glTexImage2d doesn't do anything - opengl

Question

This problem baffles me. I am testing some Haskell bindings to OpenGL, I create a vertex shader, a fragment shader, compile the program, and draw a textured rectangle to the screen after transforming the vertices... except the screen is blank.
When I render the rectangle flat white instead of using a sampler in the fragment shader, it works fine. When I go into gdebugger and use the option to replace all textures with a stub texture, it also works fine.
When I look at the allocated textures in gdebugger, there are no texture objects, only the default 2d texture. When I set a breakpoint on glTexImage2d, I see that it is being called, but no texture object appears in memory when I peek at it with gdebugger.
What's going on? Am I forgetting to set some environment variables? I'm quite frustrated. The kicker is that I had this problem before, and I managed to fix it then, but I forgot what the problem was. I hate myself >_>

Answer 1

I ported a tutorial on OpenGL to Haskell some time ago. It includes a link to a very tiny library that, among other things, helps with loading textures.
Perhaps you could compare that code with what you have to spot the differences.

Answer 2

I'm not a Haskell guy by any means, but try doing the simplest thing that could possibly work and check to see where you deviate from it:
#include <GL/glut.h>
double aspect_ratio = 0;
GLuint texID = 0;
unsigned int texBuf[] = {
0x00FFFFFF,
0x00FF0000,
0x0000FF00,
0x000000FF,
};
void display(void)
{
glEnable(GL_DEPTH_TEST);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-10*aspect_ratio, 10*aspect_ratio, -10, 10, -10, 10);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glColor3ub(255,255,255);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texID);
glScalef(8,8,8);
glTranslatef(-0.5f, -0.5f, 0.0f);
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2f(0,0);
glTexCoord2f(1,0);
glVertex2f(1,0);
glTexCoord2f(1,1);
glVertex2f(1,1);
glTexCoord2f(0,1);
glVertex2f(0,1);
glEnd();
glFlush();
glFinish();
glutSwapBuffers();
}
void reshape(int w, int h)
{
aspect_ratio = (double)w / (double)h;
glViewport(0, 0, w, h);
}
void idle()
{
glutPostRedisplay();
}
int main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
glutInitWindowSize(200,200);
glutCreateWindow("Aspect Ratio");
glGenTextures(1, &texID);
glBindTexture(GL_TEXTURE_2D, texID);
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);
glTexImage2D(GL_TEXTURE_2D, 0, 4, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, (char*)texBuf);
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutIdleFunc(idle);
glutMainLoop();
return 0;
}