diff options
Diffstat (limited to 'src/gallium/auxiliary/draw/draw_pipe_wide_line.c')
| -rw-r--r-- | src/gallium/auxiliary/draw/draw_pipe_wide_line.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/draw/draw_pipe_wide_line.c b/src/gallium/auxiliary/draw/draw_pipe_wide_line.c new file mode 100644 index 0000000000..184e363594 --- /dev/null +++ b/src/gallium/auxiliary/draw/draw_pipe_wide_line.c @@ -0,0 +1,180 @@ +/************************************************************************** + * + * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas. + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sub license, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice (including the + * next paragraph) shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. + * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + **************************************************************************/ + +/* Authors: Keith Whitwell <keith@tungstengraphics.com> + */ + +#include "pipe/p_defines.h" +#include "pipe/p_shader_tokens.h" +#include "util/u_math.h" +#include "util/u_memory.h" +#include "draw_private.h" +#include "draw_pipe.h" + + +struct wideline_stage { + struct draw_stage stage; + + float half_line_width; +}; + + + +static INLINE struct wideline_stage *wideline_stage( struct draw_stage *stage ) +{ + return (struct wideline_stage *)stage; +} + + + +/** + * Draw a wide line by drawing a quad (two triangles). + * XXX need to disable polygon stipple. + */ +static void wideline_line( struct draw_stage *stage, + struct prim_header *header ) +{ + /*const struct wideline_stage *wide = wideline_stage(stage);*/ + const unsigned pos = stage->draw->vs.position_output; + const float half_width = 0.5f * stage->draw->rasterizer->line_width; + + struct prim_header tri; + + struct vertex_header *v0 = dup_vert(stage, header->v[0], 0); + struct vertex_header *v1 = dup_vert(stage, header->v[0], 1); + struct vertex_header *v2 = dup_vert(stage, header->v[1], 2); + struct vertex_header *v3 = dup_vert(stage, header->v[1], 3); + + float *pos0 = v0->data[pos]; + float *pos1 = v1->data[pos]; + float *pos2 = v2->data[pos]; + float *pos3 = v3->data[pos]; + + const float dx = fabsf(pos0[0] - pos2[0]); + const float dy = fabsf(pos0[1] - pos2[1]); + + /* small tweak to meet GL specification */ + const float bias = 0.125f; + + /* + * Draw wide line as a quad (two tris) by "stretching" the line along + * X or Y. + * We need to tweak coords in several ways to be conformant here. + */ + + if (dx > dy) { + /* x-major line */ + pos0[1] = pos0[1] - half_width - bias; + pos1[1] = pos1[1] + half_width - bias; + pos2[1] = pos2[1] - half_width - bias; + pos3[1] = pos3[1] + half_width - bias; + if (pos0[0] < pos2[0]) { + /* left to right line */ + pos0[0] -= 0.5f; + pos1[0] -= 0.5f; + pos2[0] -= 0.5f; + pos3[0] -= 0.5f; + } + else { + /* right to left line */ + pos0[0] += 0.5f; + pos1[0] += 0.5f; + pos2[0] += 0.5f; + pos3[0] += 0.5f; + } + } + else { + /* y-major line */ + pos0[0] = pos0[0] - half_width + bias; + pos1[0] = pos1[0] + half_width + bias; + pos2[0] = pos2[0] - half_width + bias; + pos3[0] = pos3[0] + half_width + bias; + if (pos0[1] < pos2[1]) { + /* top to bottom line */ + pos0[1] -= 0.5f; + pos1[1] -= 0.5f; + pos2[1] -= 0.5f; + pos3[1] -= 0.5f; + } + else { + /* bottom to top line */ + pos0[1] += 0.5f; + pos1[1] += 0.5f; + pos2[1] += 0.5f; + pos3[1] += 0.5f; + } + } + + tri.det = header->det; /* only the sign matters */ + tri.v[0] = v0; + tri.v[1] = v2; + tri.v[2] = v3; + stage->next->tri( stage->next, &tri ); + + tri.v[0] = v0; + tri.v[1] = v3; + tri.v[2] = v1; + stage->next->tri( stage->next, &tri ); +} + + +static void wideline_flush( struct draw_stage *stage, unsigned flags ) +{ + stage->next->flush( stage->next, flags ); +} + + +static void wideline_reset_stipple_counter( struct draw_stage *stage ) +{ + stage->next->reset_stipple_counter( stage->next ); +} + + +static void wideline_destroy( struct draw_stage *stage ) +{ + draw_free_temp_verts( stage ); + FREE( stage ); +} + + +struct draw_stage *draw_wide_line_stage( struct draw_context *draw ) +{ + struct wideline_stage *wide = CALLOC_STRUCT(wideline_stage); + + draw_alloc_temp_verts( &wide->stage, 4 ); + + wide->stage.draw = draw; + wide->stage.next = NULL; + wide->stage.point = draw_pipe_passthrough_point; + wide->stage.line = wideline_line; + wide->stage.tri = draw_pipe_passthrough_tri; + wide->stage.flush = wideline_flush; + wide->stage.reset_stipple_counter = wideline_reset_stipple_counter; + wide->stage.destroy = wideline_destroy; + + return &wide->stage; +} |