mesa: allow buffers to be mapped multiple times

OpenGL allows a buffer to be mapped only once, but we also map buffers
internally, e.g. in the software primitive restart fallback, for PBOs,
vbo_get_minmax_index, etc. This has always been a problem, but it will
be a bigger problem with persistent buffer mappings, which will prevent
all Mesa functions from mapping buffers for internal purposes.

This adds a driver interface to core Mesa which supports multiple buffer
mappings and allows 2 mappings: one for the GL user and one for Mesa.

Note that Gallium supports an unlimited number of buffer and texture
mappings, so it's not really an issue for Gallium.

v2: fix unmapping in xm_dd.c, remove the GL errors there
v3: fix the intel driver (by Fredrik)

Reviewed-by: Fredrik Höglund <fredrik@kde.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/mesa/vbo/vbo_rebase.c b/src/mesa/vbo/vbo_rebase.c
index c700621..f3fe5f7 100644
--- a/src/mesa/vbo/vbo_rebase.c
+++ b/src/mesa/vbo/vbo_rebase.c
@@ -157,15 +157,16 @@ void vbo_rebase_prims( struct gl_context *ctx,
    } else if (ib) {
       /* Unfortunately need to adjust each index individually.
        */
-      GLboolean map_ib = ib->obj->Name && !ib->obj->Pointer;
+      GLboolean map_ib = ib->obj->Name &&
+                         !ib->obj->Mappings[MAP_INTERNAL].Pointer;
       void *ptr;
 
       if (map_ib) 
 	 ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
-				    ib->obj);
+				    ib->obj, MAP_INTERNAL);
 
 
-      ptr = ADD_POINTERS(ib->obj->Pointer, ib->ptr);
+      ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
 
       /* Some users might prefer it if we translated elements to
        * GLuints here.  Others wouldn't...
@@ -183,7 +184,7 @@ void vbo_rebase_prims( struct gl_context *ctx,
       }      
 
       if (map_ib) 
-	 ctx->Driver.UnmapBuffer(ctx, ib->obj);
+	 ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
 
       tmp_ib.obj = ctx->Shared->NullBufferObj;
       tmp_ib.ptr = tmp_indices;