1/*
2 * Mesa 3-D graphics library
3 * Version:  7.5
4 *
5 * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
6 * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 */
25
26
27#ifndef S_SPAN_H
28#define S_SPAN_H
29
30
31#include "main/config.h"
32#include "main/glheader.h"
33#include "main/mtypes.h"
34#include "swrast/s_chan.h"
35#include "swrast/swrast.h"
36
37
38struct gl_context;
39struct gl_renderbuffer;
40
41
42/**
43 * \defgroup SpanFlags
44 * Special bitflags to describe span data.
45 *
46 * In general, the point/line/triangle functions interpolate/emit the
47 * attributes specified by swrast->_ActiveAttribs (i.e. FRAT_BIT_* values).
48 * Some things don't fit into that, though, so we have these flags.
49 */
50/*@{*/
51#define SPAN_RGBA       0x01  /**< interpMask and arrayMask */
52#define SPAN_Z          0x02  /**< interpMask and arrayMask */
53#define SPAN_FLAT       0x04  /**< interpMask: flat shading? */
54#define SPAN_XY         0x08  /**< array.x[], y[] valid? */
55#define SPAN_MASK       0x10  /**< was array.mask[] filled in by caller? */
56#define SPAN_LAMBDA     0x20  /**< array.lambda[] valid? */
57#define SPAN_COVERAGE   0x40  /**< array.coverage[] valid? */
58/*@}*/
59
60
61/**
62 * \sw_span_arrays
63 * \brief Arrays of fragment values.
64 *
65 * These will either be computed from the span x/xStep values or
66 * filled in by glDraw/CopyPixels, etc.
67 * These arrays are separated out of sw_span to conserve memory.
68 */
69typedef struct sw_span_arrays
70{
71   /** Per-fragment attributes (indexed by FRAG_ATTRIB_* tokens) */
72   /* XXX someday look at transposing first two indexes for better memory
73    * access pattern.
74    */
75   GLfloat attribs[FRAG_ATTRIB_MAX][SWRAST_MAX_WIDTH][4];
76
77   /** This mask indicates which fragments are alive or culled */
78   GLubyte mask[SWRAST_MAX_WIDTH];
79
80   GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
81
82   /** Attribute arrays that don't fit into attribs[] array above */
83   /*@{*/
84   GLubyte rgba8[SWRAST_MAX_WIDTH][4];
85   GLushort rgba16[SWRAST_MAX_WIDTH][4];
86   GLchan (*rgba)[4];  /** either == rgba8 or rgba16 */
87   GLint   x[SWRAST_MAX_WIDTH];  /**< fragment X coords */
88   GLint   y[SWRAST_MAX_WIDTH];  /**< fragment Y coords */
89   GLuint  z[SWRAST_MAX_WIDTH];  /**< fragment Z coords */
90   GLuint  index[SWRAST_MAX_WIDTH];  /**< Color indexes */
91   GLfloat lambda[MAX_TEXTURE_COORD_UNITS][SWRAST_MAX_WIDTH]; /**< Texture LOD */
92   GLfloat coverage[SWRAST_MAX_WIDTH];  /**< Fragment coverage for AA/smoothing */
93   /*@}*/
94} SWspanarrays;
95
96
97/**
98 * The SWspan structure describes the colors, Z, fogcoord, texcoords,
99 * etc for either a horizontal run or an array of independent pixels.
100 * We can either specify a base/step to indicate interpolated values, or
101 * fill in explicit arrays of values.  The interpMask and arrayMask bitfields
102 * indicate which attributes are active interpolants or arrays, respectively.
103 *
104 * It would be interesting to experiment with multiprocessor rasterization
105 * with this structure.  The triangle rasterizer could simply emit a
106 * stream of these structures which would be consumed by one or more
107 * span-processing threads which could run in parallel.
108 */
109typedef struct sw_span
110{
111   /** Coord of first fragment in horizontal span/run */
112   GLint x, y;
113
114   /** Number of fragments in the span */
115   GLuint end;
116
117   /** for clipping left edge of spans */
118   GLuint leftClip;
119
120   /** This flag indicates that mask[] array is effectively filled with ones */
121   GLboolean writeAll;
122
123   /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
124   GLenum primitive;
125
126   /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
127   GLuint facing;
128
129   /**
130    * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
131    * which of the attrStart/StepX/StepY variables are relevant.
132    */
133   GLbitfield interpMask;
134
135   /** Fragment attribute interpolants */
136   GLfloat attrStart[FRAG_ATTRIB_MAX][4];   /**< initial value */
137   GLfloat attrStepX[FRAG_ATTRIB_MAX][4];   /**< dvalue/dx */
138   GLfloat attrStepY[FRAG_ATTRIB_MAX][4];   /**< dvalue/dy */
139
140   /* XXX the rest of these will go away eventually... */
141
142   /* For horizontal spans, step is the partial derivative wrt X.
143    * For lines, step is the delta from one fragment to the next.
144    */
145   GLfixed red, redStep;
146   GLfixed green, greenStep;
147   GLfixed blue, blueStep;
148   GLfixed alpha, alphaStep;
149   GLfixed index, indexStep;
150   GLfixed z, zStep;    /**< XXX z should probably be GLuint */
151   GLfixed intTex[2], intTexStep[2];  /**< (s,t) for unit[0] only */
152
153   /**
154    * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
155    * which of the fragment arrays in the span_arrays struct are relevant.
156    */
157   GLbitfield arrayMask;
158
159   /** Mask of FRAG_BIT_x bits */
160   GLbitfield64 arrayAttribs;
161
162   /**
163    * We store the arrays of fragment values in a separate struct so
164    * that we can allocate sw_span structs on the stack without using
165    * a lot of memory.  The span_arrays struct is about 1.4MB while the
166    * sw_span struct is only about 512 bytes.
167    */
168   SWspanarrays *array;
169} SWspan;
170
171
172
173#define INIT_SPAN(S, PRIMITIVE)			\
174do {						\
175   (S).primitive = (PRIMITIVE);			\
176   (S).interpMask = 0x0;			\
177   (S).arrayMask = 0x0;				\
178   (S).arrayAttribs = 0x0;			\
179   (S).end = 0;					\
180   (S).leftClip = 0;				\
181   (S).facing = 0;				\
182   (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;	\
183} while (0)
184
185
186
187extern void
188_swrast_span_default_attribs(struct gl_context *ctx, SWspan *span);
189
190extern void
191_swrast_span_interpolate_z( const struct gl_context *ctx, SWspan *span );
192
193extern GLfloat
194_swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
195                       GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
196                       GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
197
198
199extern void
200_swrast_write_rgba_span( struct gl_context *ctx, SWspan *span);
201
202
203extern void
204_swrast_read_rgba_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
205                       GLuint n, GLint x, GLint y, GLvoid *rgba);
206
207extern void
208_swrast_put_row(struct gl_context *ctx, struct gl_renderbuffer *rb,
209                GLenum datatype,
210                GLuint count, GLint x, GLint y,
211                const void *values, const GLubyte *mask);
212
213extern void *
214_swrast_get_dest_rgba(struct gl_context *ctx, struct gl_renderbuffer *rb,
215                      SWspan *span);
216
217#endif
218