src/mesa/swrast/s_pointtemp.h

   1 /* $Id: s_pointtemp.h,v 1.1 2001/01/03 22:17:16 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2000  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27
  28 /*
  29  * Point rendering template code.
  30  *
  31  * Set FLAGS = bitwise-OR of the following tokens:
  32  *
  33  *   RGBA = do rgba instead of color index
  34  *   SMOOTH = do antialiasing
  35  *   TEXTURE = do texture coords
  36  *   SPECULAR = do separate specular color
  37  *   LARGE = do points with diameter > 1 pixel
  38  *   ATTENUATE = compute point size attenuation
  39  *   SPRITE = GL_MESA_sprite_point
  40  *
  41  * Notes: LARGE and ATTENUATE are exclusive of each other.
  42  *        TEXTURE requires RGBA
  43  *        SPECULAR requires TEXTURE
  44  */
  45
  46
  47 /*
  48  * NOTES on antialiased point rasterization:
  49  *
  50  * Let d = distance of fragment center from vertex.
  51  * if d < rmin2 then
  52  *    fragment has 100% coverage
  53  * else if d > rmax2 then
  54  *    fragment has 0% coverage
  55  * else
  56  *    fragement has % coverage = (d - rmin2) / (rmax2 - rmin2)
  57  */
  58
  59
  60
  61 static void
  62 NAME ( GLcontext *ctx, const SWvertex *vert )
  63 {
  64    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  65    struct pixel_buffer *PB = swrast->PB;
  66
  67    const GLint z = (GLint) (vert->win[2]);
  68    const GLfixed fog = FloatToFixed( vert->fog );
  69
  70 #if FLAGS & RGBA
  71    const GLint red   = vert->color[0];
  72    const GLint green = vert->color[1];
  73    const GLint blue  = vert->color[2];
  74    GLint alpha = vert->color[3];
  75 #if FLAGS & SPECULAR
  76    const GLint sRed   = vert->specular[0];
  77    const GLint sGreen = vert->specular[1];
  78    const GLint sBlue  = vert->specular[2];
  79 #endif
  80 #else
  81    GLint index = vert->index;
  82 #endif
  83 #if FLAGS & (ATTENUATE | LARGE | SMOOTH)
  84    GLfloat size;
  85 #endif
  86 #if FLAGS & ATTENUATE
  87    GLfloat alphaAtten;
  88 #endif
  89
  90 #if FLAGS & TEXTURE
  91    GLfloat texcoord[MAX_TEXTURE_UNITS][4];
  92    GLuint u;
  93    for (u = 0; u < ctx->Const.MaxTextureUnits; u++) {
  94       if (ctx->Texture.Unit[u]._ReallyEnabled) {
  95          if (vert->texcoord[u][3] != 1.0 && vert->texcoord[u][3] != 0.0) {
  96             texcoord[u][0] = vert->texcoord[u][0] / vert->texcoord[u][3];
  97             texcoord[u][1] = vert->texcoord[u][1] / vert->texcoord[u][3];
  98             texcoord[u][2] = vert->texcoord[u][2] / vert->texcoord[u][3];
  99          }
 100          else {
 101             texcoord[u][0] = vert->texcoord[u][0];
 102             texcoord[u][1] = vert->texcoord[u][1];
 103             texcoord[u][2] = vert->texcoord[u][2];
 104          }
 105       }
 106    }
 107 #endif
 108
 109 #if FLAGS & ATTENUATE
 110    if (vert->pointSize >= ctx->Point.Threshold) {
 111       size = MIN2(vert->pointSize, ctx->Point.MaxSize);
 112       alphaAtten = 1.0F;
 113    }
 114    else {
 115       GLfloat dsize = vert->pointSize / ctx->Point.Threshold;
 116       size = MAX2(ctx->Point.Threshold, ctx->Point.MinSize);
 117       alphaAtten = dsize * dsize;
 118    }
 119 #elif FLAGS & (LARGE | SMOOTH)
 120    size = ctx->Point._Size;
 121 #endif
 122
 123 #if FLAGS & SPRITE
 124    {
 125       SWcontext *swctx = SWRAST_CONTEXT(ctx);
 126       const GLfloat radius = 0.5 * vert->pointSize;  /* XXX threshold, alpha */
 127       SWvertex v0, v1, v2, v3;
 128       GLuint unit;
 129
 130       (void) red;
 131       (void) green;
 132       (void) blue;
 133       (void) alpha;
 134       (void) fog;
 135       (void) z;
 136
 137       /* lower left corner */
 138       v0 = *vert;
 139       v0.win[0] -= radius;
 140       v0.win[1] -= radius;
 141
 142       /* lower right corner */
 143       v1 = *vert;
 144       v1.win[0] += radius;
 145       v1.win[1] -= radius;
 146
 147       /* upper right corner */
 148       v2 = *vert;
 149       v2.win[0] += radius;
 150       v2.win[1] += radius;
 151
 152       /* upper left corner */
 153       v3 = *vert;
 154       v3.win[0] -= radius;
 155       v3.win[1] += radius;
 156
 157       for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
 158          if (ctx->Texture.Unit[unit]._ReallyEnabled) {
 159             v0.texcoord[unit][0] = 0.0;
 160             v0.texcoord[unit][1] = 0.0;
 161             v1.texcoord[unit][0] = 1.0;
 162             v1.texcoord[unit][1] = 0.0;
 163             v2.texcoord[unit][0] = 1.0;
 164             v2.texcoord[unit][1] = 1.0;
 165             v3.texcoord[unit][0] = 0.0;
 166             v3.texcoord[unit][1] = 1.0;
 167          }
 168       }
 169
 170       /* XXX if radius < threshold, attenuate alpha? */
 171
 172       /* XXX need to implement clipping!!! */
 173
 174       /* render */
 175       swctx->Triangle(ctx, &v0, &v1, &v2);
 176       swctx->Triangle(ctx, &v0, &v2, &v3);
 177    }
 178
 179 #elif FLAGS & (LARGE | ATTENUATE | SMOOTH)
 180
 181    {
 182       GLint x, y;
 183       const GLfloat radius = 0.5F * size;
 184 #if FLAGS & SMOOTH
 185       const GLfloat rmin = radius - 0.7071F;  /* 0.7071 = sqrt(2)/2 */
 186       const GLfloat rmax = radius + 0.7071F;
 187       const GLfloat rmin2 = MAX2(0.0, rmin * rmin);
 188       const GLfloat rmax2 = rmax * rmax;
 189       const GLfloat cscale = 256.0F / (rmax2 - rmin2);
 190       const GLint xmin = (GLint) (vert->win[0] - radius);
 191       const GLint xmax = (GLint) (vert->win[0] + radius);
 192       const GLint ymin = (GLint) (vert->win[1] - radius);
 193       const GLint ymax = (GLint) (vert->win[1] + radius);
 194 #else
 195       /* non-smooth */
 196       GLint xmin, xmax, ymin, ymax;
 197       GLint iSize = (GLint) (size + 0.5F);
 198       GLint iRadius;
 199       iSize = MAX2(1, iSize);
 200       iRadius = iSize / 2;
 201       if (iSize & 1) {
 202          /* odd size */
 203          xmin = vert->win[0] - iRadius;
 204          xmax = vert->win[0] + iRadius;
 205          ymin = vert->win[1] - iRadius;
 206          ymax = vert->win[1] + iRadius;
 207       }
 208       else {
 209          /* even size */
 210          xmin = (GLint) vert->win[0] - iRadius + 1;
 211          xmax = xmin + iSize - 1;
 212          ymin = (GLint) vert->win[1] - iRadius + 1;
 213          ymax = ymin + iSize - 1;
 214       }
 215 #endif
 216       (void) radius;
 217
 218       for (y = ymin; y <= ymax; y++) {
 219          for (x = xmin; x <= xmax; x++) {
 220 #if FLAGS & SMOOTH
 221             /* compute coverage */
 222             const GLfloat dx = x - vert->win[0];
 223             const GLfloat dy = y - vert->win[1];
 224             const GLfloat dist2 = dx * dx + dy * dy;
 225             if (dist2 < rmax2) {
 226                alpha = vert->color[3];
 227                if (dist2 >= rmin2) {
 228                   GLint coverage = (GLint) (256.0F - (dist2 - rmin2) * cscale);
 229 #if FLAGS & RGBA
 230                   /* coverage is in [0,256] */
 231                   alpha = (alpha * coverage) >> 8;
 232 #else
 233                   /* 4 fractional index bits */
 234                   index = (index & ~f) | (coverage >> 4);  /* XXX verify */
 235 #endif
 236                }
 237 #endif /* SMOOTH */
 238
 239 #if ((FLAGS & (ATTENUATE | RGBA)) == (ATTENUATE | RGBA))
 240                alpha = (GLint) (alpha * alphaAtten);
 241 #endif
 242
 243 #if FLAGS & SPECULAR
 244                PB_WRITE_MULTITEX_SPEC_PIXEL(PB, x, y, z, fog,
 245                                             red, green, blue, alpha,
 246                                             sRed, sGreen, sBlue,
 247                                             texcoord);
 248
 249 #elif FLAGS & TEXTURE
 250                if (swrast->_MultiTextureEnabled) {
 251                   PB_WRITE_MULTITEX_PIXEL(PB, x, y, z, fog,
 252                                           red, green, blue, alpha,
 253                                           texcoord);
 254                }
 255                else {
 256                   PB_WRITE_TEX_PIXEL(PB, x,y,z, fog,
 257                                      red, green, blue, alpha,
 258                                      texcoord[0][0],
 259                                      texcoord[0][1],
 260                                      texcoord[0][2]);
 261                }
 262 #elif FLAGS & RGBA
 263                PB_WRITE_RGBA_PIXEL(PB, x, y, z, fog, red, green, blue, alpha);
 264 #else /* color index */
 265                PB_WRITE_CI_PIXEL(PB, x, y, z, fog, index);
 266 #endif
 267 #if FLAGS & SMOOTH
 268             }
 269 #endif
 270          }
 271       }
 272       PB_CHECK_FLUSH(ctx,PB);
 273    }
 274
 275 #else /* LARGE || ATTENUATE || SMOOTH*/
 276
 277    {
 278       /* size == 1 */
 279       GLint x = vert->win[0];
 280       GLint y = vert->win[1];
 281 #if ((FLAGS & (SPECULAR | TEXTURE)) == (SPECULAR | TEXTURE))
 282       PB_WRITE_MULTITEX_SPEC_PIXEL(PB, x, y, z, fog,
 283                                    red, green, blue, alpha,
 284                                    sRed, sGreen, sBlue,
 285                                    texcoord);
 286 #elif FLAGS & TEXTURE
 287       if (swrast->_MultiTextureEnabled) {
 288          PB_WRITE_MULTITEX_PIXEL(PB, x, y, z, fog,
 289                                  red, green, blue, alpha, texcoord );
 290       }
 291       else {
 292          PB_WRITE_TEX_PIXEL(PB, x, y, z, fog,
 293                             red, green, blue, alpha,
 294                             texcoord[0][0], texcoord[0][1], texcoord[0][2]);
 295       }
 296 #elif FLAGS & RGBA
 297       /* rgba size 1 point */
 298       alpha = vert->color[3];
 299       PB_WRITE_RGBA_PIXEL(PB, x, y, z, fog, red, green, blue, alpha);
 300 #else
 301       /* color index size 1 point */
 302       PB_WRITE_CI_PIXEL(PB, x, y, z, fog, index);
 303 #endif
 304    }
 305 #endif /* LARGE || ATTENUATE || SMOOTH */
 306
 307    PB_CHECK_FLUSH(ctx, PB);
 308 }
 309
 310
 311 #undef FLAGS
 312 #undef NAME