[Mesa-dev] [PATCH] st/mesa: improved is_interleaved_arrays() checking

[Jose Fonseca]

Looks good Brian.

BTW, does detecting interleaved arrays still provide any advantage for current HW drivers?

Jose

----- Original Message -----
> Check that the difference in array pointers/offsets from the 0th
> array are less than the stride, for both VBOs and user-space arrays.
> Previously, we were only doing this for the later.
> 
> This tightens up the interleaved array test and fixes a problem with
> the llvmpipe driver where we were creating way too many vertex fetch
> variants only because the pipe_vertex_element::src_offset values were
> changing frequently.  This change results in a 5x speed-up for one of
> the viewperf tests.
> 
> Also, clean up the function to make it easier to understand.
> ---
>  src/mesa/state_tracker/st_draw.c |   50
>  ++++++++++++++-----------------------
>  1 files changed, 19 insertions(+), 31 deletions(-)
> 
> diff --git a/src/mesa/state_tracker/st_draw.c
> b/src/mesa/state_tracker/st_draw.c
> index dd26db2..1bb9b80 100644
> --- a/src/mesa/state_tracker/st_draw.c
> +++ b/src/mesa/state_tracker/st_draw.c
> @@ -237,7 +237,6 @@ st_pipe_vertex_format(GLenum type, GLuint size,
> GLenum format,
>  /**
>   * Examine the active arrays to determine if we have interleaved
>   * vertex arrays all living in one VBO, or all living in user space.
> - * \param userSpace  returns whether the arrays are in user space.
>   */
>  static GLboolean
>  is_interleaved_arrays(const struct st_vertex_program *vp,
> @@ -247,8 +246,8 @@ is_interleaved_arrays(const struct
> st_vertex_program *vp,
>     GLuint attr;
>     const struct gl_buffer_object *firstBufObj = NULL;
>     GLint firstStride = -1;
> -   const GLubyte *client_addr = NULL;
> -   GLboolean user_memory = GL_FALSE;
> +   const GLubyte *firstPtr = NULL;
> +   GLboolean userSpaceBuffer = GL_FALSE;
>  
>     for (attr = 0; attr < vpv->num_inputs; attr++) {
>        const GLuint mesaAttr = vp->index_to_input[attr];
> @@ -256,37 +255,26 @@ is_interleaved_arrays(const struct
> st_vertex_program *vp,
>        const struct gl_buffer_object *bufObj = array->BufferObj;
>        const GLsizei stride = array->StrideB; /* in bytes */
>  
> -      if (firstStride < 0) {
> +      if (attr == 0) {
> +         /* save info about the first array */
>           firstStride = stride;
> -         user_memory = !bufObj || !bufObj->Name;
> -      }
> -      else if (firstStride != stride) {
> -         return GL_FALSE;
> -      }
> -
> -      if (!bufObj || !bufObj->Name) {
> -         /* Try to detect if the client-space arrays are
> -          * "close" to each other.
> -          */
> -         if (!user_memory) {
> -            return GL_FALSE;
> -         }
> -         if (!client_addr) {
> -            client_addr = array->Ptr;
> -         }
> -         else if (abs(array->Ptr - client_addr) > firstStride) {
> -            /* arrays start too far apart */
> -            return GL_FALSE;
> -         }
> -      }
> -      else if (!firstBufObj) {
> -         if (user_memory) {
> -            return GL_FALSE;
> -         }
> +         firstPtr = array->Ptr;
>           firstBufObj = bufObj;
> +         userSpaceBuffer = !bufObj || !bufObj->Name;
>        }
> -      else if (bufObj != firstBufObj) {
> -         return GL_FALSE;
> +      else {
> +         /* check if other arrays interleave with the first, in same
> buffer */
> +         if (stride != firstStride)
> +            return GL_FALSE; /* strides don't match */
> +
> +         if (bufObj != firstBufObj)
> +            return GL_FALSE; /* arrays in different VBOs */
> +
> +         if (abs(array->Ptr - firstPtr) > firstStride)
> +            return GL_FALSE; /* arrays start too far apart */
> +
> +         if ((!bufObj || !_mesa_is_bufferobj(bufObj)) !=
> userSpaceBuffer)
> +            return GL_FALSE; /* mix of VBO and user-space arrays */
>        }
>     }
>  
> --
> 1.7.3.4
> 
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