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