If I declare my shadow map texture uniform as a sampler2D value and do the comparison myself, shadow maps work perfectly:
Code :
if (shadowcoord.z>texture(texture5,shadowcoord.xy).r) attenuation=0.0;
If I declare my shadow map texture uniform as a sampler2DShadow and call texture(), shadow lookups always return zero (appear black):
Code :
attenuation *= texture(texture5,shadowcoord);
In the second situation, I also set these values for the bound texture on the client side:
Code :
glTexParameteri(gltarget,GL_TEXTURE_COMPARE_MODE,GL_COMPARE_REF_TO_TEXTURE);
glTexParameteri(gltarget,GL_TEXTURE_COMPARE_FUNC,GL_LEQUAL);

  • The shadow map lookup returns zero even if I set the shadowcoord.z value to 0.0.
  • I also tried changing the compare function to GL_GEQUAL, with the same result.

Something is obviously wrong here. Am I missing some other little trick with OpenGL 4 shadow mapping?