Why am I seeing streak artifacts on the cube map I'm rendering?

Question

I'm getting strange streaks on my cube map when rendering to it. He is my code that is being called each frame:

void drawCubeMap(void)
{


int face;
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glBindFramebuffer(GL_FRAMEBUFFER, fbo);
//glBindTexture(GL_TEXTURE_CUBE_MAP, cubeMapTexture);
//glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glViewport(0,0,sizeT, sizeT);

for (face = 0; face < 6; face++) {

   glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, cubeMapTexture, 0);
   drawSpheres();
}
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glViewport(0,0,900, 900);
}

Any idea what it might be? The streaking occurs when I'm rotating the spheres around the main sphere.

Answer 1

Since you're rendering six images to the cube map, you should set the glClear and glClearColor inside of the loop, clearing it six times. In this case, the clear color should be black, so it keeps a black background.

The same principle applies to any dynamic environment mapping techniques you use, be it a cube map, dual paraboloid map, etc.