1 /**************************************************************************
2 *
3 * Copyright 2010, 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 #include "util/u_bitcast.h"
29 #include <math.h>
30
TAG(do_cliptest)31 static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
32 struct draw_vertex_info *info,
33 const struct draw_prim_info *prim_info )
34 {
35 struct vertex_header *out = info->verts;
36 /* const */ float (*plane)[4] = pvs->draw->plane;
37 const unsigned pos = draw_current_shader_position_output(pvs->draw);
38 const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
39 unsigned cd[2];
40 const unsigned ef = pvs->draw->vs.edgeflag_output;
41 unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
42 unsigned flags = (FLAGS);
43 unsigned need_pipeline = 0;
44 unsigned j;
45 unsigned i;
46 bool have_cd = false;
47 bool uses_vp_idx = draw_current_shader_uses_viewport_index(pvs->draw);
48 unsigned viewport_index_output =
49 draw_current_shader_viewport_index_output(pvs->draw);
50 int viewport_index = 0;
51 int num_written_clipdistance =
52 draw_current_shader_num_written_clipdistances(pvs->draw);
53
54 if (uses_vp_idx) {
55 viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
56 viewport_index = draw_clamp_viewport_idx(viewport_index);
57 }
58
59 cd[0] = draw_current_shader_ccdistance_output(pvs->draw, 0);
60 cd[1] = draw_current_shader_ccdistance_output(pvs->draw, 1);
61
62 if (cd[0] != pos || cd[1] != pos)
63 have_cd = true;
64
65 /* If clipdistance semantic has been written by the shader
66 * that means we're expected to do 'user plane clipping' */
67 if (num_written_clipdistance && !(flags & DO_CLIP_USER)) {
68 flags |= DO_CLIP_USER;
69 ucp_enable = (1 << num_written_clipdistance) - 1;
70 }
71
72 assert(pos != -1);
73 unsigned prim_idx = 0, prim_vert_idx = 0;
74 for (j = 0; j < info->count; j++) {
75 float *position = out->data[pos];
76 unsigned mask = 0x0;
77
78 if (uses_vp_idx) {
79 /* only change the viewport_index for the leading vertex */
80 if (prim_vert_idx == (prim_info->primitive_lengths[prim_idx])) {
81 prim_idx++;
82 prim_vert_idx = 0;
83 viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
84 viewport_index = draw_clamp_viewport_idx(viewport_index);
85 }
86 prim_vert_idx++;
87 }
88 float *scale = pvs->draw->viewports[viewport_index].scale;
89 float *trans = pvs->draw->viewports[viewport_index].translate;
90 initialize_vertex_header(out);
91
92 if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
93 DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
94 float *clipvertex = position;
95
96 if ((flags & DO_CLIP_USER) && cv != pos) {
97 assert(cv != -1);
98 clipvertex = out->data[cv];
99 }
100
101 for (i = 0; i < 4; i++) {
102 out->clip_pos[i] = position[i];
103 }
104
105 /* Be careful with NaNs. Comparisons must be true for them. */
106 /* Do the hardwired planes first:
107 */
108 if (flags & DO_CLIP_XY_GUARD_BAND) {
109 if (!(-0.50 * position[0] + position[3] >= 0)) mask |= (1<<0);
110 if (!( 0.50 * position[0] + position[3] >= 0)) mask |= (1<<1);
111 if (!(-0.50 * position[1] + position[3] >= 0)) mask |= (1<<2);
112 if (!( 0.50 * position[1] + position[3] >= 0)) mask |= (1<<3);
113 }
114 else if (flags & DO_CLIP_XY) {
115 if (!(-position[0] + position[3] >= 0)) mask |= (1<<0);
116 if (!( position[0] + position[3] >= 0)) mask |= (1<<1);
117 if (!(-position[1] + position[3] >= 0)) mask |= (1<<2);
118 if (!( position[1] + position[3] >= 0)) mask |= (1<<3);
119 }
120
121 /* Clip Z planes according to full cube, half cube or none.
122 */
123 if (flags & DO_CLIP_FULL_Z) {
124 if (!( position[2] + position[3] >= 0)) mask |= (1<<4);
125 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
126 }
127 else if (flags & DO_CLIP_HALF_Z) {
128 if (!( position[2] >= 0)) mask |= (1<<4);
129 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
130 }
131
132 if (flags & DO_CLIP_USER) {
133 unsigned ucp_mask = ucp_enable;
134
135 while (ucp_mask) {
136 unsigned plane_idx = ffs(ucp_mask)-1;
137 ucp_mask &= ~(1 << plane_idx);
138 plane_idx += 6;
139
140 /*
141 * for user clipping check if we have a clip distance output
142 * and the shader has written to it, otherwise use clipvertex
143 * to decide when the plane is clipping.
144 */
145 if (have_cd && num_written_clipdistance) {
146 float clipdist;
147 i = plane_idx - 6;
148 /* first four clip distance in first vector etc. */
149 if (i < 4)
150 clipdist = out->data[cd[0]][i];
151 else
152 clipdist = out->data[cd[1]][i-4];
153 if (clipdist < 0 || util_is_inf_or_nan(clipdist))
154 mask |= 1 << plane_idx;
155 } else {
156 if (!(dot4(clipvertex, plane[plane_idx]) >= 0))
157 mask |= 1 << plane_idx;
158 }
159 }
160 }
161
162 out->clipmask = mask;
163 need_pipeline |= out->clipmask;
164 }
165
166 /*
167 * Transform the vertex position from clip coords to window coords,
168 * if the vertex is unclipped.
169 */
170 if ((flags & DO_VIEWPORT) && mask == 0)
171 {
172 /* divide by w */
173 float w = 1.0f / position[3];
174
175 /* Viewport mapping */
176 position[0] = position[0] * w * scale[0] + trans[0];
177 position[1] = position[1] * w * scale[1] + trans[1];
178 position[2] = position[2] * w * scale[2] + trans[2];
179 position[3] = w;
180 }
181 #ifdef DEBUG
182 /* For debug builds, set the clipped vertex's window coordinate
183 * to NaN to help catch potential errors later.
184 */
185 else {
186 position[0] =
187 position[1] =
188 position[2] =
189 position[3] = NAN;
190 }
191 #endif
192
193 if ((flags & DO_EDGEFLAG) && ef) {
194 const float *edgeflag = out->data[ef];
195 out->edgeflag = !(edgeflag[0] != 1.0f);
196 need_pipeline |= !out->edgeflag;
197 }
198
199 out = (struct vertex_header *)( (char *)out + info->stride );
200 }
201 return need_pipeline != 0;
202 }
203
204
205 #undef FLAGS
206 #undef TAG
207