1 /************************************************************************** 2 * 3 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas. 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 TUNGSTEN GRAPHICS 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 <keith (at) tungstengraphics.com> 29 */ 30 31 #include "pipe/p_context.h" 32 #include "pipe/p_defines.h" 33 #include "pipe/p_shader_tokens.h" 34 #include "util/u_math.h" 35 #include "util/u_memory.h" 36 #include "draw_private.h" 37 #include "draw_pipe.h" 38 39 40 struct wideline_stage { 41 struct draw_stage stage; 42 43 float half_line_width; 44 }; 45 46 47 48 static INLINE struct wideline_stage *wideline_stage( struct draw_stage *stage ) 49 { 50 return (struct wideline_stage *)stage; 51 } 52 53 54 55 /** 56 * Draw a wide line by drawing a quad (two triangles). 57 */ 58 static void wideline_line( struct draw_stage *stage, 59 struct prim_header *header ) 60 { 61 /*const struct wideline_stage *wide = wideline_stage(stage);*/ 62 const unsigned pos = draw_current_shader_position_output(stage->draw); 63 const float half_width = 0.5f * stage->draw->rasterizer->line_width; 64 65 struct prim_header tri; 66 67 struct vertex_header *v0 = dup_vert(stage, header->v[0], 0); 68 struct vertex_header *v1 = dup_vert(stage, header->v[0], 1); 69 struct vertex_header *v2 = dup_vert(stage, header->v[1], 2); 70 struct vertex_header *v3 = dup_vert(stage, header->v[1], 3); 71 72 float *pos0 = v0->data[pos]; 73 float *pos1 = v1->data[pos]; 74 float *pos2 = v2->data[pos]; 75 float *pos3 = v3->data[pos]; 76 77 const float dx = fabsf(pos0[0] - pos2[0]); 78 const float dy = fabsf(pos0[1] - pos2[1]); 79 80 const boolean gl_rasterization_rules = 81 stage->draw->rasterizer->gl_rasterization_rules; 82 83 /* small tweak to meet GL specification */ 84 const float bias = gl_rasterization_rules ? 0.125f : 0.0f; 85 86 /* 87 * Draw wide line as a quad (two tris) by "stretching" the line along 88 * X or Y. 89 * We need to tweak coords in several ways to be conformant here. 90 */ 91 92 if (dx > dy) { 93 /* x-major line */ 94 pos0[1] = pos0[1] - half_width - bias; 95 pos1[1] = pos1[1] + half_width - bias; 96 pos2[1] = pos2[1] - half_width - bias; 97 pos3[1] = pos3[1] + half_width - bias; 98 if (gl_rasterization_rules) { 99 if (pos0[0] < pos2[0]) { 100 /* left to right line */ 101 pos0[0] -= 0.5f; 102 pos1[0] -= 0.5f; 103 pos2[0] -= 0.5f; 104 pos3[0] -= 0.5f; 105 } 106 else { 107 /* right to left line */ 108 pos0[0] += 0.5f; 109 pos1[0] += 0.5f; 110 pos2[0] += 0.5f; 111 pos3[0] += 0.5f; 112 } 113 } 114 } 115 else { 116 /* y-major line */ 117 pos0[0] = pos0[0] - half_width + bias; 118 pos1[0] = pos1[0] + half_width + bias; 119 pos2[0] = pos2[0] - half_width + bias; 120 pos3[0] = pos3[0] + half_width + bias; 121 if (gl_rasterization_rules) { 122 if (pos0[1] < pos2[1]) { 123 /* top to bottom line */ 124 pos0[1] -= 0.5f; 125 pos1[1] -= 0.5f; 126 pos2[1] -= 0.5f; 127 pos3[1] -= 0.5f; 128 } 129 else { 130 /* bottom to top line */ 131 pos0[1] += 0.5f; 132 pos1[1] += 0.5f; 133 pos2[1] += 0.5f; 134 pos3[1] += 0.5f; 135 } 136 } 137 } 138 139 tri.det = header->det; /* only the sign matters */ 140 tri.v[0] = v0; 141 tri.v[1] = v2; 142 tri.v[2] = v3; 143 stage->next->tri( stage->next, &tri ); 144 145 tri.v[0] = v0; 146 tri.v[1] = v3; 147 tri.v[2] = v1; 148 stage->next->tri( stage->next, &tri ); 149 } 150 151 152 static void wideline_first_line( struct draw_stage *stage, 153 struct prim_header *header ) 154 { 155 struct draw_context *draw = stage->draw; 156 struct pipe_context *pipe = draw->pipe; 157 const struct pipe_rasterizer_state *rast = draw->rasterizer; 158 void *r; 159 160 /* Disable triangle culling, stippling, unfilled mode etc. */ 161 r = draw_get_rasterizer_no_cull(draw, rast->scissor, rast->flatshade); 162 draw->suspend_flushing = TRUE; 163 pipe->bind_rasterizer_state(pipe, r); 164 draw->suspend_flushing = FALSE; 165 166 stage->line = wideline_line; 167 168 wideline_line(stage, header); 169 } 170 171 172 static void wideline_flush( struct draw_stage *stage, unsigned flags ) 173 { 174 struct draw_context *draw = stage->draw; 175 struct pipe_context *pipe = draw->pipe; 176 177 stage->line = wideline_first_line; 178 stage->next->flush( stage->next, flags ); 179 180 /* restore original rasterizer state */ 181 if (draw->rast_handle) { 182 draw->suspend_flushing = TRUE; 183 pipe->bind_rasterizer_state(pipe, draw->rast_handle); 184 draw->suspend_flushing = FALSE; 185 } 186 } 187 188 189 static void wideline_reset_stipple_counter( struct draw_stage *stage ) 190 { 191 stage->next->reset_stipple_counter( stage->next ); 192 } 193 194 195 static void wideline_destroy( struct draw_stage *stage ) 196 { 197 draw_free_temp_verts( stage ); 198 FREE( stage ); 199 } 200 201 202 struct draw_stage *draw_wide_line_stage( struct draw_context *draw ) 203 { 204 struct wideline_stage *wide = CALLOC_STRUCT(wideline_stage); 205 if (wide == NULL) 206 goto fail; 207 208 wide->stage.draw = draw; 209 wide->stage.name = "wide-line"; 210 wide->stage.next = NULL; 211 wide->stage.point = draw_pipe_passthrough_point; 212 wide->stage.line = wideline_first_line; 213 wide->stage.tri = draw_pipe_passthrough_tri; 214 wide->stage.flush = wideline_flush; 215 wide->stage.reset_stipple_counter = wideline_reset_stipple_counter; 216 wide->stage.destroy = wideline_destroy; 217 218 if (!draw_alloc_temp_verts( &wide->stage, 4 )) 219 goto fail; 220 221 return &wide->stage; 222 223 fail: 224 if (wide) 225 wide->stage.destroy( &wide->stage ); 226 227 return NULL; 228 } 229
