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 (at) vmware.com> 29 */ 30 31 #include "util/u_math.h" 32 #include "util/u_memory.h" 33 #include "pipe/p_defines.h" 34 #include "pipe/p_shader_tokens.h" 35 #include "draw_vs.h" 36 #include "draw_pipe.h" 37 38 struct twoside_stage { 39 struct draw_stage stage; 40 float sign; /**< +1 or -1 */ 41 int attrib_front0, attrib_back0; 42 int attrib_front1, attrib_back1; 43 }; 44 45 46 static inline struct twoside_stage *twoside_stage( struct draw_stage *stage ) 47 { 48 return (struct twoside_stage *)stage; 49 } 50 51 /** 52 * Copy back color(s) to front color(s). 53 */ 54 static inline struct vertex_header * 55 copy_bfc( struct twoside_stage *twoside, 56 const struct vertex_header *v, 57 unsigned idx ) 58 { 59 struct vertex_header *tmp = dup_vert( &twoside->stage, v, idx ); 60 61 if (twoside->attrib_back0 >= 0 && twoside->attrib_front0 >= 0) { 62 COPY_4FV(tmp->data[twoside->attrib_front0], 63 tmp->data[twoside->attrib_back0]); 64 } 65 if (twoside->attrib_back1 >= 0 && twoside->attrib_front1 >= 0) { 66 COPY_4FV(tmp->data[twoside->attrib_front1], 67 tmp->data[twoside->attrib_back1]); 68 } 69 70 return tmp; 71 } 72 73 74 /* Twoside tri: 75 */ 76 static void twoside_tri( struct draw_stage *stage, 77 struct prim_header *header ) 78 { 79 struct twoside_stage *twoside = twoside_stage(stage); 80 81 if (header->det * twoside->sign < 0.0) { 82 /* this is a back-facing triangle */ 83 struct prim_header tmp; 84 85 tmp.det = header->det; 86 tmp.flags = header->flags; 87 tmp.pad = header->pad; 88 /* copy back attribs to front attribs */ 89 tmp.v[0] = copy_bfc(twoside, header->v[0], 0); 90 tmp.v[1] = copy_bfc(twoside, header->v[1], 1); 91 tmp.v[2] = copy_bfc(twoside, header->v[2], 2); 92 93 stage->next->tri( stage->next, &tmp ); 94 } 95 else { 96 stage->next->tri( stage->next, header ); 97 } 98 } 99 100 101 102 static void twoside_first_tri( struct draw_stage *stage, 103 struct prim_header *header ) 104 { 105 struct twoside_stage *twoside = twoside_stage(stage); 106 const struct draw_vertex_shader *vs = stage->draw->vs.vertex_shader; 107 uint i; 108 109 twoside->attrib_front0 = -1; 110 twoside->attrib_front1 = -1; 111 twoside->attrib_back0 = -1; 112 twoside->attrib_back1 = -1; 113 114 /* Find which vertex shader outputs are front/back colors */ 115 for (i = 0; i < vs->info.num_outputs; i++) { 116 if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_COLOR) { 117 if (vs->info.output_semantic_index[i] == 0) 118 twoside->attrib_front0 = i; 119 else 120 twoside->attrib_front1 = i; 121 } 122 if (vs->info.output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) { 123 if (vs->info.output_semantic_index[i] == 0) 124 twoside->attrib_back0 = i; 125 else 126 twoside->attrib_back1 = i; 127 } 128 } 129 130 /* 131 * We'll multiply the primitive's determinant by this sign to determine 132 * if the triangle is back-facing (negative). 133 * sign = -1 for CCW, +1 for CW 134 */ 135 twoside->sign = stage->draw->rasterizer->front_ccw ? -1.0f : 1.0f; 136 137 stage->tri = twoside_tri; 138 stage->tri( stage, header ); 139 } 140 141 142 static void twoside_flush( struct draw_stage *stage, unsigned flags ) 143 { 144 stage->tri = twoside_first_tri; 145 stage->next->flush( stage->next, flags ); 146 } 147 148 149 static void twoside_reset_stipple_counter( struct draw_stage *stage ) 150 { 151 stage->next->reset_stipple_counter( stage->next ); 152 } 153 154 155 static void twoside_destroy( struct draw_stage *stage ) 156 { 157 draw_free_temp_verts( stage ); 158 FREE( stage ); 159 } 160 161 162 /** 163 * Create twoside pipeline stage. 164 */ 165 struct draw_stage *draw_twoside_stage( struct draw_context *draw ) 166 { 167 struct twoside_stage *twoside = CALLOC_STRUCT(twoside_stage); 168 if (!twoside) 169 goto fail; 170 171 twoside->stage.draw = draw; 172 twoside->stage.name = "twoside"; 173 twoside->stage.next = NULL; 174 twoside->stage.point = draw_pipe_passthrough_point; 175 twoside->stage.line = draw_pipe_passthrough_line; 176 twoside->stage.tri = twoside_first_tri; 177 twoside->stage.flush = twoside_flush; 178 twoside->stage.reset_stipple_counter = twoside_reset_stipple_counter; 179 twoside->stage.destroy = twoside_destroy; 180 181 if (!draw_alloc_temp_verts( &twoside->stage, 3 )) 182 goto fail; 183 184 return &twoside->stage; 185 186 fail: 187 if (twoside) 188 twoside->stage.destroy( &twoside->stage ); 189 190 return NULL; 191 } 192
