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