summaryrefslogtreecommitdiff
path: root/src/mesa/swrast/s_context.h
blob: 5cfe7627a5d100d5284f693267e8bc28b0d8aa52 (plain)
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
/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 1999-2005  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.
 */


/**
 * \file swrast/s_context.h
 * \brief Software rasterization context and private types.
 * \author Keith Whitwell <keith@tungstengraphics.com>
 */

/**
 * \mainpage swrast module
 *
 * This module, software rasterization, contains the software fallback
 * routines for drawing points, lines, triangles, bitmaps and images.
 * All rendering boils down to writing spans (arrays) of pixels with
 * particular colors.  The span-writing routines must be implemented
 * by the device driver.
 */


#ifndef S_CONTEXT_H
#define S_CONTEXT_H

#include "mtypes.h"
#include "swrast.h"


/**
 * \defgroup SpanFlags SPAN_XXX-flags
 * Bitmasks to indicate which span_arrays need to be computed
 * (sw_span::interpMask) or have already been filled in (sw_span::arrayMask)
 */
/*@{*/
#define SPAN_RGBA         0x001
#define SPAN_SPEC         0x002
#define SPAN_INDEX        0x004
#define SPAN_Z            0x008
#define SPAN_W            0x010
#define SPAN_FOG          0x020
#define SPAN_TEXTURE      0x040
#define SPAN_INT_TEXTURE  0x080
#define SPAN_LAMBDA       0x100
#define SPAN_COVERAGE     0x200
#define SPAN_FLAT         0x400  /**< flat shading? */
#define SPAN_XY           0x800
#define SPAN_MASK        0x1000
/*@}*/


/**
 * \struct span_arrays 
 * \brief Arrays of fragment values.
 *
 * These will either be computed from the x/xStep values above or
 * filled in by glDraw/CopyPixels, etc.
 * These arrays are separated out of sw_span to conserve memory.
 */
struct span_arrays {
   /* XXX the next three fields could go into a union */
   GLchan  rgb[MAX_WIDTH][3];
   GLchan  rgba[MAX_WIDTH][4];
   GLuint  index[MAX_WIDTH];
   GLchan  spec[MAX_WIDTH][4]; /* specular color */
   GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
   GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
   GLuint  z[MAX_WIDTH];
   GLfloat fog[MAX_WIDTH];
   GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
   GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
   GLfloat coverage[MAX_WIDTH];

   /** This mask indicates which fragments are alive or culled */
   GLubyte mask[MAX_WIDTH];
};


/**
 * \struct sw_span
 * \brief Contains data for either a horizontal line or a set of
 * pixels that are passed through a pipeline of functions before being
 * drawn.
 *
 * The sw_span structure describes the colors, Z, fogcoord, texcoords,
 * etc for either a horizontal run or an array of independent pixels.
 * We can either specify a base/step to indicate interpolated values, or
 * fill in arrays of values.  The interpMask and arrayMask bitfields
 * indicate which are active.
 *
 * With this structure it's easy to hand-off span rasterization to
 * subroutines instead of doing it all inline in the triangle functions
 * like we used to do.
 * It also cleans up the local variable namespace a great deal.
 *
 * It would be interesting to experiment with multiprocessor rasterization
 * with this structure.  The triangle rasterizer could simply emit a
 * stream of these structures which would be consumed by one or more
 * span-processing threads which could run in parallel.
 */
struct sw_span {
   GLint x, y;

   /** Only need to process pixels between start <= i < end */
   /** At this time, start is always zero. */
   GLuint start, end;

   /** This flag indicates that mask[] array is effectively filled with ones */
   GLboolean writeAll;

   /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
   GLenum primitive;

   /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
   GLuint facing;

   /**
    * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
    * which of the x/xStep variables are relevant.
    */
   GLbitfield interpMask;

   /* For horizontal spans, step is the partial derivative wrt X.
    * For lines, step is the delta from one fragment to the next.
    */
#if CHAN_TYPE == GL_FLOAT
   GLfloat red, redStep;
   GLfloat green, greenStep;
   GLfloat blue, blueStep;
   GLfloat alpha, alphaStep;
   GLfloat specRed, specRedStep;
   GLfloat specGreen, specGreenStep;
   GLfloat specBlue, specBlueStep;
#else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
   GLfixed red, redStep;
   GLfixed green, greenStep;
   GLfixed blue, blueStep;
   GLfixed alpha, alphaStep;
   GLfixed specRed, specRedStep;
   GLfixed specGreen, specGreenStep;
   GLfixed specBlue, specBlueStep;
#endif
   GLfixed index, indexStep;
   GLfixed z, zStep;    /* XXX z should probably be GLuint */
   GLfloat fog, fogStep;
   GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
   GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
   GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
   GLfixed intTex[2], intTexStep[2];  /* s, t only */

   /* partial derivatives wrt X and Y. */
   GLfloat dzdx, dzdy;
   GLfloat w, dwdx, dwdy;
   GLfloat drdx, drdy;
   GLfloat dgdx, dgdy;
   GLfloat dbdx, dbdy;
   GLfloat dadx, dady;
   GLfloat dsrdx, dsrdy;
   GLfloat dsgdx, dsgdy;
   GLfloat dsbdx, dsbdy;
   GLfloat dfogdx, dfogdy;

   /**
    * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
    * which of the fragment arrays in the span_arrays struct are relevant.
    */
   GLbitfield arrayMask;

   /**
    * We store the arrays of fragment values in a separate struct so
    * that we can allocate sw_span structs on the stack without using
    * a lot of memory.  The span_arrays struct is about 400KB while the
    * sw_span struct is only about 512 bytes.
    */
   struct span_arrays *array;
};


#define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)	\
do {								\
   (S).primitive = (PRIMITIVE);					\
   (S).interpMask = (INTERP_MASK);				\
   (S).arrayMask = (ARRAY_MASK);				\
   (S).start = 0;						\
   (S).end = (END);						\
   (S).facing = 0;						\
   (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;			\
} while (0)


typedef void (*texture_sample_func)(GLcontext *ctx,
                                    const struct gl_texture_object *tObj,
                                    GLuint n, const GLfloat texcoords[][4],
                                    const GLfloat lambda[], GLchan rgba[][4]);

typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
                                    const GLubyte mask[],
                                    GLchan src[][4], CONST GLchan dst[][4] );

typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);

typedef void (*swrast_line_func)( GLcontext *ctx,
                                  const SWvertex *, const SWvertex *);

typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
                                 const SWvertex *, const SWvertex *);


/** \defgroup Bitmasks
 * Bitmasks to indicate which rasterization options are enabled
 * (RasterMask)
 */
/*@{*/
#define ALPHATEST_BIT		0x001	/**< Alpha-test pixels */
#define BLEND_BIT		0x002	/**< Blend pixels */
#define DEPTH_BIT		0x004	/**< Depth-test pixels */
#define FOG_BIT			0x008	/**< Fog pixels */
#define LOGIC_OP_BIT		0x010	/**< Apply logic op in software */
#define CLIP_BIT		0x020	/**< Scissor or window clip pixels */
#define STENCIL_BIT		0x040	/**< Stencil pixels */
#define MASKING_BIT		0x080	/**< Do glColorMask or glIndexMask */
#define MULTI_DRAW_BIT		0x400	/**< Write to more than one color- */
                                        /**< buffer or no buffers. */
#define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
#define TEXTURE_BIT		0x1000	/**< Texturing really enabled */
#define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
#define ATIFRAGSHADER_BIT       0x4000  /**< ATI Fragment shader enabled */
#define CLAMPING_BIT            0x8000  /**< Clamp colors to [0,1] */
/*@}*/

#define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|	\
			        _NEW_SCISSOR|	\
			        _NEW_COLOR|	\
			        _NEW_DEPTH|	\
			        _NEW_FOG|	\
                                _NEW_PROGRAM|   \
			        _NEW_STENCIL|	\
			        _NEW_TEXTURE|	\
			        _NEW_VIEWPORT|	\
			        _NEW_DEPTH)


/**
 * \struct SWcontext
 * \brief SWContext?
 */
typedef struct
{
   /** Driver interface:
    */
   struct swrast_device_driver Driver;

   /** Configuration mechanisms to make software rasterizer match
    * characteristics of the hardware rasterizer (if present):
    */
   GLboolean AllowVertexFog;
   GLboolean AllowPixelFog;

   /** Derived values, invalidated on statechanges, updated from
    * _swrast_validate_derived():
    */
   GLbitfield _RasterMask;
   GLfloat _BackfaceSign;
   GLboolean _PreferPixelFog;    /* Compute fog blend factor per fragment? */
   GLboolean _AnyTextureCombine;
   GLchan _FogColor[3];
   GLboolean _FogEnabled;
   GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */

   /* Accum buffer temporaries.
    */
   GLboolean _IntegerAccumMode;	/**< Storing unscaled integers? */
   GLfloat _IntegerAccumScaler;	/**< Implicit scale factor */

   /* Working values:
    */
   GLuint StippleCounter;    /**< Line stipple counter */
   GLbitfield NewState;
   GLuint StateChanges;
   GLenum Primitive;    /* current primitive being drawn (ala glBegin) */

   /** Mechanism to allow driver (like X11) to register further
    * software rasterization routines.
    */
   /*@{*/
   void (*choose_point)( GLcontext * );
   void (*choose_line)( GLcontext * );
   void (*choose_triangle)( GLcontext * );

   GLbitfield invalidate_point;
   GLbitfield invalidate_line;
   GLbitfield invalidate_triangle;
   /*@}*/

   /** Function pointers for dispatch behind public entrypoints. */
   /*@{*/
   void (*InvalidateState)( GLcontext *ctx, GLbitfield new_state );

   swrast_point_func Point;
   swrast_line_func Line;
   swrast_tri_func Triangle;
   /*@}*/

   /**
    * Placeholders for when separate specular (or secondary color) is
    * enabled but texturing is not.
    */
   /*@{*/
   swrast_point_func SpecPoint;
   swrast_line_func SpecLine;
   swrast_tri_func SpecTriangle;
   /*@}*/

   /**
    * Typically, we'll allocate a sw_span structure as a local variable
    * and set its 'array' pointer to point to this object.  The reason is
    * this object is big and causes problems when allocated on the stack
    * on some systems.
    */
   struct span_arrays *SpanArrays;

   /**
    * Used to buffer N GL_POINTS, instead of rendering one by one.
    */
   struct sw_span PointSpan;

   /** Internal hooks, kept up to date by the same mechanism as above.
    */
   blend_func BlendFunc;
   texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];

   /** Buffer for saving the sampled texture colors.
    * Needed for GL_ARB_texture_env_crossbar implementation.
    */
   GLchan *TexelBuffer;

} SWcontext;


extern void
_swrast_validate_derived( GLcontext *ctx );


#define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)

#define RENDER_START(SWctx, GLctx)			\
   do {							\
      if ((SWctx)->Driver.SpanRenderStart) {		\
         (*(SWctx)->Driver.SpanRenderStart)(GLctx);	\
      }							\
   } while (0)

#define RENDER_FINISH(SWctx, GLctx)			\
   do {							\
      if ((SWctx)->Driver.SpanRenderFinish) {		\
         (*(SWctx)->Driver.SpanRenderFinish)(GLctx);	\
      }							\
   } while (0)



/*
 * XXX these macros are just bandages for now in order to make
 * CHAN_BITS==32 compile cleanly.
 * These should probably go elsewhere at some point.
 */
#if CHAN_TYPE == GL_FLOAT
#define ChanToFixed(X)  (X)
#define FixedToChan(X)  (X)
#else
#define ChanToFixed(X)  IntToFixed(X)
#define FixedToChan(X)  FixedToInt(X)
#endif

#endif