1/*
2 * Mesa 3-D graphics library
3 * Version:  7.1
4 *
5 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
21 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25
26/*
27 * Antialiased line template.
28 */
29
30
31/*
32 * Function to render each fragment in the AA line.
33 * \param ix  - integer fragment window X coordiante
34 * \param iy  - integer fragment window Y coordiante
35 */
36static void
37NAME(plot)(struct gl_context *ctx, struct LineInfo *line, int ix, int iy)
38{
39   const SWcontext *swrast = SWRAST_CONTEXT(ctx);
40   const GLfloat fx = (GLfloat) ix;
41   const GLfloat fy = (GLfloat) iy;
42   const GLfloat coverage = compute_coveragef(line, ix, iy);
43   const GLuint i = line->span.end;
44
45   (void) swrast;
46
47   if (coverage == 0.0)
48      return;
49
50   line->span.end++;
51   line->span.array->coverage[i] = coverage;
52   line->span.array->x[i] = ix;
53   line->span.array->y[i] = iy;
54
55   /*
56    * Compute Z, color, texture coords, fog for the fragment by
57    * solving the plane equations at (ix,iy).
58    */
59#ifdef DO_Z
60   line->span.array->z[i] = (GLuint) solve_plane(fx, fy, line->zPlane);
61#endif
62   line->span.array->rgba[i][RCOMP] = solve_plane_chan(fx, fy, line->rPlane);
63   line->span.array->rgba[i][GCOMP] = solve_plane_chan(fx, fy, line->gPlane);
64   line->span.array->rgba[i][BCOMP] = solve_plane_chan(fx, fy, line->bPlane);
65   line->span.array->rgba[i][ACOMP] = solve_plane_chan(fx, fy, line->aPlane);
66#if defined(DO_ATTRIBS)
67   ATTRIB_LOOP_BEGIN
68      GLfloat (*attribArray)[4] = line->span.array->attribs[attr];
69      if (attr >= FRAG_ATTRIB_TEX0 && attr < FRAG_ATTRIB_VAR0
70          && !_swrast_use_fragment_program(ctx)) {
71         /* texcoord w/ divide by Q */
72         const GLuint unit = attr - FRAG_ATTRIB_TEX0;
73         const GLfloat invQ = solve_plane_recip(fx, fy, line->attrPlane[attr][3]);
74         GLuint c;
75         for (c = 0; c < 3; c++) {
76            attribArray[i][c] = solve_plane(fx, fy, line->attrPlane[attr][c]) * invQ;
77         }
78         line->span.array->lambda[unit][i]
79            = compute_lambda(line->attrPlane[attr][0],
80                             line->attrPlane[attr][1], invQ,
81                             line->texWidth[attr], line->texHeight[attr]);
82      }
83      else {
84         /* non-texture attrib */
85         const GLfloat invW = solve_plane_recip(fx, fy, line->wPlane);
86         GLuint c;
87         for (c = 0; c < 4; c++) {
88            attribArray[i][c] = solve_plane(fx, fy, line->attrPlane[attr][c]) * invW;
89         }
90      }
91   ATTRIB_LOOP_END
92#endif
93
94   if (line->span.end == SWRAST_MAX_WIDTH) {
95      _swrast_write_rgba_span(ctx, &(line->span));
96      line->span.end = 0; /* reset counter */
97   }
98}
99
100
101
102/*
103 * Line setup
104 */
105static void
106NAME(line)(struct gl_context *ctx, const SWvertex *v0, const SWvertex *v1)
107{
108   SWcontext *swrast = SWRAST_CONTEXT(ctx);
109   GLfloat tStart, tEnd;   /* segment start, end along line length */
110   GLboolean inSegment;
111   GLint iLen, i;
112
113   /* Init the LineInfo struct */
114   struct LineInfo line;
115   line.x0 = v0->attrib[FRAG_ATTRIB_WPOS][0];
116   line.y0 = v0->attrib[FRAG_ATTRIB_WPOS][1];
117   line.x1 = v1->attrib[FRAG_ATTRIB_WPOS][0];
118   line.y1 = v1->attrib[FRAG_ATTRIB_WPOS][1];
119   line.dx = line.x1 - line.x0;
120   line.dy = line.y1 - line.y0;
121   line.len = SQRTF(line.dx * line.dx + line.dy * line.dy);
122   line.halfWidth = 0.5F * CLAMP(ctx->Line.Width,
123                                 ctx->Const.MinLineWidthAA,
124                                 ctx->Const.MaxLineWidthAA);
125
126   if (line.len == 0.0 || IS_INF_OR_NAN(line.len))
127      return;
128
129   INIT_SPAN(line.span, GL_LINE);
130   line.span.arrayMask = SPAN_XY | SPAN_COVERAGE;
131   line.span.facing = swrast->PointLineFacing;
132   line.xAdj = line.dx / line.len * line.halfWidth;
133   line.yAdj = line.dy / line.len * line.halfWidth;
134
135#ifdef DO_Z
136   line.span.arrayMask |= SPAN_Z;
137   compute_plane(line.x0, line.y0, line.x1, line.y1,
138                 v0->attrib[FRAG_ATTRIB_WPOS][2], v1->attrib[FRAG_ATTRIB_WPOS][2], line.zPlane);
139#endif
140   line.span.arrayMask |= SPAN_RGBA;
141   if (ctx->Light.ShadeModel == GL_SMOOTH) {
142      compute_plane(line.x0, line.y0, line.x1, line.y1,
143                    v0->color[RCOMP], v1->color[RCOMP], line.rPlane);
144      compute_plane(line.x0, line.y0, line.x1, line.y1,
145                    v0->color[GCOMP], v1->color[GCOMP], line.gPlane);
146      compute_plane(line.x0, line.y0, line.x1, line.y1,
147                    v0->color[BCOMP], v1->color[BCOMP], line.bPlane);
148      compute_plane(line.x0, line.y0, line.x1, line.y1,
149                    v0->color[ACOMP], v1->color[ACOMP], line.aPlane);
150   }
151   else {
152      constant_plane(v1->color[RCOMP], line.rPlane);
153      constant_plane(v1->color[GCOMP], line.gPlane);
154      constant_plane(v1->color[BCOMP], line.bPlane);
155      constant_plane(v1->color[ACOMP], line.aPlane);
156   }
157#if defined(DO_ATTRIBS)
158   {
159      const GLfloat invW0 = v0->attrib[FRAG_ATTRIB_WPOS][3];
160      const GLfloat invW1 = v1->attrib[FRAG_ATTRIB_WPOS][3];
161      line.span.arrayMask |= SPAN_LAMBDA;
162      compute_plane(line.x0, line.y0, line.x1, line.y1, invW0, invW1, line.wPlane);
163      ATTRIB_LOOP_BEGIN
164         GLuint c;
165         if (swrast->_InterpMode[attr] == GL_FLAT) {
166            for (c = 0; c < 4; c++) {
167               constant_plane(v1->attrib[attr][c], line.attrPlane[attr][c]);
168            }
169         }
170         else {
171            for (c = 0; c < 4; c++) {
172               const GLfloat a0 = v0->attrib[attr][c] * invW0;
173               const GLfloat a1 = v1->attrib[attr][c] * invW1;
174               compute_plane(line.x0, line.y0, line.x1, line.y1, a0, a1,
175                             line.attrPlane[attr][c]);
176            }
177         }
178         line.span.arrayAttribs |= BITFIELD64_BIT(attr);
179         if (attr >= FRAG_ATTRIB_TEX0 && attr < FRAG_ATTRIB_VAR0) {
180            const GLuint u = attr - FRAG_ATTRIB_TEX0;
181            const struct gl_texture_object *obj = ctx->Texture.Unit[u]._Current;
182            const struct gl_texture_image *texImage = obj->Image[0][obj->BaseLevel];
183            line.texWidth[attr]  = (GLfloat) texImage->Width;
184            line.texHeight[attr] = (GLfloat) texImage->Height;
185         }
186      ATTRIB_LOOP_END
187   }
188#endif
189
190   tStart = tEnd = 0.0;
191   inSegment = GL_FALSE;
192   iLen = (GLint) line.len;
193
194   if (ctx->Line.StippleFlag) {
195      for (i = 0; i < iLen; i++) {
196         const GLuint bit = (swrast->StippleCounter / ctx->Line.StippleFactor) & 0xf;
197         if ((1 << bit) & ctx->Line.StipplePattern) {
198            /* stipple bit is on */
199            const GLfloat t = (GLfloat) i / (GLfloat) line.len;
200            if (!inSegment) {
201               /* start new segment */
202               inSegment = GL_TRUE;
203               tStart = t;
204            }
205            else {
206               /* still in the segment, extend it */
207               tEnd = t;
208            }
209         }
210         else {
211            /* stipple bit is off */
212            if (inSegment && (tEnd > tStart)) {
213               /* draw the segment */
214               segment(ctx, &line, NAME(plot), tStart, tEnd);
215               inSegment = GL_FALSE;
216            }
217            else {
218               /* still between segments, do nothing */
219            }
220         }
221         swrast->StippleCounter++;
222      }
223
224      if (inSegment) {
225         /* draw the final segment of the line */
226         segment(ctx, &line, NAME(plot), tStart, 1.0F);
227      }
228   }
229   else {
230      /* non-stippled */
231      segment(ctx, &line, NAME(plot), 0.0, 1.0);
232   }
233
234   _swrast_write_rgba_span(ctx, &(line.span));
235}
236
237
238
239
240#undef DO_Z
241#undef DO_ATTRIBS
242#undef NAME
243