Scopes state of depth testing and writing.
Enables or disables both depth testing and writing to the depth buffer.
Enables or disables depth comparisons and writing to the depth buffer, and specifies a depth comparison function, either GL_NEVER , GL_LESS , GL_EQUAL , GL_LEQUAL , GL_GREATER , GL_NOTEQUAL , GL_GEQUAL and GL_ALWAYS .
GL_NEVER
GL_LESS
GL_EQUAL
GL_LEQUAL
GL_GREATER
GL_NOTEQUAL
GL_GEQUAL
GL_ALWAYS