src/mesa/swrast/s_context.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5.2
   4  *
   5  * Copyright (C) 1999-2006  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 in (sw_span::arrayMask)
  54  */
  55 /*@{*/
  56 #define SPAN_RGBA         0x001
  57 #define SPAN_SPEC         0x002
  58 #define SPAN_INDEX        0x004
  59 #define SPAN_Z            0x008
  60 #define SPAN_W            0x010
  61 #define SPAN_FOG          0x020
  62 #define SPAN_TEXTURE      0x040
  63 #define SPAN_INT_TEXTURE  0x080
  64 #define SPAN_LAMBDA       0x100
  65 #define SPAN_COVERAGE     0x200
  66 #define SPAN_FLAT         0x400  /**< flat shading? */
  67 #define SPAN_XY           0x800
  68 #define SPAN_MASK        0x1000
  69 #define SPAN_VARYING     0x2000
  70 /*@}*/
  71
  72 #if 0
  73 /* alternate arrangement for code below */
  74 struct arrays2 {
  75    union {
  76       GLubyte  sz1[MAX_WIDTH][4]; /* primary color */
  77       GLushort sz2[MAX_WIDTH][4];
  78       GLfloat  sz4[MAX_WIDTH][4];
  79    } rgba;
  80    union {
  81       GLubyte  sz1[MAX_WIDTH][4]; /* specular color and temp storage */
  82       GLushort sz2[MAX_WIDTH][4];
  83       GLfloat  sz4[MAX_WIDTH][4];
  84    } spec;
  85 };
  86 #endif
  87
  88
  89 /**
  90  * \struct span_arrays
  91  * \brief Arrays of fragment values.
  92  *
  93  * These will either be computed from the x/xStep values above or
  94  * filled in by glDraw/CopyPixels, etc.
  95  * These arrays are separated out of sw_span to conserve memory.
  96  */
  97 struct span_arrays {
  98    GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
  99    union {
 100       struct {
 101          GLubyte rgba[MAX_WIDTH][4]; /**< primary color */
 102          GLubyte spec[MAX_WIDTH][4]; /**< specular color and temp storage */
 103       } sz1;
 104       struct {
 105          GLushort rgba[MAX_WIDTH][4];
 106          GLushort spec[MAX_WIDTH][4];
 107       } sz2;
 108       struct {
 109          GLfloat rgba[MAX_WIDTH][4];
 110          GLfloat spec[MAX_WIDTH][4];
 111       } sz4;
 112    } color;
 113    /** XXX these are temporary fields, pointing into above color arrays */
 114    GLchan (*rgba)[4];
 115    GLchan (*spec)[4];
 116
 117    GLuint  index[MAX_WIDTH];
 118    GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
 119    GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
 120    GLuint  z[MAX_WIDTH];
 121    GLfloat fog[MAX_WIDTH];
 122    GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
 123    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
 124    GLfloat coverage[MAX_WIDTH];
 125    GLfloat varying[MAX_WIDTH][MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 126
 127    /** This mask indicates which fragments are alive or culled */
 128    GLubyte mask[MAX_WIDTH];
 129 };
 130
 131
 132 /**
 133  * \struct sw_span
 134  * \brief Contains data for either a horizontal line or a set of
 135  * pixels that are passed through a pipeline of functions before being
 136  * drawn.
 137  *
 138  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
 139  * etc for either a horizontal run or an array of independent pixels.
 140  * We can either specify a base/step to indicate interpolated values, or
 141  * fill in arrays of values.  The interpMask and arrayMask bitfields
 142  * indicate which are active.
 143  *
 144  * With this structure it's easy to hand-off span rasterization to
 145  * subroutines instead of doing it all inline in the triangle functions
 146  * like we used to do.
 147  * It also cleans up the local variable namespace a great deal.
 148  *
 149  * It would be interesting to experiment with multiprocessor rasterization
 150  * with this structure.  The triangle rasterizer could simply emit a
 151  * stream of these structures which would be consumed by one or more
 152  * span-processing threads which could run in parallel.
 153  */
 154 struct sw_span {
 155    GLint x, y;
 156
 157    /** Only need to process pixels between start <= i < end */
 158    /** At this time, start is always zero. */
 159    GLuint start, end;
 160
 161    /** This flag indicates that mask[] array is effectively filled with ones */
 162    GLboolean writeAll;
 163
 164    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 165    GLenum primitive;
 166
 167    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 168    GLuint facing;
 169
 170    /**
 171     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 172     * which of the x/xStep variables are relevant.
 173     */
 174    GLbitfield interpMask;
 175
 176    /* For horizontal spans, step is the partial derivative wrt X.
 177     * For lines, step is the delta from one fragment to the next.
 178     */
 179 #if CHAN_TYPE == GL_FLOAT
 180    GLfloat red, redStep;
 181    GLfloat green, greenStep;
 182    GLfloat blue, blueStep;
 183    GLfloat alpha, alphaStep;
 184    GLfloat specRed, specRedStep;
 185    GLfloat specGreen, specGreenStep;
 186    GLfloat specBlue, specBlueStep;
 187 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 188    GLfixed red, redStep;
 189    GLfixed green, greenStep;
 190    GLfixed blue, blueStep;
 191    GLfixed alpha, alphaStep;
 192    GLfixed specRed, specRedStep;
 193    GLfixed specGreen, specGreenStep;
 194    GLfixed specBlue, specBlueStep;
 195 #endif
 196    GLfixed index, indexStep;
 197    GLfixed z, zStep;    /* XXX z should probably be GLuint */
 198    GLfloat fog, fogStep;
 199    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 200    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 201    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 202    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 203    GLfloat var[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 204    GLfloat varStepX[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 205    GLfloat varStepY[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 206
 207    /* partial derivatives wrt X and Y. */
 208    GLfloat dzdx, dzdy;
 209    GLfloat w, dwdx, dwdy;
 210    GLfloat drdx, drdy;
 211    GLfloat dgdx, dgdy;
 212    GLfloat dbdx, dbdy;
 213    GLfloat dadx, dady;
 214    GLfloat dsrdx, dsrdy;
 215    GLfloat dsgdx, dsgdy;
 216    GLfloat dsbdx, dsbdy;
 217    GLfloat dfogdx, dfogdy;
 218
 219    /**
 220     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 221     * which of the fragment arrays in the span_arrays struct are relevant.
 222     */
 223    GLbitfield arrayMask;
 224
 225    /**
 226     * We store the arrays of fragment values in a separate struct so
 227     * that we can allocate sw_span structs on the stack without using
 228     * a lot of memory.  The span_arrays struct is about 400KB while the
 229     * sw_span struct is only about 512 bytes.
 230     */
 231    struct span_arrays *array;
 232 };
 233
 234
 235 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 236 do {                                                            \
 237    (S).primitive = (PRIMITIVE);                                 \
 238    (S).interpMask = (INTERP_MASK);                              \
 239    (S).arrayMask = (ARRAY_MASK);                                \
 240    (S).start = 0;                                               \
 241    (S).end = (END);                                             \
 242    (S).facing = 0;                                              \
 243    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 244 } while (0)
 245
 246
 247 typedef void (*texture_sample_func)(GLcontext *ctx,
 248                                     const struct gl_texture_object *tObj,
 249                                     GLuint n, const GLfloat texcoords[][4],
 250                                     const GLfloat lambda[], GLchan rgba[][4]);
 251
 252 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 253                                     const GLubyte mask[],
 254                                     GLchan src[][4], CONST GLchan dst[][4],
 255                                     GLenum chanType);
 256
 257 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 258
 259 typedef void (*swrast_line_func)( GLcontext *ctx,
 260                                   const SWvertex *, const SWvertex *);
 261
 262 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 263                                  const SWvertex *, const SWvertex *);
 264
 265
 266 typedef void (*validate_texture_image_func)(GLcontext *ctx,
 267                                             struct gl_texture_object *texObj,
 268                                             GLuint face, GLuint level);
 269
 270
 271 /** \defgroup Bitmasks
 272  * Bitmasks to indicate which rasterization options are enabled
 273  * (RasterMask)
 274  */
 275 /*@{*/
 276 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 277 #define BLEND_BIT               0x002   /**< Blend pixels */
 278 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 279 #define FOG_BIT                 0x008   /**< Fog pixels */
 280 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 281 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 282 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 283 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 284 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 285                                         /**< buffer or no buffers. */
 286 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 287 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 288 #define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
 289 #define ATIFRAGSHADER_BIT       0x4000  /**< ATI Fragment shader enabled */
 290 #define CLAMPING_BIT            0x8000  /**< Clamp colors to [0,1] */
 291 /*@}*/
 292
 293 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 294                                 _NEW_SCISSOR|   \
 295                                 _NEW_COLOR|     \
 296                                 _NEW_DEPTH|     \
 297                                 _NEW_FOG|       \
 298                                 _NEW_PROGRAM|   \
 299                                 _NEW_STENCIL|   \
 300                                 _NEW_TEXTURE|   \
 301                                 _NEW_VIEWPORT|  \
 302                                 _NEW_DEPTH)
 303
 304
 305 /**
 306  * \struct SWcontext
 307  * \brief SWContext?
 308  */
 309 typedef struct
 310 {
 311    /** Driver interface:
 312     */
 313    struct swrast_device_driver Driver;
 314
 315    /** Configuration mechanisms to make software rasterizer match
 316     * characteristics of the hardware rasterizer (if present):
 317     */
 318    GLboolean AllowVertexFog;
 319    GLboolean AllowPixelFog;
 320
 321    /** Derived values, invalidated on statechanges, updated from
 322     * _swrast_validate_derived():
 323     */
 324    GLbitfield _RasterMask;
 325    GLfloat _BackfaceSign;
 326    GLboolean _PreferPixelFog;    /* Compute fog blend factor per fragment? */
 327    GLboolean _AnyTextureCombine;
 328    GLboolean _FogEnabled;
 329    GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */
 330
 331    /* Accum buffer temporaries.
 332     */
 333    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 334    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 335
 336    /* Working values:
 337     */
 338    GLuint StippleCounter;    /**< Line stipple counter */
 339    GLbitfield NewState;
 340    GLuint StateChanges;
 341    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 342
 343    void (*InvalidateState)( GLcontext *ctx, GLbitfield new_state );
 344
 345    /**
 346     * When the NewState mask intersects these masks, we invalidate the
 347     * Point/Line/Triangle function pointers below.
 348     */
 349    /*@{*/
 350    GLbitfield InvalidatePointMask;
 351    GLbitfield InvalidateLineMask;
 352    GLbitfield InvalidateTriangleMask;
 353    /*@}*/
 354
 355    /**
 356     * Device drivers plug in functions for these callbacks.
 357     * Will be called when the GL state change mask intersects the above masks.
 358     */
 359    /*@{*/
 360    void (*choose_point)( GLcontext * );
 361    void (*choose_line)( GLcontext * );
 362    void (*choose_triangle)( GLcontext * );
 363    /*@}*/
 364
 365    /**
 366     * Current point, line and triangle drawing functions.
 367     */
 368    /*@{*/
 369    swrast_point_func Point;
 370    swrast_line_func Line;
 371    swrast_tri_func Triangle;
 372    /*@}*/
 373
 374    /**
 375     * Placeholders for when separate specular (or secondary color) is
 376     * enabled but texturing is not.
 377     */
 378    /*@{*/
 379    swrast_point_func SpecPoint;
 380    swrast_line_func SpecLine;
 381    swrast_tri_func SpecTriangle;
 382    /*@}*/
 383
 384    /**
 385     * Typically, we'll allocate a sw_span structure as a local variable
 386     * and set its 'array' pointer to point to this object.  The reason is
 387     * this object is big and causes problems when allocated on the stack
 388     * on some systems.
 389     */
 390    struct span_arrays *SpanArrays;
 391
 392    /**
 393     * Used to buffer N GL_POINTS, instead of rendering one by one.
 394     */
 395    struct sw_span PointSpan;
 396
 397    /** Internal hooks, kept up to date by the same mechanism as above.
 398     */
 399    blend_func BlendFunc;
 400    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 401
 402    /** Buffer for saving the sampled texture colors.
 403     * Needed for GL_ARB_texture_env_crossbar implementation.
 404     */
 405    GLchan *TexelBuffer;
 406
 407    validate_texture_image_func ValidateTextureImage;
 408
 409 } SWcontext;
 410
 411
 412 extern void
 413 _swrast_validate_derived( GLcontext *ctx );
 414
 415
 416 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 417
 418 #define RENDER_START(SWctx, GLctx)                      \
 419    do {                                                 \
 420       if ((SWctx)->Driver.SpanRenderStart) {            \
 421          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 422       }                                                 \
 423    } while (0)
 424
 425 #define RENDER_FINISH(SWctx, GLctx)                     \
 426    do {                                                 \
 427       if ((SWctx)->Driver.SpanRenderFinish) {           \
 428          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 429       }                                                 \
 430    } while (0)
 431
 432
 433
 434 /*
 435  * XXX these macros are just bandages for now in order to make
 436  * CHAN_BITS==32 compile cleanly.
 437  * These should probably go elsewhere at some point.
 438  */
 439 #if CHAN_TYPE == GL_FLOAT
 440 #define ChanToFixed(X)  (X)
 441 #define FixedToChan(X)  (X)
 442 #else
 443 #define ChanToFixed(X)  IntToFixed(X)
 444 #define FixedToChan(X)  FixedToInt(X)
 445 #endif
 446
 447 #endif