As a graphics programmer i think its good to have a well rounded idea about how graphics works. Here are some things I would expect a good graphics programmer to know, beyond just programming and an API:
-Rotation view and projection matrices, and general vector math.
-Shader programming.
-Procedural primitives like voronoi, SDF and perlin.
-Image Compositing.
-Forward and deferred rendering.
-Various sampling techniques.
-Shadow and lighting techniques.
-Knowing a bit about how the art pipeline works and how to get data out of 3D apps.
-Being comfortable using a profiler and debugger.
-Capable of reading Siggraph papers.
-Knowing various spacial partitioning and volume hierarchy techniques.
-Being able to build a simple raytracer.
-Good understanding of primitives, like sprites, triangles n-gons and so on.
-Some particle and simulation experience.
-Rotation view and projection matrices, and general vector math.
-Shader programming.
-Procedural primitives like voronoi, SDF and perlin.
-Image Compositing.
-Forward and deferred rendering.
-Various sampling techniques.
-Shadow and lighting techniques.
-Knowing a bit about how the art pipeline works and how to get data out of 3D apps.
-Being comfortable using a profiler and debugger.
-Capable of reading Siggraph papers.
-Knowing various spacial partitioning and volume hierarchy techniques.
-Being able to build a simple raytracer.
-Good understanding of primitives, like sprites, triangles n-gons and so on.
-Some particle and simulation experience.