1 /**************************************************************************
3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
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29 * \brief Quad early-z testing
32 #include "pipe/p_defines.h"
33 #include "util/u_memory.h"
34 #include "sp_headers.h"
39 * All this stage does is compute the quad's Z values (which is normally
40 * done by the shading stage).
41 * The next stage will do the actual depth test.
45 struct quad_stage
*qs
,
46 struct quad_header
*quad
)
48 const float fx
= (float) quad
->x0
;
49 const float fy
= (float) quad
->y0
;
50 const float dzdx
= quad
->posCoef
->dadx
[2];
51 const float dzdy
= quad
->posCoef
->dady
[2];
52 const float z0
= quad
->posCoef
->a0
[2] + dzdx
* fx
+ dzdy
* fy
;
54 quad
->outputs
.depth
[0] = z0
;
55 quad
->outputs
.depth
[1] = z0
+ dzdx
;
56 quad
->outputs
.depth
[2] = z0
+ dzdy
;
57 quad
->outputs
.depth
[3] = z0
+ dzdx
+ dzdy
;
59 qs
->next
->run( qs
->next
, quad
);
64 struct quad_stage
*qs
)
66 qs
->next
->begin( qs
->next
);
71 struct quad_stage
*qs
)
78 struct softpipe_context
*softpipe
)
80 struct quad_stage
*stage
= CALLOC_STRUCT( quad_stage
);
82 stage
->softpipe
= softpipe
;
83 stage
->begin
= earlyz_begin
;
84 stage
->run
= earlyz_quad
;
85 stage
->destroy
= earlyz_destroy
;