CODEWITHSUNDEEP
opengl
Water
Water

Reputation: 3655

Does OpenGL have a default value for glStencilMask?

For interests sake, I'm curious if glStencilMask and glStencilMaskSeparate (and similar ones) have a default value, or if they're implementation defined, or if they're undefined.

I assume the wise thing to do is always set them from the get go, but I'm curious if they just "work" by coincidence or whether there is in fact a default value set.

Slightly related: I recall reading somewhere that on nvidia cards you don't have to set the active texture and it's at zero by default, but AMD cards require you to set it or else you can get junk results. This makes me wonder if it's the same thing (where stencil stuff just happens to work for me but just by chance) and by not setting it I've been playing a dangerous game or if this isn't the case.

I looked through the OpenGL spec [section 17.4.2] for the definitions of these functions, but couldn't resolve the answer to my question.

Upvotes: 1

Views: 196

Answers (1)

Rabbid76
Rabbid76

Reputation: 210928

The initial state of glStencilMask is clearly specified. Initially, the mask is all 1's.

OpenGL 4.6 API Core Profile Specification - 17.4.2 Fine Control of Buffer Updates; page 522:

void StencilMask( uint mask );
void StencilMaskSeparate( enum face, uint mask );

control the writing of particular bits into the stencil planes.
The least significant s bits of mask, where s is the number of bits in the stencil buffer, specify an integer mask. Where a 1 appears in this mask, the corresponding bit in the stencil buffer is written; where a 0 appears, the bit is not written.

[...]

In the initial state, the integer masks are all ones, as are the bits controlling depth value and RGBA component writing.

Upvotes: 3

Related Questions