src/mesa/swrast/s_context.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   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
  73 /**
  74  * \struct span_arrays
  75  * \brief Arrays of fragment values.
  76  *
  77  * These will either be computed from the x/xStep values above or
  78  * filled in by glDraw/CopyPixels, etc.
  79  * These arrays are separated out of sw_span to conserve memory.
  80  */
  81 struct span_arrays {
  82    /* XXX the next three fields could go into a union */
  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    GLuint  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    GLfloat varying[MAX_WIDTH][MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
  95
  96    /** This mask indicates which fragments are alive or culled */
  97    GLubyte mask[MAX_WIDTH];
  98 };
  99
 100
 101 /**
 102  * \struct sw_span
 103  * \brief Contains data for either a horizontal line or a set of
 104  * pixels that are passed through a pipeline of functions before being
 105  * drawn.
 106  *
 107  * The sw_span structure describes the colors, Z, fogcoord, texcoords,
 108  * etc for either a horizontal run or an array of independent pixels.
 109  * We can either specify a base/step to indicate interpolated values, or
 110  * fill in arrays of values.  The interpMask and arrayMask bitfields
 111  * indicate which are active.
 112  *
 113  * With this structure it's easy to hand-off span rasterization to
 114  * subroutines instead of doing it all inline in the triangle functions
 115  * like we used to do.
 116  * It also cleans up the local variable namespace a great deal.
 117  *
 118  * It would be interesting to experiment with multiprocessor rasterization
 119  * with this structure.  The triangle rasterizer could simply emit a
 120  * stream of these structures which would be consumed by one or more
 121  * span-processing threads which could run in parallel.
 122  */
 123 struct sw_span {
 124    GLint x, y;
 125
 126    /** Only need to process pixels between start <= i < end */
 127    /** At this time, start is always zero. */
 128    GLuint start, end;
 129
 130    /** This flag indicates that mask[] array is effectively filled with ones */
 131    GLboolean writeAll;
 132
 133    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 134    GLenum primitive;
 135
 136    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 137    GLuint facing;
 138
 139    /**
 140     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 141     * which of the x/xStep variables are relevant.
 142     */
 143    GLbitfield interpMask;
 144
 145    /* For horizontal spans, step is the partial derivative wrt X.
 146     * For lines, step is the delta from one fragment to the next.
 147     */
 148 #if CHAN_TYPE == GL_FLOAT
 149    GLfloat red, redStep;
 150    GLfloat green, greenStep;
 151    GLfloat blue, blueStep;
 152    GLfloat alpha, alphaStep;
 153    GLfloat specRed, specRedStep;
 154    GLfloat specGreen, specGreenStep;
 155    GLfloat specBlue, specBlueStep;
 156 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 157    GLfixed red, redStep;
 158    GLfixed green, greenStep;
 159    GLfixed blue, blueStep;
 160    GLfixed alpha, alphaStep;
 161    GLfixed specRed, specRedStep;
 162    GLfixed specGreen, specGreenStep;
 163    GLfixed specBlue, specBlueStep;
 164 #endif
 165    GLfixed index, indexStep;
 166    GLfixed z, zStep;    /* XXX z should probably be GLuint */
 167    GLfloat fog, fogStep;
 168    GLfloat tex[MAX_TEXTURE_COORD_UNITS][4];  /* s, t, r, q */
 169    GLfloat texStepX[MAX_TEXTURE_COORD_UNITS][4];
 170    GLfloat texStepY[MAX_TEXTURE_COORD_UNITS][4];
 171    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 172    GLfloat var[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 173    GLfloat varStepX[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 174    GLfloat varStepY[MAX_VARYING_VECTORS][VARYINGS_PER_VECTOR];
 175
 176    /* partial derivatives wrt X and Y. */
 177    GLfloat dzdx, dzdy;
 178    GLfloat w, dwdx, dwdy;
 179    GLfloat drdx, drdy;
 180    GLfloat dgdx, dgdy;
 181    GLfloat dbdx, dbdy;
 182    GLfloat dadx, dady;
 183    GLfloat dsrdx, dsrdy;
 184    GLfloat dsgdx, dsgdy;
 185    GLfloat dsbdx, dsbdy;
 186    GLfloat dfogdx, dfogdy;
 187
 188    /**
 189     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 190     * which of the fragment arrays in the span_arrays struct are relevant.
 191     */
 192    GLbitfield arrayMask;
 193
 194    /**
 195     * We store the arrays of fragment values in a separate struct so
 196     * that we can allocate sw_span structs on the stack without using
 197     * a lot of memory.  The span_arrays struct is about 400KB while the
 198     * sw_span struct is only about 512 bytes.
 199     */
 200    struct span_arrays *array;
 201 };
 202
 203
 204 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 205 do {                                                            \
 206    (S).primitive = (PRIMITIVE);                                 \
 207    (S).interpMask = (INTERP_MASK);                              \
 208    (S).arrayMask = (ARRAY_MASK);                                \
 209    (S).start = 0;                                               \
 210    (S).end = (END);                                             \
 211    (S).facing = 0;                                              \
 212    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 213 } while (0)
 214
 215
 216 typedef void (*texture_sample_func)(GLcontext *ctx,
 217                                     const struct gl_texture_object *tObj,
 218                                     GLuint n, const GLfloat texcoords[][4],
 219                                     const GLfloat lambda[], GLchan rgba[][4]);
 220
 221 typedef void (_ASMAPIP blend_func)( GLcontext *ctx, GLuint n,
 222                                     const GLubyte mask[],
 223                                     GLchan src[][4], CONST GLchan dst[][4] );
 224
 225 typedef void (*swrast_point_func)( GLcontext *ctx, const SWvertex *);
 226
 227 typedef void (*swrast_line_func)( GLcontext *ctx,
 228                                   const SWvertex *, const SWvertex *);
 229
 230 typedef void (*swrast_tri_func)( GLcontext *ctx, const SWvertex *,
 231                                  const SWvertex *, const SWvertex *);
 232
 233
 234 typedef void (*validate_texture_image_func)(GLcontext *ctx,
 235                                             struct gl_texture_object *texObj,
 236                                             GLuint face, GLuint level);
 237
 238
 239 /** \defgroup Bitmasks
 240  * Bitmasks to indicate which rasterization options are enabled
 241  * (RasterMask)
 242  */
 243 /*@{*/
 244 #define ALPHATEST_BIT           0x001   /**< Alpha-test pixels */
 245 #define BLEND_BIT               0x002   /**< Blend pixels */
 246 #define DEPTH_BIT               0x004   /**< Depth-test pixels */
 247 #define FOG_BIT                 0x008   /**< Fog pixels */
 248 #define LOGIC_OP_BIT            0x010   /**< Apply logic op in software */
 249 #define CLIP_BIT                0x020   /**< Scissor or window clip pixels */
 250 #define STENCIL_BIT             0x040   /**< Stencil pixels */
 251 #define MASKING_BIT             0x080   /**< Do glColorMask or glIndexMask */
 252 #define MULTI_DRAW_BIT          0x400   /**< Write to more than one color- */
 253                                         /**< buffer or no buffers. */
 254 #define OCCLUSION_BIT           0x800   /**< GL_HP_occlusion_test enabled */
 255 #define TEXTURE_BIT             0x1000  /**< Texturing really enabled */
 256 #define FRAGPROG_BIT            0x2000  /**< Fragment program enabled */
 257 #define ATIFRAGSHADER_BIT       0x4000  /**< ATI Fragment shader enabled */
 258 #define CLAMPING_BIT            0x8000  /**< Clamp colors to [0,1] */
 259 /*@}*/
 260
 261 #define _SWRAST_NEW_RASTERMASK (_NEW_BUFFERS|   \
 262                                 _NEW_SCISSOR|   \
 263                                 _NEW_COLOR|     \
 264                                 _NEW_DEPTH|     \
 265                                 _NEW_FOG|       \
 266                                 _NEW_PROGRAM|   \
 267                                 _NEW_STENCIL|   \
 268                                 _NEW_TEXTURE|   \
 269                                 _NEW_VIEWPORT|  \
 270                                 _NEW_DEPTH)
 271
 272
 273 /**
 274  * \struct SWcontext
 275  * \brief SWContext?
 276  */
 277 typedef struct
 278 {
 279    /** Driver interface:
 280     */
 281    struct swrast_device_driver Driver;
 282
 283    /** Configuration mechanisms to make software rasterizer match
 284     * characteristics of the hardware rasterizer (if present):
 285     */
 286    GLboolean AllowVertexFog;
 287    GLboolean AllowPixelFog;
 288
 289    /** Derived values, invalidated on statechanges, updated from
 290     * _swrast_validate_derived():
 291     */
 292    GLbitfield _RasterMask;
 293    GLfloat _BackfaceSign;
 294    GLboolean _PreferPixelFog;    /* Compute fog blend factor per fragment? */
 295    GLboolean _AnyTextureCombine;
 296    GLchan _FogColor[3];
 297    GLboolean _FogEnabled;
 298    GLenum _FogMode;  /* either GL_FOG_MODE or fragment program's fog mode */
 299
 300    /* Accum buffer temporaries.
 301     */
 302    GLboolean _IntegerAccumMode; /**< Storing unscaled integers? */
 303    GLfloat _IntegerAccumScaler; /**< Implicit scale factor */
 304
 305    /* Working values:
 306     */
 307    GLuint StippleCounter;    /**< Line stipple counter */
 308    GLbitfield NewState;
 309    GLuint StateChanges;
 310    GLenum Primitive;    /* current primitive being drawn (ala glBegin) */
 311
 312    void (*InvalidateState)( GLcontext *ctx, GLbitfield new_state );
 313
 314    /**
 315     * When the NewState mask intersects these masks, we invalidate the
 316     * Point/Line/Triangle function pointers below.
 317     */
 318    /*@{*/
 319    GLbitfield InvalidatePointMask;
 320    GLbitfield InvalidateLineMask;
 321    GLbitfield InvalidateTriangleMask;
 322    /*@}*/
 323
 324    /**
 325     * Device drivers plug in functions for these callbacks.
 326     * Will be called when the GL state change mask intersects the above masks.
 327     */
 328    /*@{*/
 329    void (*choose_point)( GLcontext * );
 330    void (*choose_line)( GLcontext * );
 331    void (*choose_triangle)( GLcontext * );
 332    /*@}*/
 333
 334    /**
 335     * Current point, line and triangle drawing functions.
 336     */
 337    /*@{*/
 338    swrast_point_func Point;
 339    swrast_line_func Line;
 340    swrast_tri_func Triangle;
 341    /*@}*/
 342
 343    /**
 344     * Placeholders for when separate specular (or secondary color) is
 345     * enabled but texturing is not.
 346     */
 347    /*@{*/
 348    swrast_point_func SpecPoint;
 349    swrast_line_func SpecLine;
 350    swrast_tri_func SpecTriangle;
 351    /*@}*/
 352
 353    /**
 354     * Typically, we'll allocate a sw_span structure as a local variable
 355     * and set its 'array' pointer to point to this object.  The reason is
 356     * this object is big and causes problems when allocated on the stack
 357     * on some systems.
 358     */
 359    struct span_arrays *SpanArrays;
 360
 361    /**
 362     * Used to buffer N GL_POINTS, instead of rendering one by one.
 363     */
 364    struct sw_span PointSpan;
 365
 366    /** Internal hooks, kept up to date by the same mechanism as above.
 367     */
 368    blend_func BlendFunc;
 369    texture_sample_func TextureSample[MAX_TEXTURE_IMAGE_UNITS];
 370
 371    /** Buffer for saving the sampled texture colors.
 372     * Needed for GL_ARB_texture_env_crossbar implementation.
 373     */
 374    GLchan *TexelBuffer;
 375
 376    validate_texture_image_func ValidateTextureImage;
 377
 378 } SWcontext;
 379
 380
 381 extern void
 382 _swrast_validate_derived( GLcontext *ctx );
 383
 384
 385 #define SWRAST_CONTEXT(ctx) ((SWcontext *)ctx->swrast_context)
 386
 387 #define RENDER_START(SWctx, GLctx)                      \
 388    do {                                                 \
 389       if ((SWctx)->Driver.SpanRenderStart) {            \
 390          (*(SWctx)->Driver.SpanRenderStart)(GLctx);     \
 391       }                                                 \
 392    } while (0)
 393
 394 #define RENDER_FINISH(SWctx, GLctx)                     \
 395    do {                                                 \
 396       if ((SWctx)->Driver.SpanRenderFinish) {           \
 397          (*(SWctx)->Driver.SpanRenderFinish)(GLctx);    \
 398       }                                                 \
 399    } while (0)
 400
 401
 402
 403 /*
 404  * XXX these macros are just bandages for now in order to make
 405  * CHAN_BITS==32 compile cleanly.
 406  * These should probably go elsewhere at some point.
 407  */
 408 #if CHAN_TYPE == GL_FLOAT
 409 #define ChanToFixed(X)  (X)
 410 #define FixedToChan(X)  (X)
 411 #else
 412 #define ChanToFixed(X)  IntToFixed(X)
 413 #define FixedToChan(X)  FixedToInt(X)
 414 #endif
 415
 416 #endif