[Mesa-dev] [PATCH 5/5] draw: implement distance culling
Zack Rusin
zackr at vmware.com
Tue Jun 11 14:26:52 PDT 2013
Thanks a lot for the reviews Brian!
----- Original Message -----
> On 06/10/2013 08:31 AM, Zack Rusin wrote:
> > Works similarly to clip distance. If the cull distance is negative
> > for all vertices against a specific plane then the primitive
> > is culled.
> >
> > Signed-off-by: Zack Rusin <zackr at vmware.com>
> > ---
> > src/gallium/auxiliary/draw/draw_context.c | 17 ++++
> > src/gallium/auxiliary/draw/draw_gs.c | 6 ++
> > src/gallium/auxiliary/draw/draw_gs.h | 1 +
> > src/gallium/auxiliary/draw/draw_pipe_cull.c | 124
> > ++++++++++++++++++-----
> > src/gallium/auxiliary/draw/draw_pipe_validate.c | 11 +-
> > src/gallium/auxiliary/draw/draw_private.h | 2 +
> > src/gallium/auxiliary/draw/draw_vs.c | 5 +
> > src/gallium/auxiliary/draw/draw_vs.h | 1 +
> > 8 files changed, 137 insertions(+), 30 deletions(-)
> >
> > diff --git a/src/gallium/auxiliary/draw/draw_context.c
> > b/src/gallium/auxiliary/draw/draw_context.c
> > index e8480f6..470e7ac 100644
> > --- a/src/gallium/auxiliary/draw/draw_context.c
> > +++ b/src/gallium/auxiliary/draw/draw_context.c
> > @@ -751,6 +751,23 @@ draw_current_shader_num_written_clipdistances(const
> > struct draw_context *draw)
> > return draw->vs.vertex_shader->info.num_written_clipdistance;
> > }
> >
> > +
> > +uint
> > +draw_current_shader_culldistance_output(const struct draw_context *draw,
> > int index)
> > +{
> > + if (draw->gs.geometry_shader)
> > + return draw->gs.geometry_shader->culldistance_output[index];
> > + return draw->vs.vertex_shader->culldistance_output[index];
> > +}
> > +
> > +uint
> > +draw_current_shader_num_written_culldistances(const struct draw_context
> > *draw)
> > +{
> > + if (draw->gs.geometry_shader)
> > + return draw->gs.geometry_shader->info.num_written_culldistance;
> > + return draw->vs.vertex_shader->info.num_written_culldistance;
> > +}
> > +
> > /**
> > * Return a pointer/handle for a driver/CSO rasterizer object which
> > * disabled culling, stippling, unfilled tris, etc.
> > diff --git a/src/gallium/auxiliary/draw/draw_gs.c
> > b/src/gallium/auxiliary/draw/draw_gs.c
> > index 74c6279..dc1298d 100644
> > --- a/src/gallium/auxiliary/draw/draw_gs.c
> > +++ b/src/gallium/auxiliary/draw/draw_gs.c
> > @@ -797,6 +797,12 @@ draw_create_geometry_shader(struct draw_context *draw,
> > else
> > gs->clipdistance_output[1] = i;
> > }
> > + if (gs->info.output_semantic_name[i] == TGSI_SEMANTIC_CULLDIST) {
> > + if (gs->info.output_semantic_index[i] == 0)
> > + gs->culldistance_output[0] = i;
> > + else
> > + gs->culldistance_output[1] = i;
> > + }
> > }
> >
> > gs->machine = draw->gs.tgsi.machine;
> > diff --git a/src/gallium/auxiliary/draw/draw_gs.h
> > b/src/gallium/auxiliary/draw/draw_gs.h
> > index 543b32d..05d666d 100644
> > --- a/src/gallium/auxiliary/draw/draw_gs.h
> > +++ b/src/gallium/auxiliary/draw/draw_gs.h
> > @@ -68,6 +68,7 @@ struct draw_geometry_shader {
> > unsigned position_output;
> > unsigned viewport_index_output;
> > unsigned clipdistance_output[2];
> > + unsigned culldistance_output[2];
> >
> > unsigned max_output_vertices;
> > unsigned primitive_boundary;
> > diff --git a/src/gallium/auxiliary/draw/draw_pipe_cull.c
> > b/src/gallium/auxiliary/draw/draw_pipe_cull.c
> > index 2f4d01d..2636ffb 100644
> > --- a/src/gallium/auxiliary/draw/draw_pipe_cull.c
> > +++ b/src/gallium/auxiliary/draw/draw_pipe_cull.c
> > @@ -33,6 +33,7 @@
> > */
> >
> >
> > +#include "util/u_math.h"
> > #include "util/u_memory.h"
> > #include "pipe/p_defines.h"
> > #include "draw_pipe.h"
> > @@ -51,42 +52,109 @@ static INLINE struct cull_stage *cull_stage( struct
> > draw_stage *stage )
> > }
> >
> >
> > +
>
>
> Could you put a comment on this function explaining that it implements
> the culldistance feature?
>
>
> > +static void cull_line( struct draw_stage *stage,
> > + struct prim_header *header )
> > +{
> > + const unsigned num_written_culldistances =
> > + draw_current_shader_num_written_culldistances(stage->draw);
> > +
> > + if (num_written_culldistances) {
> > + unsigned i;
> > + boolean culled = FALSE;
> > + for (i = 0; i < num_written_culldistances; ++i) {
> > + unsigned cull_idx = (i >= 4) ? 1 : 0;
>
> In case there's ever more cull distances, could that be
> unsigned cull_idx = i / 4;
>
>
> > + unsigned out_idx =
> > + draw_current_shader_culldistance_output(stage->draw,
> > cull_idx);
> > + unsigned idx = i % 4;
> > + float cull1 = header->v[0]->data[out_idx][idx];
> > + float cull2 = header->v[1]->data[out_idx][idx];
> > + boolean vert1_out = (cull1 < 0) || util_is_inf_or_nan(cull1);
> > + boolean vert2_out = (cull2 < 0) || util_is_inf_or_nan(cull2);
>
> s/0/0.0f/ to silence potential MSVC warnings.
>
>
> > + if (vert1_out && vert2_out)
> > + culled = TRUE;
> > + }
> > + if (!culled)
> > + stage->next->line( stage->next, header );
> > + }
> > +}
> > +
>
>
> Any a comment for this function saying it does conventional
> front/back-face culling plus culldistance?
>
>
> > static void cull_tri( struct draw_stage *stage,
> > struct prim_header *header )
> > {
> > - const unsigned pos = draw_current_shader_position_output(stage->draw);
> > -
> > - /* Window coords: */
> > - const float *v0 = header->v[0]->data[pos];
> > - const float *v1 = header->v[1]->data[pos];
> > - const float *v2 = header->v[2]->data[pos];
> > -
> > - /* edge vectors: e = v0 - v2, f = v1 - v2 */
> > - const float ex = v0[0] - v2[0];
> > - const float ey = v0[1] - v2[1];
> > - const float fx = v1[0] - v2[0];
> > - const float fy = v1[1] - v2[1];
> > + const unsigned num_written_culldistances =
> > + draw_current_shader_num_written_culldistances(stage->draw);
> > +
> > + if (num_written_culldistances) {
> > + unsigned i;
> > + boolean culled = FALSE;
> > + for (i = 0; i < num_written_culldistances; ++i) {
> > + unsigned cull_idx = (i >= 4) ? 1 : 0;
>
> Same as above.
>
>
> > + unsigned out_idx =
> > + draw_current_shader_culldistance_output(stage->draw,
> > cull_idx);
> > + unsigned idx = i % 4;
> > + float cull1 = header->v[0]->data[out_idx][idx];
> > + float cull2 = header->v[1]->data[out_idx][idx];
> > + float cull3 = header->v[2]->data[out_idx][idx];
> > + boolean vert1_out = (cull1 < 0) || util_is_inf_or_nan(cull1);
> > + boolean vert2_out = (cull2 < 0) || util_is_inf_or_nan(cull2);
> > + boolean vert3_out = (cull3 < 0) || util_is_inf_or_nan(cull3);
>
> 0.0f
>
> > + if (vert1_out && vert2_out && vert3_out)
> > + culled = TRUE;
> > + }
> > + if (!culled)
> > + stage->next->line( stage->next, header );
> > + } else {
> > + const unsigned pos =
> > draw_current_shader_position_output(stage->draw);
> > + /* Window coords: */
> > + const float *v0 = header->v[0]->data[pos];
> > + const float *v1 = header->v[1]->data[pos];
> > + const float *v2 = header->v[2]->data[pos];
> > +
> > + /* edge vectors: e = v0 - v2, f = v1 - v2 */
> > + const float ex = v0[0] - v2[0];
> > + const float ey = v0[1] - v2[1];
> > + const float fx = v1[0] - v2[0];
> > + const float fy = v1[1] - v2[1];
> > +
> >
> > - /* det = cross(e,f).z */
> > - header->det = ex * fy - ey * fx;
> > -
> > - if (header->det != 0) {
> > - /* if det < 0 then Z points toward the camera and the triangle is
> > - * counter-clockwise winding.
> > - */
> > - unsigned ccw = (header->det < 0);
> > - unsigned face = ((ccw == cull_stage(stage)->front_ccw) ?
> > - PIPE_FACE_FRONT :
> > - PIPE_FACE_BACK);
> > -
> > - if ((face & cull_stage(stage)->cull_face) == 0) {
> > - /* triangle is not culled, pass to next stage */
> > - stage->next->tri( stage->next, header );
> > + /* det = cross(e,f).z */
> > + header->det = ex * fy - ey * fx;
> > +
> > + if (header->det != 0) {
> > + /* if det < 0 then Z points toward the camera and the triangle is
> > + * counter-clockwise winding.
> > + */
> > + unsigned ccw = (header->det < 0);
> > + unsigned face = ((ccw == cull_stage(stage)->front_ccw) ?
> > + PIPE_FACE_FRONT :
> > + PIPE_FACE_BACK);
> > +
> > + if ((face & cull_stage(stage)->cull_face) == 0) {
> > + /* triangle is not culled, pass to next stage */
> > + stage->next->tri( stage->next, header );
> > + }
> > }
> > }
> > }
> >
> >
> > +
> > +static void cull_first_line( struct draw_stage *stage,
> > + struct prim_header *header )
> > +{
> > + const unsigned num_written_culldistances =
> > + draw_current_shader_num_written_culldistances(stage->draw);
> > +
> > + if (num_written_culldistances) {
> > + stage->line = cull_line;
> > + stage->line( stage, header );
> > + } else {
> > + stage->line = draw_pipe_passthrough_line;
> > + stage->line( stage, header );
> > + }
> > +}
> > +
> > static void cull_first_tri( struct draw_stage *stage,
> > struct prim_header *header )
> > {
> > @@ -133,7 +201,7 @@ struct draw_stage *draw_cull_stage( struct draw_context
> > *draw )
> > cull->stage.name = "cull";
> > cull->stage.next = NULL;
> > cull->stage.point = draw_pipe_passthrough_point;
> > - cull->stage.line = draw_pipe_passthrough_line;
> > + cull->stage.line = cull_first_line;
> > cull->stage.tri = cull_first_tri;
> > cull->stage.flush = cull_flush;
> > cull->stage.reset_stipple_counter = cull_reset_stipple_counter;
> > diff --git a/src/gallium/auxiliary/draw/draw_pipe_validate.c
> > b/src/gallium/auxiliary/draw/draw_pipe_validate.c
> > index 4b0ed14..2dbb95c 100644
> > --- a/src/gallium/auxiliary/draw/draw_pipe_validate.c
> > +++ b/src/gallium/auxiliary/draw/draw_pipe_validate.c
> > @@ -93,6 +93,9 @@ draw_need_pipeline(const struct draw_context *draw,
> > /* AA lines */
> > if (rasterizer->line_smooth && draw->pipeline.aaline)
> > return TRUE;
> > +
> > + if (draw_current_shader_num_written_culldistances(draw))
> > + return TRUE;
> > }
> >
> > if (points(prim))
> > @@ -136,6 +139,9 @@ draw_need_pipeline(const struct draw_context *draw,
> > /* two-side lighting */
> > if (rasterizer->light_twoside)
> > return TRUE;
> > +
> > + if (draw_current_shader_num_written_culldistances(draw))
> > + return TRUE;
> > }
> >
> > /* polygon cull - this is difficult - hardware can cull just fine
> > @@ -145,7 +151,7 @@ draw_need_pipeline(const struct draw_context *draw,
> > *
> > if (rasterizer->cull_mode)
> > return TRUE;
> > - */
> > + */
> >
> > return FALSE;
> > }
> > @@ -260,7 +266,8 @@ static struct draw_stage *validate_pipeline( struct
> > draw_stage *stage )
> > * to less work emitting vertices, smaller vertex buffers, etc.
> > * It's difficult to say whether this will be true in general.
> > */
> > - if (need_det || rast->cull_face != PIPE_FACE_NONE) {
> > + if (need_det || rast->cull_face != PIPE_FACE_NONE ||
> > + draw_current_shader_num_written_culldistances(draw)) {
> > draw->pipeline.cull->next = next;
> > next = draw->pipeline.cull;
> > }
> > diff --git a/src/gallium/auxiliary/draw/draw_private.h
> > b/src/gallium/auxiliary/draw/draw_private.h
> > index fa0b19b..351bd2b 100644
> > --- a/src/gallium/auxiliary/draw/draw_private.h
> > +++ b/src/gallium/auxiliary/draw/draw_private.h
> > @@ -390,6 +390,8 @@ uint draw_current_shader_viewport_index_output(const
> > struct draw_context *draw);
> > uint draw_current_shader_clipvertex_output(const struct draw_context
> > *draw);
> > uint draw_current_shader_clipdistance_output(const struct draw_context
> > *draw, int index);
> > uint draw_current_shader_num_written_clipdistances(const struct
> > draw_context *draw);
> > +uint draw_current_shader_culldistance_output(const struct draw_context
> > *draw, int index);
> > +uint draw_current_shader_num_written_culldistances(const struct
> > draw_context *draw);
> > int draw_alloc_extra_vertex_attrib(struct draw_context *draw,
> > uint semantic_name, uint
> > semantic_index);
> > void draw_remove_extra_vertex_attribs(struct draw_context *draw);
> > diff --git a/src/gallium/auxiliary/draw/draw_vs.c
> > b/src/gallium/auxiliary/draw/draw_vs.c
> > index 95f678a..44845ff 100644
> > --- a/src/gallium/auxiliary/draw/draw_vs.c
> > +++ b/src/gallium/auxiliary/draw/draw_vs.c
> > @@ -90,6 +90,11 @@ draw_create_vertex_shader(struct draw_context *draw,
> > vs->clipdistance_output[0] = i;
> > else
> > vs->clipdistance_output[1] = i;
> > + } else if (vs->info.output_semantic_name[i] ==
> > TGSI_SEMANTIC_CULLDIST) {
> > + if (vs->info.output_semantic_index[i] == 0)
> > + vs->culldistance_output[0] = i;
> > + else
> > + vs->culldistance_output[1] = i;
> > }
> > }
> > if (!found_clipvertex)
> > diff --git a/src/gallium/auxiliary/draw/draw_vs.h
> > b/src/gallium/auxiliary/draw/draw_vs.h
> > index 798b004..7635aba 100644
> > --- a/src/gallium/auxiliary/draw/draw_vs.h
> > +++ b/src/gallium/auxiliary/draw/draw_vs.h
> > @@ -113,6 +113,7 @@ struct draw_vertex_shader {
> > unsigned edgeflag_output;
> > unsigned clipvertex_output;
> > unsigned clipdistance_output[2];
> > + unsigned culldistance_output[2];
> > /* Extracted from shader:
> > */
> > const float (*immediates)[4];
> >
>
> Reviewed-by: Brian Paul <brianp at vmware.com>
>
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