src/mesa/state_tracker/st_cb_rasterpos.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 VMware, Inc.
   4  * All Rights Reserved.
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   7  * copy of this software and associated documentation files (the
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  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
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  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 #include "main/feedback.h"
  42 #include "main/rastpos.h"
  43
  44 #include "st_context.h"
  45 #include "st_atom.h"
  46 #include "st_draw.h"
  47 #include "st_cb_rasterpos.h"
  48 #include "draw/draw_context.h"
  49 #include "draw/draw_pipe.h"
  50 #include "vbo/vbo.h"
  51
  52
  53 /**
  54  * Our special drawing pipeline stage (replaces rasterization).
  55  */
  56 struct rastpos_stage
  57 {
  58    struct draw_stage stage;   /**< Base class */
  59    struct gl_context *ctx;            /**< Rendering context */
  60
  61    /* vertex attrib info we can setup once and re-use */
  62    struct gl_vertex_array array[VERT_ATTRIB_MAX];
  63    const struct gl_vertex_array *arrays[VERT_ATTRIB_MAX];
  64    struct _mesa_prim prim;
  65 };
  66
  67
  68 static inline struct rastpos_stage *
  69 rastpos_stage( struct draw_stage *stage )
  70 {
  71    return (struct rastpos_stage *) stage;
  72 }
  73
  74 static void
  75 rastpos_flush( struct draw_stage *stage, unsigned flags )
  76 {
  77    /* no-op */
  78 }
  79
  80 static void
  81 rastpos_reset_stipple_counter( struct draw_stage *stage )
  82 {
  83    /* no-op */
  84 }
  85
  86 static void
  87 rastpos_tri( struct draw_stage *stage, struct prim_header *prim )
  88 {
  89    /* should never get here */
  90    assert(0);
  91 }
  92
  93 static void
  94 rastpos_line( struct draw_stage *stage, struct prim_header *prim )
  95 {
  96    /* should never get here */
  97    assert(0);
  98 }
  99
 100 static void
 101 rastpos_destroy(struct draw_stage *stage)
 102 {
 103    free(stage);
 104 }
 105
 106
 107 /**
 108  * Update a raster pos attribute from the vertex result if it's present,
 109  * else copy the current attrib.
 110  */
 111 static void
 112 update_attrib(struct gl_context *ctx, const ubyte *outputMapping,
 113               const struct vertex_header *vert,
 114               GLfloat *dest,
 115               GLuint result, GLuint defaultAttrib)
 116 {
 117    const GLfloat *src;
 118    const GLuint k = outputMapping[result];
 119    if (k != ~0U)
 120       src = vert->data[k];
 121    else
 122       src = ctx->Current.Attrib[defaultAttrib];
 123    COPY_4V(dest, src);
 124 }
 125
 126
 127 /**
 128  * Normally, this function would render a GL_POINT.
 129  */
 130 static void
 131 rastpos_point(struct draw_stage *stage, struct prim_header *prim)
 132 {
 133    struct rastpos_stage *rs = rastpos_stage(stage);
 134    struct gl_context *ctx = rs->ctx;
 135    struct st_context *st = st_context(ctx);
 136    const GLfloat height = (GLfloat) ctx->DrawBuffer->Height;
 137    const ubyte *outputMapping = st->vertex_result_to_slot;
 138    const GLfloat *pos;
 139    GLuint i;
 140
 141    /* if we get here, we didn't get clipped */
 142    ctx->Current.RasterPosValid = GL_TRUE;
 143
 144    /* update raster pos */
 145    pos = prim->v[0]->data[0];
 146    ctx->Current.RasterPos[0] = pos[0];
 147    if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP)
 148       ctx->Current.RasterPos[1] = height - pos[1]; /* invert Y */
 149    else
 150       ctx->Current.RasterPos[1] = pos[1];
 151    ctx->Current.RasterPos[2] = pos[2];
 152    ctx->Current.RasterPos[3] = pos[3];
 153
 154    /* update other raster attribs */
 155    update_attrib(ctx, outputMapping, prim->v[0],
 156                  ctx->Current.RasterColor,
 157                  VARYING_SLOT_COL0, VERT_ATTRIB_COLOR0);
 158
 159    update_attrib(ctx, outputMapping, prim->v[0],
 160                  ctx->Current.RasterSecondaryColor,
 161                  VARYING_SLOT_COL1, VERT_ATTRIB_COLOR1);
 162
 163    for (i = 0; i < ctx->Const.MaxTextureCoordUnits; i++) {
 164       update_attrib(ctx, outputMapping, prim->v[0],
 165                     ctx->Current.RasterTexCoords[i],
 166                     VARYING_SLOT_TEX0 + i, VERT_ATTRIB_TEX0 + i);
 167    }
 168
 169    if (ctx->RenderMode == GL_SELECT) {
 170       _mesa_update_hitflag( ctx, ctx->Current.RasterPos[2] );
 171    }
 172 }
 173
 174
 175 /**
 176  * Create rasterpos "drawing" stage.
 177  */
 178 static struct rastpos_stage *
 179 new_draw_rastpos_stage(struct gl_context *ctx, struct draw_context *draw)
 180 {
 181    struct rastpos_stage *rs = ST_CALLOC_STRUCT(rastpos_stage);
 182    GLuint i;
 183
 184    rs->stage.draw = draw;
 185    rs->stage.next = NULL;
 186    rs->stage.point = rastpos_point;
 187    rs->stage.line = rastpos_line;
 188    rs->stage.tri = rastpos_tri;
 189    rs->stage.flush = rastpos_flush;
 190    rs->stage.destroy = rastpos_destroy;
 191    rs->stage.reset_stipple_counter = rastpos_reset_stipple_counter;
 192    rs->stage.destroy = rastpos_destroy;
 193    rs->ctx = ctx;
 194
 195    for (i = 0; i < ARRAY_SIZE(rs->array); i++) {
 196       rs->array[i].Size = 4;
 197       rs->array[i].Type = GL_FLOAT;
 198       rs->array[i].Format = GL_RGBA;
 199       rs->array[i].StrideB = 0;
 200       rs->array[i].Ptr = (GLubyte *) ctx->Current.Attrib[i];
 201       rs->array[i].Normalized = GL_TRUE;
 202       rs->array[i].BufferObj = NULL;
 203       rs->arrays[i] = &rs->array[i];
 204    }
 205
 206    rs->prim.mode = GL_POINTS;
 207    rs->prim.indexed = 0;
 208    rs->prim.begin = 1;
 209    rs->prim.end = 1;
 210    rs->prim.weak = 0;
 211    rs->prim.start = 0;
 212    rs->prim.count = 1;
 213
 214    return rs;
 215 }
 216
 217
 218 static void
 219 st_RasterPos(struct gl_context *ctx, const GLfloat v[4])
 220 {
 221    struct st_context *st = st_context(ctx);
 222    struct draw_context *draw = st_get_draw_context(st);
 223    struct rastpos_stage *rs;
 224    const struct gl_vertex_array **saved_arrays = ctx->Array._DrawArrays;
 225
 226    if (!st->draw)
 227       return;
 228
 229    if (ctx->VertexProgram._Current == NULL ||
 230        ctx->VertexProgram._Current == ctx->VertexProgram._TnlProgram) {
 231       /* No vertex shader/program is enabled, used the simple/fast fixed-
 232        * function implementation of RasterPos.
 233        */
 234       _mesa_RasterPos(ctx, v);
 235       return;
 236    }
 237
 238    if (st->rastpos_stage) {
 239       /* get rastpos stage info */
 240       rs = rastpos_stage(st->rastpos_stage);
 241    }
 242    else {
 243       /* create rastpos draw stage */
 244       rs = new_draw_rastpos_stage(ctx, draw);
 245       st->rastpos_stage = &rs->stage;
 246    }
 247
 248    /* plug our rastpos stage into the draw module */
 249    draw_set_rasterize_stage(st->draw, st->rastpos_stage);
 250
 251    /* make sure everything's up to date */
 252    st_validate_state(st, ST_PIPELINE_RENDER);
 253
 254    /* This will get set only if rastpos_point(), above, gets called */
 255    ctx->Current.RasterPosValid = GL_FALSE;
 256
 257    /* All vertex attribs but position were previously initialized above.
 258     * Just plug in position pointer now.
 259     */
 260    rs->array[0].Ptr = (GLubyte *) v;
 261
 262    /* Draw the point.
 263     *
 264     * Don't set DriverFlags.NewArray.
 265     * st_feedback_draw_vbo doesn't check for that flag. */
 266    ctx->Array._DrawArrays = rs->arrays;
 267    st_feedback_draw_vbo(ctx, &rs->prim, 1, NULL, GL_TRUE, 0, 1,
 268                         NULL, 0, NULL);
 269    ctx->Array._DrawArrays = saved_arrays;
 270
 271    /* restore draw's rasterization stage depending on rendermode */
 272    if (ctx->RenderMode == GL_FEEDBACK) {
 273       draw_set_rasterize_stage(draw, st->feedback_stage);
 274    }
 275    else if (ctx->RenderMode == GL_SELECT) {
 276       draw_set_rasterize_stage(draw, st->selection_stage);
 277    }
 278 }
 279
 280
 281
 282 void st_init_rasterpos_functions(struct dd_function_table *functions)
 283 {
 284    functions->RasterPos = st_RasterPos;
 285 }