| /************************************************************************** |
| * |
| * 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> |
| */ |
| |
| /* Implement line stipple by cutting lines up into smaller lines. |
| * There are hundreds of ways to implement line stipple, this is one |
| * choice that should work in all situations, requires no state |
| * manipulations, but with a penalty in terms of large amounts of |
| * generated geometry. |
| */ |
| |
| |
| #include "pipe/p_defines.h" |
| #include "pipe/p_shader_tokens.h" |
| #include "util/u_math.h" |
| #include "util/u_memory.h" |
| |
| #include "draw/draw_pipe.h" |
| |
| |
| /** Subclass of draw_stage */ |
| struct stipple_stage { |
| struct draw_stage stage; |
| float counter; |
| uint pattern; |
| uint factor; |
| }; |
| |
| |
| static INLINE struct stipple_stage * |
| stipple_stage(struct draw_stage *stage) |
| { |
| return (struct stipple_stage *) stage; |
| } |
| |
| |
| /** |
| * Compute interpolated vertex attributes for 'dst' at position 't' |
| * between 'v0' and 'v1'. |
| * XXX using linear interpolation for all attribs at this time. |
| */ |
| static void |
| screen_interp( struct draw_context *draw, |
| struct vertex_header *dst, |
| float t, |
| const struct vertex_header *v0, |
| const struct vertex_header *v1 ) |
| { |
| uint attr; |
| int num_outputs = draw_current_shader_outputs(draw); |
| for (attr = 0; attr < num_outputs; attr++) { |
| const float *val0 = v0->data[attr]; |
| const float *val1 = v1->data[attr]; |
| float *newv = dst->data[attr]; |
| uint i; |
| for (i = 0; i < 4; i++) { |
| newv[i] = val0[i] + t * (val1[i] - val0[i]); |
| } |
| } |
| } |
| |
| |
| static void |
| emit_segment(struct draw_stage *stage, struct prim_header *header, |
| float t0, float t1) |
| { |
| struct vertex_header *v0new = dup_vert(stage, header->v[0], 0); |
| struct vertex_header *v1new = dup_vert(stage, header->v[1], 1); |
| struct prim_header newprim = *header; |
| |
| if (t0 > 0.0) { |
| screen_interp( stage->draw, v0new, t0, header->v[0], header->v[1] ); |
| newprim.v[0] = v0new; |
| } |
| |
| if (t1 < 1.0) { |
| screen_interp( stage->draw, v1new, t1, header->v[0], header->v[1] ); |
| newprim.v[1] = v1new; |
| } |
| |
| stage->next->line( stage->next, &newprim ); |
| } |
| |
| |
| static INLINE unsigned |
| stipple_test(int counter, ushort pattern, int factor) |
| { |
| int b = (counter / factor) & 0xf; |
| return (1 << b) & pattern; |
| } |
| |
| |
| static void |
| stipple_line(struct draw_stage *stage, struct prim_header *header) |
| { |
| struct stipple_stage *stipple = stipple_stage(stage); |
| struct vertex_header *v0 = header->v[0]; |
| struct vertex_header *v1 = header->v[1]; |
| const unsigned pos = draw_current_shader_position_output(stage->draw); |
| const float *pos0 = v0->data[pos]; |
| const float *pos1 = v1->data[pos]; |
| float start = 0; |
| int state = 0; |
| |
| float x0 = pos0[0]; |
| float x1 = pos1[0]; |
| float y0 = pos0[1]; |
| float y1 = pos1[1]; |
| |
| float dx = x0 > x1 ? x0 - x1 : x1 - x0; |
| float dy = y0 > y1 ? y0 - y1 : y1 - y0; |
| |
| float length = MAX2(dx, dy); |
| int i; |
| |
| if (header->flags & DRAW_PIPE_RESET_STIPPLE) |
| stipple->counter = 0; |
| |
| |
| /* XXX ToDo: intead of iterating pixel-by-pixel, use a look-up table. |
| */ |
| for (i = 0; i < length; i++) { |
| int result = stipple_test( (int) stipple->counter+i, |
| (ushort) stipple->pattern, stipple->factor ); |
| if (result != state) { |
| /* changing from "off" to "on" or vice versa */ |
| if (state) { |
| if (start != i) { |
| /* finishing an "on" segment */ |
| emit_segment( stage, header, start / length, i / length ); |
| } |
| } |
| else { |
| /* starting an "on" segment */ |
| start = (float) i; |
| } |
| state = result; |
| } |
| } |
| |
| if (state && start < length) |
| emit_segment( stage, header, start / length, 1.0 ); |
| |
| stipple->counter += length; |
| } |
| |
| |
| static void |
| reset_stipple_counter(struct draw_stage *stage) |
| { |
| struct stipple_stage *stipple = stipple_stage(stage); |
| stipple->counter = 0; |
| stage->next->reset_stipple_counter( stage->next ); |
| } |
| |
| static void |
| stipple_reset_point(struct draw_stage *stage, struct prim_header *header) |
| { |
| struct stipple_stage *stipple = stipple_stage(stage); |
| stipple->counter = 0; |
| stage->next->point(stage->next, header); |
| } |
| |
| static void |
| stipple_reset_tri(struct draw_stage *stage, struct prim_header *header) |
| { |
| struct stipple_stage *stipple = stipple_stage(stage); |
| stipple->counter = 0; |
| stage->next->tri(stage->next, header); |
| } |
| |
| |
| static void |
| stipple_first_line(struct draw_stage *stage, |
| struct prim_header *header) |
| { |
| struct stipple_stage *stipple = stipple_stage(stage); |
| struct draw_context *draw = stage->draw; |
| |
| stipple->pattern = draw->rasterizer->line_stipple_pattern; |
| stipple->factor = draw->rasterizer->line_stipple_factor + 1; |
| |
| stage->line = stipple_line; |
| stage->line( stage, header ); |
| } |
| |
| |
| static void |
| stipple_flush(struct draw_stage *stage, unsigned flags) |
| { |
| stage->line = stipple_first_line; |
| stage->next->flush( stage->next, flags ); |
| } |
| |
| |
| |
| |
| static void |
| stipple_destroy( struct draw_stage *stage ) |
| { |
| draw_free_temp_verts( stage ); |
| FREE( stage ); |
| } |
| |
| |
| /** |
| * Create line stippler stage |
| */ |
| struct draw_stage *draw_stipple_stage( struct draw_context *draw ) |
| { |
| struct stipple_stage *stipple = CALLOC_STRUCT(stipple_stage); |
| if (stipple == NULL) |
| goto fail; |
| |
| stipple->stage.draw = draw; |
| stipple->stage.name = "stipple"; |
| stipple->stage.next = NULL; |
| stipple->stage.point = stipple_reset_point; |
| stipple->stage.line = stipple_first_line; |
| stipple->stage.tri = stipple_reset_tri; |
| stipple->stage.reset_stipple_counter = reset_stipple_counter; |
| stipple->stage.flush = stipple_flush; |
| stipple->stage.destroy = stipple_destroy; |
| |
| if (!draw_alloc_temp_verts( &stipple->stage, 2 )) |
| goto fail; |
| |
| return &stipple->stage; |
| |
| fail: |
| if (stipple) |
| stipple->stage.destroy( &stipple->stage ); |
| |
| return NULL; |
| } |