src/mesa/swrast/s_context.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.1
   4  *
   5  * Copyright (C) 1999-2004  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  * \file swrast/s_context.h
  28  * \brief Software rasterization context and private types.
  29  * \author Keith Whitwell <keith@tungstengraphics.com>
  30  */
  31
  32 /**
  33  * \mainpage swrast module
  34  *
  35  * This module, software rasterization, contains the software fallback
  36  * routines for drawing points, lines, triangles, bitmaps and images.
  37  * All rendering boils down to writing spans (arrays) of pixels with
  38  * particular colors.  The span-writing routines must be implemented
  39  * by the device driver.
  40  */
  41
  42
  43 #ifndef S_CONTEXT_H
  44 #define S_CONTEXT_H
  45
  46 #include "mtypes.h"
  47 #include "swrast.h"
  48
  49
  50 /**
  51  * \defgroup SpanFlags SPAN_XXX-flags
  52  * Bitmasks to indicate which span_arrays need to be computed
  53  * (sw_span::interpMask) or have already been filled
  54  * (sw_span::arrayMask)
  55  */
  56 /*@{*/
  57 #define SPAN_RGBA         0x001
  58 #define SPAN_SPEC         0x002
  59 #define SPAN_INDEX        0x004
  60 #define SPAN_Z            0x008
  61 #define SPAN_W            0x010
  62 #define SPAN_FOG          0x020
  63 #define SPAN_TEXTURE      0x040
  64 #define SPAN_INT_TEXTURE  0x080
  65 #define SPAN_LAMBDA       0x100
  66 #define SPAN_COVERAGE     0x200
  67 #define SPAN_FLAT         0x400  /**< flat shading? */
  68 /** sw_span::arrayMask only - for span_arrays::x, span_arrays::y */
  69 #define SPAN_XY           0x800
  70 #define SPAN_MASK        0x1000  /**< sw_span::arrayMask only */
  71 /*@}*/
  72
  73
  74 /**
  75  * \struct span_arrays
  76  * \brief Arrays of fragment values.
  77  *
  78  * These will either be computed from the x/xStep values above or
  79  * filled in by glDraw/CopyPixels, etc.
  80  * These arrays are separated out of sw_span to conserve memory.
  81  */
  82 struct span_arrays {
  83    GLchan  rgb[MAX_WIDTH][3];
  84    GLchan  rgba[MAX_WIDTH][4];
  85    GLuint  index[MAX_WIDTH];
  86    GLchan  spec[MAX_WIDTH][4]; /* specular color */
  87    GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  88    GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  89    GLdepth z[MAX_WIDTH];
  90    GLfloat fog[MAX_WIDTH];
  91    GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
  92    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
  93    GLfloat coverage[MAX_WIDTH];
  94
  95    /** This mask indicates if fragment is alive or culled */
  96    GLubyte mask[MAX_WIDTH];
  97 };
  98
  99
 100 /**
 101  * \struct sw_span
 102  * \brief Contains data for either a horizontal line or a set of
 103  * pixels that are passed through a pipeline of functions before being
 104  * drawn.
 105  *
 106  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
 107  * etc for either a horizontal run or an array of independent pixels.
 108  * We can either specify a base/step to indicate interpolated values, or
 109  * fill in arrays of values.  The interpMask and arrayMask bitfields
 110  * indicate which are active.
 111  *
 112  * With this structure it's easy to hand-off span rasterization to
 113  * subroutines instead of doing it all inline in the triangle functions
 114  * like we used to do.
 115  * It also cleans up the local variable namespace a great deal.
 116  *
 117  * It would be interesting to experiment with multiprocessor rasterization
 118  * with this structure.  The triangle rasterizer could simply emit a
 119  * stream of these structures which would be consumed by one or more
 120  * span-processing threads which could run in parallel.
 121  */
 122 struct sw_span {
 123    GLint x, y;
 124
 125    /** Only need to process pixels between start <= i < end */
 126    /** At this time, start is always zero. */
 127    GLuint start, end;
 128
 129    /** This flag indicates that mask[] array is effectively filled with ones */
 130    GLboolean writeAll;
 131
 132    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 133    GLenum primitive;
 134
 135    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 136    GLuint facing;
 137
 138    /**
 139     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 140     * which of the x/xStep variables are relevant.
 141     */
 142    GLuint interpMask;
 143
 144    /* For horizontal spans, step is the partial derivative wrt X.
 145     * For lines, step is the delta from one fragment to the next.
 146     */
 147 #if CHAN_TYPE == GL_FLOAT
 148    GLfloat red, redStep;
 149    GLfloat green, greenStep;
 150    GLfloat blue, blueStep;
 151    GLfloat alpha, alphaStep;
 152    GLfloat specRed, specRedStep;
 153    GLfloat specGreen, specGreenStep;
 154    GLfloat specBlue, specBlueStep;
 155 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 156    GLfixed red, redStep;
 157    GLfixed green, greenStep;
 158    GLfixed blue, blueStep;
 159    GLfixed alpha, alphaStep;
 160    GLfixed specRed, specRedStep;
 161    GLfixed specGreen, specGreenStep;
 162    GLfixed specBlue, specBlueStep;
 163 #endif
 164    GLfixed index, indexStep;
 165    GLfixed z, zStep;
 166    GLfloat fog, fogStep;
 167    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 168    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 169    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 170    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 171
 172    /* partial derivatives wrt X and Y. */
 173    GLfloat dzdx, dzdy;
 174    GLfloat w, dwdx, dwdy;
 175    GLfloat drdx, drdy;
 176    GLfloat dgdx, dgdy;
 177    GLfloat dbdx, dbdy;
 178    GLfloat dadx, dady;
 179    GLfloat dsrdx, dsrdy;
 180    GLfloat dsgdx, dsgdy;
 181    GLfloat dsbdx, dsbdy;
 182    GLfloat dfogdx, dfogdy;
 183
 184    /**
 185     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 186     * which of the fragment arrays in the span_arrays struct are relevant.
 187     */
 188    GLuint arrayMask;
 189
 190    /**
 191     * We store the arrays of fragment values in a separate struct so
 192     * that we can allocate sw_span structs on the stack without using
 193     * a lot of memory.  The span_arrays struct is about 400KB while the
 194     * sw_span struct is only about 512 bytes.
 195     */
 196    struct span_arrays *array;
 197 };
 198
 199
 200 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 201 do {                                                            \
 202    (S).primitive = (PRIMITIVE);                                 \
 203    (S).interpMask = (INTERP_MASK);                              \
 204    (S).arrayMask = (ARRAY_MASK);                                \
 205    (S).start = 0;                                               \
 206    (S).end = (END);                                             \
 207    (S).facing = 0;                                              \
 208    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 209 } while (0)
 210
 211
 212 typedef void (*texture_sample_func)(GLcontext *ctx, GLuint texUnit,
 213                                     const struct gl_texture_object *tObj,
 214                                     GLuint n, const GLfloat texcoords[][4],
 215                                     const GLfloat lambda[], GLchan rgba[][4]);
 216
 217 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 218                                     const GLubyte mask[],
 219                                     GLchan src[][4], CONST GLchan dst[][4] );
 220
 221 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 222
 223 typedef void (*swrast_line_func)( GLcontext *ctx,
 224                                   const SWvertex *, const SWvertex *);
 225
 226 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 227                                  const SWvertex *, const SWvertex *);
 228
 229
 230 /** \defgroup Bitmasks
 231  * Bitmasks to indicate which rasterization options are enabled
 232  * (RasterMask)
 233  */
 234 /*@{*/
 235 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 236 #define BLEND_BIT               0x002   /**< Blend pixels */
 237 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 238 #define FOG_BIT                 0x008   /**< Fog pixels */
 239 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 240 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 241 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 242 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 243 #define ALPHABUF_BIT            0x100   /**< Using software alpha buffer */
 244 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 245                                         /**< buffer or no buffers. */
 246 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 247 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 248 #define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
 249 /*@}*/
 250
 251 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 252                                 _NEW_SCISSOR|   \
 253                                 _NEW_COLOR|     \
 254                                 _NEW_DEPTH|     \
 255                                 _NEW_FOG|       \
 256                                 _NEW_PROGRAM|   \
 257                                 _NEW_STENCIL|   \
 258                                 _NEW_TEXTURE|   \
 259                                 _NEW_VIEWPORT|  \
 260                                 _NEW_DEPTH)
 261
 262
 263 /**
 264  * \struct SWcontext
 265  * \brief SWContext?
 266  */
 267 typedef struct
 268 {
 269    /** Driver interface:
 270     */
 271    struct swrast_device_driver Driver;
 272
 273    /** Configuration mechanisms to make software rasterizer match
 274     * characteristics of the hardware rasterizer (if present):
 275     */
 276    GLboolean AllowVertexFog;
 277    GLboolean AllowPixelFog;
 278
 279    /** Derived values, invalidated on statechanges, updated from
 280     * _swrast_validate_derived():
 281     */
 282    GLuint _RasterMask;
 283    GLfloat _MinMagThresh[MAX_TEXTURE_IMAGE_UNITS];
 284    GLfloat _BackfaceSign;
 285    GLboolean _PreferPixelFog;    /* Compute fog blend factor per fragment? */
 286    GLboolean _AnyTextureCombine;
 287    GLchan _FogColor[3];
 288    GLboolean _FogEnabled;
 289    GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */
 290
 291    /* Accum buffer temporaries.
 292     */
 293    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 294    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 295
 296    GLchan *CurAuxBuffer;
 297
 298    /* Working values:
 299     */
 300    GLuint StippleCounter;    /**< Line stipple counter */
 301    GLuint NewState;
 302    GLuint StateChanges;
 303    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 304    GLbitfield CurrentBufferBit; /* exactly one the of DD_*_BIT buffer bits */
 305
 306    /** Mechanism to allow driver (like X11) to register further
 307     * software rasterization routines.
 308     */
 309    /*@{*/
 310    void (*choose_point)( GLcontext * );
 311    void (*choose_line)( GLcontext * );
 312    void (*choose_triangle)( GLcontext * );
 313
 314    GLuint invalidate_point;
 315    GLuint invalidate_line;
 316    GLuint invalidate_triangle;
 317    /*@}*/
 318
 319    /** Function pointers for dispatch behind public entrypoints. */
 320    /*@{*/
 321    void (*InvalidateState)( GLcontext *ctx, GLuint new_state );
 322
 323    swrast_point_func Point;
 324    swrast_line_func Line;
 325    swrast_tri_func Triangle;
 326    /*@}*/
 327
 328    /**
 329     * Placeholders for when separate specular (or secondary color) is
 330     * enabled but texturing is not.
 331     */
 332    /*@{*/
 333    swrast_point_func SpecPoint;
 334    swrast_line_func SpecLine;
 335    swrast_tri_func SpecTriangle;
 336    /*@}*/
 337
 338    /**
 339     * Typically, we'll allocate a sw_span structure as a local variable
 340     * and set its 'array' pointer to point to this object.  The reason is
 341     * this object is big and causes problems when allocated on the stack
 342     * on some systems.
 343     */
 344    struct span_arrays *SpanArrays;
 345
 346    /**
 347     * Used to buffer N GL_POINTS, instead of rendering one by one.
 348     */
 349    struct sw_span PointSpan;
 350
 351    /** Internal hooks, kept uptodate by the same mechanism as above.
 352     */
 353    blend_func BlendFunc;
 354    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 355
 356    /** Buffer for saving the sampled texture colors.
 357     * Needed for GL_ARB_texture_env_crossbar implementation.
 358     */
 359    GLchan *TexelBuffer;
 360
 361 } SWcontext;
 362
 363
 364 extern void
 365 _swrast_validate_derived( GLcontext *ctx );
 366
 367
 368 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 369
 370 #define RENDER_START(SWctx, GLctx)                      \
 371    do {                                                 \
 372       if ((SWctx)->Driver.SpanRenderStart) {            \
 373          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 374       }                                                 \
 375    } while (0)
 376
 377 #define RENDER_FINISH(SWctx, GLctx)                     \
 378    do {                                                 \
 379       if ((SWctx)->Driver.SpanRenderFinish) {           \
 380          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 381       }                                                 \
 382    } while (0)
 383
 384
 385
 386 /*
 387  * XXX these macros are just bandages for now in order to make
 388  * CHAN_BITS==32 compile cleanly.
 389  * These should probably go elsewhere at some point.
 390  */
 391 #if CHAN_TYPE == GL_FLOAT
 392 #define ChanToFixed(X)  (X)
 393 #define FixedToChan(X)  (X)
 394 #else
 395 #define ChanToFixed(X)  IntToFixed(X)
 396 #define FixedToChan(X)  FixedToInt(X)
 397 #endif
 398
 399
 400
 401 extern void
 402 _swrast_translate_program( GLcontext *ctx );
 403
 404 extern GLboolean
 405 _swrast_execute_codegen_program(GLcontext *ctx,
 406                                 const struct fragment_program *program,
 407                                 GLuint maxInst,
 408                                 struct fp_machine *machine,
 409                                 const struct sw_span *span,
 410                                 GLuint column );
 411
 412
 413 #endif