[Mesa-dev] [PATCH 10/10] vbo: convert display list GL_LINE_LOOP prims to GL_LINE_STRIP

[Sinclair Yeh]

Acked-by: Sinclair Yeh <syeh at vmware.com>


On Fri, Oct 16, 2015 at 03:25:17PM -0600, Brian Paul wrote:
> When a long GL_LINE_LOOP prim was split across primitives we drew
> stray lines.  See previous commit for details.
> 
> This patch converts GL_LINE_LOOP prims into GL_LINE_STRIP prims so
> that drivers don't have to worry about the _mesa_prim::begin/end flags.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81174
> ---
>  src/mesa/vbo/vbo_save_api.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/src/mesa/vbo/vbo_save_api.c b/src/mesa/vbo/vbo_save_api.c
> index 6688ba0..d49aa15 100644
> --- a/src/mesa/vbo/vbo_save_api.c
> +++ b/src/mesa/vbo/vbo_save_api.c
> @@ -360,6 +360,51 @@ merge_prims(struct _mesa_prim *prim_list,
>     *prim_count = prev_prim - prim_list + 1;
>  }
>  
> +
> +/**
> + * Convert GL_LINE_LOOP primitive into GL_LINE_STRIP so that drivers
> + * don't have to worry about handling the _mesa_prim::begin/end flags.
> + * See https://bugs.freedesktop.org/show_bug.cgi?id=81174
> + */
> +static void
> +convert_line_loop_to_strip(struct vbo_save_context *save,
> +                           struct vbo_save_vertex_list *node)
> +{
> +   struct _mesa_prim *prim = &node->prim[node->prim_count - 1];
> +
> +   assert(prim->mode == GL_LINE_LOOP);
> +
> +   if (prim->end) {
> +      /* Copy the 0th vertex to end of the buffer and extend the
> +       * vertex count by one to finish the line loop.
> +       */
> +      const GLuint sz = save->vertex_size;
> +      /* 0th vertex: */
> +      const fi_type *src = save->buffer + prim->start * sz;
> +      /* end of buffer: */
> +      fi_type *dst = save->buffer + (prim->start + prim->count) * sz;
> +
> +      memcpy(dst, src, sz * sizeof(float));
> +
> +      prim->count++;
> +      node->count++;
> +      save->vert_count++;
> +      save->buffer_ptr += sz;
> +      save->vertex_store->used += sz;
> +   }
> +
> +   if (!prim->begin) {
> +      /* Drawing the second or later section of a long line loop.
> +       * Skip the 0th vertex.
> +       */
> +      prim->start++;
> +      prim->count--;
> +   }
> +
> +   prim->mode = GL_LINE_STRIP;
> +}
> +
> +
>  /**
>   * Insert the active immediate struct onto the display list currently
>   * being built.
> @@ -441,6 +486,10 @@ _save_compile_vertex_list(struct gl_context *ctx)
>      */
>     save->copied.nr = _save_copy_vertices(ctx, node, save->buffer);
>  
> +   if (node->prim[node->prim_count - 1].mode == GL_LINE_LOOP) {
> +      convert_line_loop_to_strip(save, node);
> +   }
> +
>     merge_prims(node->prim, &node->prim_count);
>  
>     /* Deal with GL_COMPILE_AND_EXECUTE:
> @@ -482,6 +531,10 @@ _save_compile_vertex_list(struct gl_context *ctx)
>        save->buffer_ptr = vbo_save_map_vertex_store(ctx, save->vertex_store);
>        save->out_of_memory = save->buffer_ptr == NULL;
>     }
> +   else {
> +      /* update buffer_ptr for next vertex */
> +      save->buffer_ptr = save->vertex_store->buffer + save->vertex_store->used;
> +   }
>  
>     if (save->prim_store->used > VBO_SAVE_PRIM_SIZE - 6) {
>        save->prim_store->refcount--;
> -- 
> 1.9.1
>