src/mesa/swrast/s_context.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  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 /*@}*/
  70
  71
  72 /**
  73  * \struct span_arrays
  74  * \brief Arrays of fragment values.
  75  *
  76  * These will either be computed from the x/xStep values above or
  77  * filled in by glDraw/CopyPixels, etc.
  78  * These arrays are separated out of sw_span to conserve memory.
  79  */
  80 struct span_arrays {
  81    /* XXX the next three fields could go into a union */
  82    GLchan  rgb[MAX_WIDTH][3];
  83    GLchan  rgba[MAX_WIDTH][4];
  84    GLuint  index[MAX_WIDTH];
  85    GLchan  spec[MAX_WIDTH][4]; /* specular color */
  86    GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  87    GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  88    GLuint  z[MAX_WIDTH];
  89    GLfloat fog[MAX_WIDTH];
  90    GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
  91    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
  92    GLfloat coverage[MAX_WIDTH];
  93
  94    /** This mask indicates which fragments are alive or culled */
  95    GLubyte mask[MAX_WIDTH];
  96 };
  97
  98
  99 /**
 100  * \struct sw_span
 101  * \brief Contains data for either a horizontal line or a set of
 102  * pixels that are passed through a pipeline of functions before being
 103  * drawn.
 104  *
 105  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
 106  * etc for either a horizontal run or an array of independent pixels.
 107  * We can either specify a base/step to indicate interpolated values, or
 108  * fill in arrays of values.  The interpMask and arrayMask bitfields
 109  * indicate which are active.
 110  *
 111  * With this structure it's easy to hand-off span rasterization to
 112  * subroutines instead of doing it all inline in the triangle functions
 113  * like we used to do.
 114  * It also cleans up the local variable namespace a great deal.
 115  *
 116  * It would be interesting to experiment with multiprocessor rasterization
 117  * with this structure.  The triangle rasterizer could simply emit a
 118  * stream of these structures which would be consumed by one or more
 119  * span-processing threads which could run in parallel.
 120  */
 121 struct sw_span {
 122    GLint x, y;
 123
 124    /** Only need to process pixels between start <= i < end */
 125    /** At this time, start is always zero. */
 126    GLuint start, end;
 127
 128    /** This flag indicates that mask[] array is effectively filled with ones */
 129    GLboolean writeAll;
 130
 131    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 132    GLenum primitive;
 133
 134    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 135    GLuint facing;
 136
 137    /**
 138     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 139     * which of the x/xStep variables are relevant.
 140     */
 141    GLbitfield interpMask;
 142
 143    /* For horizontal spans, step is the partial derivative wrt X.
 144     * For lines, step is the delta from one fragment to the next.
 145     */
 146 #if CHAN_TYPE == GL_FLOAT
 147    GLfloat red, redStep;
 148    GLfloat green, greenStep;
 149    GLfloat blue, blueStep;
 150    GLfloat alpha, alphaStep;
 151    GLfloat specRed, specRedStep;
 152    GLfloat specGreen, specGreenStep;
 153    GLfloat specBlue, specBlueStep;
 154 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 155    GLfixed red, redStep;
 156    GLfixed green, greenStep;
 157    GLfixed blue, blueStep;
 158    GLfixed alpha, alphaStep;
 159    GLfixed specRed, specRedStep;
 160    GLfixed specGreen, specGreenStep;
 161    GLfixed specBlue, specBlueStep;
 162 #endif
 163    GLfixed index, indexStep;
 164    GLfixed z, zStep;    /* XXX z should probably be GLuint */
 165    GLfloat fog, fogStep;
 166    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 167    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 168    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 169    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 170
 171    /* partial derivatives wrt X and Y. */
 172    GLfloat dzdx, dzdy;
 173    GLfloat w, dwdx, dwdy;
 174    GLfloat drdx, drdy;
 175    GLfloat dgdx, dgdy;
 176    GLfloat dbdx, dbdy;
 177    GLfloat dadx, dady;
 178    GLfloat dsrdx, dsrdy;
 179    GLfloat dsgdx, dsgdy;
 180    GLfloat dsbdx, dsbdy;
 181    GLfloat dfogdx, dfogdy;
 182
 183    /**
 184     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 185     * which of the fragment arrays in the span_arrays struct are relevant.
 186     */
 187    GLbitfield arrayMask;
 188
 189    /**
 190     * We store the arrays of fragment values in a separate struct so
 191     * that we can allocate sw_span structs on the stack without using
 192     * a lot of memory.  The span_arrays struct is about 400KB while the
 193     * sw_span struct is only about 512 bytes.
 194     */
 195    struct span_arrays *array;
 196 };
 197
 198
 199 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 200 do {                                                            \
 201    (S).primitive = (PRIMITIVE);                                 \
 202    (S).interpMask = (INTERP_MASK);                              \
 203    (S).arrayMask = (ARRAY_MASK);                                \
 204    (S).start = 0;                                               \
 205    (S).end = (END);                                             \
 206    (S).facing = 0;                                              \
 207    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 208 } while (0)
 209
 210
 211 typedef void (*texture_sample_func)(GLcontext *ctx,
 212                                     const struct gl_texture_object *tObj,
 213                                     GLuint n, const GLfloat texcoords[][4],
 214                                     const GLfloat lambda[], GLchan rgba[][4]);
 215
 216 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 217                                     const GLubyte mask[],
 218                                     GLchan src[][4], CONST GLchan dst[][4] );
 219
 220 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 221
 222 typedef void (*swrast_line_func)( GLcontext *ctx,
 223                                   const SWvertex *, const SWvertex *);
 224
 225 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 226                                  const SWvertex *, const SWvertex *);
 227
 228
 229 /** \defgroup Bitmasks
 230  * Bitmasks to indicate which rasterization options are enabled
 231  * (RasterMask)
 232  */
 233 /*@{*/
 234 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 235 #define BLEND_BIT               0x002   /**< Blend pixels */
 236 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 237 #define FOG_BIT                 0x008   /**< Fog pixels */
 238 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 239 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 240 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 241 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 242 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 243                                         /**< buffer or no buffers. */
 244 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 245 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 246 #define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
 247 #define ATIFRAGSHADER_BIT       0x4000  /**< ATI Fragment shader enabled */
 248 /*@}*/
 249
 250 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 251                                 _NEW_SCISSOR|   \
 252                                 _NEW_COLOR|     \
 253                                 _NEW_DEPTH|     \
 254                                 _NEW_FOG|       \
 255                                 _NEW_PROGRAM|   \
 256                                 _NEW_STENCIL|   \
 257                                 _NEW_TEXTURE|   \
 258                                 _NEW_VIEWPORT|  \
 259                                 _NEW_DEPTH)
 260
 261
 262 /**
 263  * \struct SWcontext
 264  * \brief SWContext?
 265  */
 266 typedef struct
 267 {
 268    /** Driver interface:
 269     */
 270    struct swrast_device_driver Driver;
 271
 272    /** Configuration mechanisms to make software rasterizer match
 273     * characteristics of the hardware rasterizer (if present):
 274     */
 275    GLboolean AllowVertexFog;
 276    GLboolean AllowPixelFog;
 277
 278    /** Derived values, invalidated on statechanges, updated from
 279     * _swrast_validate_derived():
 280     */
 281    GLbitfield _RasterMask;
 282    GLfloat _BackfaceSign;
 283    GLboolean _PreferPixelFog;    /* Compute fog blend factor per fragment? */
 284    GLboolean _AnyTextureCombine;
 285    GLchan _FogColor[3];
 286    GLboolean _FogEnabled;
 287    GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */
 288
 289    /* Accum buffer temporaries.
 290     */
 291    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 292    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 293
 294    /* Working values:
 295     */
 296    GLuint StippleCounter;    /**< Line stipple counter */
 297    GLbitfield NewState;
 298    GLuint StateChanges;
 299    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 300
 301    /** Mechanism to allow driver (like X11) to register further
 302     * software rasterization routines.
 303     */
 304    /*@{*/
 305    void (*choose_point)( GLcontext * );
 306    void (*choose_line)( GLcontext * );
 307    void (*choose_triangle)( GLcontext * );
 308
 309    GLbitfield invalidate_point;
 310    GLbitfield invalidate_line;
 311    GLbitfield invalidate_triangle;
 312    /*@}*/
 313
 314    /** Function pointers for dispatch behind public entrypoints. */
 315    /*@{*/
 316    void (*InvalidateState)( GLcontext *ctx, GLbitfield new_state );
 317
 318    swrast_point_func Point;
 319    swrast_line_func Line;
 320    swrast_tri_func Triangle;
 321    /*@}*/
 322
 323    /**
 324     * Placeholders for when separate specular (or secondary color) is
 325     * enabled but texturing is not.
 326     */
 327    /*@{*/
 328    swrast_point_func SpecPoint;
 329    swrast_line_func SpecLine;
 330    swrast_tri_func SpecTriangle;
 331    /*@}*/
 332
 333    /**
 334     * Typically, we'll allocate a sw_span structure as a local variable
 335     * and set its 'array' pointer to point to this object.  The reason is
 336     * this object is big and causes problems when allocated on the stack
 337     * on some systems.
 338     */
 339    struct span_arrays *SpanArrays;
 340
 341    /**
 342     * Used to buffer N GL_POINTS, instead of rendering one by one.
 343     */
 344    struct sw_span PointSpan;
 345
 346    /** Internal hooks, kept up to date by the same mechanism as above.
 347     */
 348    blend_func BlendFunc;
 349    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 350
 351    /** Buffer for saving the sampled texture colors.
 352     * Needed for GL_ARB_texture_env_crossbar implementation.
 353     */
 354    GLchan *TexelBuffer;
 355
 356 } SWcontext;
 357
 358
 359 extern void
 360 _swrast_validate_derived( GLcontext *ctx );
 361
 362
 363 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 364
 365 #define RENDER_START(SWctx, GLctx)                      \
 366    do {                                                 \
 367       if ((SWctx)->Driver.SpanRenderStart) {            \
 368          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 369       }                                                 \
 370    } while (0)
 371
 372 #define RENDER_FINISH(SWctx, GLctx)                     \
 373    do {                                                 \
 374       if ((SWctx)->Driver.SpanRenderFinish) {           \
 375          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 376       }                                                 \
 377    } while (0)
 378
 379
 380
 381 /*
 382  * XXX these macros are just bandages for now in order to make
 383  * CHAN_BITS==32 compile cleanly.
 384  * These should probably go elsewhere at some point.
 385  */
 386 #if CHAN_TYPE == GL_FLOAT
 387 #define ChanToFixed(X)  (X)
 388 #define FixedToChan(X)  (X)
 389 #else
 390 #define ChanToFixed(X)  IntToFixed(X)
 391 #define FixedToChan(X)  FixedToInt(X)
 392 #endif
 393
 394 #endif