This looks like a sensible thing to do, but I don't remember all the
details of the vbo module.
Reviewed-by: Marek Olšák <marek.ol...@amd.com>
Marek
On Thu, Oct 15, 2015 at 9:02 PM, Brian Paul <bri...@vmware.com> wrote:
> Whenever we got a glColor, glNormal, glTexCoord, etc. call outside a
> glBegin/End pair, we'd immediately map a vertex buffer to begin
> accumulating vertex data. In some cases, such as with display lists,
> this led to excessive vertex buffer mapping. For example, if we have
> a display list such as:
>
> glNewList(42, GL_COMPILE);
> glBegin(prim);
> glVertex2f();
> ...
> glVertex2f();
> glEnd();
> glEndList();
>
> Then did:
>
> glColor3f();
> glCallList(42);
>
> We'd map a vertex buffer as soon as we saw glColor3f but we'd never
> actually write anything to it. Note that the vertex position data
> was put into a vertex buffer during display list compilation.
>
> With this change, we delay mapping the vertex buffer until we actually
> have a vertex to write to it (triggered by a glVertex() call). In the
> above case, we no longer map a vertex buffer when setting the color and
> calling the list.
>
> For drivers such as VMware's, reducing buffer mappings gives improved
> performance.
> ---
> src/mesa/vbo/vbo_exec_api.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/src/mesa/vbo/vbo_exec_api.c b/src/mesa/vbo/vbo_exec_api.c
> index 7ae08fe..789869a 100644
> --- a/src/mesa/vbo/vbo_exec_api.c
> +++ b/src/mesa/vbo/vbo_exec_api.c
> @@ -446,10 +446,6 @@ do {
> \
> \
> assert(sz == 1 || sz == 2); \
> \
> - if (unlikely(!(ctx->Driver.NeedFlush & FLUSH_UPDATE_CURRENT))) { \
> - vbo_exec_begin_vertices(ctx); \
> - } \
> - \
> /* check if attribute size or type is changing */ \
> if (unlikely(exec->vtx.active_sz[A] != N * sz) || \
> unlikely(exec->vtx.attrtype[A] != T)) { \
> @@ -470,6 +466,15 @@ do {
> \
> /* This is a glVertex call */ \
> GLuint i;
> \
> \
> + if (unlikely((ctx->Driver.NeedFlush & FLUSH_UPDATE_CURRENT) == 0)) { \
> + vbo_exec_begin_vertices(ctx); \
> + } \
> + \
> + if (unlikely(!exec->vtx.buffer_ptr)) { \
> + vbo_exec_vtx_map(exec); \
> + } \
> + assert(exec->vtx.buffer_ptr); \
> + \
> /* copy 32-bit words */ \
> for (i = 0; i < exec->vtx.vertex_size; i++) \
> exec->vtx.buffer_ptr[i] = exec->vtx.vertex[i]; \
> @@ -482,7 +487,10 @@ do {
> \
> \
> if (++exec->vtx.vert_count >= exec->vtx.max_vert)
> \
> vbo_exec_vtx_wrap( exec ); \
> - } \
> + } else { \
> + /* we now have accumulated per-vertex attributes */ \
> + ctx->Driver.NeedFlush |= FLUSH_UPDATE_CURRENT; \
> + } \
> } while (0)
>
> #define ERROR(err) _mesa_error( ctx, err, __func__ )
> --
> 1.9.1
>
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