[lemma=combiner] [□]
[lemma=combiner] [□=□]
[lemma=combiner] [□ & □]
The state required for the register combiners is a bit indicating whether register combiners are enabled or disabled , an integer indicating how many general combiners are active , a bit indicating whether or not the color sum clamp to 1 should be performed , two RGBA constant colors , sets of general combiner stage state where is the value of MAX_GENERAL_COMBINERS_NV , and the final combiner stage state . At the end of the sequence of general combiner stages , there is a final combiner stage that operates in a different manner than the general combiner stages . The register combiners can mimic the TNT operation with a post-operation complement only by taking pains to complement on input any uses of the output in later combiner stages . The final combiner stage operates differently from the general combiner stages . The register combiner mechanism supports at least two general combiner stages and then a special final combiner stage appropriate for applying a color sum and fog computation ( TNT provides two simpler combiner stages , and TNT 's color sum and fog stages are hard-wired and not subsumed by the combiner mechanism as in register combiners ) . When the general combiner stage 's register set is written based on the computed outputs , the updated register set is copied to the register set of the subsequent combiner stage in the combiner sequence .