mesa: Set default access flags based on the run-time API

The default access flags for OpenGL ES (via GL_OES_map_buffer) and
desktop OpenGL are different.  The code previously tried to handle
this, but the decision was made at compile time.  Since the same
driver binary can be used for both OpenGL ES and desktop OpenGL, the
decision must be made at run-time.

This should fix bug #44433.  It appears that the test case does
various map and unmap operations and inspects the state of the buffer
object around each.  When it sees that GL_BUFFER_ACCESS does not match
its expectations, it fails.

NOTE: This is a candidate for release branches.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Brian Paul <[email protected]>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44433

2 files changed, 33 insertions, 14 deletions

diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 5f8071f587f..5b6db78d821 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -49,13 +49,6 @@
 /*#define BOUNDS_CHECK*/
 
 
-#if FEATURE_OES_mapbuffer
-#define DEFAULT_ACCESS GL_MAP_WRITE_BIT
-#else
-#define DEFAULT_ACCESS (GL_MAP_READ_BIT | GL_MAP_WRITE_BIT)
-#endif
-
-
 /**
  * Used as a placeholder for buffer objects between glGenBuffers() and
  * glBindBuffer() so that glIsBuffer() can work correctly.
@@ -122,6 +115,30 @@ get_buffer(struct gl_context *ctx, GLenum target)
 }
 
 
+static inline GLenum
+default_access_mode(const struct gl_context *ctx)
+{
+   /* Table 2.6 on page 31 (page 44 of the PDF) of the OpenGL 1.5 spec says:
+    *
+    * Name           Type  Initial Value  Legal Values
+    * ...            ...   ...            ...
+    * BUFFER_ACCESS  enum  READ_WRITE     READ_ONLY, WRITE_ONLY
+    *                                     READ_WRITE
+    *
+    * However, table 6.8 in the GL_OES_mapbuffer extension says:
+    *
+    * Get Value         Type Get Command          Value          Description
+    * ---------         ---- -----------          -----          -----------
+    * BUFFER_ACCESS_OES Z1   GetBufferParameteriv WRITE_ONLY_OES buffer map flag
+    *
+    * The difference is because GL_OES_mapbuffer only supports mapping buffers
+    * write-only.
+    */
+   return (ctx->API == API_OPENGLES)
+      ? GL_MAP_WRITE_BIT : (GL_MAP_READ_BIT | GL_MAP_WRITE_BIT);
+}
+
+
 /**
  * Convert a GLbitfield describing the mapped buffer access flags
  * into one of GL_READ_WRITE, GL_READ_ONLY, or GL_WRITE_ONLY.
@@ -213,7 +230,7 @@ _mesa_new_buffer_object( struct gl_context *ctx, GLuint name, GLenum target )
    (void) ctx;
 
    obj = MALLOC_STRUCT(gl_buffer_object);
-   _mesa_initialize_buffer_object(obj, name, target);
+   _mesa_initialize_buffer_object(ctx, obj, name, target);
    return obj;
 }
 
@@ -311,7 +328,8 @@ _mesa_reference_buffer_object_(struct gl_context *ctx,
  * Initialize a buffer object to default values.
  */
 void
-_mesa_initialize_buffer_object( struct gl_buffer_object *obj,
+_mesa_initialize_buffer_object( struct gl_context *ctx,
+				struct gl_buffer_object *obj,
 				GLuint name, GLenum target )
 {
    (void) target;
@@ -321,7 +339,7 @@ _mesa_initialize_buffer_object( struct gl_buffer_object *obj,
    obj->RefCount = 1;
    obj->Name = name;
    obj->Usage = GL_STATIC_DRAW_ARB;
-   obj->AccessFlags = DEFAULT_ACCESS;
+   obj->AccessFlags = default_access_mode(ctx);
 }
 
 
@@ -740,7 +758,7 @@ _mesa_DeleteBuffersARB(GLsizei n, const GLuint *ids)
          if (_mesa_bufferobj_mapped(bufObj)) {
             /* if mapped, unmap it now */
             ctx->Driver.UnmapBuffer(ctx, bufObj);
-            bufObj->AccessFlags = DEFAULT_ACCESS;
+            bufObj->AccessFlags = default_access_mode(ctx);
             bufObj->Pointer = NULL;
          }
 
@@ -900,7 +918,7 @@ _mesa_BufferDataARB(GLenum target, GLsizeiptrARB size,
    if (_mesa_bufferobj_mapped(bufObj)) {
       /* Unmap the existing buffer.  We'll replace it now.  Not an error. */
       ctx->Driver.UnmapBuffer(ctx, bufObj);
-      bufObj->AccessFlags = DEFAULT_ACCESS;
+      bufObj->AccessFlags = default_access_mode(ctx);
       ASSERT(bufObj->Pointer == NULL);
    }  
 
@@ -1119,7 +1137,7 @@ _mesa_UnmapBufferARB(GLenum target)
 #endif
 
    status = ctx->Driver.UnmapBuffer( ctx, bufObj );
-   bufObj->AccessFlags = DEFAULT_ACCESS;
+   bufObj->AccessFlags = default_access_mode(ctx);
    ASSERT(bufObj->Pointer == NULL);
    ASSERT(bufObj->Offset == 0);
    ASSERT(bufObj->Length == 0);
diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
index c0d5a641a46..a7ce3792898 100644
--- a/src/mesa/main/bufferobj.h
+++ b/src/mesa/main/bufferobj.h
@@ -71,7 +71,8 @@ extern struct gl_buffer_object *
 _mesa_lookup_bufferobj(struct gl_context *ctx, GLuint buffer);
 
 extern void
-_mesa_initialize_buffer_object( struct gl_buffer_object *obj,
+_mesa_initialize_buffer_object( struct gl_context *ctx,
+				struct gl_buffer_object *obj,
 				GLuint name, GLenum target );
 
 extern void