src/mesa/swrast/s_context.h

   1 /* $Id: s_context.h,v 1.24 2003/02/23 04:10:54 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  5.1
   6  *
   7  * Copyright (C) 1999-2003  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27
  28 /**
  29  * \file swrast/s_context.h
  30  * \brief Software rasterization context and private types.
  31  * \author Keith Whitwell <keith@tungstengraphics.com>
  32  */
  33
  34 #ifndef S_CONTEXT_H
  35 #define S_CONTEXT_H
  36
  37 #include "mtypes.h"
  38 #include "swrast.h"
  39
  40
  41 /**
  42  * \struct sw_span
  43  * \brief Contains data for either a horizontal line or a set of
  44  * pixels that are passed through a pipeline of functions before being
  45  * drawn.
  46  *
  47  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
  48  * etc for either a horizontal run or a set of independent pixels.  We
  49  * can either specify a base/step to indicate interpolated values, or
  50  * fill in arrays of values.  The interpMask and arrayMask bitfields
  51  * indicate which are active.
  52  *
  53  * With this structure it's easy to hand-off span rasterization to
  54  * subroutines instead of doing it all inline in the triangle functions
  55  * like we used to do.
  56  * It also cleans up the local variable namespace a great deal.
  57  *
  58  * It would be interesting to experiment with multiprocessor rasterization
  59  * with this structure.  The triangle rasterizer could simply emit a
  60  * stream of these structures which would be consumed by one or more
  61  * span-processing threads which could run in parallel.
  62  */
  63
  64
  65 /**
  66  * \defgroup SpanFlags SPAN_XXX-flags
  67  * Bitmasks to indicate which span_arrays need to be computed
  68  * (sw_span::interpMask) or have already been filled
  69  * (sw_span::arrayMask)
  70  */
  71 /*@{*/
  72 #define SPAN_RGBA         0x001
  73 #define SPAN_SPEC         0x002
  74 #define SPAN_INDEX        0x004
  75 #define SPAN_Z            0x008
  76 #define SPAN_FOG          0x010
  77 #define SPAN_TEXTURE      0x020
  78 #define SPAN_INT_TEXTURE  0x040
  79 #define SPAN_LAMBDA       0x080
  80 #define SPAN_COVERAGE     0x100
  81 #define SPAN_FLAT         0x200  /**< flat shading? */
  82 /** sw_span::arrayMask only - for span_arrays::x, span_arrays::y */
  83 #define SPAN_XY           0x400
  84 #define SPAN_MASK         0x800  /**< sw_span::arrayMask only */
  85 /*@}*/
  86
  87
  88 /**
  89  * \struct span_arrays
  90  * \brief Arrays of fragment values.
  91  *
  92  * These will either be computed from the x/xStep values above or
  93  * filled in by glDraw/CopyPixels, etc.
  94  * These arrays are separated out of sw_span to conserve memory.
  95  */
  96 struct span_arrays {
  97    GLchan  rgb[MAX_WIDTH][3];
  98    GLchan  rgba[MAX_WIDTH][4];
  99    GLuint  index[MAX_WIDTH];
 100    GLchan  spec[MAX_WIDTH][4]; /* specular color */
 101    GLint   x[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
 102    GLint   y[MAX_WIDTH];  /**< X/Y used for point/line rendering only */
 103    GLdepth z[MAX_WIDTH];
 104    GLfloat fog[MAX_WIDTH];
 105    GLfloat texcoords[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH][4];
 106    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH];
 107    GLfloat coverage[MAX_WIDTH];
 108
 109    /** This mask indicates if fragment is alive or culled */
 110    GLubyte mask[MAX_WIDTH];
 111 };
 112
 113
 114 struct sw_span {
 115    GLint x, y;
 116
 117    /** Only need to process pixels between start <= i < end */
 118    /** At this time, start is always zero. */
 119    GLuint start, end;
 120
 121    /** This flag indicates that mask[] array is effectively filled with ones */
 122    GLboolean writeAll;
 123
 124    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 125    GLenum primitive;
 126
 127    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 128    GLuint facing;
 129
 130    /**
 131     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 132     * which of the x/xStep variables are relevant.
 133     */
 134    GLuint interpMask;
 135
 136 #if CHAN_TYPE == GL_FLOAT
 137    GLfloat red, redStep;
 138    GLfloat green, greenStep;
 139    GLfloat blue, blueStep;
 140    GLfloat alpha, alphaStep;
 141    GLfloat specRed, specRedStep;
 142    GLfloat specGreen, specGreenStep;
 143    GLfloat specBlue, specBlueStep;
 144 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED SHORT */
 145    GLfixed red, redStep;
 146    GLfixed green, greenStep;
 147    GLfixed blue, blueStep;
 148    GLfixed alpha, alphaStep;
 149    GLfixed specRed, specRedStep;
 150    GLfixed specGreen, specGreenStep;
 151    GLfixed specBlue, specBlueStep;
 152 #endif
 153    GLfixed index, indexStep;
 154    GLfixed z, zStep;
 155    GLfloat fog, fogStep;
 156    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 157    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 158    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 159    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 160
 161    /**
 162     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 163     * which of the fragment arrays in the span_arrays struct are relevant.
 164     */
 165    GLuint arrayMask;
 166
 167    /**
 168     * We store the arrays of fragment values in a separate struct so
 169     * that we can allocate sw_span structs on the stack without using
 170     * a lot of memory.  The span_arrays struct is about 400KB while the
 171     * sw_span struct is only about 512 bytes.
 172     */
 173    struct span_arrays *array;
 174 };
 175
 176
 177 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 178 do {                                                            \
 179    (S).primitive = (PRIMITIVE);                                 \
 180    (S).interpMask = (INTERP_MASK);                              \
 181    (S).arrayMask = (ARRAY_MASK);                                \
 182    (S).start = 0;                                               \
 183    (S).end = (END);                                             \
 184    (S).facing = 0;                                              \
 185    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 186 } while (0)
 187
 188
 189 typedef void (*texture_sample_func)(GLcontext *ctx, GLuint texUnit,
 190                                     const struct gl_texture_object *tObj,
 191                                     GLuint n, const GLfloat texcoords[][4],
 192                                     const GLfloat lambda[], GLchan rgba[][4]);
 193
 194 #ifdef USE_MMX_ASM
 195 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 196                                     const GLubyte mask[],
 197                                     GLchan src[][4], CONST GLchan dst[][4] );
 198 #else
 199 typedef void (*blend_func)( GLcontext *ctx, GLuint n, const GLubyte mask[],
 200                             GLchan src[][4], CONST GLchan dst[][4] );
 201 #endif
 202
 203 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 204
 205 typedef void (*swrast_line_func)( GLcontext *ctx,
 206                                   const SWvertex *, const SWvertex *);
 207
 208 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 209                                  const SWvertex *, const SWvertex *);
 210
 211
 212 /** \defgroup Bitmasks
 213  * Bitmasks to indicate which rasterization options are enabled
 214  * (RasterMask)
 215  */
 216 /*@{*/
 217 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 218 #define BLEND_BIT               0x002   /**< Blend pixels */
 219 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 220 #define FOG_BIT                 0x008   /**< Fog pixels */
 221 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 222 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 223 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 224 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 225 #define ALPHABUF_BIT            0x100   /**< Using software alpha buffer */
 226 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 227                                         /**< buffer or no buffers. */
 228 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 229 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 230 /*@}*/
 231
 232 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 233                                 _NEW_SCISSOR|   \
 234                                 _NEW_COLOR|     \
 235                                 _NEW_DEPTH|     \
 236                                 _NEW_FOG|       \
 237                                 _NEW_STENCIL|   \
 238                                 _NEW_TEXTURE|   \
 239                                 _NEW_VIEWPORT|  \
 240                                 _NEW_DEPTH)
 241
 242
 243 /**
 244  * \struct SWcontext
 245  * \brief SWContext?
 246  */
 247 typedef struct
 248 {
 249    /** Driver interface:
 250     */
 251    struct swrast_device_driver Driver;
 252
 253    /** Configuration mechanisms to make software rasterizer match
 254     * characteristics of the hardware rasterizer (if present):
 255     */
 256    GLboolean AllowVertexFog;
 257    GLboolean AllowPixelFog;
 258
 259    /** Derived values, invalidated on statechanges, updated from
 260     * _swrast_validate_derived():
 261     */
 262    GLuint _RasterMask;
 263    GLfloat _MinMagThresh[MAX_TEXTURE_IMAGE_UNITS];
 264    GLfloat _backface_sign;
 265    GLboolean _PreferPixelFog;
 266    GLboolean _AnyTextureCombine;
 267
 268    /* Accum buffer temporaries.
 269     */
 270    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 271    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 272
 273
 274    /* Working values:
 275     */
 276    GLuint StippleCounter;    /**< Line stipple counter */
 277    GLuint NewState;
 278    GLuint StateChanges;
 279    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 280    GLuint CurrentBuffer; /* exactly one of FRONT_LEFT_BIT, BACK_LEFT_BIT, etc*/
 281
 282    /** Mechanism to allow driver (like X11) to register further
 283     * software rasterization routines.
 284     */
 285    /*@{*/
 286    void (*choose_point)( GLcontext * );
 287    void (*choose_line)( GLcontext * );
 288    void (*choose_triangle)( GLcontext * );
 289
 290    GLuint invalidate_point;
 291    GLuint invalidate_line;
 292    GLuint invalidate_triangle;
 293    /*@}*/
 294
 295    /** Function pointers for dispatch behind public entrypoints. */
 296    /*@{*/
 297    void (*InvalidateState)( GLcontext *ctx, GLuint new_state );
 298
 299    swrast_point_func Point;
 300    swrast_line_func Line;
 301    swrast_tri_func Triangle;
 302    /*@}*/
 303
 304    /**
 305     * Placeholders for when separate specular (or secondary color) is
 306     * enabled but texturing is not.
 307     */
 308    /*@{*/
 309    swrast_point_func SpecPoint;
 310    swrast_line_func SpecLine;
 311    swrast_tri_func SpecTriangle;
 312    /*@}*/
 313
 314    /**
 315     * Typically, we'll allocate a sw_span structure as a local variable
 316     * and set its 'array' pointer to point to this object.  The reason is
 317     * this object is big and causes problems when allocated on the stack
 318     * on some systems.
 319     */
 320    struct span_arrays *SpanArrays;
 321
 322    /**
 323     * Used to buffer N GL_POINTS, instead of rendering one by one.
 324     */
 325    struct sw_span PointSpan;
 326
 327    /** Internal hooks, kept uptodate by the same mechanism as above.
 328     */
 329    blend_func BlendFunc;
 330    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 331
 332    /** Buffer for saving the sampled texture colors.
 333     * Needed for GL_ARB_texture_env_crossbar implementation.
 334     */
 335    GLchan *TexelBuffer;
 336
 337 } SWcontext;
 338
 339
 340 extern void
 341 _swrast_validate_derived( GLcontext *ctx );
 342
 343
 344 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 345
 346 #define RENDER_START(SWctx, GLctx)                      \
 347    do {                                                 \
 348       if ((SWctx)->Driver.SpanRenderStart) {            \
 349          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 350       }                                                 \
 351    } while (0)
 352
 353 #define RENDER_FINISH(SWctx, GLctx)                     \
 354    do {                                                 \
 355       if ((SWctx)->Driver.SpanRenderFinish) {           \
 356          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 357       }                                                 \
 358    } while (0)
 359
 360
 361
 362 /*
 363  * XXX these macros are just bandages for now in order to make
 364  * CHAN_BITS==32 compile cleanly.
 365  * These should probably go elsewhere at some point.
 366  */
 367 #if CHAN_TYPE == GL_FLOAT
 368 #define ChanToFixed(X)  (X)
 369 #define FixedToChan(X)  (X)
 370 #else
 371 #define ChanToFixed(X)  IntToFixed(X)
 372 #define FixedToChan(X)  FixedToInt(X)
 373 #endif
 374
 375 #endif