1/**************************************************************************
2 *
3 * Copyright 2007 VMware, Inc.
4 * All Rights Reserved.
5 *
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:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
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.
25 *
26 **************************************************************************/
27
28/* Authors:  Keith Whitwell <keithw@vmware.com>
29 */
30
31#include "util/u_math.h"
32#include "util/u_memory.h"
33
34#include "pipe/p_shader_tokens.h"
35#include "draw_vs.h"
36#include "draw_fs.h"
37#include "draw_pipe.h"
38
39
40/** subclass of draw_stage */
41struct flat_stage
42{
43   struct draw_stage stage;
44
45   uint num_flat_attribs;
46   uint flat_attribs[PIPE_MAX_SHADER_OUTPUTS];  /* flatshaded attribs */
47};
48
49
50static inline struct flat_stage *
51flat_stage(struct draw_stage *stage)
52{
53   return (struct flat_stage *) stage;
54}
55
56
57/** Copy all the constant attributes from 'src' vertex to 'dst' vertex */
58static inline void copy_flats( struct draw_stage *stage,
59                               struct vertex_header *dst,
60                               const struct vertex_header *src )
61{
62   const struct flat_stage *flat = flat_stage(stage);
63   uint i;
64
65   for (i = 0; i < flat->num_flat_attribs; i++) {
66      const uint attr = flat->flat_attribs[i];
67      COPY_4FV(dst->data[attr], src->data[attr]);
68   }
69}
70
71
72/** Copy all the color attributes from src vertex to dst0 & dst1 vertices */
73static inline void copy_flats2( struct draw_stage *stage,
74                                struct vertex_header *dst0,
75                                struct vertex_header *dst1,
76                                const struct vertex_header *src )
77{
78   const struct flat_stage *flat = flat_stage(stage);
79   uint i;
80   for (i = 0; i < flat->num_flat_attribs; i++) {
81      const uint attr = flat->flat_attribs[i];
82      COPY_4FV(dst0->data[attr], src->data[attr]);
83      COPY_4FV(dst1->data[attr], src->data[attr]);
84   }
85}
86
87
88/**
89 * Flatshade tri. Not required for clipping which handles this on its own,
90 * but required for unfilled tris and other primitive-changing stages
91 * (like widelines). If no such stages are active, handled by hardware.
92 */
93static void flatshade_tri_0( struct draw_stage *stage,
94                             struct prim_header *header )
95{
96   struct prim_header tmp;
97
98   tmp.det = header->det;
99   tmp.flags = header->flags;
100   tmp.pad = header->pad;
101   tmp.v[0] = header->v[0];
102   tmp.v[1] = dup_vert(stage, header->v[1], 0);
103   tmp.v[2] = dup_vert(stage, header->v[2], 1);
104
105   copy_flats2(stage, tmp.v[1], tmp.v[2], tmp.v[0]);
106
107   stage->next->tri( stage->next, &tmp );
108}
109
110
111static void flatshade_tri_2( struct draw_stage *stage,
112                             struct prim_header *header )
113{
114   struct prim_header tmp;
115
116   tmp.det = header->det;
117   tmp.flags = header->flags;
118   tmp.pad = header->pad;
119   tmp.v[0] = dup_vert(stage, header->v[0], 0);
120   tmp.v[1] = dup_vert(stage, header->v[1], 1);
121   tmp.v[2] = header->v[2];
122
123   copy_flats2(stage, tmp.v[0], tmp.v[1], tmp.v[2]);
124
125   stage->next->tri( stage->next, &tmp );
126}
127
128
129/**
130 * Flatshade line.
131 */
132static void flatshade_line_0( struct draw_stage *stage,
133                              struct prim_header *header )
134{
135   struct prim_header tmp;
136
137   tmp.det = header->det;
138   tmp.flags = header->flags;
139   tmp.pad = header->pad;
140   tmp.v[0] = header->v[0];
141   tmp.v[1] = dup_vert(stage, header->v[1], 0);
142
143   copy_flats(stage, tmp.v[1], tmp.v[0]);
144
145   stage->next->line( stage->next, &tmp );
146}
147
148
149static void flatshade_line_1( struct draw_stage *stage,
150                              struct prim_header *header )
151{
152   struct prim_header tmp;
153
154   tmp.det = header->det;
155   tmp.flags = header->flags;
156   tmp.pad = header->pad;
157   tmp.v[0] = dup_vert(stage, header->v[0], 0);
158   tmp.v[1] = header->v[1];
159
160   copy_flats(stage, tmp.v[0], tmp.v[1]);
161
162   stage->next->line( stage->next, &tmp );
163}
164
165
166static int
167find_interp(const struct draw_fragment_shader *fs, int *indexed_interp,
168            uint semantic_name, uint semantic_index)
169{
170   int interp;
171   /* If it's gl_{Front,Back}{,Secondary}Color, pick up the mode
172    * from the array we've filled before. */
173   if (semantic_name == TGSI_SEMANTIC_COLOR ||
174       semantic_name == TGSI_SEMANTIC_BCOLOR) {
175      interp = indexed_interp[semantic_index];
176   } else {
177      /* Otherwise, search in the FS inputs, with a decent default
178       * if we don't find it.
179       */
180      uint j;
181      interp = TGSI_INTERPOLATE_PERSPECTIVE;
182      if (fs) {
183         for (j = 0; j < fs->info.num_inputs; j++) {
184            if (semantic_name == fs->info.input_semantic_name[j] &&
185                semantic_index == fs->info.input_semantic_index[j]) {
186               interp = fs->info.input_interpolate[j];
187               break;
188            }
189         }
190      }
191   }
192   return interp;
193}
194
195
196static void flatshade_init_state( struct draw_stage *stage )
197{
198   struct flat_stage *flat = flat_stage(stage);
199   const struct draw_context *draw = stage->draw;
200   const struct draw_fragment_shader *fs = draw->fs.fragment_shader;
201   const struct tgsi_shader_info *info = draw_get_shader_info(draw);
202   uint i, j;
203
204   /* Find which vertex shader outputs need constant interpolation, make a list */
205
206   /* XXX: this code is a near exact copy of the one in clip_init_state.
207    * The latter also cares about perspective though.
208    */
209
210   /* First pick up the interpolation mode for
211    * gl_Color/gl_SecondaryColor, with the correct default.
212    */
213   int indexed_interp[2];
214   indexed_interp[0] = indexed_interp[1] = draw->rasterizer->flatshade ?
215      TGSI_INTERPOLATE_CONSTANT : TGSI_INTERPOLATE_PERSPECTIVE;
216
217   if (fs) {
218      for (i = 0; i < fs->info.num_inputs; i++) {
219         if (fs->info.input_semantic_name[i] == TGSI_SEMANTIC_COLOR) {
220            if (fs->info.input_interpolate[i] != TGSI_INTERPOLATE_COLOR)
221               indexed_interp[fs->info.input_semantic_index[i]] = fs->info.input_interpolate[i];
222         }
223      }
224   }
225
226   /* Then resolve the interpolation mode for every output attribute.
227    *
228    * Given how the rest of the code, the most efficient way is to
229    * have a vector of flat-mode attributes.
230    */
231   flat->num_flat_attribs = 0;
232   for (i = 0; i < info->num_outputs; i++) {
233      /* Find the interpolation mode for a specific attribute */
234      int interp = find_interp(fs, indexed_interp,
235                               info->output_semantic_name[i],
236                               info->output_semantic_index[i]);
237      /* If it's flat, add it to the flat vector. */
238
239      if (interp == TGSI_INTERPOLATE_CONSTANT) {
240         flat->flat_attribs[flat->num_flat_attribs] = i;
241         flat->num_flat_attribs++;
242      }
243   }
244   /* Search the extra vertex attributes */
245   for (j = 0; j < draw->extra_shader_outputs.num; j++) {
246      /* Find the interpolation mode for a specific attribute */
247      int interp = find_interp(fs, indexed_interp,
248                               draw->extra_shader_outputs.semantic_name[j],
249                               draw->extra_shader_outputs.semantic_index[j]);
250      /* If it's flat, add it to the flat vector. */
251      if (interp == TGSI_INTERPOLATE_CONSTANT) {
252         flat->flat_attribs[flat->num_flat_attribs] = i + j;
253         flat->num_flat_attribs++;
254      }
255   }
256
257   /* Choose flatshade routine according to provoking vertex:
258    */
259   if (draw->rasterizer->flatshade_first) {
260      stage->line = flatshade_line_0;
261      stage->tri = flatshade_tri_0;
262   }
263   else {
264      stage->line = flatshade_line_1;
265      stage->tri = flatshade_tri_2;
266   }
267}
268
269static void flatshade_first_tri( struct draw_stage *stage,
270                                 struct prim_header *header )
271{
272   flatshade_init_state( stage );
273   stage->tri( stage, header );
274}
275
276static void flatshade_first_line( struct draw_stage *stage,
277                                  struct prim_header *header )
278{
279   flatshade_init_state( stage );
280   stage->line( stage, header );
281}
282
283
284static void flatshade_flush( struct draw_stage *stage,
285                             unsigned flags )
286{
287   stage->tri = flatshade_first_tri;
288   stage->line = flatshade_first_line;
289   stage->next->flush( stage->next, flags );
290}
291
292
293static void flatshade_reset_stipple_counter( struct draw_stage *stage )
294{
295   stage->next->reset_stipple_counter( stage->next );
296}
297
298
299static void flatshade_destroy( struct draw_stage *stage )
300{
301   draw_free_temp_verts( stage );
302   FREE( stage );
303}
304
305
306/**
307 * Create flatshading drawing stage.
308 */
309struct draw_stage *draw_flatshade_stage( struct draw_context *draw )
310{
311   struct flat_stage *flatshade = CALLOC_STRUCT(flat_stage);
312   if (!flatshade)
313      goto fail;
314
315   flatshade->stage.draw = draw;
316   flatshade->stage.name = "flatshade";
317   flatshade->stage.next = NULL;
318   flatshade->stage.point = draw_pipe_passthrough_point;
319   flatshade->stage.line = flatshade_first_line;
320   flatshade->stage.tri = flatshade_first_tri;
321   flatshade->stage.flush = flatshade_flush;
322   flatshade->stage.reset_stipple_counter = flatshade_reset_stipple_counter;
323   flatshade->stage.destroy = flatshade_destroy;
324
325   if (!draw_alloc_temp_verts( &flatshade->stage, 2 ))
326      goto fail;
327
328   return &flatshade->stage;
329
330 fail:
331   if (flatshade)
332      flatshade->stage.destroy( &flatshade->stage );
333
334   return NULL;
335}
336
337
338