1/*
2 Copyright (C) Intel Corp.  2006.  All Rights Reserved.
3 Intel funded Tungsten Graphics to
4 develop this 3D driver.
5
6 Permission is hereby granted, free of charge, to any person obtaining
7 a 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, sublicense, 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
16 portions of the Software.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
21 IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25
26 **********************************************************************/
27 /*
28  * Authors:
29  *   Keith Whitwell <keithw@vmware.com>
30  */
31
32#include "main/macros.h"
33#include "main/enums.h"
34#include "program/program.h"
35
36#include "brw_clip.h"
37#include "brw_prim.h"
38
39static void brw_clip_line_alloc_regs( struct brw_clip_compile *c )
40{
41   const struct intel_device_info *devinfo = c->func.devinfo;
42   GLuint i = 0,j;
43
44   /* Register usage is static, precompute here:
45    */
46   c->reg.R0 = retype(brw_vec8_grf(i, 0), BRW_REGISTER_TYPE_UD); i++;
47
48   if (c->key.nr_userclip) {
49      c->reg.fixed_planes = brw_vec4_grf(i, 0);
50      i += (6 + c->key.nr_userclip + 1) / 2;
51
52      c->prog_data.curb_read_length = (6 + c->key.nr_userclip + 1) / 2;
53   }
54   else
55      c->prog_data.curb_read_length = 0;
56
57
58   /* Payload vertices plus space for more generated vertices:
59    */
60   for (j = 0; j < 4; j++) {
61      c->reg.vertex[j] = brw_vec4_grf(i, 0);
62      i += c->nr_regs;
63   }
64
65   c->reg.t           = brw_vec1_grf(i, 0);
66   c->reg.t0          = brw_vec1_grf(i, 1);
67   c->reg.t1          = brw_vec1_grf(i, 2);
68   c->reg.planemask   = retype(brw_vec1_grf(i, 3), BRW_REGISTER_TYPE_UD);
69   c->reg.plane_equation = brw_vec4_grf(i, 4);
70   i++;
71
72   c->reg.dp0         = brw_vec1_grf(i, 0); /* fixme - dp4 will clobber r.1,2,3 */
73   c->reg.dp1         = brw_vec1_grf(i, 4);
74   i++;
75
76   if (!c->key.nr_userclip) {
77      c->reg.fixed_planes = brw_vec8_grf(i, 0);
78      i++;
79   }
80
81   c->reg.vertex_src_mask = retype(brw_vec1_grf(i, 0), BRW_REGISTER_TYPE_UD);
82   c->reg.clipdistance_offset = retype(brw_vec1_grf(i, 1), BRW_REGISTER_TYPE_W);
83   i++;
84
85   if (devinfo->ver == 5) {
86      c->reg.ff_sync = retype(brw_vec1_grf(i, 0), BRW_REGISTER_TYPE_UD);
87      i++;
88   }
89
90   c->first_tmp = i;
91   c->last_tmp = i;
92
93   c->prog_data.urb_read_length = c->nr_regs; /* ? */
94   c->prog_data.total_grf = i;
95}
96
97
98/* Line clipping, more or less following the following algorithm:
99 *
100 *  for (p=0;p<MAX_PLANES;p++) {
101 *     if (clipmask & (1 << p)) {
102 *        GLfloat dp0 = DOTPROD( vtx0, plane[p] );
103 *        GLfloat dp1 = DOTPROD( vtx1, plane[p] );
104 *
105 *        if (dp1 < 0.0f) {
106 *           GLfloat t = dp1 / (dp1 - dp0);
107 *           if (t > t1) t1 = t;
108 *        } else {
109 *           GLfloat t = dp0 / (dp0 - dp1);
110 *           if (t > t0) t0 = t;
111 *        }
112 *
113 *        if (t0 + t1 >= 1.0)
114 *           return;
115 *     }
116 *  }
117 *
118 *  interp( ctx, newvtx0, vtx0, vtx1, t0 );
119 *  interp( ctx, newvtx1, vtx1, vtx0, t1 );
120 *
121 */
122static void clip_and_emit_line( struct brw_clip_compile *c )
123{
124   struct brw_codegen *p = &c->func;
125   struct brw_indirect vtx0     = brw_indirect(0, 0);
126   struct brw_indirect vtx1      = brw_indirect(1, 0);
127   struct brw_indirect newvtx0   = brw_indirect(2, 0);
128   struct brw_indirect newvtx1   = brw_indirect(3, 0);
129   struct brw_indirect plane_ptr = brw_indirect(4, 0);
130   struct brw_reg v1_null_ud = retype(vec1(brw_null_reg()), BRW_REGISTER_TYPE_UD);
131   GLuint hpos_offset = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
132   GLint clipdist0_offset = c->key.nr_userclip
133      ? brw_varying_to_offset(&c->vue_map, VARYING_SLOT_CLIP_DIST0)
134      : 0;
135
136   brw_MOV(p, get_addr_reg(vtx0),      brw_address(c->reg.vertex[0]));
137   brw_MOV(p, get_addr_reg(vtx1),      brw_address(c->reg.vertex[1]));
138   brw_MOV(p, get_addr_reg(newvtx0),   brw_address(c->reg.vertex[2]));
139   brw_MOV(p, get_addr_reg(newvtx1),   brw_address(c->reg.vertex[3]));
140   brw_MOV(p, get_addr_reg(plane_ptr), brw_clip_plane0_address(c));
141
142   /* Note: init t0, t1 together:
143    */
144   brw_MOV(p, vec2(c->reg.t0), brw_imm_f(0));
145
146   brw_clip_init_planes(c);
147   brw_clip_init_clipmask(c);
148
149   /* -ve rhw workaround */
150   if (p->devinfo->has_negative_rhw_bug) {
151      brw_AND(p, brw_null_reg(), get_element_ud(c->reg.R0, 2),
152              brw_imm_ud(1<<20));
153      brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
154      brw_OR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(0x3f));
155      brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
156   }
157
158   /* Set the initial vertex source mask: The first 6 planes are the bounds
159    * of the view volume; the next 8 planes are the user clipping planes.
160    */
161   brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0x3fc0));
162
163   /* Set the initial clipdistance offset to be 6 floats before gl_ClipDistance[0].
164    * We'll increment 6 times before we start hitting actual user clipping. */
165   brw_MOV(p, c->reg.clipdistance_offset, brw_imm_d(clipdist0_offset - 6*sizeof(float)));
166
167   brw_DO(p, BRW_EXECUTE_1);
168   {
169      /* if (planemask & 1)
170       */
171      brw_AND(p, v1_null_ud, c->reg.planemask, brw_imm_ud(1));
172      brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
173
174      brw_IF(p, BRW_EXECUTE_1);
175      {
176         brw_AND(p, v1_null_ud, c->reg.vertex_src_mask, brw_imm_ud(1));
177         brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
178         brw_IF(p, BRW_EXECUTE_1);
179         {
180            /* user clip distance: just fetch the correct float from each vertex */
181            struct brw_indirect temp_ptr = brw_indirect(7, 0);
182            brw_ADD(p, get_addr_reg(temp_ptr), get_addr_reg(vtx0), c->reg.clipdistance_offset);
183            brw_MOV(p, c->reg.dp0, deref_1f(temp_ptr, 0));
184            brw_ADD(p, get_addr_reg(temp_ptr), get_addr_reg(vtx1), c->reg.clipdistance_offset);
185            brw_MOV(p, c->reg.dp1, deref_1f(temp_ptr, 0));
186         }
187         brw_ELSE(p);
188         {
189            /* fixed plane: fetch the hpos, dp4 against the plane. */
190            if (c->key.nr_userclip)
191               brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
192            else
193               brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
194
195            brw_DP4(p, vec4(c->reg.dp0), deref_4f(vtx0, hpos_offset), c->reg.plane_equation);
196            brw_DP4(p, vec4(c->reg.dp1), deref_4f(vtx1, hpos_offset), c->reg.plane_equation);
197         }
198         brw_ENDIF(p);
199
200         brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_L, vec1(c->reg.dp1), brw_imm_f(0.0f));
201
202         brw_IF(p, BRW_EXECUTE_1);
203         {
204             /*
205              * Both can be negative on GM965/G965 due to RHW workaround
206              * if so, this object should be rejected.
207              */
208             if (p->devinfo->has_negative_rhw_bug) {
209                 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_LE, c->reg.dp0, brw_imm_f(0.0));
210                 brw_IF(p, BRW_EXECUTE_1);
211                 {
212                     brw_clip_kill_thread(c);
213                 }
214                 brw_ENDIF(p);
215             }
216
217             brw_ADD(p, c->reg.t, c->reg.dp1, negate(c->reg.dp0));
218             brw_math_invert(p, c->reg.t, c->reg.t);
219             brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp1);
220
221             brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t1 );
222             brw_MOV(p, c->reg.t1, c->reg.t);
223             brw_inst_set_pred_control(p->devinfo, brw_last_inst,
224                                       BRW_PREDICATE_NORMAL);
225	 }
226	 brw_ELSE(p);
227	 {
228             /* Coming back in.  We know that both cannot be negative
229              * because the line would have been culled in that case.
230              */
231
232             /* If both are positive, do nothing */
233             /* Only on GM965/G965 */
234             if (p->devinfo->has_negative_rhw_bug) {
235                 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.dp0, brw_imm_f(0.0));
236                 brw_IF(p, BRW_EXECUTE_1);
237             }
238
239             {
240                 brw_ADD(p, c->reg.t, c->reg.dp0, negate(c->reg.dp1));
241                 brw_math_invert(p, c->reg.t, c->reg.t);
242                 brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp0);
243
244                 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t0 );
245                 brw_MOV(p, c->reg.t0, c->reg.t);
246                 brw_inst_set_pred_control(p->devinfo, brw_last_inst,
247                                           BRW_PREDICATE_NORMAL);
248             }
249
250             if (p->devinfo->has_negative_rhw_bug) {
251                 brw_ENDIF(p);
252             }
253         }
254	 brw_ENDIF(p);
255      }
256      brw_ENDIF(p);
257
258      /* plane_ptr++;
259       */
260      brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));
261
262      /* while (planemask>>=1) != 0
263       */
264      brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
265      brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);
266      brw_SHR(p, c->reg.vertex_src_mask, c->reg.vertex_src_mask, brw_imm_ud(1));
267      brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
268      brw_ADD(p, c->reg.clipdistance_offset, c->reg.clipdistance_offset, brw_imm_w(sizeof(float)));
269      brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
270   }
271   brw_WHILE(p);
272   brw_inst_set_pred_control(p->devinfo, brw_last_inst, BRW_PREDICATE_NORMAL);
273
274   brw_ADD(p, c->reg.t, c->reg.t0, c->reg.t1);
275   brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.t, brw_imm_f(1.0));
276   brw_IF(p, BRW_EXECUTE_1);
277   {
278      brw_clip_interp_vertex(c, newvtx0, vtx0, vtx1, c->reg.t0, false);
279      brw_clip_interp_vertex(c, newvtx1, vtx1, vtx0, c->reg.t1, false);
280
281      brw_clip_emit_vue(c, newvtx0, BRW_URB_WRITE_ALLOCATE_COMPLETE,
282                        (_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
283                        | URB_WRITE_PRIM_START);
284      brw_clip_emit_vue(c, newvtx1, BRW_URB_WRITE_EOT_COMPLETE,
285                        (_3DPRIM_LINESTRIP << URB_WRITE_PRIM_TYPE_SHIFT)
286                        | URB_WRITE_PRIM_END);
287   }
288   brw_ENDIF(p);
289   brw_clip_kill_thread(c);
290}
291
292
293
294void brw_emit_line_clip( struct brw_clip_compile *c )
295{
296   brw_clip_line_alloc_regs(c);
297   brw_clip_init_ff_sync(c);
298
299   if (c->key.contains_flat_varying) {
300      if (c->key.pv_first)
301         brw_clip_copy_flatshaded_attributes(c, 1, 0);
302      else
303         brw_clip_copy_flatshaded_attributes(c, 0, 1);
304   }
305
306   clip_and_emit_line(c);
307}
308