src/mesa/pipe/softpipe/sp_quad_fs.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /* Vertices are just an array of floats, with all the attributes
  26  * packed.  We currently assume a layout like:
  27  *
  28  * attr[0][0..3] - window position
  29  * attr[1..n][0..3] - remaining attributes.
  30  *
  31  * Attributes are assumed to be 4 floats wide but are packed so that
  32  * all the enabled attributes run contiguously.
  33  */
  34
  35 #include "glheader.h"
  36 #include "imports.h"
  37 #include "sp_context.h"
  38 #include "sp_headers.h"
  39 #include "sp_quad.h"
  40
  41 struct exec_machine {
  42    const struct setup_coefficient *coef;
  43
  44    GLfloat attr[FRAG_ATTRIB_MAX][4][QUAD_SIZE];
  45 };
  46
  47
  48 /**
  49  * Compute quad's attributes values, as constants (GL_FLAT shading).
  50  */
  51 static INLINE void cinterp( struct exec_machine *exec,
  52                             GLuint attrib,
  53                             GLuint i )
  54 {
  55    GLuint j;
  56
  57    for (j = 0; j < QUAD_SIZE; j++) {
  58       exec->attr[attrib][i][j] = exec->coef[attrib].a0[i];
  59    }
  60 }
  61
  62
  63 /**
  64  * Compute quad's attribute values by linear interpolation.
  65  *
  66  * Push into the fp:
  67  *
  68  *   INPUT[attr] = MAD COEF_A0[attr], COEF_DADX[attr], INPUT_WPOS.xxxx
  69  *   INPUT[attr] = MAD INPUT[attr],   COEF_DADY[attr], INPUT_WPOS.yyyy
  70  */
  71 static INLINE void linterp( struct exec_machine *exec,
  72                             GLuint attrib,
  73                             GLuint i )
  74 {
  75    GLuint j;
  76
  77    for (j = 0; j < QUAD_SIZE; j++) {
  78       const GLfloat x = exec->attr[FRAG_ATTRIB_WPOS][0][j];
  79       const GLfloat y = exec->attr[FRAG_ATTRIB_WPOS][1][j];
  80       exec->attr[attrib][i][j] = (exec->coef[attrib].a0[i] +
  81                                   exec->coef[attrib].dadx[i] * x +
  82                                   exec->coef[attrib].dady[i] * y);
  83    }
  84 }
  85
  86
  87 /**
  88  * Compute quad's attribute values by linear interpolation with
  89  * perspective correction.
  90  *
  91  * Push into the fp:
  92  *
  93  *   INPUT[attr] = MAD COEF_A0[attr], COEF_DADX[attr], INPUT_WPOS.xxxx
  94  *   INPUT[attr] = MAD INPUT[attr],   COEF_DADY[attr], INPUT_WPOS.yyyy
  95  *   INPUT[attr] = MUL INPUT[attr],   INPUT_WPOS.wwww
  96  *
  97  * (Or should that be 1/w ???)
  98  */
  99 static INLINE void pinterp( struct exec_machine *exec,
 100                             GLuint attrib,
 101                             GLuint i )
 102 {
 103    GLuint j;
 104
 105    for (j = 0; j < QUAD_SIZE; j++) {
 106       const GLfloat x = exec->attr[FRAG_ATTRIB_WPOS][0][j];
 107       const GLfloat y = exec->attr[FRAG_ATTRIB_WPOS][1][j];
 108       const GLfloat invW = exec->attr[FRAG_ATTRIB_WPOS][3][j];
 109       exec->attr[attrib][i][j] = ((exec->coef[attrib].a0[i] +
 110                                    exec->coef[attrib].dadx[i] * x +
 111                                    exec->coef[attrib].dady[i] * y) * invW);
 112    }
 113 }
 114
 115
 116
 117 /* This should be done by the fragment shader execution unit (code
 118  * generated from the decl instructions).  Do it here for now.
 119  */
 120 static void
 121 shade_quad( struct quad_stage *qs, struct quad_header *quad )
 122 {
 123    struct softpipe_context *softpipe = qs->softpipe;
 124    struct exec_machine exec;
 125    GLfloat fx = quad->x0;
 126    GLfloat fy = quad->y0;
 127    GLuint i, j;
 128    GLboolean need_z = softpipe->depth_test.enabled; /* XXX hack */
 129
 130    exec.coef = quad->coef;
 131
 132    /* Position:
 133     */
 134    exec.attr[FRAG_ATTRIB_WPOS][0][0] = fx;
 135    exec.attr[FRAG_ATTRIB_WPOS][0][1] = fx + 1.0;
 136    exec.attr[FRAG_ATTRIB_WPOS][0][2] = fx;
 137    exec.attr[FRAG_ATTRIB_WPOS][0][3] = fx + 1.0;
 138
 139    exec.attr[FRAG_ATTRIB_WPOS][1][0] = fy;
 140    exec.attr[FRAG_ATTRIB_WPOS][1][1] = fy;
 141    exec.attr[FRAG_ATTRIB_WPOS][1][2] = fy + 1.0;
 142    exec.attr[FRAG_ATTRIB_WPOS][1][3] = fy + 1.0;
 143
 144    /* Z and W are done by linear interpolation:
 145     * XXX we'll probably have to use integers for Z
 146     */
 147    if (/*softpipe->*/need_z) {
 148       linterp(&exec, 0, 2);   /* attr[0].z */
 149    }
 150
 151    if (softpipe->need_w) {
 152       linterp(&exec, 0, 3);  /* attr[0].w */
 153 //      invert(&exec, 0, 3);
 154    }
 155
 156    /* Interpolate all the remaining attributes.  This will get pushed
 157     * into the fragment program's responsibilities at some point.
 158     */
 159    for (i = 1; i < quad->nr_attrs; i++) {
 160 #if 1
 161       for (j = 0; j < NUM_CHANNELS; j++)
 162          linterp(&exec, i, j);
 163 #else
 164       switch (quad->interp[i]) {
 165       case INTERP_CONSTANT:
 166          for (j = 0; j < NUM_CHANNELS; j++)
 167             cinterp(&exec, i, j);
 168          break;
 169
 170       case INTERP_LINEAR:
 171          for (j = 0; j < NUM_CHANNELS; j++)
 172             linterp(&exec, i, j);
 173          break;
 174
 175       case INTERP_PERSPECTIVE:
 176          for (j = 0; j < NUM_CHANNELS; j++)
 177             pinterp(&exec, i, j);
 178          break;
 179       }
 180 #endif
 181    }
 182
 183 #if 0
 184    softpipe->run_fs( tri->fp, quad, &tri->outputs );
 185 #else
 186    {
 187       GLuint attr = softpipe->fp_attr_to_slot[FRAG_ATTRIB_COL0];
 188       assert(attr);
 189
 190       memcpy(quad->outputs.color,
 191              exec.attr[attr],
 192              sizeof(quad->outputs.color));
 193
 194       if (need_z) {
 195          quad->outputs.depth[0] = exec.attr[0][2][0];
 196          quad->outputs.depth[1] = exec.attr[0][2][1];
 197          quad->outputs.depth[2] = exec.attr[0][2][2];
 198          quad->outputs.depth[3] = exec.attr[0][2][3];
 199       }
 200    }
 201 #endif
 202
 203    qs->next->run(qs->next, quad);
 204 }
 205
 206
 207
 208 struct quad_stage *sp_quad_shade_stage( struct softpipe_context *softpipe )
 209 {
 210    struct quad_stage *stage = CALLOC_STRUCT(quad_stage);
 211
 212    stage->softpipe = softpipe;
 213    stage->run = shade_quad;
 214
 215    return stage;
 216 }