1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
|
/*
* Mesa 3-D graphics library
* Version: 7.0
*
* Copyright (C) 1999-2007 Brian Paul 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, sublicense,
* 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 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 NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL 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.
*/
/*
* Line Rasterizer Template
*
* This file is #include'd to generate custom line rasterizers.
*
* The following macros may be defined to indicate what auxillary information
* must be interplated along the line:
* INTERP_Z - if defined, interpolate Z values
* INTERP_ATTRIBS - if defined, interpolate attribs (texcoords, varying, etc)
*
* When one can directly address pixels in the color buffer the following
* macros can be defined and used to directly compute pixel addresses during
* rasterization (see pixelPtr):
* PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint)
* BYTES_PER_ROW - number of bytes per row in the color buffer
* PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where
* Y==0 at bottom of screen and increases upward.
*
* Similarly, for direct depth buffer access, this type is used for depth
* buffer addressing:
* DEPTH_TYPE - either GLushort or GLuint
*
* Optionally, one may provide one-time setup code
* SETUP_CODE - code which is to be executed once per line
*
* To actually "plot" each pixel the PLOT macro must be defined...
* PLOT(X,Y) - code to plot a pixel. Example:
* if (Z < *zPtr) {
* *zPtr = Z;
* color = pack_rgb( FixedToInt(r0), FixedToInt(g0),
* FixedToInt(b0) );
* put_pixel( X, Y, color );
* }
*
* This code was designed for the origin to be in the lower-left corner.
*
*/
static void
NAME( GLcontext *ctx, const SWvertex *vert0, const SWvertex *vert1 )
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
SWspan span;
GLuint interpFlags = 0;
GLint x0 = (GLint) vert0->attrib[FRAG_ATTRIB_WPOS][0];
GLint x1 = (GLint) vert1->attrib[FRAG_ATTRIB_WPOS][0];
GLint y0 = (GLint) vert0->attrib[FRAG_ATTRIB_WPOS][1];
GLint y1 = (GLint) vert1->attrib[FRAG_ATTRIB_WPOS][1];
GLint dx, dy;
GLint numPixels;
GLint xstep, ystep;
#if defined(DEPTH_TYPE)
const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
struct gl_renderbuffer *zrb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
#define FixedToDepth(F) ((F) >> fixedToDepthShift)
GLint zPtrXstep, zPtrYstep;
DEPTH_TYPE *zPtr;
#elif defined(INTERP_Z)
const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
/*ctx->Visual.depthBits;*/
#endif
#ifdef PIXEL_ADDRESS
PIXEL_TYPE *pixelPtr;
GLint pixelXstep, pixelYstep;
#endif
#ifdef SETUP_CODE
SETUP_CODE
#endif
(void) swrast;
/* Cull primitives with malformed coordinates.
*/
{
GLfloat tmp = vert0->attrib[FRAG_ATTRIB_WPOS][0] + vert0->attrib[FRAG_ATTRIB_WPOS][1]
+ vert1->attrib[FRAG_ATTRIB_WPOS][0] + vert1->attrib[FRAG_ATTRIB_WPOS][1];
if (IS_INF_OR_NAN(tmp))
return;
}
/*
printf("%s():\n", __FUNCTION__);
printf(" (%f, %f, %f) -> (%f, %f, %f)\n",
vert0->attrib[FRAG_ATTRIB_WPOS][0],
vert0->attrib[FRAG_ATTRIB_WPOS][1],
vert0->attrib[FRAG_ATTRIB_WPOS][2],
vert1->attrib[FRAG_ATTRIB_WPOS][0],
vert1->attrib[FRAG_ATTRIB_WPOS][1],
vert1->attrib[FRAG_ATTRIB_WPOS][2]);
printf(" (%d, %d, %d) -> (%d, %d, %d)\n",
vert0->color[0], vert0->color[1], vert0->color[2],
vert1->color[0], vert1->color[1], vert1->color[2]);
printf(" (%d, %d, %d) -> (%d, %d, %d)\n",
vert0->specular[0], vert0->specular[1], vert0->specular[2],
vert1->specular[0], vert1->specular[1], vert1->specular[2]);
*/
/*
* Despite being clipped to the view volume, the line's window coordinates
* may just lie outside the window bounds. That is, if the legal window
* coordinates are [0,W-1][0,H-1], it's possible for x==W and/or y==H.
* This quick and dirty code nudges the endpoints inside the window if
* necessary.
*/
#ifdef CLIP_HACK
{
GLint w = ctx->DrawBuffer->Width;
GLint h = ctx->DrawBuffer->Height;
if ((x0==w) | (x1==w)) {
if ((x0==w) & (x1==w))
return;
x0 -= x0==w;
x1 -= x1==w;
}
if ((y0==h) | (y1==h)) {
if ((y0==h) & (y1==h))
return;
y0 -= y0==h;
y1 -= y1==h;
}
}
#endif
dx = x1 - x0;
dy = y1 - y0;
if (dx == 0 && dy == 0)
return;
/*
printf("%s %d,%d %g %g %g %g %g %g %g %g\n", __FUNCTION__, dx, dy,
vert0->attrib[FRAG_ATTRIB_COL1][0],
vert0->attrib[FRAG_ATTRIB_COL1][1],
vert0->attrib[FRAG_ATTRIB_COL1][2],
vert0->attrib[FRAG_ATTRIB_COL1][3],
vert1->attrib[FRAG_ATTRIB_COL1][0],
vert1->attrib[FRAG_ATTRIB_COL1][1],
vert1->attrib[FRAG_ATTRIB_COL1][2],
vert1->attrib[FRAG_ATTRIB_COL1][3]);
*/
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) zrb->GetPointer(ctx, zrb, x0, y0);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE *) PIXEL_ADDRESS(x0,y0);
#endif
if (dx<0) {
dx = -dx; /* make positive */
xstep = -1;
#ifdef DEPTH_TYPE
zPtrXstep = -((GLint)sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = -((GLint)sizeof(PIXEL_TYPE));
#endif
}
else {
xstep = 1;
#ifdef DEPTH_TYPE
zPtrXstep = ((GLint)sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = ((GLint)sizeof(PIXEL_TYPE));
#endif
}
if (dy<0) {
dy = -dy; /* make positive */
ystep = -1;
#ifdef DEPTH_TYPE
zPtrYstep = -((GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE)));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = BYTES_PER_ROW;
#endif
}
else {
ystep = 1;
#ifdef DEPTH_TYPE
zPtrYstep = (GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = -(BYTES_PER_ROW);
#endif
}
ASSERT(dx >= 0);
ASSERT(dy >= 0);
numPixels = MAX2(dx, dy);
/*
* Span setup: compute start and step values for all interpolated values.
*/
interpFlags |= SPAN_RGBA;
if (ctx->Light.ShadeModel == GL_SMOOTH) {
span.red = ChanToFixed(vert0->color[0]);
span.green = ChanToFixed(vert0->color[1]);
span.blue = ChanToFixed(vert0->color[2]);
span.alpha = ChanToFixed(vert0->color[3]);
span.redStep = (ChanToFixed(vert1->color[0]) - span.red ) / numPixels;
span.greenStep = (ChanToFixed(vert1->color[1]) - span.green) / numPixels;
span.blueStep = (ChanToFixed(vert1->color[2]) - span.blue ) / numPixels;
span.alphaStep = (ChanToFixed(vert1->color[3]) - span.alpha) / numPixels;
}
else {
span.red = ChanToFixed(vert1->color[0]);
span.green = ChanToFixed(vert1->color[1]);
span.blue = ChanToFixed(vert1->color[2]);
span.alpha = ChanToFixed(vert1->color[3]);
span.redStep = 0;
span.greenStep = 0;
span.blueStep = 0;
span.alphaStep = 0;
}
#if defined(INTERP_Z) || defined(DEPTH_TYPE)
interpFlags |= SPAN_Z;
{
if (depthBits <= 16) {
span.z = FloatToFixed(vert0->attrib[FRAG_ATTRIB_WPOS][2]) + FIXED_HALF;
span.zStep = FloatToFixed( vert1->attrib[FRAG_ATTRIB_WPOS][2]
- vert0->attrib[FRAG_ATTRIB_WPOS][2]) / numPixels;
}
else {
/* don't use fixed point */
span.z = (GLuint) vert0->attrib[FRAG_ATTRIB_WPOS][2];
span.zStep = (GLint) (( vert1->attrib[FRAG_ATTRIB_WPOS][2]
- vert0->attrib[FRAG_ATTRIB_WPOS][2]) / numPixels);
}
}
#endif
#if defined(INTERP_ATTRIBS)
{
const GLfloat invLen = 1.0F / numPixels;
const GLfloat invw0 = vert0->attrib[FRAG_ATTRIB_WPOS][3];
const GLfloat invw1 = vert1->attrib[FRAG_ATTRIB_WPOS][3];
span.attrStart[FRAG_ATTRIB_WPOS][3] = invw0;
span.attrStepX[FRAG_ATTRIB_WPOS][3] = (invw1 - invw0) * invLen;
span.attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0;
ATTRIB_LOOP_BEGIN
if (swrast->_InterpMode[attr] == GL_FLAT) {
COPY_4V(span.attrStart[attr], vert1->attrib[attr]);
ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0);
}
else {
GLuint c;
for (c = 0; c < 4; c++) {
float da;
span.attrStart[attr][c] = invw0 * vert0->attrib[attr][c];
da = (invw1 * vert1->attrib[attr][c]) - span.attrStart[attr][c];
span.attrStepX[attr][c] = da * invLen;
}
}
ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0);
ATTRIB_LOOP_END
}
#endif
INIT_SPAN(span, GL_LINE);
span.end = numPixels;
span.interpMask = interpFlags;
span.arrayMask = SPAN_XY;
span.facing = swrast->PointLineFacing;
/*
* Draw
*/
if (dx > dy) {
/*** X-major line ***/
GLint i;
GLint errorInc = dy+dy;
GLint error = errorInc-dx;
GLint errorDec = error-dx;
for (i = 0; i < dx; i++) {
#ifdef DEPTH_TYPE
GLuint Z = FixedToDepth(span.z);
#endif
#ifdef PLOT
PLOT( x0, y0 );
#else
span.array->x[i] = x0;
span.array->y[i] = y0;
#endif
x0 += xstep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep);
span.z += span.zStep;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
if (error < 0) {
error += errorInc;
}
else {
error += errorDec;
y0 += ystep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrYstep);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep);
#endif
}
}
}
else {
/*** Y-major line ***/
GLint i;
GLint errorInc = dx+dx;
GLint error = errorInc-dy;
GLint errorDec = error-dy;
for (i=0;i<dy;i++) {
#ifdef DEPTH_TYPE
GLuint Z = FixedToDepth(span.z);
#endif
#ifdef PLOT
PLOT( x0, y0 );
#else
span.array->x[i] = x0;
span.array->y[i] = y0;
#endif
y0 += ystep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrYstep);
span.z += span.zStep;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep);
#endif
if (error<0) {
error += errorInc;
}
else {
error += errorDec;
x0 += xstep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
}
}
}
#ifdef RENDER_SPAN
RENDER_SPAN( span );
#endif
(void)span;
}
#undef NAME
#undef INTERP_Z
#undef INTERP_ATTRIBS
#undef PIXEL_ADDRESS
#undef PIXEL_TYPE
#undef DEPTH_TYPE
#undef BYTES_PER_ROW
#undef SETUP_CODE
#undef PLOT
#undef CLIP_HACK
#undef FixedToDepth
#undef RENDER_SPAN
|
