src/mesa/swrast/s_span.h

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  * Copyright (C) 2009  VMware, Inc.  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  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 #ifndef S_SPAN_H
  28 #define S_SPAN_H
  29
  30
  31 #include "main/config.h"
  32 #include "main/glheader.h"
  33 #include "main/mtypes.h"
  34 #include "swrast/s_chan.h"
  35 #include "swrast/swrast.h"
  36
  37
  38 struct gl_context;
  39 struct gl_renderbuffer;
  40
  41
  42 /**
  43  * \defgroup SpanFlags
  44  * Special bitflags to describe span data.
  45  *
  46  * In general, the point/line/triangle functions interpolate/emit the
  47  * attributes specified by swrast->_ActiveAttribs (i.e. FRAT_BIT_* values).
  48  * Some things don't fit into that, though, so we have these flags.
  49  */
  50 /*@{*/
  51 #define SPAN_RGBA       0x01  /**< interpMask and arrayMask */
  52 #define SPAN_Z          0x02  /**< interpMask and arrayMask */
  53 #define SPAN_FLAT       0x04  /**< interpMask: flat shading? */
  54 #define SPAN_XY         0x08  /**< array.x[], y[] valid? */
  55 #define SPAN_MASK       0x10  /**< was array.mask[] filled in by caller? */
  56 #define SPAN_LAMBDA     0x20  /**< array.lambda[] valid? */
  57 #define SPAN_COVERAGE   0x40  /**< array.coverage[] valid? */
  58 /*@}*/
  59
  60
  61 /**
  62  * \sw_span_arrays
  63  * \brief Arrays of fragment values.
  64  *
  65  * These will either be computed from the span x/xStep values or
  66  * filled in by glDraw/CopyPixels, etc.
  67  * These arrays are separated out of sw_span to conserve memory.
  68  */
  69 typedef struct sw_span_arrays
  70 {
  71    /** Per-fragment attributes (indexed by VARYING_SLOT_* tokens) */
  72    /* XXX someday look at transposing first two indexes for better memory
  73     * access pattern.
  74     */
  75    GLfloat attribs[VARYING_SLOT_MAX][SWRAST_MAX_WIDTH][4];
  76
  77    /** This mask indicates which fragments are alive or culled */
  78    GLubyte mask[SWRAST_MAX_WIDTH];
  79
  80    GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
  81
  82    /** Attribute arrays that don't fit into attribs[] array above */
  83    /*@{*/
  84    GLubyte rgba8[SWRAST_MAX_WIDTH][4];
  85    GLushort rgba16[SWRAST_MAX_WIDTH][4];
  86    GLchan (*rgba)[4];  /** either == rgba8 or rgba16 */
  87    GLint   x[SWRAST_MAX_WIDTH];  /**< fragment X coords */
  88    GLint   y[SWRAST_MAX_WIDTH];  /**< fragment Y coords */
  89    GLuint  z[SWRAST_MAX_WIDTH];  /**< fragment Z coords */
  90    GLuint  index[SWRAST_MAX_WIDTH];  /**< Color indexes */
  91    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][SWRAST_MAX_WIDTH]; /**< Texture LOD */
  92    GLfloat coverage[SWRAST_MAX_WIDTH];  /**< Fragment coverage for AA/smoothing */
  93    /*@}*/
  94 } SWspanarrays;
  95
  96
  97 /**
  98  * The SWspan structure describes the colors, Z, fogcoord, texcoords,
  99  * etc for either a horizontal run or an array of independent pixels.
 100  * We can either specify a base/step to indicate interpolated values, or
 101  * fill in explicit arrays of values.  The interpMask and arrayMask bitfields
 102  * indicate which attributes are active interpolants or arrays, respectively.
 103  *
 104  * It would be interesting to experiment with multiprocessor rasterization
 105  * with this structure.  The triangle rasterizer could simply emit a
 106  * stream of these structures which would be consumed by one or more
 107  * span-processing threads which could run in parallel.
 108  */
 109 typedef struct sw_span
 110 {
 111    /** Coord of first fragment in horizontal span/run */
 112    GLint x, y;
 113
 114    /** Number of fragments in the span */
 115    GLuint end;
 116
 117    /** for clipping left edge of spans */
 118    GLuint leftClip;
 119
 120    /** This flag indicates that mask[] array is effectively filled with ones */
 121    GLboolean writeAll;
 122
 123    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 124    GLenum primitive;
 125
 126    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 127    GLuint facing;
 128
 129    /**
 130     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 131     * which of the attrStart/StepX/StepY variables are relevant.
 132     */
 133    GLbitfield interpMask;
 134
 135    /** Fragment attribute interpolants */
 136    GLfloat attrStart[VARYING_SLOT_MAX][4];   /**< initial value */
 137    GLfloat attrStepX[VARYING_SLOT_MAX][4];   /**< dvalue/dx */
 138    GLfloat attrStepY[VARYING_SLOT_MAX][4];   /**< dvalue/dy */
 139
 140    /* XXX the rest of these will go away eventually... */
 141
 142    /* For horizontal spans, step is the partial derivative wrt X.
 143     * For lines, step is the delta from one fragment to the next.
 144     */
 145    GLfixed red, redStep;
 146    GLfixed green, greenStep;
 147    GLfixed blue, blueStep;
 148    GLfixed alpha, alphaStep;
 149    GLfixed index, indexStep;
 150    GLfixed z, zStep;    /**< XXX z should probably be GLuint */
 151    GLfixed intTex[2], intTexStep[2];  /**< (s,t) for unit[0] only */
 152
 153    /**
 154     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 155     * which of the fragment arrays in the span_arrays struct are relevant.
 156     */
 157    GLbitfield arrayMask;
 158
 159    /** Mask of VARYING_BIT_x bits */
 160    GLbitfield64 arrayAttribs;
 161
 162    /**
 163     * We store the arrays of fragment values in a separate struct so
 164     * that we can allocate sw_span structs on the stack without using
 165     * a lot of memory.  The span_arrays struct is about 1.4MB while the
 166     * sw_span struct is only about 512 bytes.
 167     */
 168    SWspanarrays *array;
 169 } SWspan;
 170
 171
 172
 173 #define INIT_SPAN(S, PRIMITIVE)                 \
 174 do {                                            \
 175    (S).primitive = (PRIMITIVE);                 \
 176    (S).interpMask = 0x0;                        \
 177    (S).arrayMask = 0x0;                         \
 178    (S).arrayAttribs = 0x0;                      \
 179    (S).end = 0;                                 \
 180    (S).leftClip = 0;                            \
 181    (S).facing = 0;                              \
 182    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays; \
 183 } while (0)
 184
 185
 186
 187 extern void
 188 _swrast_span_default_attribs(struct gl_context *ctx, SWspan *span);
 189
 190 extern void
 191 _swrast_span_interpolate_z( const struct gl_context *ctx, SWspan *span );
 192
 193 extern GLfloat
 194 _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
 195                        GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
 196                        GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
 197
 198
 199 extern void
 200 _swrast_write_rgba_span( struct gl_context *ctx, SWspan *span);
 201
 202
 203 extern void
 204 _swrast_read_rgba_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
 205                        GLuint n, GLint x, GLint y, GLvoid *rgba);
 206
 207 extern void
 208 _swrast_put_row(struct gl_context *ctx, struct gl_renderbuffer *rb,
 209                 GLenum datatype,
 210                 GLuint count, GLint x, GLint y,
 211                 const void *values, const GLubyte *mask);
 212
 213 extern void *
 214 _swrast_get_dest_rgba(struct gl_context *ctx, struct gl_renderbuffer *rb,
 215                       SWspan *span);
 216
 217 #endif