[Mesa-dev] [PATCH] swr: fix transform feedback logic
Ilia Mirkin
imirkin at alum.mit.edu
Sun Jul 23 18:51:30 UTC 2017
On Sun, Jul 23, 2017 at 12:27 PM, Kyriazis, George
<george.kyriazis at intel.com> wrote:
>
> On Jul 23, 2017, at 11:21 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>
> On Sun, Jul 23, 2017 at 12:08 PM, George Kyriazis
> <george.kyriazis at intel.com> wrote:
>
> The shader that is used to copy vertex data out of the vs/gs shaders to
> the user-specified buffer (streamout os SO shader) was not using the
> correct offsets.
>
> Adjust the offsets that are used just for the SO shader:
> - Make sure that position is handled in the same special way
> as in the vs/gs shaders
> - Use the correct offset to be passed in the core
> - consolidate register slot mapping logic into one function, since it's
> been calculated in 2 different places (one for calcuating the slot mask,
> and one for the register offsets themselves
>
> Also make room for all attibutes in the backend vertex area.
>
> Fixes:
> - all vtk GL2PS tests
> - 18 piglit tests (16 ext_transform_feedback tests,
> arb-quads-follow-provoking-vertex and primitive-type gl_points
> ---
> src/gallium/drivers/swr/swr_draw.cpp | 11 ++++++++---
> src/gallium/drivers/swr/swr_state.cpp | 31 +++++++++++++++++++++++++++++--
> src/gallium/drivers/swr/swr_state.h | 3 +++
> 3 files changed, 40 insertions(+), 5 deletions(-)
>
> diff --git a/src/gallium/drivers/swr/swr_draw.cpp
> b/src/gallium/drivers/swr/swr_draw.cpp
> index 62ad3f7..218de0f 100644
> --- a/src/gallium/drivers/swr/swr_draw.cpp
> +++ b/src/gallium/drivers/swr/swr_draw.cpp
> @@ -26,6 +26,7 @@
> #include "swr_resource.h"
> #include "swr_fence.h"
> #include "swr_query.h"
> +#include "swr_state.h"
> #include "jit_api.h"
>
> #include "util/u_draw.h"
> @@ -81,8 +82,11 @@ swr_draw_vbo(struct pipe_context *pipe, const struct
> pipe_draw_info *info)
> offsets[output_buffer] = so->output[i].dst_offset;
> }
>
> + unsigned attrib_slot = so->output[i].register_index;
> + attrib_slot = swr_so_adjust_attrib(attrib_slot, ctx->vs);
> +
> state.stream.decl[num].bufferIndex = output_buffer;
> - state.stream.decl[num].attribSlot =
> so->output[i].register_index - 1;
> + state.stream.decl[num].attribSlot = attrib_slot;
> state.stream.decl[num].componentMask =
> ((1 << so->output[i].num_components) - 1)
> << so->output[i].start_component;
> @@ -130,9 +134,10 @@ swr_draw_vbo(struct pipe_context *pipe, const struct
> pipe_draw_info *info)
> SWR_FRONTEND_STATE feState = {0};
>
> feState.vsVertexSize =
> - VERTEX_ATTRIB_START_SLOT +
> + VERTEX_ATTRIB_START_SLOT
> + ctx->vs->info.base.num_outputs
> - - (ctx->vs->info.base.writes_position ? 1 : 0);
> + - (ctx->vs->info.base.writes_position ? 1 : 0)
> + + ctx->fs->info.base.num_outputs;
Why do you care about the number of fs outputs in the vertex size?
>
> if (ctx->rasterizer->flatshade_first) {
> feState.provokingVertex = {1, 0, 0};
> diff --git a/src/gallium/drivers/swr/swr_state.cpp
> b/src/gallium/drivers/swr/swr_state.cpp
> index 501fdea..3e07929 100644
> --- a/src/gallium/drivers/swr/swr_state.cpp
> +++ b/src/gallium/drivers/swr/swr_state.cpp
> @@ -345,13 +345,15 @@ swr_create_vs_state(struct pipe_context *pipe,
> // soState.streamToRasterizer not used
>
> for (uint32_t i = 0; i < stream_output->num_outputs; i++) {
> + unsigned attrib_slot = stream_output->output[i].register_index;
> + attrib_slot = swr_so_adjust_attrib(attrib_slot, swr_vs);
> swr_vs->soState.streamMasks[stream_output->output[i].stream] |=
> - 1 << (stream_output->output[i].register_index - 1);
> + (1 << attrib_slot);
> }
> for (uint32_t i = 0; i < MAX_SO_STREAMS; i++) {
> swr_vs->soState.streamNumEntries[i] =
> _mm_popcnt_u32(swr_vs->soState.streamMasks[i]);
> - swr_vs->soState.vertexAttribOffset[i] = VERTEX_ATTRIB_START_SLOT;
> // TODO: optimize
> + swr_vs->soState.vertexAttribOffset[i] = 0;
> }
> }
>
> @@ -1777,6 +1779,31 @@ swr_update_derived(struct pipe_context *pipe,
> ctx->dirty = post_update_dirty_flags;
> }
>
> +unsigned
> +swr_so_adjust_attrib(unsigned in_attrib,
> + swr_vertex_shader *swr_vs)
> +{
> + ubyte semantic_name;
> + unsigned attrib;
> +
> + attrib = in_attrib + VERTEX_ATTRIB_START_SLOT;
> +
> + if (swr_vs) {
> + semantic_name = swr_vs->info.base.output_semantic_name[in_attrib];
> + if (semantic_name == TGSI_SEMANTIC_POSITION) {
>
>
> But it's not just the position... there are plenty of other attributes
> that need similar treatment. e.g. pointsize, layer, viewport index.
>
>
> Yes, we want to deal with the other attributes, too, but lack the testing
> time, due to the 17.2 schedule. Since position fixes the vtk tests (that we
> are mostly concerned about), that is what this patch covers. It’s in our
> plan to deal with the rest of the attributes in the near future (before we
> get distracted).
OK, well your guys's call on how to tackle all this. I somewhat hate
partial solutions, but I realize you have more tangible goals than
'perfection'.
Either way ... doesn't this all break if there's a geometry shader?
You're only ever looking at the VS, not at the last pre-rast stage
(which might be GS, TES, or VS). I believe that TF currently works for
GS, and you're going to be adjusting GS output attrib positions based
on VS output indices. [Note that my change was written before GS was a
thing in swr, so it also doesn't take this into account.]
>
> I tried to fix this a while back but IIRC my solution was left wanting:
>
> https://github.com/imirkin/mesa/commits/swr
>
> (see the WIP commits at the top).
>
> I ended up getting distracted and never completed the work. Feel free
> to copy/ignore/whatever the above commits. I also tried to provide a
> ARB_tf2 impl as well (i.e. pause/resume).
>
> + attrib = VERTEX_POSITION_SLOT;
> + } else {
> + for (int i = 0; i < PIPE_MAX_SHADER_OUTPUTS; i++) {
> + if (swr_vs->info.base.output_semantic_name[i] ==
> TGSI_SEMANTIC_POSITION) {
> + attrib--;
> + break;
> + }
> + }
> + }
> + }
> +
> + return attrib;
> +}
>
> static struct pipe_stream_output_target *
> swr_create_so_target(struct pipe_context *pipe,
> diff --git a/src/gallium/drivers/swr/swr_state.h
> b/src/gallium/drivers/swr/swr_state.h
> index 7940a96..8cbd463 100644
> --- a/src/gallium/drivers/swr/swr_state.h
> +++ b/src/gallium/drivers/swr/swr_state.h
> @@ -110,6 +110,9 @@ struct swr_derived_state {
> void swr_update_derived(struct pipe_context *,
> const struct pipe_draw_info * = nullptr);
>
> +unsigned swr_so_adjust_attrib(unsigned in_attrib,
> + swr_vertex_shader *swr_vs);
> +
> /*
> * Conversion functions: Convert mesa state defines to SWR.
> */
> --
> 2.7.4
>
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