src/mesa/swrast/s_span.h

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.5
   4  *
   5  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   6  * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included
  16  * in all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  21  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  22  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  23  * CONNECTION WITH THE SOFTWARE OR THE USE OR 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
  36
  37 struct gl_context;
  38 struct gl_renderbuffer;
  39
  40
  41 /**
  42  * \defgroup SpanFlags
  43  * Special bitflags to describe span data.
  44  *
  45  * In general, the point/line/triangle functions interpolate/emit the
  46  * attributes specified by swrast->_ActiveAttribs (i.e. FRAT_BIT_* values).
  47  * Some things don't fit into that, though, so we have these flags.
  48  */
  49 /*@{*/
  50 #define SPAN_RGBA       0x01  /**< interpMask and arrayMask */
  51 #define SPAN_Z          0x02  /**< interpMask and arrayMask */
  52 #define SPAN_FLAT       0x04  /**< interpMask: flat shading? */
  53 #define SPAN_XY         0x08  /**< array.x[], y[] valid? */
  54 #define SPAN_MASK       0x10  /**< was array.mask[] filled in by caller? */
  55 #define SPAN_LAMBDA     0x20  /**< array.lambda[] valid? */
  56 #define SPAN_COVERAGE   0x40  /**< array.coverage[] valid? */
  57 /*@}*/
  58
  59
  60 /**
  61  * \sw_span_arrays
  62  * \brief Arrays of fragment values.
  63  *
  64  * These will either be computed from the span x/xStep values or
  65  * filled in by glDraw/CopyPixels, etc.
  66  * These arrays are separated out of sw_span to conserve memory.
  67  */
  68 typedef struct sw_span_arrays
  69 {
  70    /** Per-fragment attributes (indexed by FRAG_ATTRIB_* tokens) */
  71    /* XXX someday look at transposing first two indexes for better memory
  72     * access pattern.
  73     */
  74    GLfloat attribs[FRAG_ATTRIB_MAX][MAX_WIDTH][4];
  75
  76    /** This mask indicates which fragments are alive or culled */
  77    GLubyte mask[MAX_WIDTH];
  78
  79    GLenum ChanType; /**< Color channel type, GL_UNSIGNED_BYTE, GL_FLOAT */
  80
  81    /** Attribute arrays that don't fit into attribs[] array above */
  82    /*@{*/
  83    GLubyte rgba8[MAX_WIDTH][4];
  84    GLushort rgba16[MAX_WIDTH][4];
  85    GLchan (*rgba)[4];  /** either == rgba8 or rgba16 */
  86    GLint   x[MAX_WIDTH];  /**< fragment X coords */
  87    GLint   y[MAX_WIDTH];  /**< fragment Y coords */
  88    GLuint  z[MAX_WIDTH];  /**< fragment Z coords */
  89    GLuint  index[MAX_WIDTH];  /**< Color indexes */
  90    GLfloat lambda[MAX_TEXTURE_COORD_UNITS][MAX_WIDTH]; /**< Texture LOD */
  91    GLfloat coverage[MAX_WIDTH];  /**< Fragment coverage for AA/smoothing */
  92    /*@}*/
  93 } SWspanarrays;
  94
  95
  96 /**
  97  * The SWspan structure describes the colors, Z, fogcoord, texcoords,
  98  * etc for either a horizontal run or an array of independent pixels.
  99  * We can either specify a base/step to indicate interpolated values, or
 100  * fill in explicit arrays of values.  The interpMask and arrayMask bitfields
 101  * indicate which attributes are active interpolants or arrays, respectively.
 102  *
 103  * It would be interesting to experiment with multiprocessor rasterization
 104  * with this structure.  The triangle rasterizer could simply emit a
 105  * stream of these structures which would be consumed by one or more
 106  * span-processing threads which could run in parallel.
 107  */
 108 typedef struct sw_span
 109 {
 110    /** Coord of first fragment in horizontal span/run */
 111    GLint x, y;
 112
 113    /** Number of fragments in the span */
 114    GLuint end;
 115
 116    /** for clipping left edge of spans */
 117    GLuint leftClip;
 118
 119    /** This flag indicates that mask[] array is effectively filled with ones */
 120    GLboolean writeAll;
 121
 122    /** either GL_POLYGON, GL_LINE, GL_POLYGON, GL_BITMAP */
 123    GLenum primitive;
 124
 125    /** 0 = front-facing span, 1 = back-facing span (for two-sided stencil) */
 126    GLuint facing;
 127
 128    /**
 129     * This bitmask (of  \link SpanFlags SPAN_* flags\endlink) indicates
 130     * which of the attrStart/StepX/StepY variables are relevant.
 131     */
 132    GLbitfield interpMask;
 133
 134    /** Fragment attribute interpolants */
 135    GLfloat attrStart[FRAG_ATTRIB_MAX][4];   /**< initial value */
 136    GLfloat attrStepX[FRAG_ATTRIB_MAX][4];   /**< dvalue/dx */
 137    GLfloat attrStepY[FRAG_ATTRIB_MAX][4];   /**< dvalue/dy */
 138
 139    /* XXX the rest of these will go away eventually... */
 140
 141    /* For horizontal spans, step is the partial derivative wrt X.
 142     * For lines, step is the delta from one fragment to the next.
 143     */
 144    GLfixed red, redStep;
 145    GLfixed green, greenStep;
 146    GLfixed blue, blueStep;
 147    GLfixed alpha, alphaStep;
 148    GLfixed index, indexStep;
 149    GLfixed z, zStep;    /**< XXX z should probably be GLuint */
 150    GLfixed intTex[2], intTexStep[2];  /**< (s,t) for unit[0] only */
 151
 152    /**
 153     * This bitmask (of \link SpanFlags SPAN_* flags\endlink) indicates
 154     * which of the fragment arrays in the span_arrays struct are relevant.
 155     */
 156    GLbitfield arrayMask;
 157
 158    /** Mask of FRAG_BIT_x bits */
 159    GLbitfield64 arrayAttribs;
 160
 161    /**
 162     * We store the arrays of fragment values in a separate struct so
 163     * that we can allocate sw_span structs on the stack without using
 164     * a lot of memory.  The span_arrays struct is about 1.4MB while the
 165     * sw_span struct is only about 512 bytes.
 166     */
 167    SWspanarrays *array;
 168 } SWspan;
 169
 170
 171
 172 #define INIT_SPAN(S, PRIMITIVE)                 \
 173 do {                                            \
 174    (S).primitive = (PRIMITIVE);                 \
 175    (S).interpMask = 0x0;                        \
 176    (S).arrayMask = 0x0;                         \
 177    (S).arrayAttribs = 0x0;                      \
 178    (S).end = 0;                                 \
 179    (S).leftClip = 0;                            \
 180    (S).facing = 0;                              \
 181    (S).array = SWRAST_CONTEXT(ctx)->SpanArrays; \
 182 } while (0)
 183
 184
 185
 186 extern void
 187 _swrast_span_default_attribs(struct gl_context *ctx, SWspan *span);
 188
 189 extern void
 190 _swrast_span_interpolate_z( const struct gl_context *ctx, SWspan *span );
 191
 192 extern GLfloat
 193 _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
 194                        GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
 195                        GLfloat s, GLfloat t, GLfloat q, GLfloat invQ);
 196
 197
 198 extern void
 199 _swrast_write_rgba_span( struct gl_context *ctx, SWspan *span);
 200
 201
 202 extern void
 203 _swrast_read_rgba_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
 204                        GLuint n, GLint x, GLint y, GLvoid *rgba);
 205
 206 extern void
 207 _swrast_put_row(struct gl_context *ctx, struct gl_renderbuffer *rb,
 208                 GLenum datatype,
 209                 GLuint count, GLint x, GLint y,
 210                 const void *values, const GLubyte *mask);
 211
 212 extern void *
 213 _swrast_get_dest_rgba(struct gl_context *ctx, struct gl_renderbuffer *rb,
 214                       SWspan *span);
 215
 216 #endif