shown black pixels as red

I’ve drawn a BMP image with glTexImage2D() and I need black pixels to be shown as red. How can I do it? Any ideas?

You can do that by a simple shader.

void main()
    vec4 color = texture2D(myTexture, texCoord.xy);
    if(color.rgb == vec3(0,0,0))
       color.rgb = vec3(1,0,0);

    gl_FragColor = color;

Or you can use oldstyle opengl colortable.