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 <[email protected]>

1 files changed, 8 insertions, 12 deletions

diff --git a/src/mesa/drivers/x11/xm_dd.c b/src/mesa/drivers/x11/xm_dd.c
index fc0b956743d..c0dcb61e234 100644
--- a/src/mesa/drivers/x11/xm_dd.c
+++ b/src/mesa/drivers/x11/xm_dd.c
@@ -366,12 +366,10 @@ xmesa_DrawPixels_8R8G8B( struct gl_context *ctx,
          buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0,
 						      unpack->BufferObj->Size,
 						      GL_MAP_READ_BIT,
-						      unpack->BufferObj);
+						      unpack->BufferObj,
+                                                      MAP_INTERNAL);
          if (!buf) {
-            /* buffer is already mapped - that's an error */
-            _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawPixels(PBO is mapped)");
-            return;
+            return; /* error */
          }
          pixels = ADD_POINTERS(buf, pixels);
       }
@@ -417,7 +415,7 @@ xmesa_DrawPixels_8R8G8B( struct gl_context *ctx,
       }
 
       if (_mesa_is_bufferobj(unpack->BufferObj)) {
-         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
       }
    }
    else {
@@ -500,12 +498,10 @@ xmesa_DrawPixels_5R6G5B( struct gl_context *ctx,
          buf = (GLubyte *) ctx->Driver.MapBufferRange(ctx, 0,
 						      unpack->BufferObj->Size,
 						      GL_MAP_READ_BIT,
-						      unpack->BufferObj);
+						      unpack->BufferObj,
+                                                      MAP_INTERNAL);
          if (!buf) {
-            /* buffer is already mapped - that's an error */
-            _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "glDrawPixels(PBO is mapped)");
-            return;
+            return; /* error */
          }
          pixels = ADD_POINTERS(buf, pixels);
       }
@@ -550,7 +546,7 @@ xmesa_DrawPixels_5R6G5B( struct gl_context *ctx,
       }
 
       if (unpack->BufferObj->Name) {
-         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj);
+         ctx->Driver.UnmapBuffer(ctx, unpack->BufferObj, MAP_INTERNAL);
       }
    }
    else {