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