2 Copyright (C) Intel Corp. 2006. All Rights Reserved.
3 Intel funded Tungsten Graphics (http://www.tungstengraphics.com) to
4 develop this 3D driver.
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:
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.
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.
26 **********************************************************************/
29 * Keith Whitwell <keith@tungstengraphics.com>
36 #include "shader/program.h"
37 #include "intel_batchbuffer.h"
39 #include "brw_defines.h"
40 #include "brw_context.h"
47 static void brw_clip_line_alloc_regs( struct brw_clip_compile *c )
51 /* Register usage is static, precompute here:
53 c->reg.R0 = retype(brw_vec8_grf(i, 0), BRW_REGISTER_TYPE_UD); i++;
55 if (c->key.nr_userclip) {
56 c->reg.fixed_planes = brw_vec4_grf(i, 0);
57 i += (6 + c->key.nr_userclip + 1) / 2;
59 c->prog_data.curb_read_length = (6 + c->key.nr_userclip + 1) / 2;
62 c->prog_data.curb_read_length = 0;
65 /* Payload vertices plus space for more generated vertices:
67 for (j = 0; j < 4; j++) {
68 c->reg.vertex[j] = brw_vec4_grf(i, 0);
72 c->reg.t = brw_vec1_grf(i, 0);
73 c->reg.t0 = brw_vec1_grf(i, 1);
74 c->reg.t1 = brw_vec1_grf(i, 2);
75 c->reg.planemask = retype(brw_vec1_grf(i, 3), BRW_REGISTER_TYPE_UD);
76 c->reg.plane_equation = brw_vec4_grf(i, 4);
79 c->reg.dp0 = brw_vec1_grf(i, 0); /* fixme - dp4 will clobber r.1,2,3 */
80 c->reg.dp1 = brw_vec1_grf(i, 4);
83 if (!c->key.nr_userclip) {
84 c->reg.fixed_planes = brw_vec8_grf(i, 0);
92 c->prog_data.urb_read_length = c->nr_regs; /* ? */
93 c->prog_data.total_grf = i;
98 /* Line clipping, more or less following the following algorithm:
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] );
105 * if (IS_NEGATIVE(dp1)) {
106 * GLfloat t = dp1 / (dp1 - dp0);
107 * if (t > t1) t1 = t;
109 * GLfloat t = dp0 / (dp0 - dp1);
110 * if (t > t0) t0 = t;
113 * if (t0 + t1 >= 1.0)
118 * interp( ctx, newvtx0, vtx0, vtx1, t0 );
119 * interp( ctx, newvtx1, vtx1, vtx0, t1 );
122 static void clip_and_emit_line( struct brw_clip_compile *c )
124 struct brw_compile *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_instruction *plane_loop;
131 struct brw_instruction *plane_active;
132 struct brw_instruction *is_negative;
133 struct brw_instruction *is_neg2;
134 struct brw_instruction *not_culled;
135 struct brw_reg v1_null_ud = retype(vec1(brw_null_reg()), BRW_REGISTER_TYPE_UD);
137 brw_MOV(p, get_addr_reg(vtx0), brw_address(c->reg.vertex[0]));
138 brw_MOV(p, get_addr_reg(vtx1), brw_address(c->reg.vertex[1]));
139 brw_MOV(p, get_addr_reg(newvtx0), brw_address(c->reg.vertex[2]));
140 brw_MOV(p, get_addr_reg(newvtx1), brw_address(c->reg.vertex[3]));
141 brw_MOV(p, get_addr_reg(plane_ptr), brw_clip_plane0_address(c));
143 /* Note: init t0, t1 together:
145 brw_MOV(p, vec2(c->reg.t0), brw_imm_f(0));
147 brw_clip_init_planes(c);
148 brw_clip_init_clipmask(c);
150 plane_loop = brw_DO(p, BRW_EXECUTE_1);
152 /* if (planemask & 1)
154 brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
155 brw_AND(p, v1_null_ud, c->reg.planemask, brw_imm_ud(1));
157 plane_active = brw_IF(p, BRW_EXECUTE_1);
159 if (c->key.nr_userclip)
160 brw_MOV(p, c->reg.plane_equation, deref_4f(plane_ptr, 0));
162 brw_MOV(p, c->reg.plane_equation, deref_4b(plane_ptr, 0));
164 /* dp = DP4(vtx->position, plane)
166 brw_DP4(p, vec4(c->reg.dp0), deref_4f(vtx0, c->offset[VERT_RESULT_HPOS]), c->reg.plane_equation);
168 /* if (IS_NEGATIVE(dp1))
170 brw_set_conditionalmod(p, BRW_CONDITIONAL_L);
171 brw_DP4(p, vec4(c->reg.dp1), deref_4f(vtx1, c->offset[VERT_RESULT_HPOS]), c->reg.plane_equation);
172 is_negative = brw_IF(p, BRW_EXECUTE_1);
174 brw_ADD(p, c->reg.t, c->reg.dp1, negate(c->reg.dp0));
175 brw_math_invert(p, c->reg.t, c->reg.t);
176 brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp1);
178 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t1 );
179 brw_MOV(p, c->reg.t1, c->reg.t);
180 brw_set_predicate_control(p, BRW_PREDICATE_NONE);
182 is_negative = brw_ELSE(p, is_negative);
184 /* Coming back in. We know that both cannot be negative
185 * because the line would have been culled in that case.
188 /* If both are positive, do nothing */
189 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.dp0, brw_imm_f(0.0));
190 is_neg2 = brw_IF(p, BRW_EXECUTE_1);
192 brw_ADD(p, c->reg.t, c->reg.dp0, negate(c->reg.dp1));
193 brw_math_invert(p, c->reg.t, c->reg.t);
194 brw_MUL(p, c->reg.t, c->reg.t, c->reg.dp0);
196 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_G, c->reg.t, c->reg.t0 );
197 brw_MOV(p, c->reg.t0, c->reg.t);
198 brw_set_predicate_control(p, BRW_PREDICATE_NONE);
200 brw_ENDIF(p, is_neg2);
202 brw_ENDIF(p, is_negative);
204 brw_ENDIF(p, plane_active);
208 brw_ADD(p, get_addr_reg(plane_ptr), get_addr_reg(plane_ptr), brw_clip_plane_stride(c));
210 /* while (planemask>>=1) != 0
212 brw_set_conditionalmod(p, BRW_CONDITIONAL_NZ);
213 brw_SHR(p, c->reg.planemask, c->reg.planemask, brw_imm_ud(1));
215 brw_WHILE(p, plane_loop);
217 brw_ADD(p, c->reg.t, c->reg.t0, c->reg.t1);
218 brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L, c->reg.t, brw_imm_f(1.0));
219 not_culled = brw_IF(p, BRW_EXECUTE_1);
221 brw_clip_interp_vertex(c, newvtx0, vtx0, vtx1, c->reg.t0, GL_FALSE);
222 brw_clip_interp_vertex(c, newvtx1, vtx1, vtx0, c->reg.t1, GL_FALSE);
224 brw_clip_emit_vue(c, newvtx0, 1, 0, (_3DPRIM_LINESTRIP << 2) | R02_PRIM_START);
225 brw_clip_emit_vue(c, newvtx1, 0, 1, (_3DPRIM_LINESTRIP << 2) | R02_PRIM_END);
227 brw_ENDIF(p, not_culled);
228 brw_clip_kill_thread(c);
233 void brw_emit_line_clip( struct brw_clip_compile *c )
235 brw_clip_line_alloc_regs(c);
237 if (c->key.do_flat_shading)
238 brw_clip_copy_colors(c, 0, 1);
240 clip_and_emit_line(c);