title: sampler2DShadow bias component not working in GLSL?
body: <p>I am trying to implement shadow maps in opengl core 3.3.  When I send a bias to the texture function in GLSL it doesn't seem to do anything at all. Am I using it wrong?</p>
  
  <pre><code>#version 330
  uniform sampler2D diffusetex;
  uniform sampler2D normaltex;
  uniform sampler2D postex;
  uniform sampler2D depthtex;
  
  uniform sampler2DShadow shadowmap;
  uniform mat4 shadowmat;
  
  in vec2 uv;
  
  layout (location=0) out vec4 outColor;
  
  
  void main(){
      vec3 normal = normalize(texture(normaltex, uv).xyz);
      vec3 world_position = texture(postex, uv).xyz;
  
      vec4 shadowcoord = shadowmat*vec4(world_position, 1);
      float shadow = texture(shadowmap, shadowcoord.xyz,0.5);
  
      float luma = max(0.1,shadow);//ambient light
      outColor = texture(diffusetex, uv)*luma;
  }
  </code></pre>
  
  <p>I am using linux, the nvidia proprietary drivers and golang. Doubt it has anything to do with it but just in case, there it is.</p>