2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
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:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
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.
26 * Triangle Rasterizer Template
28 * This file is #include'd to generate custom triangle rasterizers.
30 * The following macros may be defined to indicate what auxillary information
31 * must be interplated across the triangle:
32 * INTERP_Z - if defined, interpolate vertex Z values
33 * INTERP_W - if defined, interpolate vertex W values
34 * INTERP_FOG - if defined, interpolate fog values
35 * INTERP_RGB - if defined, interpolate RGB values
36 * INTERP_ALPHA - if defined, interpolate Alpha values (req's INTERP_RGB)
37 * INTERP_SPEC - if defined, interpolate specular RGB values
38 * INTERP_INDEX - if defined, interpolate color index values
39 * INTERP_INT_TEX - if defined, interpolate integer ST texcoords
40 * (fast, simple 2-D texture mapping)
41 * INTERP_TEX - if defined, interpolate set 0 float STRQ texcoords
42 * NOTE: OpenGL STRQ = Mesa STUV (R was taken for red)
43 * INTERP_MULTITEX - if defined, interpolate N units of STRQ texcoords
45 * When one can directly address pixels in the color buffer the following
46 * macros can be defined and used to compute pixel addresses during
47 * rasterization (see pRow):
48 * PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint)
49 * BYTES_PER_ROW - number of bytes per row in the color buffer
50 * PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where
51 * Y==0 at bottom of screen and increases upward.
53 * Similarly, for direct depth buffer access, this type is used for depth
55 * DEPTH_TYPE - either GLushort or GLuint
57 * Optionally, one may provide one-time setup code per triangle:
58 * SETUP_CODE - code which is to be executed once per triangle
59 * CLEANUP_CODE - code to execute at end of triangle
61 * The following macro MUST be defined:
62 * RENDER_SPAN(span) - code to write a span of pixels.
64 * This code was designed for the origin to be in the lower-left corner.
66 * Inspired by triangle rasterizer code written by Allen Akin. Thanks Allen!
69 * Some notes on rasterization accuracy:
71 * This code uses fixed point arithmetic (the GLfixed type) to iterate
72 * over the triangle edges and interpolate ancillary data (such as Z,
73 * color, secondary color, etc). The number of fractional bits in
74 * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the
75 * accuracy of rasterization.
77 * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest
78 * 1/16 of a pixel. If we're walking up a long, nearly vertical edge
79 * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in
80 * GLfixed to walk the edge without error. If the maximum viewport
81 * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits.
83 * Historically, Mesa has used 11 fractional bits in GLfixed, snaps
84 * vertices to 1/16 pixel and allowed a maximum viewport height of 2K
85 * pixels. 11 fractional bits is actually insufficient for accurately
86 * rasterizing some triangles. More recently, the maximum viewport
87 * height was increased to 4K pixels. Thus, Mesa should be using 16
88 * fractional bits in GLfixed. Unfortunately, there may be some issues
89 * with setting FIXED_FRAC_BITS=16, such as multiplication overflow.
90 * This will have to be examined in some detail...
92 * For now, if you find rasterization errors, particularly with tall,
93 * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing
98 * ColorTemp is used for intermediate color values.
100 #if CHAN_TYPE == GL_FLOAT
101 #define ColorTemp GLfloat
103 #define ColorTemp GLint /* same as GLfixed */
108 * Walk triangle edges with GLfixed or GLdouble
110 #if TRIANGLE_WALK_DOUBLE
111 #define GLinterp GLdouble
112 #define InterpToInt(X) ((GLint) (X))
113 #define INTERP_ONE 1.0
115 #define GLinterp GLfixed
116 #define InterpToInt(X) FixedToInt(X)
117 #define INTERP_ONE FIXED_ONE
122 * Either loop over all texture units, or just use unit zero.
124 #ifdef INTERP_MULTITEX
125 #define TEX_UNIT_LOOP(CODE) \
128 for (u = 0; u < ctx->Const.MaxTextureUnits; u++) { \
129 if (ctx->Texture._EnabledCoordUnits & (1 << u)) { \
135 #elif defined(INTERP_TEX)
136 #define TEX_UNIT_LOOP(CODE) \
138 const GLuint u = 0; \
146 * Some code we unfortunately need to prevent negative interpolated colors.
148 #ifndef CLAMP_INTERPOLANT
149 #define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN) \
151 GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP; \
153 span.CHANNEL -= endVal; \
155 if (span.CHANNEL < 0) { \
162 static void NAME(GLcontext
*ctx
, const SWvertex
*v0
,
167 const SWvertex
*v0
, *v1
; /* Y(v0) < Y(v1) */
168 #if TRIANGLE_WALK_DOUBLE
169 GLdouble dx
; /* X(v1) - X(v0) */
170 GLdouble dy
; /* Y(v1) - Y(v0) */
171 GLdouble dxdy
; /* dx/dy */
172 GLdouble adjy
; /* adjust from v[0]->fy to fsy, scaled */
173 GLdouble fsx
; /* first sample point x coord */
175 GLdouble fx0
; /*X of lower endpoint */
177 GLfloat dx
; /* X(v1) - X(v0) */
178 GLfloat dy
; /* Y(v1) - Y(v0) */
179 GLfloat dxdy
; /* dx/dy */
180 GLfixed fdxdy
; /* dx/dy in fixed-point */
181 GLfloat adjy
; /* adjust from v[0]->fy to fsy, scaled */
182 GLfixed fsx
; /* first sample point x coord */
184 GLfixed fx0
; /* fixed pt X of lower endpoint */
186 GLint lines
; /* number of lines to be sampled on this edge */
190 const GLint depthBits
= ctx
->DrawBuffer
->Visual
.depthBits
;
191 const GLint fixedToDepthShift
= depthBits
<= 16 ? FIXED_SHIFT
: 0;
192 const GLfloat maxDepth
= ctx
->DrawBuffer
->_DepthMaxF
;
193 #define FixedToDepth(F) ((F) >> fixedToDepthShift)
195 EdgeT eMaj
, eTop
, eBot
;
197 const SWvertex
*vMin
, *vMid
, *vMax
; /* Y(vMin)<=Y(vMid)<=Y(vMax) */
198 GLfloat bf
= SWRAST_CONTEXT(ctx
)->_BackfaceSign
;
199 #if !TRIANGLE_WALK_DOUBLE
200 const GLint snapMask
= ~((FIXED_ONE
/ (1 << SUB_PIXEL_BITS
)) - 1); /* for x/y coord snapping */
202 GLinterp vMin_fx
, vMin_fy
, vMid_fx
, vMid_fy
, vMax_fx
, vMax_fy
;
206 INIT_SPAN(span
, GL_POLYGON
, 0, 0, 0);
209 (void) fixedToDepthShift
;
213 printf("%s()\n", __FUNCTION__);
214 printf(" %g, %g, %g\n", v0->win[0], v0->win[1], v0->win[2]);
215 printf(" %g, %g, %g\n", v1->win[0], v1->win[1], v1->win[2]);
216 printf(" %g, %g, %g\n", v2->win[0], v2->win[1], v2->win[2]);
219 ASSERT(v0->win[2] >= 0.0);
220 ASSERT(v1->win[2] >= 0.0);
221 ASSERT(v2->win[2] >= 0.0);
223 /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
224 * And find the order of the 3 vertices along the Y axis.
227 #if TRIANGLE_WALK_DOUBLE
228 const GLdouble fy0
= v0
->win
[1] - 0.5;
229 const GLdouble fy1
= v1
->win
[1] - 0.5;
230 const GLdouble fy2
= v2
->win
[1] - 0.5;
232 const GLfixed fy0
= FloatToFixed(v0
->win
[1] - 0.5F
) & snapMask
;
233 const GLfixed fy1
= FloatToFixed(v1
->win
[1] - 0.5F
) & snapMask
;
234 const GLfixed fy2
= FloatToFixed(v2
->win
[1] - 0.5F
) & snapMask
;
239 vMin
= v0
; vMid
= v1
; vMax
= v2
;
240 vMin_fy
= fy0
; vMid_fy
= fy1
; vMax_fy
= fy2
;
242 else if (fy2
<= fy0
) {
244 vMin
= v2
; vMid
= v0
; vMax
= v1
;
245 vMin_fy
= fy2
; vMid_fy
= fy0
; vMax_fy
= fy1
;
249 vMin
= v0
; vMid
= v2
; vMax
= v1
;
250 vMin_fy
= fy0
; vMid_fy
= fy2
; vMax_fy
= fy1
;
257 vMin
= v1
; vMid
= v0
; vMax
= v2
;
258 vMin_fy
= fy1
; vMid_fy
= fy0
; vMax_fy
= fy2
;
261 else if (fy2
<= fy1
) {
263 vMin
= v2
; vMid
= v1
; vMax
= v0
;
264 vMin_fy
= fy2
; vMid_fy
= fy1
; vMax_fy
= fy0
;
269 vMin
= v1
; vMid
= v2
; vMax
= v0
;
270 vMin_fy
= fy1
; vMid_fy
= fy2
; vMax_fy
= fy0
;
274 /* fixed point X coords */
275 #if TRIANGLE_WALK_DOUBLE
276 vMin_fx
= vMin
->win
[0] + 0.5;
277 vMid_fx
= vMid
->win
[0] + 0.5;
278 vMax_fx
= vMax
->win
[0] + 0.5;
280 vMin_fx
= FloatToFixed(vMin
->win
[0] + 0.5F
) & snapMask
;
281 vMid_fx
= FloatToFixed(vMid
->win
[0] + 0.5F
) & snapMask
;
282 vMax_fx
= FloatToFixed(vMax
->win
[0] + 0.5F
) & snapMask
;
286 /* vertex/edge relationship */
287 eMaj
.v0
= vMin
; eMaj
.v1
= vMax
; /*TODO: .v1's not needed */
288 eTop
.v0
= vMid
; eTop
.v1
= vMax
;
289 eBot
.v0
= vMin
; eBot
.v1
= vMid
;
291 /* compute deltas for each edge: vertex[upper] - vertex[lower] */
292 #if TRIANGLE_WALK_DOUBLE
293 eMaj
.dx
= vMax_fx
- vMin_fx
;
294 eMaj
.dy
= vMax_fy
- vMin_fy
;
295 eTop
.dx
= vMax_fx
- vMid_fx
;
296 eTop
.dy
= vMax_fy
- vMid_fy
;
297 eBot
.dx
= vMid_fx
- vMin_fx
;
298 eBot
.dy
= vMid_fy
- vMin_fy
;
300 eMaj
.dx
= FixedToFloat(vMax_fx
- vMin_fx
);
301 eMaj
.dy
= FixedToFloat(vMax_fy
- vMin_fy
);
302 eTop
.dx
= FixedToFloat(vMax_fx
- vMid_fx
);
303 eTop
.dy
= FixedToFloat(vMax_fy
- vMid_fy
);
304 eBot
.dx
= FixedToFloat(vMid_fx
- vMin_fx
);
305 eBot
.dy
= FixedToFloat(vMid_fy
- vMin_fy
);
308 /* compute area, oneOverArea and perform backface culling */
310 #if TRIANGLE_WALK_DOUBLE
311 const GLdouble area
= eMaj
.dx
* eBot
.dy
- eBot
.dx
* eMaj
.dy
;
313 const GLfloat area
= eMaj
.dx
* eBot
.dy
- eBot
.dx
* eMaj
.dy
;
315 /* Do backface culling */
319 if (IS_INF_OR_NAN(area
) || area
== 0.0F
)
322 oneOverArea
= 1.0F
/ area
;
326 span
.facing
= ctx
->_Facing
; /* for 2-sided stencil test */
328 /* Edge setup. For a triangle strip these could be reused... */
330 #if TRIANGLE_WALK_DOUBLE
331 eMaj
.fsy
= CEILF(vMin_fy
);
332 eMaj
.lines
= (GLint
) CEILF(vMax_fy
- eMaj
.fsy
);
334 eMaj
.fsy
= FixedCeil(vMin_fy
);
335 eMaj
.lines
= FixedToInt(FixedCeil(vMax_fy
- eMaj
.fsy
));
337 if (eMaj
.lines
> 0) {
338 eMaj
.dxdy
= eMaj
.dx
/ eMaj
.dy
;
339 #if TRIANGLE_WALK_DOUBLE
340 eMaj
.adjy
= (eMaj
.fsy
- vMin_fy
) * FIXED_SCALE
; /* SCALED! */
342 eMaj
.fsx
= eMaj
.fx0
+ (eMaj
.adjy
* eMaj
.dxdy
) / (GLdouble
) FIXED_SCALE
;
344 eMaj
.fdxdy
= SignedFloatToFixed(eMaj
.dxdy
);
345 eMaj
.adjy
= (GLfloat
) (eMaj
.fsy
- vMin_fy
); /* SCALED! */
347 eMaj
.fsx
= eMaj
.fx0
+ (GLfixed
) (eMaj
.adjy
* eMaj
.dxdy
);
354 #if TRIANGLE_WALK_DOUBLE
355 eTop
.fsy
= CEILF(vMid_fy
);
356 eTop
.lines
= (GLint
) CEILF(vMax_fy
- eTop
.fsy
);
358 eTop
.fsy
= FixedCeil(vMid_fy
);
359 eTop
.lines
= FixedToInt(FixedCeil(vMax_fy
- eTop
.fsy
));
361 if (eTop
.lines
> 0) {
362 eTop
.dxdy
= eTop
.dx
/ eTop
.dy
;
363 #if TRIANGLE_WALK_DOUBLE
364 eTop
.adjy
= (eTop
.fsy
- vMid_fy
) * FIXED_SCALE
; /* SCALED! */
366 eTop
.fsx
= eTop
.fx0
+ (eTop
.adjy
* eTop
.dxdy
) / (GLdouble
) FIXED_SCALE
;
368 eTop
.fdxdy
= SignedFloatToFixed(eTop
.dxdy
);
369 eTop
.adjy
= (GLfloat
) (eTop
.fsy
- vMid_fy
); /* SCALED! */
371 eTop
.fsx
= eTop
.fx0
+ (GLfixed
) (eTop
.adjy
* eTop
.dxdy
);
375 #if TRIANGLE_WALK_DOUBLE
376 eBot
.fsy
= CEILF(vMin_fy
);
377 eBot
.lines
= (GLint
) CEILF(vMid_fy
- eBot
.fsy
);
379 eBot
.fsy
= FixedCeil(vMin_fy
);
380 eBot
.lines
= FixedToInt(FixedCeil(vMid_fy
- eBot
.fsy
));
382 if (eBot
.lines
> 0) {
383 eBot
.dxdy
= eBot
.dx
/ eBot
.dy
;
384 #if TRIANGLE_WALK_DOUBLE
385 eBot
.adjy
= (eBot
.fsy
- vMin_fy
) * FIXED_SCALE
; /* SCALED! */
387 eBot
.fsx
= eBot
.fx0
+ (eBot
.adjy
* eBot
.dxdy
) / (GLdouble
) FIXED_SCALE
;
389 eBot
.fdxdy
= SignedFloatToFixed(eBot
.dxdy
);
390 eBot
.adjy
= (GLfloat
) (eBot
.fsy
- vMin_fy
); /* SCALED! */
392 eBot
.fsx
= eBot
.fx0
+ (GLfixed
) (eBot
.adjy
* eBot
.dxdy
);
398 * Conceptually, we view a triangle as two subtriangles
399 * separated by a perfectly horizontal line. The edge that is
400 * intersected by this line is one with maximal absolute dy; we
401 * call it a ``major'' edge. The other two edges are the
402 * ``top'' edge (for the upper subtriangle) and the ``bottom''
403 * edge (for the lower subtriangle). If either of these two
404 * edges is horizontal or very close to horizontal, the
405 * corresponding subtriangle might cover zero sample points;
406 * we take care to handle such cases, for performance as well
409 * By stepping rasterization parameters along the major edge,
410 * we can avoid recomputing them at the discontinuity where
411 * the top and bottom edges meet. However, this forces us to
412 * be able to scan both left-to-right and right-to-left.
413 * Also, we must determine whether the major edge is at the
414 * left or right side of the triangle. We do this by
415 * computing the magnitude of the cross-product of the major
416 * and top edges. Since this magnitude depends on the sine of
417 * the angle between the two edges, its sign tells us whether
418 * we turn to the left or to the right when travelling along
419 * the major edge to the top edge, and from this we infer
420 * whether the major edge is on the left or the right.
422 * Serendipitously, this cross-product magnitude is also a
423 * value we need to compute the iteration parameter
424 * derivatives for the triangle, and it can be used to perform
425 * backface culling because its sign tells us whether the
426 * triangle is clockwise or counterclockwise. In this code we
427 * refer to it as ``area'' because it's also proportional to
428 * the pixel area of the triangle.
432 GLint scan_from_left_to_right
; /* true if scanning left-to-right */
438 * Execute user-supplied setup code
444 scan_from_left_to_right
= (oneOverArea
< 0.0F
);
447 /* compute d?/dx and d?/dy derivatives */
449 span
.interpMask
|= SPAN_Z
;
451 GLfloat eMaj_dz
= vMax
->win
[2] - vMin
->win
[2];
452 GLfloat eBot_dz
= vMid
->win
[2] - vMin
->win
[2];
453 span
.dzdx
= oneOverArea
* (eMaj_dz
* eBot
.dy
- eMaj
.dy
* eBot_dz
);
454 if (span
.dzdx
> maxDepth
|| span
.dzdx
< -maxDepth
) {
455 /* probably a sliver triangle */
460 span
.dzdy
= oneOverArea
* (eMaj
.dx
* eBot_dz
- eMaj_dz
* eBot
.dx
);
463 span
.zStep
= SignedFloatToFixed(span
.dzdx
);
465 span
.zStep
= (GLint
) span
.dzdx
;
469 span
.interpMask
|= SPAN_W
;
471 const GLfloat eMaj_dw
= vMax
->win
[3] - vMin
->win
[3];
472 const GLfloat eBot_dw
= vMid
->win
[3] - vMin
->win
[3];
473 span
.dwdx
= oneOverArea
* (eMaj_dw
* eBot
.dy
- eMaj
.dy
* eBot_dw
);
474 span
.dwdy
= oneOverArea
* (eMaj
.dx
* eBot_dw
- eMaj_dw
* eBot
.dx
);
478 span
.interpMask
|= SPAN_FOG
;
481 const GLfloat wMax
= vMax
->win
[3], wMin
= vMin
->win
[3], wMid
= vMid
->win
[3];
482 const GLfloat eMaj_dfog
= vMax
->fog
* wMax
- vMin
->fog
* wMin
;
483 const GLfloat eBot_dfog
= vMid
->fog
* wMid
- vMin
->fog
* wMin
;
485 const GLfloat eMaj_dfog
= vMax
->fog
- vMin
->fog
;
486 const GLfloat eBot_dfog
= vMid
->fog
- vMin
->fog
;
488 span
.dfogdx
= oneOverArea
* (eMaj_dfog
* eBot
.dy
- eMaj
.dy
* eBot_dfog
);
489 span
.dfogdy
= oneOverArea
* (eMaj
.dx
* eBot_dfog
- eMaj_dfog
* eBot
.dx
);
490 span
.fogStep
= span
.dfogdx
;
494 span
.interpMask
|= SPAN_RGBA
;
495 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
496 GLfloat eMaj_dr
= (GLfloat
) ((ColorTemp
) vMax
->color
[RCOMP
] - (ColorTemp
) vMin
->color
[RCOMP
]);
497 GLfloat eBot_dr
= (GLfloat
) ((ColorTemp
) vMid
->color
[RCOMP
] - (ColorTemp
) vMin
->color
[RCOMP
]);
498 GLfloat eMaj_dg
= (GLfloat
) ((ColorTemp
) vMax
->color
[GCOMP
] - (ColorTemp
) vMin
->color
[GCOMP
]);
499 GLfloat eBot_dg
= (GLfloat
) ((ColorTemp
) vMid
->color
[GCOMP
] - (ColorTemp
) vMin
->color
[GCOMP
]);
500 GLfloat eMaj_db
= (GLfloat
) ((ColorTemp
) vMax
->color
[BCOMP
] - (ColorTemp
) vMin
->color
[BCOMP
]);
501 GLfloat eBot_db
= (GLfloat
) ((ColorTemp
) vMid
->color
[BCOMP
] - (ColorTemp
) vMin
->color
[BCOMP
]);
503 GLfloat eMaj_da
= (GLfloat
) ((ColorTemp
) vMax
->color
[ACOMP
] - (ColorTemp
) vMin
->color
[ACOMP
]);
504 GLfloat eBot_da
= (GLfloat
) ((ColorTemp
) vMid
->color
[ACOMP
] - (ColorTemp
) vMin
->color
[ACOMP
]);
506 span
.drdx
= oneOverArea
* (eMaj_dr
* eBot
.dy
- eMaj
.dy
* eBot_dr
);
507 span
.drdy
= oneOverArea
* (eMaj
.dx
* eBot_dr
- eMaj_dr
* eBot
.dx
);
508 span
.dgdx
= oneOverArea
* (eMaj_dg
* eBot
.dy
- eMaj
.dy
* eBot_dg
);
509 span
.dgdy
= oneOverArea
* (eMaj
.dx
* eBot_dg
- eMaj_dg
* eBot
.dx
);
510 span
.dbdx
= oneOverArea
* (eMaj_db
* eBot
.dy
- eMaj
.dy
* eBot_db
);
511 span
.dbdy
= oneOverArea
* (eMaj
.dx
* eBot_db
- eMaj_db
* eBot
.dx
);
512 # if CHAN_TYPE == GL_FLOAT
513 span
.redStep
= span
.drdx
;
514 span
.greenStep
= span
.dgdx
;
515 span
.blueStep
= span
.dbdx
;
517 span
.redStep
= SignedFloatToFixed(span
.drdx
);
518 span
.greenStep
= SignedFloatToFixed(span
.dgdx
);
519 span
.blueStep
= SignedFloatToFixed(span
.dbdx
);
520 # endif /* GL_FLOAT */
522 span
.dadx
= oneOverArea
* (eMaj_da
* eBot
.dy
- eMaj
.dy
* eBot_da
);
523 span
.dady
= oneOverArea
* (eMaj
.dx
* eBot_da
- eMaj_da
* eBot
.dx
);
524 # if CHAN_TYPE == GL_FLOAT
525 span
.alphaStep
= span
.dadx
;
527 span
.alphaStep
= SignedFloatToFixed(span
.dadx
);
528 # endif /* GL_FLOAT */
529 # endif /* INTERP_ALPHA */
532 ASSERT(ctx
->Light
.ShadeModel
== GL_FLAT
);
533 span
.interpMask
|= SPAN_FLAT
;
534 span
.drdx
= span
.drdy
= 0.0F
;
535 span
.dgdx
= span
.dgdy
= 0.0F
;
536 span
.dbdx
= span
.dbdy
= 0.0F
;
537 # if CHAN_TYPE == GL_FLOAT
539 span
.greenStep
= 0.0F
;
540 span
.blueStep
= 0.0F
;
545 # endif /* GL_FLOAT */
547 span
.dadx
= span
.dady
= 0.0F
;
548 # if CHAN_TYPE == GL_FLOAT
549 span
.alphaStep
= 0.0F
;
552 # endif /* GL_FLOAT */
555 #endif /* INTERP_RGB */
557 span
.interpMask
|= SPAN_SPEC
;
558 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
559 GLfloat eMaj_dsr
= (GLfloat
) ((ColorTemp
) vMax
->specular
[RCOMP
] - (ColorTemp
) vMin
->specular
[RCOMP
]);
560 GLfloat eBot_dsr
= (GLfloat
) ((ColorTemp
) vMid
->specular
[RCOMP
] - (ColorTemp
) vMin
->specular
[RCOMP
]);
561 GLfloat eMaj_dsg
= (GLfloat
) ((ColorTemp
) vMax
->specular
[GCOMP
] - (ColorTemp
) vMin
->specular
[GCOMP
]);
562 GLfloat eBot_dsg
= (GLfloat
) ((ColorTemp
) vMid
->specular
[GCOMP
] - (ColorTemp
) vMin
->specular
[GCOMP
]);
563 GLfloat eMaj_dsb
= (GLfloat
) ((ColorTemp
) vMax
->specular
[BCOMP
] - (ColorTemp
) vMin
->specular
[BCOMP
]);
564 GLfloat eBot_dsb
= (GLfloat
) ((ColorTemp
) vMid
->specular
[BCOMP
] - (ColorTemp
) vMin
->specular
[BCOMP
]);
565 span
.dsrdx
= oneOverArea
* (eMaj_dsr
* eBot
.dy
- eMaj
.dy
* eBot_dsr
);
566 span
.dsrdy
= oneOverArea
* (eMaj
.dx
* eBot_dsr
- eMaj_dsr
* eBot
.dx
);
567 span
.dsgdx
= oneOverArea
* (eMaj_dsg
* eBot
.dy
- eMaj
.dy
* eBot_dsg
);
568 span
.dsgdy
= oneOverArea
* (eMaj
.dx
* eBot_dsg
- eMaj_dsg
* eBot
.dx
);
569 span
.dsbdx
= oneOverArea
* (eMaj_dsb
* eBot
.dy
- eMaj
.dy
* eBot_dsb
);
570 span
.dsbdy
= oneOverArea
* (eMaj
.dx
* eBot_dsb
- eMaj_dsb
* eBot
.dx
);
571 # if CHAN_TYPE == GL_FLOAT
572 span
.specRedStep
= span
.dsrdx
;
573 span
.specGreenStep
= span
.dsgdx
;
574 span
.specBlueStep
= span
.dsbdx
;
576 span
.specRedStep
= SignedFloatToFixed(span
.dsrdx
);
577 span
.specGreenStep
= SignedFloatToFixed(span
.dsgdx
);
578 span
.specBlueStep
= SignedFloatToFixed(span
.dsbdx
);
582 span
.dsrdx
= span
.dsrdy
= 0.0F
;
583 span
.dsgdx
= span
.dsgdy
= 0.0F
;
584 span
.dsbdx
= span
.dsbdy
= 0.0F
;
585 # if CHAN_TYPE == GL_FLOAT
586 span
.specRedStep
= 0.0F
;
587 span
.specGreenStep
= 0.0F
;
588 span
.specBlueStep
= 0.0F
;
590 span
.specRedStep
= 0;
591 span
.specGreenStep
= 0;
592 span
.specBlueStep
= 0;
595 #endif /* INTERP_SPEC */
597 span
.interpMask
|= SPAN_INDEX
;
598 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
599 GLfloat eMaj_di
= vMax
->index
- vMin
->index
;
600 GLfloat eBot_di
= vMid
->index
- vMin
->index
;
601 didx
= oneOverArea
* (eMaj_di
* eBot
.dy
- eMaj
.dy
* eBot_di
);
602 didy
= oneOverArea
* (eMaj
.dx
* eBot_di
- eMaj_di
* eBot
.dx
);
603 span
.indexStep
= SignedFloatToFixed(didx
);
606 span
.interpMask
|= SPAN_FLAT
;
611 #ifdef INTERP_INT_TEX
612 span
.interpMask
|= SPAN_INT_TEXTURE
;
614 GLfloat eMaj_ds
= (vMax
->texcoord
[0][0] - vMin
->texcoord
[0][0]) * S_SCALE
;
615 GLfloat eBot_ds
= (vMid
->texcoord
[0][0] - vMin
->texcoord
[0][0]) * S_SCALE
;
616 GLfloat eMaj_dt
= (vMax
->texcoord
[0][1] - vMin
->texcoord
[0][1]) * T_SCALE
;
617 GLfloat eBot_dt
= (vMid
->texcoord
[0][1] - vMin
->texcoord
[0][1]) * T_SCALE
;
618 span
.texStepX
[0][0] = oneOverArea
* (eMaj_ds
* eBot
.dy
- eMaj
.dy
* eBot_ds
);
619 span
.texStepY
[0][0] = oneOverArea
* (eMaj
.dx
* eBot_ds
- eMaj_ds
* eBot
.dx
);
620 span
.texStepX
[0][1] = oneOverArea
* (eMaj_dt
* eBot
.dy
- eMaj
.dy
* eBot_dt
);
621 span
.texStepY
[0][1] = oneOverArea
* (eMaj
.dx
* eBot_dt
- eMaj_dt
* eBot
.dx
);
622 span
.intTexStep
[0] = SignedFloatToFixed(span
.texStepX
[0][0]);
623 span
.intTexStep
[1] = SignedFloatToFixed(span
.texStepX
[0][1]);
627 span
.interpMask
|= SPAN_TEXTURE
;
630 const GLfloat wMax
= vMax
->win
[3], wMin
= vMin
->win
[3], wMid
= vMid
->win
[3];
632 GLfloat eMaj_ds
= vMax
->texcoord
[u
][0] * wMax
- vMin
->texcoord
[u
][0] * wMin
;
633 GLfloat eBot_ds
= vMid
->texcoord
[u
][0] * wMid
- vMin
->texcoord
[u
][0] * wMin
;
634 GLfloat eMaj_dt
= vMax
->texcoord
[u
][1] * wMax
- vMin
->texcoord
[u
][1] * wMin
;
635 GLfloat eBot_dt
= vMid
->texcoord
[u
][1] * wMid
- vMin
->texcoord
[u
][1] * wMin
;
636 GLfloat eMaj_du
= vMax
->texcoord
[u
][2] * wMax
- vMin
->texcoord
[u
][2] * wMin
;
637 GLfloat eBot_du
= vMid
->texcoord
[u
][2] * wMid
- vMin
->texcoord
[u
][2] * wMin
;
638 GLfloat eMaj_dv
= vMax
->texcoord
[u
][3] * wMax
- vMin
->texcoord
[u
][3] * wMin
;
639 GLfloat eBot_dv
= vMid
->texcoord
[u
][3] * wMid
- vMin
->texcoord
[u
][3] * wMin
;
640 span
.texStepX
[u
][0] = oneOverArea
* (eMaj_ds
* eBot
.dy
- eMaj
.dy
* eBot_ds
);
641 span
.texStepY
[u
][0] = oneOverArea
* (eMaj
.dx
* eBot_ds
- eMaj_ds
* eBot
.dx
);
642 span
.texStepX
[u
][1] = oneOverArea
* (eMaj_dt
* eBot
.dy
- eMaj
.dy
* eBot_dt
);
643 span
.texStepY
[u
][1] = oneOverArea
* (eMaj
.dx
* eBot_dt
- eMaj_dt
* eBot
.dx
);
644 span
.texStepX
[u
][2] = oneOverArea
* (eMaj_du
* eBot
.dy
- eMaj
.dy
* eBot_du
);
645 span
.texStepY
[u
][2] = oneOverArea
* (eMaj
.dx
* eBot_du
- eMaj_du
* eBot
.dx
);
646 span
.texStepX
[u
][3] = oneOverArea
* (eMaj_dv
* eBot
.dy
- eMaj
.dy
* eBot_dv
);
647 span
.texStepY
[u
][3] = oneOverArea
* (eMaj
.dx
* eBot_dv
- eMaj_dv
* eBot
.dx
);
653 * We always sample at pixel centers. However, we avoid
654 * explicit half-pixel offsets in this code by incorporating
655 * the proper offset in each of x and y during the
656 * transformation to window coordinates.
658 * We also apply the usual rasterization rules to prevent
659 * cracks and overlaps. A pixel is considered inside a
660 * subtriangle if it meets all of four conditions: it is on or
661 * to the right of the left edge, strictly to the left of the
662 * right edge, on or below the top edge, and strictly above
663 * the bottom edge. (Some edges may be degenerate.)
665 * The following discussion assumes left-to-right scanning
666 * (that is, the major edge is on the left); the right-to-left
667 * case is a straightforward variation.
669 * We start by finding the half-integral y coordinate that is
670 * at or below the top of the triangle. This gives us the
671 * first scan line that could possibly contain pixels that are
672 * inside the triangle.
674 * Next we creep down the major edge until we reach that y,
675 * and compute the corresponding x coordinate on the edge.
676 * Then we find the half-integral x that lies on or just
677 * inside the edge. This is the first pixel that might lie in
678 * the interior of the triangle. (We won't know for sure
679 * until we check the other edges.)
681 * As we rasterize the triangle, we'll step down the major
682 * edge. For each step in y, we'll move an integer number
683 * of steps in x. There are two possible x step sizes, which
684 * we'll call the ``inner'' step (guaranteed to land on the
685 * edge or inside it) and the ``outer'' step (guaranteed to
686 * land on the edge or outside it). The inner and outer steps
687 * differ by one. During rasterization we maintain an error
688 * term that indicates our distance from the true edge, and
689 * select either the inner step or the outer step, whichever
690 * gets us to the first pixel that falls inside the triangle.
692 * All parameters (z, red, etc.) as well as the buffer
693 * addresses for color and z have inner and outer step values,
694 * so that we can increment them appropriately. This method
695 * eliminates the need to adjust parameters by creeping a
696 * sub-pixel amount into the triangle at each scanline.
701 GLinterp fxLeftEdge
= 0, fxRightEdge
= 0;
702 GLinterp fdxLeftEdge
= 0, fdxRightEdge
= 0;
703 GLinterp fError
= 0, fdError
= 0;
705 PIXEL_TYPE
*pRow
= NULL
;
706 GLint dPRowOuter
= 0, dPRowInner
; /* offset in bytes */
710 struct gl_renderbuffer
*zrb
711 = ctx
->DrawBuffer
->Attachment
[BUFFER_DEPTH
].Renderbuffer
;
712 DEPTH_TYPE
*zRow
= NULL
;
713 GLint dZRowOuter
= 0, dZRowInner
; /* offset in bytes */
716 GLfixed fdzOuter
= 0, fdzInner
;
719 GLfloat wLeft
= 0, dwOuter
= 0, dwInner
;
722 GLfloat fogLeft
= 0, dfogOuter
= 0, dfogInner
;
725 ColorTemp rLeft
= 0, fdrOuter
= 0, fdrInner
;
726 ColorTemp gLeft
= 0, fdgOuter
= 0, fdgInner
;
727 ColorTemp bLeft
= 0, fdbOuter
= 0, fdbInner
;
730 ColorTemp aLeft
= 0, fdaOuter
= 0, fdaInner
;
733 ColorTemp srLeft
=0, dsrOuter
=0, dsrInner
;
734 ColorTemp sgLeft
=0, dsgOuter
=0, dsgInner
;
735 ColorTemp sbLeft
=0, dsbOuter
=0, dsbInner
;
738 GLfixed iLeft
=0, diOuter
=0, diInner
;
740 #ifdef INTERP_INT_TEX
741 GLfixed sLeft
=0, dsOuter
=0, dsInner
;
742 GLfixed tLeft
=0, dtOuter
=0, dtInner
;
745 GLfloat sLeft
[MAX_TEXTURE_COORD_UNITS
];
746 GLfloat tLeft
[MAX_TEXTURE_COORD_UNITS
];
747 GLfloat uLeft
[MAX_TEXTURE_COORD_UNITS
];
748 GLfloat vLeft
[MAX_TEXTURE_COORD_UNITS
];
749 GLfloat dsOuter
[MAX_TEXTURE_COORD_UNITS
], dsInner
[MAX_TEXTURE_COORD_UNITS
];
750 GLfloat dtOuter
[MAX_TEXTURE_COORD_UNITS
], dtInner
[MAX_TEXTURE_COORD_UNITS
];
751 GLfloat duOuter
[MAX_TEXTURE_COORD_UNITS
], duInner
[MAX_TEXTURE_COORD_UNITS
];
752 GLfloat dvOuter
[MAX_TEXTURE_COORD_UNITS
], dvInner
[MAX_TEXTURE_COORD_UNITS
];
755 for (subTriangle
=0; subTriangle
<=1; subTriangle
++) {
756 EdgeT
*eLeft
, *eRight
;
757 int setupLeft
, setupRight
;
760 if (subTriangle
==0) {
762 if (scan_from_left_to_right
) {
765 lines
= eRight
->lines
;
772 lines
= eLeft
->lines
;
779 if (scan_from_left_to_right
) {
782 lines
= eRight
->lines
;
789 lines
= eLeft
->lines
;
797 if (setupLeft
&& eLeft
->lines
> 0) {
798 const SWvertex
*vLower
= eLeft
->v0
;
799 #if TRIANGLE_WALK_DOUBLE
800 const GLdouble fsy
= eLeft
->fsy
;
801 const GLdouble fsx
= eLeft
->fsx
;
802 const GLdouble fx
= CEILF(fsx
);
803 const GLdouble adjx
= (fx
- eLeft
->fx0
) * FIXED_SCALE
; /* SCALED! */
805 const GLfixed fsy
= eLeft
->fsy
;
806 const GLfixed fsx
= eLeft
->fsx
; /* no fractional part */
807 const GLfixed fx
= FixedCeil(fsx
); /* no fractional part */
808 const GLfixed adjx
= (GLinterp
) (fx
- eLeft
->fx0
); /* SCALED! */
810 const GLinterp adjy
= (GLinterp
) eLeft
->adjy
; /* SCALED! */
812 #if TRIANGLE_WALK_DOUBLE
815 fError
= fx
- fsx
- 1.0;
817 fdxLeftEdge
= eLeft
->dxdy
;
818 dxOuter
= FLOORF(fdxLeftEdge
);
819 fdError
= dxOuter
- fdxLeftEdge
+ 1.0;
820 idxOuter
= (GLint
) dxOuter
;
821 span
.y
= (GLint
) fsy
;
826 fError
= fx
- fsx
- FIXED_ONE
;
827 fxLeftEdge
= fsx
- FIXED_EPSILON
;
828 fdxLeftEdge
= eLeft
->fdxdy
;
829 fdxOuter
= FixedFloor(fdxLeftEdge
- FIXED_EPSILON
);
830 fdError
= fdxOuter
- fdxLeftEdge
+ FIXED_ONE
;
831 idxOuter
= FixedToInt(fdxOuter
);
832 dxOuter
= (GLfloat
) idxOuter
;
833 span
.y
= FixedToInt(fsy
);
836 /* silence warnings on some compilers */
844 pRow
= (PIXEL_TYPE
*) PIXEL_ADDRESS(InterpToInt(fxLeftEdge
), span
.y
);
845 dPRowOuter
= -((int)BYTES_PER_ROW
) + idxOuter
* sizeof(PIXEL_TYPE
);
846 /* negative because Y=0 at bottom and increases upward */
850 * Now we need the set of parameter (z, color, etc.) values at
851 * the point (fx, fsy). This gives us properly-sampled parameter
852 * values that we can step from pixel to pixel. Furthermore,
853 * although we might have intermediate results that overflow
854 * the normal parameter range when we step temporarily outside
855 * the triangle, we shouldn't overflow or underflow for any
856 * pixel that's actually inside the triangle.
861 GLfloat z0
= vLower
->win
[2];
862 if (depthBits
<= 16) {
863 /* interpolate fixed-pt values */
864 GLfloat tmp
= (z0
* FIXED_SCALE
+ span
.dzdx
* adjx
865 + span
.dzdy
* adjy
) + FIXED_HALF
;
866 if (tmp
< MAX_GLUINT
/ 2)
867 zLeft
= (GLfixed
) tmp
;
869 zLeft
= MAX_GLUINT
/ 2;
870 fdzOuter
= SignedFloatToFixed(span
.dzdy
+ dxOuter
* span
.dzdx
);
873 /* interpolate depth values w/out scaling */
874 zLeft
= (GLuint
) (z0
+ span
.dzdx
* FixedToFloat(adjx
)
875 + span
.dzdy
* FixedToFloat(adjy
));
876 fdzOuter
= (GLint
) (span
.dzdy
+ dxOuter
* span
.dzdx
);
879 zRow
= (DEPTH_TYPE
*)
880 zrb
->GetPointer(ctx
, zrb
, InterpToInt(fxLeftEdge
), span
.y
);
881 dZRowOuter
= (ctx
->DrawBuffer
->Width
+ idxOuter
) * sizeof(DEPTH_TYPE
);
886 wLeft
= vLower
->win
[3] + (span
.dwdx
* adjx
+ span
.dwdy
* adjy
) * (1.0F
/FIXED_SCALE
);
887 dwOuter
= span
.dwdy
+ dxOuter
* span
.dwdx
;
891 fogLeft
= vLower
->fog
* vLower
->win
[3] + (span
.dfogdx
* adjx
+ span
.dfogdy
* adjy
) * (1.0F
/FIXED_SCALE
);
893 fogLeft
= vLower
->fog
+ (span
.dfogdx
* adjx
+ span
.dfogdy
* adjy
) * (1.0F
/FIXED_SCALE
);
895 dfogOuter
= span
.dfogdy
+ dxOuter
* span
.dfogdx
;
898 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
899 # if CHAN_TYPE == GL_FLOAT
900 rLeft
= vLower
->color
[RCOMP
] + (span
.drdx
* adjx
+ span
.drdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
901 gLeft
= vLower
->color
[GCOMP
] + (span
.dgdx
* adjx
+ span
.dgdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
902 bLeft
= vLower
->color
[BCOMP
] + (span
.dbdx
* adjx
+ span
.dbdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
903 fdrOuter
= span
.drdy
+ dxOuter
* span
.drdx
;
904 fdgOuter
= span
.dgdy
+ dxOuter
* span
.dgdx
;
905 fdbOuter
= span
.dbdy
+ dxOuter
* span
.dbdx
;
907 rLeft
= (GLint
)(ChanToFixed(vLower
->color
[RCOMP
]) + span
.drdx
* adjx
+ span
.drdy
* adjy
) + FIXED_HALF
;
908 gLeft
= (GLint
)(ChanToFixed(vLower
->color
[GCOMP
]) + span
.dgdx
* adjx
+ span
.dgdy
* adjy
) + FIXED_HALF
;
909 bLeft
= (GLint
)(ChanToFixed(vLower
->color
[BCOMP
]) + span
.dbdx
* adjx
+ span
.dbdy
* adjy
) + FIXED_HALF
;
910 fdrOuter
= SignedFloatToFixed(span
.drdy
+ dxOuter
* span
.drdx
);
911 fdgOuter
= SignedFloatToFixed(span
.dgdy
+ dxOuter
* span
.dgdx
);
912 fdbOuter
= SignedFloatToFixed(span
.dbdy
+ dxOuter
* span
.dbdx
);
915 # if CHAN_TYPE == GL_FLOAT
916 aLeft
= vLower
->color
[ACOMP
] + (span
.dadx
* adjx
+ span
.dady
* adjy
) * (1.0F
/ FIXED_SCALE
);
917 fdaOuter
= span
.dady
+ dxOuter
* span
.dadx
;
919 aLeft
= (GLint
)(ChanToFixed(vLower
->color
[ACOMP
]) + span
.dadx
* adjx
+ span
.dady
* adjy
) + FIXED_HALF
;
920 fdaOuter
= SignedFloatToFixed(span
.dady
+ dxOuter
* span
.dadx
);
925 ASSERT(ctx
->Light
.ShadeModel
== GL_FLAT
);
926 # if CHAN_TYPE == GL_FLOAT
927 rLeft
= v2
->color
[RCOMP
];
928 gLeft
= v2
->color
[GCOMP
];
929 bLeft
= v2
->color
[BCOMP
];
930 fdrOuter
= fdgOuter
= fdbOuter
= 0.0F
;
932 rLeft
= ChanToFixed(v2
->color
[RCOMP
]);
933 gLeft
= ChanToFixed(v2
->color
[GCOMP
]);
934 bLeft
= ChanToFixed(v2
->color
[BCOMP
]);
935 fdrOuter
= fdgOuter
= fdbOuter
= 0;
938 # if CHAN_TYPE == GL_FLOAT
939 aLeft
= v2
->color
[ACOMP
];
942 aLeft
= ChanToFixed(v2
->color
[ACOMP
]);
947 #endif /* INTERP_RGB */
951 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
952 # if CHAN_TYPE == GL_FLOAT
953 srLeft
= vLower
->specular
[RCOMP
] + (span
.dsrdx
* adjx
+ span
.dsrdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
954 sgLeft
= vLower
->specular
[GCOMP
] + (span
.dsgdx
* adjx
+ span
.dsgdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
955 sbLeft
= vLower
->specular
[BCOMP
] + (span
.dsbdx
* adjx
+ span
.dsbdy
* adjy
) * (1.0F
/ FIXED_SCALE
);
956 dsrOuter
= span
.dsrdy
+ dxOuter
* span
.dsrdx
;
957 dsgOuter
= span
.dsgdy
+ dxOuter
* span
.dsgdx
;
958 dsbOuter
= span
.dsbdy
+ dxOuter
* span
.dsbdx
;
960 srLeft
= (GLfixed
) (ChanToFixed(vLower
->specular
[RCOMP
]) + span
.dsrdx
* adjx
+ span
.dsrdy
* adjy
) + FIXED_HALF
;
961 sgLeft
= (GLfixed
) (ChanToFixed(vLower
->specular
[GCOMP
]) + span
.dsgdx
* adjx
+ span
.dsgdy
* adjy
) + FIXED_HALF
;
962 sbLeft
= (GLfixed
) (ChanToFixed(vLower
->specular
[BCOMP
]) + span
.dsbdx
* adjx
+ span
.dsbdy
* adjy
) + FIXED_HALF
;
963 dsrOuter
= SignedFloatToFixed(span
.dsrdy
+ dxOuter
* span
.dsrdx
);
964 dsgOuter
= SignedFloatToFixed(span
.dsgdy
+ dxOuter
* span
.dsgdx
);
965 dsbOuter
= SignedFloatToFixed(span
.dsbdy
+ dxOuter
* span
.dsbdx
);
969 ASSERT(ctx
->Light
.ShadeModel
== GL_FLAT
);
970 #if CHAN_TYPE == GL_FLOAT
971 srLeft
= v2
->specular
[RCOMP
];
972 sgLeft
= v2
->specular
[GCOMP
];
973 sbLeft
= v2
->specular
[BCOMP
];
974 dsrOuter
= dsgOuter
= dsbOuter
= 0.0F
;
976 srLeft
= ChanToFixed(v2
->specular
[RCOMP
]);
977 sgLeft
= ChanToFixed(v2
->specular
[GCOMP
]);
978 sbLeft
= ChanToFixed(v2
->specular
[BCOMP
]);
979 dsrOuter
= dsgOuter
= dsbOuter
= 0;
985 if (ctx
->Light
.ShadeModel
== GL_SMOOTH
) {
986 iLeft
= (GLfixed
)(vLower
->index
* FIXED_SCALE
987 + didx
* adjx
+ didy
* adjy
) + FIXED_HALF
;
988 diOuter
= SignedFloatToFixed(didy
+ dxOuter
* didx
);
991 ASSERT(ctx
->Light
.ShadeModel
== GL_FLAT
);
992 iLeft
= FloatToFixed(v2
->index
);
996 #ifdef INTERP_INT_TEX
999 s0
= vLower
->texcoord
[0][0] * S_SCALE
;
1000 sLeft
= (GLfixed
)(s0
* FIXED_SCALE
+ span
.texStepX
[0][0] * adjx
1001 + span
.texStepY
[0][0] * adjy
) + FIXED_HALF
;
1002 dsOuter
= SignedFloatToFixed(span
.texStepY
[0][0] + dxOuter
* span
.texStepX
[0][0]);
1004 t0
= vLower
->texcoord
[0][1] * T_SCALE
;
1005 tLeft
= (GLfixed
)(t0
* FIXED_SCALE
+ span
.texStepX
[0][1] * adjx
1006 + span
.texStepY
[0][1] * adjy
) + FIXED_HALF
;
1007 dtOuter
= SignedFloatToFixed(span
.texStepY
[0][1] + dxOuter
* span
.texStepX
[0][1]);
1012 const GLfloat invW
= vLower
->win
[3];
1013 const GLfloat s0
= vLower
->texcoord
[u
][0] * invW
;
1014 const GLfloat t0
= vLower
->texcoord
[u
][1] * invW
;
1015 const GLfloat u0
= vLower
->texcoord
[u
][2] * invW
;
1016 const GLfloat v0
= vLower
->texcoord
[u
][3] * invW
;
1017 sLeft
[u
] = s0
+ (span
.texStepX
[u
][0] * adjx
+ span
.texStepY
[u
][0] * adjy
) * (1.0F
/FIXED_SCALE
);
1018 tLeft
[u
] = t0
+ (span
.texStepX
[u
][1] * adjx
+ span
.texStepY
[u
][1] * adjy
) * (1.0F
/FIXED_SCALE
);
1019 uLeft
[u
] = u0
+ (span
.texStepX
[u
][2] * adjx
+ span
.texStepY
[u
][2] * adjy
) * (1.0F
/FIXED_SCALE
);
1020 vLeft
[u
] = v0
+ (span
.texStepX
[u
][3] * adjx
+ span
.texStepY
[u
][3] * adjy
) * (1.0F
/FIXED_SCALE
);
1021 dsOuter
[u
] = span
.texStepY
[u
][0] + dxOuter
* span
.texStepX
[u
][0];
1022 dtOuter
[u
] = span
.texStepY
[u
][1] + dxOuter
* span
.texStepX
[u
][1];
1023 duOuter
[u
] = span
.texStepY
[u
][2] + dxOuter
* span
.texStepX
[u
][2];
1024 dvOuter
[u
] = span
.texStepY
[u
][3] + dxOuter
* span
.texStepX
[u
][3];
1030 if (setupRight
&& eRight
->lines
>0) {
1031 #if TRIANGLE_WALK_DOUBLE
1032 fxRightEdge
= eRight
->fsx
;
1033 fdxRightEdge
= eRight
->dxdy
;
1035 fxRightEdge
= eRight
->fsx
- FIXED_EPSILON
;
1036 fdxRightEdge
= eRight
->fdxdy
;
1045 /* Rasterize setup */
1046 #ifdef PIXEL_ADDRESS
1047 dPRowInner
= dPRowOuter
+ sizeof(PIXEL_TYPE
);
1051 dZRowInner
= dZRowOuter
+ sizeof(DEPTH_TYPE
);
1053 fdzInner
= fdzOuter
+ span
.zStep
;
1056 dwInner
= dwOuter
+ span
.dwdx
;
1059 dfogInner
= dfogOuter
+ span
.dfogdx
;
1062 fdrInner
= fdrOuter
+ span
.redStep
;
1063 fdgInner
= fdgOuter
+ span
.greenStep
;
1064 fdbInner
= fdbOuter
+ span
.blueStep
;
1067 fdaInner
= fdaOuter
+ span
.alphaStep
;
1070 dsrInner
= dsrOuter
+ span
.specRedStep
;
1071 dsgInner
= dsgOuter
+ span
.specGreenStep
;
1072 dsbInner
= dsbOuter
+ span
.specBlueStep
;
1075 diInner
= diOuter
+ span
.indexStep
;
1077 #ifdef INTERP_INT_TEX
1078 dsInner
= dsOuter
+ span
.intTexStep
[0];
1079 dtInner
= dtOuter
+ span
.intTexStep
[1];
1083 dsInner
[u
] = dsOuter
[u
] + span
.texStepX
[u
][0];
1084 dtInner
[u
] = dtOuter
[u
] + span
.texStepX
[u
][1];
1085 duInner
[u
] = duOuter
[u
] + span
.texStepX
[u
][2];
1086 dvInner
[u
] = dvOuter
[u
] + span
.texStepX
[u
][3];
1091 /* initialize the span interpolants to the leftmost value */
1092 /* ff = fixed-pt fragment */
1093 const GLint right
= InterpToInt(fxRightEdge
);
1094 span
.x
= InterpToInt(fxLeftEdge
);
1095 if (right
<= span
.x
)
1098 span
.end
= right
- span
.x
;
1118 span
.specRed
= srLeft
;
1119 span
.specGreen
= sgLeft
;
1120 span
.specBlue
= sbLeft
;
1125 #ifdef INTERP_INT_TEX
1126 span
.intTex
[0] = sLeft
;
1127 span
.intTex
[1] = tLeft
;
1132 span
.tex
[u
][0] = sLeft
[u
];
1133 span
.tex
[u
][1] = tLeft
[u
];
1134 span
.tex
[u
][2] = uLeft
[u
];
1135 span
.tex
[u
][3] = vLeft
[u
];
1139 /* This is where we actually generate fragments */
1140 /* XXX the test for span.y > 0 _shouldn't_ be needed but
1141 * it fixes a problem on 64-bit Opterons (bug 4842).
1143 if (span
.end
> 0 && span
.y
>= 0) {
1144 const GLint len
= span
.end
- 1;
1147 CLAMP_INTERPOLANT(red
, redStep
, len
);
1148 CLAMP_INTERPOLANT(green
, greenStep
, len
);
1149 CLAMP_INTERPOLANT(blue
, blueStep
, len
);
1152 CLAMP_INTERPOLANT(alpha
, alphaStep
, len
);
1155 CLAMP_INTERPOLANT(specRed
, specRedStep
, len
);
1156 CLAMP_INTERPOLANT(specGreen
, specGreenStep
, len
);
1157 CLAMP_INTERPOLANT(specBlue
, specBlueStep
, len
);
1160 CLAMP_INTERPOLANT(index
, indexStep
, len
);
1163 RENDER_SPAN( span
);
1168 * Advance to the next scan line. Compute the
1169 * new edge coordinates, and adjust the
1170 * pixel-center x coordinate so that it stays
1171 * on or inside the major edge.
1176 fxLeftEdge
+= fdxLeftEdge
;
1177 fxRightEdge
+= fdxRightEdge
;
1181 fError
-= INTERP_ONE
;
1183 #ifdef PIXEL_ADDRESS
1184 pRow
= (PIXEL_TYPE
*) ((GLubyte
*) pRow
+ dPRowOuter
);
1188 zRow
= (DEPTH_TYPE
*) ((GLubyte
*) zRow
+ dZRowOuter
);
1196 fogLeft
+= dfogOuter
;
1214 #ifdef INTERP_INT_TEX
1220 sLeft
[u
] += dsOuter
[u
];
1221 tLeft
[u
] += dtOuter
[u
];
1222 uLeft
[u
] += duOuter
[u
];
1223 vLeft
[u
] += dvOuter
[u
];
1228 #ifdef PIXEL_ADDRESS
1229 pRow
= (PIXEL_TYPE
*) ((GLubyte
*) pRow
+ dPRowInner
);
1233 zRow
= (DEPTH_TYPE
*) ((GLubyte
*) zRow
+ dZRowInner
);
1241 fogLeft
+= dfogInner
;
1259 #ifdef INTERP_INT_TEX
1265 sLeft
[u
] += dsInner
[u
];
1266 tLeft
[u
] += dtInner
[u
];
1267 uLeft
[u
] += duInner
[u
];
1268 vLeft
[u
] += dvInner
[u
];
1274 } /* for subTriangle */
1288 #undef BYTES_PER_ROW
1289 #undef PIXEL_ADDRESS
1299 #undef INTERP_INT_TEX
1301 #undef INTERP_MULTITEX
1302 #undef TEX_UNIT_LOOP