound texture is actually used for drawing (unless drawing with GL_LINE or GL_POINT) - unless first binding 0.

Here is the code:-

//link library
//opengl32

//linker options
//-lmingw32 -lSDL2main -lSDL2

//include SDL2 dirs-
//compiler-
//SDL2-2.0.4\i686-w64-mingw32\include\SDL2
//linker-
//SDL2-2.0.4\i686-w64-mingw32\lib


#include <SDL.h>
#include <SDL_opengl.h>


void draw();

bool fix = false;
bool wire = false;

GLuint tex1 = 0;
GLuint tex2 = 0;


int main(int argc, char *argv[])
{
    SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER);

    SDL_Window* mywindow = SDL_CreateWindow("press q or w to toggle fixes...",100,100,640,480,SDL_WINDOW_OPENGL|SDL_WINDOW_SHOWN);

    SDL_GL_CreateContext(mywindow);

    glEnable(GL_TEXTURE_2D);



    bool loop = true;
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    while (loop)
    {
        SDL_Event event;
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
                loop = false;

            if (event.type == SDL_KEYDOWN)
            {
                switch (event.key.keysym.sym)
                {
                case SDLK_ESCAPE:
                    loop = false;
                    break;
                case SDLK_q:
                    fix = !fix;
                break;

                case SDLK_w:
                    if(wire)
                    {
                        glPolygonMode(GL_FRONT, GL_FILL);
                    }
                    else
                    {
                        glPolygonMode(GL_FRONT, GL_LINE);
                    }
                    wire = !wire;
                break;




                default:
                    break;
                }
            }
        }
        draw();
        SDL_GL_SwapWindow(mywindow);
    }
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);

    glDeleteTextures(1, &tex1);
    glDeleteTextures(1, &tex2);


    return 0;
}




void texturator(GLuint* tex, unsigned char r, unsigned char g, unsigned char b)
{
    if(!(*tex))
    {
        glGenTextures(1, tex) ;

        glBindTexture(GL_TEXTURE_2D, *tex);

        unsigned char text[4*4*4];//4*w*h
        for(unsigned int x = 0;x<4;x++)
        {
            for(unsigned int y = 0;y<4;y++)
            {
                unsigned char* pix = &(text[((y*4)+x)*4]);
                pix[0] = x*r;
                pix[1] = y*g;
                pix[2] = x*b;
                pix[3] = 255;
            }
        }

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 4, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, text);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    }
    else
    {
        if(fix)
        {
            glBindTexture(GL_TEXTURE_2D, 0);
        }
        glBindTexture(GL_TEXTURE_2D, *tex);
    }
}





void draw()
{



    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    GLfloat mat1[] = {1.0, 0, 0, 0,    0, 1.0, 0, 0,     0, 0, 1.0, 0,     0, 0, 0, 1};
    glLoadMatrixf(mat1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    GLfloat verts[] = {0.0f,0.0f,0.0f,  1.0f,0.0f,0.0f, 1.0f,1.0f,0.0f, 0.0f,1.0f,0.0f};
    GLfloat uvs[] = {0.0f,0.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f,1.0f};

    glVertexPointer(3, GL_FLOAT, 0, verts);
    glTexCoordPointer(2, GL_FLOAT, 0, uvs);



    texturator(&tex1,0,60,60);


    GLuint elem[] = {0,1,2, 2,3,0};
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, elem);



    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    GLfloat mat2[] = {1, 0, 0, 0,    -0, 1, 0, 0,     0, 0, 1, 0,    -1, 0, 0, 1};
    glLoadMatrixf(mat2);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();



    texturator(&tex2,60,10,0);



    glTexCoordPointer(2, GL_FLOAT, 0, uvs);
    glVertexPointer(3, GL_FLOAT, 0, verts);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);


}

Am I doing something fundamentally wrong here? (incidentally, I’m now getting wrongness of a different sort involving textures using shaders and multiple texture units with apple’s opengl 2.0 software renderer on osx 10.4 - and i don’t have a newer one to test on right now - I will be making a simple thing that displays this and posting about it later.)

Can anyone help? Cheers!