[Mesa-dev] [PATCH 08/18] meta/blit: Don't pollute the sampler object namespace in _mesa_meta_setup_sampler

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

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 at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92363
---
 src/mesa/drivers/common/meta_blit.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c
index fc4c87a..9191163 100644
--- a/src/mesa/drivers/common/meta_blit.c
+++ b/src/mesa/drivers/common/meta_blit.c
@@ -840,8 +840,7 @@ _mesa_meta_fb_tex_blit_end(struct gl_context *ctx, GLenum target,
 
    _mesa_bind_sampler(ctx, ctx->Texture.CurrentUnit, blit->samp_obj_save);
    _mesa_reference_sampler_object(ctx, &blit->samp_obj_save, NULL);
-   _mesa_DeleteSamplers(1, &blit->samp_obj->Name);
-   blit->samp_obj = NULL;
+   _mesa_reference_sampler_object(ctx, &blit->samp_obj, NULL);
 
    if (blit->tempTex)
       _mesa_DeleteTextures(1, &blit->tempTex);
@@ -891,16 +890,14 @@ _mesa_meta_setup_sampler(struct gl_context *ctx,
                          const struct gl_texture_object *texObj,
                          GLenum target, GLenum filter, GLuint srcLevel)
 {
-   GLuint sampler;
    struct gl_sampler_object *samp_obj;
    GLenum tex_filter = (filter == GL_SCALED_RESOLVE_FASTEST_EXT ||
                         filter == GL_SCALED_RESOLVE_NICEST_EXT) ?
                        GL_NEAREST : filter;
 
-   _mesa_GenSamplers(1, &sampler);
-
-   samp_obj = _mesa_lookup_samplerobj(ctx, sampler);
-   assert(samp_obj != NULL && samp_obj->Name == sampler);
+   samp_obj =  ctx->Driver.NewSamplerObject(ctx, 0xDEADBEEF);
+   if (samp_obj == NULL)
+      return NULL;
 
    _mesa_bind_sampler(ctx, ctx->Texture.CurrentUnit, samp_obj);
    _mesa_set_sampler_filters(ctx, samp_obj, tex_filter, tex_filter);
-- 
2.5.0