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meta/decompress: Don't pollute the sampler object namespace 

tl;dr: For many types of GL object, we can *NEVER* use the Gen function.

In OpenGL ES (all versions!) and OpenGL compatibility profile,
applications don't have to call Gen functions.  The GL spec is very
clear about how you can mix-and-match generated names and non-generated
names: you can use any name you want for a particular object type until
you call the Gen function for that object type.

Here's the problem scenario:

 - Application calls a meta function that generates a name.  The first
   Gen will probably return 1.

 - Application decides to use the same name for an object of the same
   type without calling Gen.  Many demo programs use names 1, 2, 3,
   etc. without calling Gen.

 - Application calls the meta function again, and the meta function
   replaces the data.  The application's data is lost, and the app
   fails.  Have fun debugging that.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92363
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
This commit is contained in:
Ian Romanick 2015-11-10 16:33:02 -08:00
parent b03ee127d8
commit ae50157363
1 changed files with 15 additions and 7 deletions
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22
src/mesa/drivers/common/meta.c
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@ -2986,8 +2986,7 @@ meta_decompress_cleanup(struct gl_context *ctx,
_mesa_reference_buffer_object(ctx, &decompress->buf_obj, NULL);
}
if (decompress->samp_obj != NULL)
_mesa_DeleteSamplers(1, &decompress->samp_obj->Name);
_mesa_reference_sampler_object(ctx, &decompress->samp_obj, NULL);
memset(decompress, 0, sizeof(*decompress));
}
@ -3114,12 +3113,21 @@ decompress_texture_image(struct gl_context *ctx,
}
if (decompress->samp_obj == NULL) {
GLuint sampler;
decompress->samp_obj = ctx->Driver.NewSamplerObject(ctx, 0xDEADBEEF);
if (decompress->samp_obj == NULL) {
_mesa_meta_end(ctx);
_mesa_GenSamplers(1, &sampler);
decompress->samp_obj = _mesa_lookup_samplerobj(ctx, sampler);
assert(decompress->samp_obj != NULL && decompress->samp_obj->Name == sampler);
/* This is a bit lazy. Flag out of memory, and then don't bother to
* clean up. Once out of memory is flagged, the only realistic next
* move is to destroy the context. That will trigger all the right
* clean up.
*
* Returning true prevents other GetTexImage methods from attempting
* anything since they will likely fail too.
*/
_mesa_error(ctx, GL_OUT_OF_MEMORY, "glGetTexImage");
return true;
}
_mesa_bind_sampler(ctx, ctx->Texture.CurrentUnit, decompress->samp_obj);
/* nearest filtering */