draw_pipe_cull.c File Reference

Include dependency graph for draw_pipe_cull.c:

Go to the source code of this file.

Data Structures
struct	cull_stage
	Drawing stage for polygon culling. More...
Functions
static struct cull_stage *	cull_stage (struct draw_stage *stage)
static void	cull_tri (struct draw_stage *stage, struct prim_header *header)
static void	cull_first_tri (struct draw_stage *stage, struct prim_header *header)
static void	cull_flush (struct draw_stage *stage, unsigned flags)
static void	cull_reset_stipple_counter (struct draw_stage *stage)
static void	cull_destroy (struct draw_stage *stage)
struct draw_stage *	draw_cull_stage (struct draw_context *draw)
	Create a new polygon culling stage.

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Function Documentation

static void cull_destroy

(

struct draw_stage *

stage

)

[static]

Definition at line 112 of file draw_pipe_cull.c.

References draw_free_temp_verts(), and FREE.

{
   draw_free_temp_verts( stage );
   FREE( stage );
}

static void cull_first_tri	(	struct draw_stage *	stage,
		struct prim_header *	header
	)			[static]

Definition at line 87 of file draw_pipe_cull.c.

References pipe_rasterizer_state::cull_mode, cull_stage(), cull_tri(), draw_stage::draw, draw_context::rasterizer, draw_stage::tri, and cull_stage::winding.

{
   struct cull_stage *cull = cull_stage(stage);

   cull->winding = stage->draw->rasterizer->cull_mode;

   stage->tri = cull_tri;
   stage->tri( stage, header );
}

static void cull_flush	(	struct draw_stage *	stage,
		unsigned	flags
	)			[static]

Definition at line 100 of file draw_pipe_cull.c.

References cull_first_tri(), draw_stage::flush, draw_stage::next, and draw_stage::tri.

{
   stage->tri = cull_first_tri;
   stage->next->flush( stage->next, flags );
}

static void cull_reset_stipple_counter

(

struct draw_stage *

stage

)

[static]

Definition at line 106 of file draw_pipe_cull.c.

References draw_stage::next, and draw_stage::reset_stipple_counter.

{
   stage->next->reset_stipple_counter( stage->next );
}

static struct cull_stage* cull_stage

(

struct draw_stage *

stage

)

[static, read]

Definition at line 47 of file draw_pipe_cull.c.

{
   return (struct cull_stage *)stage;
}

static void cull_tri	(	struct draw_stage *	stage,
		struct prim_header *	header
	)			[static]

Definition at line 55 of file draw_pipe_cull.c.

References cull_stage(), vertex_header::data, prim_header::det, draw_stage::draw, draw_stage::next, PIPE_WINDING_CCW, PIPE_WINDING_CW, draw_context::position_output, draw_stage::tri, prim_header::v, draw_context::vs, and cull_stage::winding.

{
   const unsigned pos = stage->draw->vs.position_output;

   /* 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 camera and triangle is 
       * counter-clockwise winding.
       */
      unsigned winding = (header->det < 0) ? PIPE_WINDING_CCW : PIPE_WINDING_CW;

      if ((winding & cull_stage(stage)->winding) == 0) {
         /* triangle is not culled, pass to next stage */
         stage->next->tri( stage->next, header );
      }
   }
}

struct draw_stage* draw_cull_stage

(

struct draw_context *

draw

)

[read]

Create a new polygon culling stage.

Definition at line 122 of file draw_pipe_cull.c.

References CALLOC_STRUCT, cull_destroy(), cull_first_tri(), cull_flush(), cull_reset_stipple_counter(), draw_stage::destroy, draw_stage::draw, draw_alloc_temp_verts(), draw_pipe_passthrough_line(), draw_pipe_passthrough_point(), draw_stage::flush, draw_stage::line, draw_stage::next, draw_stage::point, draw_stage::reset_stipple_counter, cull_stage::stage, and draw_stage::tri.

{
   struct cull_stage *cull = CALLOC_STRUCT(cull_stage);
   if (cull == NULL)
      goto fail;

   if (!draw_alloc_temp_verts( &cull->stage, 0 ))
      goto fail;

   cull->stage.draw = draw;
   cull->stage.next = NULL;
   cull->stage.point = draw_pipe_passthrough_point;
   cull->stage.line = draw_pipe_passthrough_line;
   cull->stage.tri = cull_first_tri;
   cull->stage.flush = cull_flush;
   cull->stage.reset_stipple_counter = cull_reset_stipple_counter;
   cull->stage.destroy = cull_destroy;

   return &cull->stage;

 fail:
   if (cull)
      cull->stage.destroy( &cull->stage );

   return NULL;
}

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