src/mesa/state_tracker/st_cb_rasterpos.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   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 TUNGSTEN GRAPHICS 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  * glRasterPos implementation.  Basically render a GL_POINT with our
  30  * private draw module.  Plug in a special "rasterpos" stage at the end
  31  * of the 'draw' pipeline to capture the results and update the current
  32  * raster pos attributes.
  33  *
  34  * Authors:
  35  *   Brian Paul
  36  */
  37
  38
  39 #include "main/imports.h"
  40 #include "main/macros.h"
  41
  42 #include "st_context.h"
  43 #include "st_atom.h"
  44 #include "st_draw.h"
  45 #include "st_cb_rasterpos.h"
  46 #include "st_draw.h"
  47 #include "pipe/draw/draw_context.h"
  48 #include "pipe/draw/draw_private.h"
  49 #include "shader/prog_instruction.h"
  50 #include "vbo/vbo.h"
  51
  52
  53
  54 /**
  55  * Our special drawing pipeline stage (replaces rasterization).
  56  */
  57 struct rastpos_stage
  58 {
  59    struct draw_stage stage;   /**< Base class */
  60    GLcontext *ctx;            /**< Rendering context */
  61
  62    /* vertex attrib info we can setup once and re-use */
  63    struct gl_client_array array[VERT_ATTRIB_MAX];
  64    const struct gl_client_array *arrays[VERT_ATTRIB_MAX];
  65    struct _mesa_prim prim;
  66 };
  67
  68
  69 static INLINE struct rastpos_stage *
  70 rastpos_stage( struct draw_stage *stage )
  71 {
  72    return (struct rastpos_stage *) stage;
  73 }
  74
  75 static void
  76 rastpos_begin( struct draw_stage *stage )
  77 {
  78    /* no-op */
  79 }
  80
  81 static void
  82 rastpos_end( struct draw_stage *stage )
  83 {
  84    /* no-op */
  85 }
  86
  87 static void
  88 rastpos_reset_stipple_counter( struct draw_stage *stage )
  89 {
  90    /* no-op */
  91 }
  92
  93 static void
  94 rastpos_tri( struct draw_stage *stage, struct prim_header *prim )
  95 {
  96    /* should never get here */
  97    assert(0);
  98 }
  99
 100 static void
 101 rastpos_line( struct draw_stage *stage, struct prim_header *prim )
 102 {
 103    /* should never get here */
 104    assert(0);
 105 }
 106
 107
 108 /**
 109  * Update a raster pos attribute from the vertex result if it's present,
 110  * else copy the current attrib.
 111  */
 112 static void
 113 update_attrib(GLcontext *ctx, const GLuint *outputMapping,
 114               const struct vertex_header *vert,
 115               GLfloat *dest,
 116               GLuint result, GLuint defaultAttrib)
 117 {
 118    const GLfloat *src;
 119    const GLuint k = outputMapping[result];
 120    if (k != ~0)
 121       src = vert->data[k];
 122    else
 123       src = ctx->Current.Attrib[defaultAttrib];
 124    COPY_4V(dest, src);
 125 }
 126
 127
 128 /**
 129  * Normally, this function would render a GL_POINT.
 130  */
 131 static void
 132 rastpos_point(struct draw_stage *stage, struct prim_header *prim)
 133 {
 134    struct rastpos_stage *rs = rastpos_stage(stage);
 135    GLcontext *ctx = rs->ctx;
 136    struct st_context *st = ctx->st;
 137    const GLfloat height = ctx->DrawBuffer->Height;
 138    const GLuint *outputMapping = st->vertex_result_to_slot;
 139    const GLfloat *pos;
 140    GLuint i;
 141
 142    /* if we get here, we didn't get clipped */
 143    ctx->Current.RasterPosValid = GL_TRUE;
 144
 145    /* update raster pos */
 146    pos = prim->v[0]->data[0];
 147    ctx->Current.RasterPos[0] = pos[0];
 148    ctx->Current.RasterPos[1] = height - 1 - pos[1];
 149    ctx->Current.RasterPos[2] = pos[2];
 150    ctx->Current.RasterPos[3] = pos[3];
 151
 152    /* update other raster attribs */
 153    update_attrib(ctx, outputMapping, prim->v[0],
 154                  ctx->Current.RasterColor,
 155                  VERT_RESULT_COL0, VERT_ATTRIB_COLOR0);
 156
 157    update_attrib(ctx, outputMapping, prim->v[0],
 158                  ctx->Current.RasterSecondaryColor,
 159                  VERT_RESULT_COL1, VERT_ATTRIB_COLOR1);
 160
 161    for (i = 0; i < MAX_TEXTURE_UNITS; i++) {
 162       update_attrib(ctx, outputMapping, prim->v[0],
 163                     ctx->Current.RasterTexCoords[i],
 164                     VERT_RESULT_TEX0 + i, VERT_ATTRIB_TEX0 + i);
 165    }
 166 }
 167
 168
 169 /**
 170  * Create rasterpos "drawing" stage.
 171  */
 172 static struct rastpos_stage *
 173 new_draw_rastpos_stage(GLcontext *ctx, struct draw_context *draw)
 174 {
 175    struct rastpos_stage *rs = CALLOC_STRUCT(rastpos_stage);
 176
 177    rs->stage.draw = draw;
 178    rs->stage.next = NULL;
 179    rs->stage.begin = rastpos_begin;
 180    rs->stage.point = rastpos_point;
 181    rs->stage.line = rastpos_line;
 182    rs->stage.tri = rastpos_tri;
 183    rs->stage.end = rastpos_end;
 184    rs->stage.reset_stipple_counter = rastpos_reset_stipple_counter;
 185    rs->ctx = ctx;
 186
 187    return rs;
 188 }
 189
 190
 191 static void
 192 st_RasterPos(GLcontext *ctx, const GLfloat v[4])
 193 {
 194    struct st_context *st = ctx->st;
 195    struct draw_context *draw = st->draw;
 196    struct rastpos_stage *rs;
 197
 198    if (st->rastpos_stage) {
 199       /* get rastpos stage info */
 200       rs = rastpos_stage(st->rastpos_stage);
 201    }
 202    else {
 203       /* create rastpos draw stage */
 204       GLuint i;
 205
 206       rs = new_draw_rastpos_stage(ctx, draw);
 207       st->rastpos_stage = &rs->stage;
 208
 209       /* one-time init */
 210       for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 211          rs->array[i].Size = 4;
 212          rs->array[i].Type = GL_FLOAT;
 213          rs->array[i].Stride = 0;
 214          rs->array[i].StrideB = 0;
 215          rs->array[i].Ptr = (GLubyte *) ctx->Current.Attrib[i];
 216          rs->array[i].Enabled = GL_TRUE;
 217          rs->array[i].Normalized = GL_TRUE;
 218          rs->array[i].BufferObj = NULL;
 219          rs->arrays[i] = &rs->array[i];
 220       }
 221
 222       rs->prim.mode = GL_POINTS;
 223       rs->prim.indexed = 0;
 224       rs->prim.begin = 1;
 225       rs->prim.end = 1;
 226       rs->prim.weak = 0;
 227       rs->prim.start = 0;
 228       rs->prim.count = 1;
 229    }
 230
 231    /* plug our rastpos stage into the draw module */
 232    draw_set_rasterize_stage(st->draw, st->rastpos_stage);
 233
 234    /* make sure everything's up to date */
 235    st_validate_state(ctx->st);
 236
 237    /* This will get set only if rastpos_point(), above, gets called */
 238    ctx->Current.RasterPosValid = GL_FALSE;
 239
 240    /* All vertex attribs but position were previously initialized above.
 241     * Just plug in position pointer now.
 242     */
 243    rs->array[0].Ptr = (GLubyte *) v;
 244
 245    /* draw the point */
 246    st_feedback_draw_vbo(ctx, rs->arrays, &rs->prim, 1, NULL, 0, 1);
 247 }
 248
 249
 250
 251 void st_init_rasterpos_functions(struct dd_function_table *functions)
 252 {
 253    functions->RasterPos = st_RasterPos;
 254 }