[PATCH 1/5] wined3d: Respect the BO memory offset for vertex buffers.

[Henri Verbeet]

On Thu, 18 Nov 2021 at 01:09, Zebediah Figura <zfigura at codeweavers.com> wrote:
> @@ -5123,12 +5123,12 @@ void wined3d_context_gl_load_tex_coords(const struct wined3d_context_gl *context
>              TRACE("Setting up texture %u, idx %u, coord_idx %u, data %s.\n",
>                      texture_idx, mapped_stage, coord_idx, debug_bo_address(&e->data));
>
> -            bo = wined3d_bo_gl_id(e->data.buffer_object);
> -            if (*current_bo != bo)
> +            bo_gl = wined3d_bo_gl(e->data.buffer_object);
> +            if (*current_bo != bo_gl->id)
>              {
I think "e->data.buffer_object" can be NULL here.

> @@ -5137,7 +5137,7 @@ void wined3d_context_gl_load_tex_coords(const struct wined3d_context_gl *context
>              /* The coords to supply depend completely on the fvf/vertex shader. */
>              format_gl = wined3d_format_gl(e->format);
>              gl_info->gl_ops.gl.p_glTexCoordPointer(format_gl->vtx_format, format_gl->vtx_type, e->stride,
> -                    e->data.addr + state->load_base_vertex_index * e->stride);
> +                    bo_gl->b.memory_offset + e->data.addr + state->load_base_vertex_index * e->stride);

I think it's a little unfortunate to use "memory_offset" here. (And I
don't think the original version of these patches did that.) The
"memory_offset" field contains the offset from the start of the
underlying memory allocation (i.e., VkDeviceMemory in Vulkan), while
"buffer_offset" is the offset from the start of the buffer object
(i.e., VkBuffer in Vulkan). We're addressing relative to the buffer
object here.

Of course, in OpenGL, these are generally the same. (But, note that
GL_EXT_memory_object exists.) For clarity though, it seems preferable
to use these in a consistent way between the Vulkan and GL backends.