1 /**************************************************************************
3 * Copyright 2007 VMware, Inc.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 **************************************************************************/
28 /* Authors: Keith Whitwell <keithw@vmware.com>
31 /* Implement line stipple by cutting lines up into smaller lines.
32 * There are hundreds of ways to implement line stipple, this is one
33 * choice that should work in all situations, requires no state
34 * manipulations, but with a penalty in terms of large amounts of
39 #include "pipe/p_defines.h"
40 #include "pipe/p_shader_tokens.h"
41 #include "util/u_math.h"
42 #include "util/u_memory.h"
44 #include "draw/draw_pipe.h"
47 /** Subclass of draw_stage */
48 struct stipple_stage
{
49 struct draw_stage stage
;
57 static inline struct stipple_stage
*
58 stipple_stage(struct draw_stage
*stage
)
60 return (struct stipple_stage
*) stage
;
65 * Compute interpolated vertex attributes for 'dst' at position 't'
66 * between 'v0' and 'v1'.
67 * XXX using linear interpolation for all attribs at this time.
70 screen_interp(struct draw_context
*draw
,
71 struct vertex_header
*dst
,
73 const struct vertex_header
*v0
,
74 const struct vertex_header
*v1
)
77 uint num_outputs
= draw_current_shader_outputs(draw
);
78 for (attr
= 0; attr
< num_outputs
; attr
++) {
79 const float *val0
= v0
->data
[attr
];
80 const float *val1
= v1
->data
[attr
];
81 float *newv
= dst
->data
[attr
];
83 for (i
= 0; i
< 4; i
++) {
84 newv
[i
] = val0
[i
] + t
* (val1
[i
] - val0
[i
]);
91 emit_segment(struct draw_stage
*stage
, struct prim_header
*header
,
94 struct vertex_header
*v0new
= dup_vert(stage
, header
->v
[0], 0);
95 struct vertex_header
*v1new
= dup_vert(stage
, header
->v
[1], 1);
96 struct prim_header newprim
= *header
;
99 screen_interp(stage
->draw
, v0new
, t0
, header
->v
[0], header
->v
[1]);
100 newprim
.v
[0] = v0new
;
104 screen_interp(stage
->draw
, v1new
, t1
, header
->v
[0], header
->v
[1]);
105 newprim
.v
[1] = v1new
;
108 stage
->next
->line(stage
->next
, &newprim
);
113 stipple_test(int counter
, ushort pattern
, ushort factor
)
115 int b
= (counter
/ factor
) & 0xf;
116 return !!((1 << b
) & pattern
);
121 stipple_line(struct draw_stage
*stage
, struct prim_header
*header
)
123 struct stipple_stage
*stipple
= stipple_stage(stage
);
124 struct vertex_header
*v0
= header
->v
[0];
125 struct vertex_header
*v1
= header
->v
[1];
126 const unsigned pos
= draw_current_shader_position_output(stage
->draw
);
127 const float *pos0
= v0
->data
[pos
];
128 const float *pos1
= v1
->data
[pos
];
141 if (header
->flags
& DRAW_PIPE_RESET_STIPPLE
)
142 stipple
->counter
= 0;
144 if (stipple
->smooth
) {
147 length
= sqrtf(dx
*dx
+ dy
*dy
);
149 float dx
= x0
> x1
? x0
- x1
: x1
- x0
;
150 float dy
= y0
> y1
? y0
- y1
: y1
- y0
;
151 length
= MAX2(dx
, dy
);
154 if (util_is_inf_or_nan(length
))
157 intlength
= ceilf(length
);
159 /* XXX ToDo: instead of iterating pixel-by-pixel, use a look-up table.
161 for (i
= 0; i
< intlength
; i
++) {
162 bool result
= stipple_test((int)stipple
->counter
+ i
,
163 stipple
->pattern
, stipple
->factor
);
164 if (result
!= state
) {
165 /* changing from "off" to "on" or vice versa */
167 /* finishing an "on" segment */
168 emit_segment(stage
, header
, start
/ length
, i
/ length
);
171 /* starting an "on" segment */
178 if (state
&& start
< length
)
179 emit_segment(stage
, header
, start
/ length
, 1.0);
181 stipple
->counter
+= length
;
186 reset_stipple_counter(struct draw_stage
*stage
)
188 struct stipple_stage
*stipple
= stipple_stage(stage
);
189 stipple
->counter
= 0;
190 stage
->next
->reset_stipple_counter(stage
->next
);
194 stipple_reset_point(struct draw_stage
*stage
, struct prim_header
*header
)
196 struct stipple_stage
*stipple
= stipple_stage(stage
);
197 stipple
->counter
= 0;
198 stage
->next
->point(stage
->next
, header
);
202 stipple_reset_tri(struct draw_stage
*stage
, struct prim_header
*header
)
204 struct stipple_stage
*stipple
= stipple_stage(stage
);
205 stipple
->counter
= 0;
206 stage
->next
->tri(stage
->next
, header
);
211 stipple_first_line(struct draw_stage
*stage
,
212 struct prim_header
*header
)
214 struct stipple_stage
*stipple
= stipple_stage(stage
);
215 struct draw_context
*draw
= stage
->draw
;
217 stipple
->pattern
= draw
->rasterizer
->line_stipple_pattern
;
218 stipple
->factor
= draw
->rasterizer
->line_stipple_factor
+ 1;
219 stipple
->smooth
= draw
->rasterizer
->line_smooth
;
221 stage
->line
= stipple_line
;
222 stage
->line(stage
, header
);
227 stipple_flush(struct draw_stage
*stage
, unsigned flags
)
229 stage
->line
= stipple_first_line
;
230 stage
->next
->flush(stage
->next
, flags
);
235 stipple_destroy(struct draw_stage
*stage
)
237 draw_free_temp_verts(stage
);
243 * Create line stippler stage
246 draw_stipple_stage(struct draw_context
*draw
)
248 struct stipple_stage
*stipple
= CALLOC_STRUCT(stipple_stage
);
252 stipple
->stage
.draw
= draw
;
253 stipple
->stage
.name
= "stipple";
254 stipple
->stage
.next
= NULL
;
255 stipple
->stage
.point
= stipple_reset_point
;
256 stipple
->stage
.line
= stipple_first_line
;
257 stipple
->stage
.tri
= stipple_reset_tri
;
258 stipple
->stage
.reset_stipple_counter
= reset_stipple_counter
;
259 stipple
->stage
.flush
= stipple_flush
;
260 stipple
->stage
.destroy
= stipple_destroy
;
262 if (!draw_alloc_temp_verts(&stipple
->stage
, 2))
265 return &stipple
->stage
;
269 stipple
->stage
.destroy(&stipple
->stage
);