draw_pipe_offset.c File Reference

Include dependency graph for draw_pipe_offset.c:

Go to the source code of this file.

Data Structures
struct	offset_stage
	polygon offset state More...
Functions
static struct offset_stage *	offset_stage (struct draw_stage *stage)
static void	do_offset_tri (struct draw_stage *stage, struct prim_header *header)
	Offset tri Z.
static void	offset_tri (struct draw_stage *stage, struct prim_header *header)
static void	offset_first_tri (struct draw_stage *stage, struct prim_header *header)
static void	offset_flush (struct draw_stage *stage, unsigned flags)
static void	offset_reset_stipple_counter (struct draw_stage *stage)
static void	offset_destroy (struct draw_stage *stage)
struct draw_stage *	draw_offset_stage (struct draw_context *draw)
	Create polygon offset drawing stage.

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Function Documentation

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

Offset tri Z.

Some hardware can handle this, but not usually when doing unfilled rendering.

Definition at line 63 of file draw_pipe_offset.c.

References CLAMP, vertex_header::data, prim_header::det, draw_stage::draw, MAX2, draw_stage::next, offset(), offset_stage(), draw_context::position_output, offset_stage::scale, draw_stage::tri, offset_stage::units, prim_header::v, and draw_context::vs.

{
   const unsigned pos = stage->draw->vs.position_output;
   struct offset_stage *offset = offset_stage(stage);   
   float inv_det = 1.0f / header->det;

   /* Window coords:
    */
   float *v0 = header->v[0]->data[pos];
   float *v1 = header->v[1]->data[pos];
   float *v2 = header->v[2]->data[pos];

   /* edge vectors e = v0 - v2, f = v1 - v2 */
   float ex = v0[0] - v2[0];
   float ey = v0[1] - v2[1];
   float ez = v0[2] - v2[2];
   float fx = v1[0] - v2[0];
   float fy = v1[1] - v2[1];
   float fz = v1[2] - v2[2];

   /* (a,b) = cross(e,f).xy */
   float a = ey*fz - ez*fy;
   float b = ez*fx - ex*fz;

   float dzdx = fabsf(a * inv_det);
   float dzdy = fabsf(b * inv_det);

   float zoffset = offset->units + MAX2(dzdx, dzdy) * offset->scale;

   /*
    * Note: we're applying the offset and clamping per-vertex.
    * Ideally, the offset is applied per-fragment prior to fragment shading.
    */
   v0[2] = CLAMP(v0[2] + zoffset, 0.0f, 1.0f);
   v1[2] = CLAMP(v1[2] + zoffset, 0.0f, 1.0f);
   v2[2] = CLAMP(v2[2] + zoffset, 0.0f, 1.0f);

   stage->next->tri( stage->next, header );
}

struct draw_stage* draw_offset_stage

(

struct draw_context *

draw

)

[read]

Create polygon offset drawing stage.

Definition at line 160 of file draw_pipe_offset.c.

References CALLOC_STRUCT, 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, offset(), offset_destroy(), offset_first_tri(), offset_flush(), offset_reset_stipple_counter(), draw_stage::point, draw_stage::reset_stipple_counter, offset_stage::stage, and draw_stage::tri.

{
   struct offset_stage *offset = CALLOC_STRUCT(offset_stage);
   if (offset == NULL)
      goto fail;

   draw_alloc_temp_verts( &offset->stage, 3 );

   offset->stage.draw = draw;
   offset->stage.next = NULL;
   offset->stage.point = draw_pipe_passthrough_point;
   offset->stage.line = draw_pipe_passthrough_line;
   offset->stage.tri = offset_first_tri;
   offset->stage.flush = offset_flush;
   offset->stage.reset_stipple_counter = offset_reset_stipple_counter;
   offset->stage.destroy = offset_destroy;

   return &offset->stage;

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

   return NULL;
}

static void offset_destroy

(

struct draw_stage *

stage

)

[static]

Definition at line 150 of file draw_pipe_offset.c.

References draw_free_temp_verts(), and FREE.

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

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

Definition at line 121 of file draw_pipe_offset.c.

References draw_stage::draw, draw_context::mrd, offset(), pipe_rasterizer_state::offset_scale, offset_stage(), offset_tri(), pipe_rasterizer_state::offset_units, draw_context::rasterizer, offset_stage::scale, draw_stage::tri, and offset_stage::units.

{
   struct offset_stage *offset = offset_stage(stage);

   offset->units = (float) (stage->draw->rasterizer->offset_units * stage->draw->mrd);
   offset->scale = stage->draw->rasterizer->offset_scale;

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

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

Definition at line 136 of file draw_pipe_offset.c.

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

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

static void offset_reset_stipple_counter

(

struct draw_stage *

stage

)

[static]

Definition at line 144 of file draw_pipe_offset.c.

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

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

static struct offset_stage* offset_stage

(

struct draw_stage *

stage

)

[static, read]

Definition at line 50 of file draw_pipe_offset.c.

{
   return (struct offset_stage *) stage;
}

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

Definition at line 105 of file draw_pipe_offset.c.

References prim_header::det, do_offset_tri(), dup_vert(), prim_header::flags, prim_header::pad, and prim_header::v.

{
   struct prim_header tmp;

   tmp.det = header->det;
   tmp.flags = header->flags;
   tmp.pad = header->pad;
   tmp.v[0] = dup_vert(stage, header->v[0], 0);
   tmp.v[1] = dup_vert(stage, header->v[1], 1);
   tmp.v[2] = dup_vert(stage, header->v[2], 2);

   do_offset_tri( stage, &tmp );
}

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