src/gallium/drivers/llvmpipe/lp_setup_point.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2010, VMware Inc.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * 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
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 /*
  29  * Binning code for points
  30  */
  31
  32 #include "lp_setup_context.h"
  33 #include "util/u_math.h"
  34 #include "util/u_memory.h"
  35 #include "lp_perf.h"
  36 #include "lp_setup_context.h"
  37 #include "lp_rast.h"
  38 #include "lp_state_fs.h"
  39
  40 #define NUM_CHANNELS 4
  41
  42 struct point_info {
  43    /* x,y deltas */
  44    int dy01, dy12;
  45    int dx01, dx12;
  46
  47    const float (*v0)[4];
  48 };
  49
  50
  51 /**
  52  * Compute a0 for a constant-valued coefficient (GL_FLAT shading).
  53  */
  54 static void constant_coef( struct lp_setup_context *setup,
  55                            struct lp_rast_triangle *point,
  56                            unsigned slot,
  57                            const float value,
  58                            unsigned i )
  59 {
  60    point->inputs.a0[slot][i] = value;
  61    point->inputs.dadx[slot][i] = 0.0f;
  62    point->inputs.dady[slot][i] = 0.0f;
  63 }
  64
  65 /**
  66  * Special coefficient setup for gl_FragCoord.
  67  * X and Y are trivial
  68  * Z and W are copied from position_coef which should have already been computed.
  69  * We could do a bit less work if we'd examine gl_FragCoord's swizzle mask.
  70  */
  71 static void
  72 setup_point_fragcoord_coef(struct lp_setup_context *setup,
  73                            struct lp_rast_triangle *point,
  74                            const struct point_info *info,
  75                            unsigned slot,
  76                            unsigned usage_mask)
  77 {
  78    /*X*/
  79    if (usage_mask & TGSI_WRITEMASK_X) {
  80       point->inputs.a0[slot][0] = 0.0;
  81       point->inputs.dadx[slot][0] = 1.0;
  82       point->inputs.dady[slot][0] = 0.0;
  83    }
  84
  85    /*Y*/
  86    if (usage_mask & TGSI_WRITEMASK_Y) {
  87       point->inputs.a0[slot][1] = 0.0;
  88       point->inputs.dadx[slot][1] = 0.0;
  89       point->inputs.dady[slot][1] = 1.0;
  90    }
  91
  92    /*Z*/
  93    if (usage_mask & TGSI_WRITEMASK_Z) {
  94       constant_coef(setup, point, slot, info->v0[0][2], 2);
  95    }
  96
  97    /*W*/
  98    if (usage_mask & TGSI_WRITEMASK_W) {
  99       constant_coef(setup, point, slot, info->v0[0][3], 3);
 100    }
 101 }
 102
 103 /**
 104  * Compute the point->coef[] array dadx, dady, a0 values.
 105  */
 106 static void
 107 setup_point_coefficients( struct lp_setup_context *setup,
 108                           struct lp_rast_triangle *point,
 109                           const struct point_info *info)
 110 {
 111    unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ;
 112    unsigned slot;
 113
 114    /* setup interpolation for all the remaining attributes:
 115     */
 116    for (slot = 0; slot < setup->fs.nr_inputs; slot++) {
 117       unsigned vert_attr = setup->fs.input[slot].src_index;
 118       unsigned usage_mask = setup->fs.input[slot].usage_mask;
 119       unsigned i;
 120
 121       switch (setup->fs.input[slot].interp) {
 122       case LP_INTERP_POSITION:
 123          /*
 124           * The generated pixel interpolators will pick up the coeffs from
 125           * slot 0, so all need to ensure that the usage mask is covers all
 126           * usages.
 127           */
 128          fragcoord_usage_mask |= usage_mask;
 129          break;
 130
 131       default:
 132          for (i = 0; i < NUM_CHANNELS; i++) {
 133             if (usage_mask & (1 << i))
 134                constant_coef(setup, point, slot+1, info->v0[vert_attr][i], i);
 135          }
 136       }
 137    }
 138
 139    /* The internal position input is in slot zero:
 140     */
 141    setup_point_fragcoord_coef(setup, point, info, 0,
 142                               fragcoord_usage_mask);
 143 }
 144
 145 static INLINE int
 146 subpixel_snap(float a)
 147 {
 148    return util_iround(FIXED_ONE * a);
 149 }
 150
 151
 152 static void lp_setup_point( struct lp_setup_context *setup,
 153                             const float (*v0)[4] )
 154 {
 155    /* x/y positions in fixed point */
 156    const int sizeAttr = setup->psize;
 157    const float size
 158       = sizeAttr > 0 ? v0[sizeAttr][0]
 159       : setup->point_size;
 160
 161    /* Point size as fixed point integer, remove rounding errors
 162     * and gives minimum width for very small points
 163     */
 164    int fixed_width = MAX2(FIXED_ONE,
 165                           (subpixel_snap(size) + FIXED_ONE/2 - 1) & ~(FIXED_ONE-1));
 166
 167    const int x0 = subpixel_snap(v0[0][0] - setup->pixel_offset) - fixed_width/2;
 168    const int y0 = subpixel_snap(v0[0][1] - setup->pixel_offset) - fixed_width/2;
 169
 170    struct lp_scene *scene = lp_setup_get_current_scene(setup);
 171    struct lp_rast_triangle *point;
 172    unsigned bytes;
 173    struct u_rect bbox;
 174    unsigned nr_planes = 4;
 175    struct point_info info;
 176
 177
 178    /* Bounding rectangle (in pixels) */
 179    {
 180       /* Yes this is necessary to accurately calculate bounding boxes
 181        * with the two fill-conventions we support.  GL (normally) ends
 182        * up needing a bottom-left fill convention, which requires
 183        * slightly different rounding.
 184        */
 185       int adj = (setup->pixel_offset != 0) ? 1 : 0;
 186
 187       bbox.x0 = (x0 + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 188       bbox.x1 = (x0 + fixed_width + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
 189       bbox.y0 = (y0 + (FIXED_ONE-1)) >> FIXED_ORDER;
 190       bbox.y1 = (y0 + fixed_width + (FIXED_ONE-1)) >> FIXED_ORDER;
 191
 192       /* Inclusive coordinates:
 193        */
 194       bbox.x1--;
 195       bbox.y1--;
 196    }
 197
 198    if (!u_rect_test_intersection(&setup->draw_region, &bbox)) {
 199       if (0) debug_printf("offscreen\n");
 200       LP_COUNT(nr_culled_tris);
 201       return;
 202    }
 203
 204    u_rect_find_intersection(&setup->draw_region, &bbox);
 205
 206    point = lp_setup_alloc_triangle(scene,
 207                                    setup->fs.nr_inputs,
 208                                    nr_planes,
 209                                    &bytes);
 210    if (!point)
 211       return;
 212
 213 #ifdef DEBUG
 214    point->v[0][0] = v0[0][0];
 215    point->v[0][1] = v0[0][1];
 216 #endif
 217
 218    info.v0 = v0;
 219    info.dx01 = 0;
 220    info.dx12 = fixed_width;
 221    info.dy01 = fixed_width;
 222    info.dy12 = 0;
 223
 224    /* Setup parameter interpolants:
 225     */
 226    setup_point_coefficients(setup, point, &info);
 227
 228    point->inputs.facing = 1.0F;
 229    point->inputs.state = setup->fs.stored;
 230
 231    {
 232       point->plane[0].dcdx = -1;
 233       point->plane[0].dcdy = 0;
 234       point->plane[0].c = 1-bbox.x0;
 235       point->plane[0].ei = 0;
 236       point->plane[0].eo = 1;
 237
 238       point->plane[1].dcdx = 1;
 239       point->plane[1].dcdy = 0;
 240       point->plane[1].c = bbox.x1+1;
 241       point->plane[1].ei = -1;
 242       point->plane[1].eo = 0;
 243
 244       point->plane[2].dcdx = 0;
 245       point->plane[2].dcdy = 1;
 246       point->plane[2].c = 1-bbox.y0;
 247       point->plane[2].ei = 0;
 248       point->plane[2].eo = 1;
 249
 250       point->plane[3].dcdx = 0;
 251       point->plane[3].dcdy = -1;
 252       point->plane[3].c = bbox.y1+1;
 253       point->plane[3].ei = -1;
 254       point->plane[3].eo = 0;
 255    }
 256
 257    lp_setup_bin_triangle(setup, point, &bbox, nr_planes);
 258 }
 259
 260
 261 void
 262 lp_setup_choose_point( struct lp_setup_context *setup )
 263 {
 264    setup->point = lp_setup_point;
 265 }
 266
 267