/************************************************************************** * * Copyright 2007 VMware, Inc. * 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 VMWARE 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 */ /* 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; uint 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) 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; }