src/mesa/swrast/s_context.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  5.1
   4  *
   5  * Copyright (C) 1999-2003  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 #ifndef S_CONTEXT_H
  33 #define S_CONTEXT_H
  34
  35 #include "mtypes.h"
  36 #include "swrast.h"
  37
  38
  39 /**
  40  * \defgroup SpanFlags SPAN_XXX-flags
  41  * Bitmasks to indicate which span_arrays need to be computed
  42  * (sw_span::interpMask) or have already been filled
  43  * (sw_span::arrayMask)
  44  */
  45 /*@{*/
  46 #define SPAN_RGBA         0x001
  47 #define SPAN_SPEC         0x002
  48 #define SPAN_INDEX        0x004
  49 #define SPAN_Z            0x008
  50 #define SPAN_FOG          0x010
  51 #define SPAN_TEXTURE      0x020
  52 #define SPAN_INT_TEXTURE  0x040
  53 #define SPAN_LAMBDA       0x080
  54 #define SPAN_COVERAGE     0x100
  55 #define SPAN_FLAT         0x200  /**< flat shading? */
  56 /** sw_span::arrayMask only - for span_arrays::x, span_arrays::y */
  57 #define SPAN_XY           0x400
  58 #define SPAN_MASK         0x800  /**< sw_span::arrayMask only */
  59 /*@}*/
  60
  61
  62 /**
  63  * \struct span_arrays
  64  * \brief Arrays of fragment values.
  65  *
  66  * These will either be computed from the x/xStep values above or
  67  * filled in by glDraw/CopyPixels, etc.
  68  * These arrays are separated out of sw_span to conserve memory.
  69  */
  70 struct span_arrays {
  71    GLchan  rgb[MAX_WIDTH][3];
  72    GLchan  rgba[MAX_WIDTH][4];
  73    GLuint  index[MAX_WIDTH];
  74    GLchan  spec[MAX_WIDTH][4]; /* specular color */
  75    GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  76    GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
  77    GLdepth z[MAX_WIDTH];
  78    GLfloat fog[MAX_WIDTH];
  79    GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
  80    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
  81    GLfloat coverage[MAX_WIDTH];
  82
  83    /** This mask indicates if fragment is alive or culled */
  84    GLubyte mask[MAX_WIDTH];
  85 };
  86
  87
  88 /**
  89  * \struct sw_span
  90  * \brief Contains data for either a horizontal line or a set of
  91  * pixels that are passed through a pipeline of functions before being
  92  * drawn.
  93  *
  94  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
  95  * etc for either a horizontal run or an array of independent pixels.
  96  * We can either specify a base/step to indicate interpolated values, or
  97  * fill in arrays of values.  The interpMask and arrayMask bitfields
  98  * indicate which are active.
  99  *
 100  * With this structure it's easy to hand-off span rasterization to
 101  * subroutines instead of doing it all inline in the triangle functions
 102  * like we used to do.
 103  * It also cleans up the local variable namespace a great deal.
 104  *
 105  * It would be interesting to experiment with multiprocessor rasterization
 106  * with this structure.  The triangle rasterizer could simply emit a
 107  * stream of these structures which would be consumed by one or more
 108  * span-processing threads which could run in parallel.
 109  */
 110 struct sw_span {
 111    GLint x, y;
 112
 113    /** Only need to process pixels between start <= i < end */
 114    /** At this time, start is always zero. */
 115    GLuint start, end;
 116
 117    /** This flag indicates that mask[] array is effectively filled with ones */
 118    GLboolean writeAll;
 119
 120    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 121    GLenum primitive;
 122
 123    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 124    GLuint facing;
 125
 126    /**
 127     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 128     * which of the x/xStep variables are relevant.
 129     */
 130    GLuint interpMask;
 131
 132    /* For horizontal spans, step is the partial derivative wrt X.
 133     * For lines, step is the delta from one fragment to the next.
 134     */
 135 #if CHAN_TYPE == GL_FLOAT
 136    GLfloat red, redStep;
 137    GLfloat green, greenStep;
 138    GLfloat blue, blueStep;
 139    GLfloat alpha, alphaStep;
 140    GLfloat specRed, specRedStep;
 141    GLfloat specGreen, specGreenStep;
 142    GLfloat specBlue, specBlueStep;
 143 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 144    GLfixed red, redStep;
 145    GLfixed green, greenStep;
 146    GLfixed blue, blueStep;
 147    GLfixed alpha, alphaStep;
 148    GLfixed specRed, specRedStep;
 149    GLfixed specGreen, specGreenStep;
 150    GLfixed specBlue, specBlueStep;
 151 #endif
 152    GLfixed index, indexStep;
 153    GLfixed z, zStep;
 154    GLfloat fog, fogStep;
 155    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 156    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 157    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 158    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 159
 160    /* partial derivatives wrt X and Y. */
 161    GLfloat dzdx, dzdy;
 162    GLfloat w, dwdx, dwdy;
 163    GLfloat drdx, drdy;
 164    GLfloat dgdx, dgdy;
 165    GLfloat dbdx, dbdy;
 166    GLfloat dadx, dady;
 167    GLfloat dsrdx, dsrdy;
 168    GLfloat dsgdx, dsgdy;
 169    GLfloat dsbdx, dsbdy;
 170    GLfloat dfogdx, dfogdy;
 171
 172    /**
 173     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 174     * which of the fragment arrays in the span_arrays struct are relevant.
 175     */
 176    GLuint arrayMask;
 177
 178    /**
 179     * We store the arrays of fragment values in a separate struct so
 180     * that we can allocate sw_span structs on the stack without using
 181     * a lot of memory.  The span_arrays struct is about 400KB while the
 182     * sw_span struct is only about 512 bytes.
 183     */
 184    struct span_arrays *array;
 185 };
 186
 187
 188 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 189 do {                                                            \
 190    (S).primitive = (PRIMITIVE);                                 \
 191    (S).interpMask = (INTERP_MASK);                              \
 192    (S).arrayMask = (ARRAY_MASK);                                \
 193    (S).start = 0;                                               \
 194    (S).end = (END);                                             \
 195    (S).facing = 0;                                              \
 196    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 197 } while (0)
 198
 199
 200 typedef void (*texture_sample_func)(GLcontext *ctx, GLuint texUnit,
 201                                     const struct gl_texture_object *tObj,
 202                                     GLuint n, const GLfloat texcoords[][4],
 203                                     const GLfloat lambda[], GLchan rgba[][4]);
 204
 205 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 206                                     const GLubyte mask[],
 207                                     GLchan src[][4], CONST GLchan dst[][4] );
 208
 209 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 210
 211 typedef void (*swrast_line_func)( GLcontext *ctx,
 212                                   const SWvertex *, const SWvertex *);
 213
 214 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 215                                  const SWvertex *, const SWvertex *);
 216
 217
 218 /** \defgroup Bitmasks
 219  * Bitmasks to indicate which rasterization options are enabled
 220  * (RasterMask)
 221  */
 222 /*@{*/
 223 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 224 #define BLEND_BIT               0x002   /**< Blend pixels */
 225 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 226 #define FOG_BIT                 0x008   /**< Fog pixels */
 227 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 228 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 229 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 230 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 231 #define ALPHABUF_BIT            0x100   /**< Using software alpha buffer */
 232 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 233                                         /**< buffer or no buffers. */
 234 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 235 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 236 #define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
 237 /*@}*/
 238
 239 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 240                                 _NEW_SCISSOR|   \
 241                                 _NEW_COLOR|     \
 242                                 _NEW_DEPTH|     \
 243                                 _NEW_FOG|       \
 244                                 _NEW_PROGRAM|   \
 245                                 _NEW_STENCIL|   \
 246                                 _NEW_TEXTURE|   \
 247                                 _NEW_VIEWPORT|  \
 248                                 _NEW_DEPTH)
 249
 250
 251 /**
 252  * \struct SWcontext
 253  * \brief SWContext?
 254  */
 255 typedef struct
 256 {
 257    /** Driver interface:
 258     */
 259    struct swrast_device_driver Driver;
 260
 261    /** Configuration mechanisms to make software rasterizer match
 262     * characteristics of the hardware rasterizer (if present):
 263     */
 264    GLboolean AllowVertexFog;
 265    GLboolean AllowPixelFog;
 266
 267    /** Derived values, invalidated on statechanges, updated from
 268     * _swrast_validate_derived():
 269     */
 270    GLuint _RasterMask;
 271    GLfloat _MinMagThresh[MAX_TEXTURE_IMAGE_UNITS];
 272    GLfloat _BackfaceSign;
 273    GLboolean _PreferPixelFog;
 274    GLboolean _AnyTextureCombine;
 275
 276    /* Accum buffer temporaries.
 277     */
 278    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 279    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 280
 281
 282    /* Working values:
 283     */
 284    GLuint StippleCounter;    /**< Line stipple counter */
 285    GLuint NewState;
 286    GLuint StateChanges;
 287    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 288    GLuint CurrentBuffer; /* exactly one of FRONT_LEFT_BIT, BACK_LEFT_BIT, etc*/
 289
 290    /** Mechanism to allow driver (like X11) to register further
 291     * software rasterization routines.
 292     */
 293    /*@{*/
 294    void (*choose_point)( GLcontext * );
 295    void (*choose_line)( GLcontext * );
 296    void (*choose_triangle)( GLcontext * );
 297
 298    GLuint invalidate_point;
 299    GLuint invalidate_line;
 300    GLuint invalidate_triangle;
 301    /*@}*/
 302
 303    /** Function pointers for dispatch behind public entrypoints. */
 304    /*@{*/
 305    void (*InvalidateState)( GLcontext *ctx, GLuint new_state );
 306
 307    swrast_point_func Point;
 308    swrast_line_func Line;
 309    swrast_tri_func Triangle;
 310    /*@}*/
 311
 312    /**
 313     * Placeholders for when separate specular (or secondary color) is
 314     * enabled but texturing is not.
 315     */
 316    /*@{*/
 317    swrast_point_func SpecPoint;
 318    swrast_line_func SpecLine;
 319    swrast_tri_func SpecTriangle;
 320    /*@}*/
 321
 322    /**
 323     * Typically, we'll allocate a sw_span structure as a local variable
 324     * and set its 'array' pointer to point to this object.  The reason is
 325     * this object is big and causes problems when allocated on the stack
 326     * on some systems.
 327     */
 328    struct span_arrays *SpanArrays;
 329
 330    /**
 331     * Used to buffer N GL_POINTS, instead of rendering one by one.
 332     */
 333    struct sw_span PointSpan;
 334
 335    /** Internal hooks, kept uptodate by the same mechanism as above.
 336     */
 337    blend_func BlendFunc;
 338    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 339
 340    /** Buffer for saving the sampled texture colors.
 341     * Needed for GL_ARB_texture_env_crossbar implementation.
 342     */
 343    GLchan *TexelBuffer;
 344
 345 } SWcontext;
 346
 347
 348 extern void
 349 _swrast_validate_derived( GLcontext *ctx );
 350
 351
 352 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 353
 354 #define RENDER_START(SWctx, GLctx)                      \
 355    do {                                                 \
 356       if ((SWctx)->Driver.SpanRenderStart) {            \
 357          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 358       }                                                 \
 359    } while (0)
 360
 361 #define RENDER_FINISH(SWctx, GLctx)                     \
 362    do {                                                 \
 363       if ((SWctx)->Driver.SpanRenderFinish) {           \
 364          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 365       }                                                 \
 366    } while (0)
 367
 368
 369
 370 /*
 371  * XXX these macros are just bandages for now in order to make
 372  * CHAN_BITS==32 compile cleanly.
 373  * These should probably go elsewhere at some point.
 374  */
 375 #if CHAN_TYPE == GL_FLOAT
 376 #define ChanToFixed(X)  (X)
 377 #define FixedToChan(X)  (X)
 378 #else
 379 #define ChanToFixed(X)  IntToFixed(X)
 380 #define FixedToChan(X)  FixedToInt(X)
 381 #endif
 382
 383 #endif