src/mesa/swrast/s_span.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 #ifndef S_SPAN_H
  27 #define S_SPAN_H
  28
  29
  30 #include "mtypes.h"
  31 #include "swrast.h"
  32
  33
  34 /**
  35  * \defgroup SpanFlags
  36  * Bitflags used for interpMask and arrayMask fields below to indicate
  37  * which interpolant values and fragment arrays are in use, respectively.
  38  *
  39  * XXX We should replace these flags with the FRAG_BIT_ values someday...
  40  */
  41 /*@{*/
  42 #define SPAN_RGBA         0x001
  43 #define SPAN_SPEC         0x002
  44 #define SPAN_INDEX        0x004
  45 #define SPAN_Z            0x008
  46 #define SPAN_W            0x010
  47 #define SPAN_FOG          0x020
  48 #define SPAN_TEXTURE      0x040
  49 #define SPAN_INT_TEXTURE  0x080
  50 #define SPAN_LAMBDA       0x100
  51 #define SPAN_COVERAGE     0x200
  52 #define SPAN_FLAT         0x400  /**< flat shading? */
  53 #define SPAN_XY           0x800
  54 #define SPAN_MASK        0x1000
  55 #define SPAN_VARYING     0x2000
  56 /*@}*/
  57
  58
  59 #if 0
  60 /* alternate arrangement for code below */
  61 struct arrays2 {
  62    union {
  63       GLubyte  sz1[MAX_WIDTH][4]; /* primary color */
  64       GLushort sz2[MAX_WIDTH][4];
  65    } rgba;
  66    union {
  67       GLubyte  sz1[MAX_WIDTH][4]; /* specular color and temp storage */
  68       GLushort sz2[MAX_WIDTH][4];
  69    } spec;
  70 };
  71 #endif
  72
  73
  74
  75 /**
  76  * \sw_span_arrays
  77  * \brief Arrays of fragment values.
  78  *
  79  * These will either be computed from the span x/xStep values or
  80  * filled in by glDraw/CopyPixels, etc.
  81  * These arrays are separated out of sw_span to conserve memory.
  82  */
  83 typedef struct sw_span_arrays
  84 {
  85    /** Per-fragment attributes (indexed by FRAG_ATTRIB_* tokens) */
  86    /* XXX someday look at transposing first two indexes for better memory
  87     * access pattern.
  88     */
  89    GLfloat attribs[FRAG_ATTRIB_MAX][MAX_WIDTH][4];
  90
  91    /** This mask indicates which fragments are alive or culled */
  92    GLubyte mask[MAX_WIDTH];
  93
  94    GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
  95    union {
  96       struct {
  97          GLubyte rgba[MAX_WIDTH][4]; /**< primary color */
  98          GLubyte spec[MAX_WIDTH][4]; /**< specular color and temp storage */
  99       } sz1;
 100       struct {
 101          GLushort rgba[MAX_WIDTH][4];
 102          GLushort spec[MAX_WIDTH][4];
 103       } sz2;
 104    } color;
 105    /** XXX these are temporary fields, pointing into above color arrays */
 106    GLchan (*rgba)[4];
 107    GLchan (*spec)[4];
 108
 109    GLint   x[MAX_WIDTH];  /**< fragment X coords */
 110    GLint   y[MAX_WIDTH];  /**< fragment Y coords */
 111    GLuint  z[MAX_WIDTH];  /**< fragment Z coords */
 112    GLuint  index[MAX_WIDTH];  /**< Color indexes */
 113    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH]; /**< Texture LOD */
 114    GLfloat coverage[MAX_WIDTH];  /**< Fragment coverage for AA/smoothing */
 115 } SWspanarrays;
 116
 117
 118 /**
 119  * The SWspan structure describes the colors, Z, fogcoord, texcoords,
 120  * etc for either a horizontal run or an array of independent pixels.
 121  * We can either specify a base/step to indicate interpolated values, or
 122  * fill in explicit arrays of values.  The interpMask and arrayMask bitfields
 123  * indicate which attributes are active interpolants or arrays, respectively.
 124  *
 125  * It would be interesting to experiment with multiprocessor rasterization
 126  * with this structure.  The triangle rasterizer could simply emit a
 127  * stream of these structures which would be consumed by one or more
 128  * span-processing threads which could run in parallel.
 129  */
 130 typedef struct sw_span
 131 {
 132    /** Coord of first fragment in horizontal span/run */
 133    GLint x, y;
 134
 135    /** Number of fragments in the span */
 136    GLuint end;
 137
 138    /** This flag indicates that mask[] array is effectively filled with ones */
 139    GLboolean writeAll;
 140
 141    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 142    GLenum primitive;
 143
 144    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 145    GLuint facing;
 146
 147    /**
 148     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 149     * which of the attrStart/StepX/StepY variables are relevant.
 150     */
 151    GLbitfield interpMask;
 152
 153    /** Fragment attribute interpolants */
 154    GLfloat attrStart[FRAG_ATTRIB_MAX][4];   /**< initial value */
 155    GLfloat attrStepX[FRAG_ATTRIB_MAX][4];   /**< dvalue/dx */
 156    GLfloat attrStepY[FRAG_ATTRIB_MAX][4];   /**< dvalue/dy */
 157
 158    /* XXX the rest of these will go away eventually... */
 159
 160    /* For horizontal spans, step is the partial derivative wrt X.
 161     * For lines, step is the delta from one fragment to the next.
 162     */
 163 #if CHAN_TYPE == GL_FLOAT
 164    GLfloat red, redStep;
 165    GLfloat green, greenStep;
 166    GLfloat blue, blueStep;
 167    GLfloat alpha, alphaStep;
 168    GLfloat specRed, specRedStep;
 169    GLfloat specGreen, specGreenStep;
 170    GLfloat specBlue, specBlueStep;
 171 #else /* CHAN_TYPE == GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT */
 172    GLfixed red, redStep;
 173    GLfixed green, greenStep;
 174    GLfixed blue, blueStep;
 175    GLfixed alpha, alphaStep;
 176    GLfixed specRed, specRedStep;
 177    GLfixed specGreen, specGreenStep;
 178    GLfixed specBlue, specBlueStep;
 179 #endif
 180    GLfixed index, indexStep;
 181    GLfixed z, zStep;    /* XXX z should probably be GLuint */
 182    GLfixed intTex[2], intTexStep[2];  /* s, t only */
 183
 184    /**
 185     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 186     * which of the fragment arrays in the span_arrays struct are relevant.
 187     */
 188    GLbitfield arrayMask;
 189
 190    /**
 191     * We store the arrays of fragment values in a separate struct so
 192     * that we can allocate sw_span structs on the stack without using
 193     * a lot of memory.  The span_arrays struct is about 1.4MB while the
 194     * sw_span struct is only about 512 bytes.
 195     */
 196    SWspanarrays *array;
 197 } SWspan;
 198
 199
 200
 201 #define INIT_SPAN(S, PRIMITIVE, END, INTERP_MASK, ARRAY_MASK)   \
 202 do {                                                            \
 203    (S).primitive = (PRIMITIVE);                                 \
 204    (S).interpMask = (INTERP_MASK);                              \
 205    (S).arrayMask = (ARRAY_MASK);                                \
 206    (S).end = (END);                                             \
 207    (S).facing = 0;                                              \
 208    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays;                 \
 209 } while (0)
 210
 211
 212
 213 extern void
 214 _swrast_span_default_z( GLcontext *ctx, SWspan *span );
 215
 216 extern void
 217 _swrast_span_interpolate_z( const GLcontext *ctx, SWspan *span );
 218
 219 extern void
 220 _swrast_span_default_fog( GLcontext *ctx, SWspan *span );
 221
 222 extern void
 223 _swrast_span_default_color( GLcontext *ctx, SWspan *span );
 224
 225 extern void
 226 _swrast_span_default_secondary_color(GLcontext *ctx, SWspan *span);
 227
 228 extern void
 229 _swrast_span_default_texcoords( GLcontext *ctx, SWspan *span );
 230
 231 extern GLfloat
 232 _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
 233                        GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
 234                        GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
 235
 236 extern void
 237 _swrast_write_index_span( GLcontext *ctx, SWspan *span);
 238
 239
 240 extern void
 241 _swrast_write_rgba_span( GLcontext *ctx, SWspan *span);
 242
 243
 244 extern void
 245 _swrast_read_rgba_span(GLcontext *ctx, struct gl_renderbuffer *rb,
 246                        GLuint n, GLint x, GLint y, GLenum type, GLvoid *rgba);
 247
 248 extern void
 249 _swrast_read_index_span( GLcontext *ctx, struct gl_renderbuffer *rb,
 250                          GLuint n, GLint x, GLint y, GLuint indx[] );
 251
 252 extern void
 253 _swrast_get_values(GLcontext *ctx, struct gl_renderbuffer *rb,
 254                    GLuint count, const GLint x[], const GLint y[],
 255                    void *values, GLuint valueSize);
 256
 257 extern void
 258 _swrast_put_row(GLcontext *ctx, struct gl_renderbuffer *rb,
 259                 GLuint count, GLint x, GLint y,
 260                 const GLvoid *values, GLuint valueSize);
 261
 262 extern void
 263 _swrast_get_row(GLcontext *ctx, struct gl_renderbuffer *rb,
 264                 GLuint count, GLint x, GLint y,
 265                 GLvoid *values, GLuint valueSize);
 266
 267
 268 extern void *
 269 _swrast_get_dest_rgba(GLcontext *ctx, struct gl_renderbuffer *rb,
 270                       SWspan *span);
 271
 272 #endif