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i965: Configure how to store *64*PASSTHRU vertex components

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From the Broadwell specification, structure VERTEX_ELEMENT_STATE
description:

   "When SourceElementFormat is set to one of the *64*_PASSTHRU
    formats,  64-bit components are stored in the URB without any
    conversion. In this case, vertex elements must be written as 128
    or 256 bits, with VFCOMP_STORE_0 being used to pad the output
    as required. E.g., if R64_PASSTHRU is used to copy a 64-bit Red component into
    the URB, Component 1 must be specified as VFCOMP_STORE_0 (with
    Components 2,3 set to VFCOMP_NOSTORE) in order to output a 128-bit
    vertex element, or Components 1-3 must be specified as VFCOMP_STORE_0
    in order to output a 256-bit vertex element. Likewise, use of
    R64G64B64_PASSTHRU requires Component 3 to be specified as VFCOMP_STORE_0
    in order to output a 256-bit vertex element."

Uses 128-bits to write double and dvec2 vertex elements, and 256-bits for
dvec3 and dvec4 vertex elements.

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Signed-off-by: Antia Puentes <apuentes@igalia.com>

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Antia Puentes 2016-04-15 11:32:46 +02:00 • committed by Alejandro Piñeiro
parent 71150b73c8
commit 8b0a334b5e
1 changed files with 35 additions and 0 deletions
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35
src/mesa/drivers/dri/i965/gen8_draw_upload.c
View file

@ -217,6 +217,41 @@ gen8_emit_vertices(struct brw_context *brw)
break;
}
/* From the BDW PRM, Volume 2d, page 586 (VERTEX_ELEMENT_STATE):
*
* "When SourceElementFormat is set to one of the *64*_PASSTHRU
* formats, 64-bit components are stored in the URB without any
* conversion. In this case, vertex elements must be written as 128
* or 256 bits, with VFCOMP_STORE_0 being used to pad the output
* as required. E.g., if R64_PASSTHRU is used to copy a 64-bit Red
* component into the URB, Component 1 must be specified as
* VFCOMP_STORE_0 (with Components 2,3 set to VFCOMP_NOSTORE)
* in order to output a 128-bit vertex element, or Components 1-3 must
* be specified as VFCOMP_STORE_0 in order to output a 256-bit vertex
* element. Likewise, use of R64G64B64_PASSTHRU requires Component 3
* to be specified as VFCOMP_STORE_0 in order to output a 256-bit vertex
* element."
*/
if (input->glarray->Doubles) {
switch (input->glarray->Size) {
case 0:
case 1:
case 2:
/* Use 128-bits instead of 256-bits to write double and dvec2
* vertex elements.
*/
comp2 = BRW_VE1_COMPONENT_NOSTORE;
comp3 = BRW_VE1_COMPONENT_NOSTORE;
break;
case 3:
/* Pad the output using VFCOMP_STORE_0 as suggested
* by the BDW PRM.
*/
comp3 = BRW_VE1_COMPONENT_STORE_0;
break;
}
}
OUT_BATCH((input->buffer << GEN6_VE0_INDEX_SHIFT) |
GEN6_VE0_VALID |
(format << BRW_VE0_FORMAT_SHIFT) |