src/mesa/state_tracker/st_cb_rasterpos.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 VMware, Inc.
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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
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  13  *
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  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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  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
  43 #include "st_context.h"
  44 #include "st_atom.h"
  45 #include "st_draw.h"
  46 #include "st_cb_rasterpos.h"
  47 #include "draw/draw_context.h"
  48 #include "draw/draw_pipe.h"
  49 #include "vbo/vbo.h"
  50
  51
  52 /**
  53  * Our special drawing pipeline stage (replaces rasterization).
  54  */
  55 struct rastpos_stage
  56 {
  57    struct draw_stage stage;   /**< Base class */
  58    struct gl_context *ctx;            /**< Rendering context */
  59
  60    /* vertex attrib info we can setup once and re-use */
  61    struct gl_client_array array[VERT_ATTRIB_MAX];
  62    const struct gl_client_array *arrays[VERT_ATTRIB_MAX];
  63    struct _mesa_prim prim;
  64 };
  65
  66
  67 static inline struct rastpos_stage *
  68 rastpos_stage( struct draw_stage *stage )
  69 {
  70    return (struct rastpos_stage *) stage;
  71 }
  72
  73 static void
  74 rastpos_flush( struct draw_stage *stage, unsigned flags )
  75 {
  76    /* no-op */
  77 }
  78
  79 static void
  80 rastpos_reset_stipple_counter( struct draw_stage *stage )
  81 {
  82    /* no-op */
  83 }
  84
  85 static void
  86 rastpos_tri( struct draw_stage *stage, struct prim_header *prim )
  87 {
  88    /* should never get here */
  89    assert(0);
  90 }
  91
  92 static void
  93 rastpos_line( struct draw_stage *stage, struct prim_header *prim )
  94 {
  95    /* should never get here */
  96    assert(0);
  97 }
  98
  99 static void
 100 rastpos_destroy(struct draw_stage *stage)
 101 {
 102    free(stage);
 103 }
 104
 105
 106 /**
 107  * Update a raster pos attribute from the vertex result if it's present,
 108  * else copy the current attrib.
 109  */
 110 static void
 111 update_attrib(struct gl_context *ctx, const GLuint *outputMapping,
 112               const struct vertex_header *vert,
 113               GLfloat *dest,
 114               GLuint result, GLuint defaultAttrib)
 115 {
 116    const GLfloat *src;
 117    const GLuint k = outputMapping[result];
 118    if (k != ~0U)
 119       src = vert->data[k];
 120    else
 121       src = ctx->Current.Attrib[defaultAttrib];
 122    COPY_4V(dest, src);
 123 }
 124
 125
 126 /**
 127  * Normally, this function would render a GL_POINT.
 128  */
 129 static void
 130 rastpos_point(struct draw_stage *stage, struct prim_header *prim)
 131 {
 132    struct rastpos_stage *rs = rastpos_stage(stage);
 133    struct gl_context *ctx = rs->ctx;
 134    struct st_context *st = st_context(ctx);
 135    const GLfloat height = (GLfloat) ctx->DrawBuffer->Height;
 136    const GLuint *outputMapping = st->vertex_result_to_slot;
 137    const GLfloat *pos;
 138    GLuint i;
 139
 140    /* if we get here, we didn't get clipped */
 141    ctx->Current.RasterPosValid = GL_TRUE;
 142
 143    /* update raster pos */
 144    pos = prim->v[0]->data[0];
 145    ctx->Current.RasterPos[0] = pos[0];
 146    if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP)
 147       ctx->Current.RasterPos[1] = height - pos[1]; /* invert Y */
 148    else
 149       ctx->Current.RasterPos[1] = pos[1];
 150    ctx->Current.RasterPos[2] = pos[2];
 151    ctx->Current.RasterPos[3] = pos[3];
 152
 153    /* update other raster attribs */
 154    update_attrib(ctx, outputMapping, prim->v[0],
 155                  ctx->Current.RasterColor,
 156                  VARYING_SLOT_COL0, VERT_ATTRIB_COLOR0);
 157
 158    update_attrib(ctx, outputMapping, prim->v[0],
 159                  ctx->Current.RasterSecondaryColor,
 160                  VARYING_SLOT_COL1, VERT_ATTRIB_COLOR1);
 161
 162    for (i = 0; i < ctx->Const.MaxTextureCoordUnits; i++) {
 163       update_attrib(ctx, outputMapping, prim->v[0],
 164                     ctx->Current.RasterTexCoords[i],
 165                     VARYING_SLOT_TEX0 + i, VERT_ATTRIB_TEX0 + i);
 166    }
 167
 168    if (ctx->RenderMode == GL_SELECT) {
 169       _mesa_update_hitflag( ctx, ctx->Current.RasterPos[2] );
 170    }
 171 }
 172
 173
 174 /**
 175  * Create rasterpos "drawing" stage.
 176  */
 177 static struct rastpos_stage *
 178 new_draw_rastpos_stage(struct gl_context *ctx, struct draw_context *draw)
 179 {
 180    struct rastpos_stage *rs = ST_CALLOC_STRUCT(rastpos_stage);
 181    GLuint i;
 182
 183    rs->stage.draw = draw;
 184    rs->stage.next = NULL;
 185    rs->stage.point = rastpos_point;
 186    rs->stage.line = rastpos_line;
 187    rs->stage.tri = rastpos_tri;
 188    rs->stage.flush = rastpos_flush;
 189    rs->stage.destroy = rastpos_destroy;
 190    rs->stage.reset_stipple_counter = rastpos_reset_stipple_counter;
 191    rs->stage.destroy = rastpos_destroy;
 192    rs->ctx = ctx;
 193
 194    for (i = 0; i < Elements(rs->array); i++) {
 195       rs->array[i].Size = 4;
 196       rs->array[i].Type = GL_FLOAT;
 197       rs->array[i].Format = GL_RGBA;
 198       rs->array[i].Stride = 0;
 199       rs->array[i].StrideB = 0;
 200       rs->array[i].Ptr = (GLubyte *) ctx->Current.Attrib[i];
 201       rs->array[i].Enabled = GL_TRUE;
 202       rs->array[i].Normalized = GL_TRUE;
 203       rs->array[i].BufferObj = NULL;
 204       rs->arrays[i] = &rs->array[i];
 205    }
 206
 207    rs->prim.mode = GL_POINTS;
 208    rs->prim.indexed = 0;
 209    rs->prim.begin = 1;
 210    rs->prim.end = 1;
 211    rs->prim.weak = 0;
 212    rs->prim.start = 0;
 213    rs->prim.count = 1;
 214
 215    return rs;
 216 }
 217
 218
 219 static void
 220 st_RasterPos(struct gl_context *ctx, const GLfloat v[4])
 221 {
 222    struct st_context *st = st_context(ctx);
 223    struct draw_context *draw = st->draw;
 224    struct rastpos_stage *rs;
 225    const struct gl_client_array **saved_arrays = ctx->Array._DrawArrays;
 226
 227    if (st->rastpos_stage) {
 228       /* get rastpos stage info */
 229       rs = rastpos_stage(st->rastpos_stage);
 230    }
 231    else {
 232       /* create rastpos draw stage */
 233       rs = new_draw_rastpos_stage(ctx, draw);
 234       st->rastpos_stage = &rs->stage;
 235    }
 236
 237    /* plug our rastpos stage into the draw module */
 238    draw_set_rasterize_stage(st->draw, st->rastpos_stage);
 239
 240    /* make sure everything's up to date */
 241    st_validate_state(st);
 242
 243    /* This will get set only if rastpos_point(), above, gets called */
 244    ctx->Current.RasterPosValid = GL_FALSE;
 245
 246    /* All vertex attribs but position were previously initialized above.
 247     * Just plug in position pointer now.
 248     */
 249    rs->array[0].Ptr = (GLubyte *) v;
 250
 251    /* Draw the point.
 252     *
 253     * Don't set DriverFlags.NewArray.
 254     * st_feedback_draw_vbo doesn't check for that flag. */
 255    ctx->Array._DrawArrays = rs->arrays;
 256    st_feedback_draw_vbo(ctx, &rs->prim, 1, NULL, GL_TRUE, 0, 1,
 257                         NULL, NULL);
 258    ctx->Array._DrawArrays = saved_arrays;
 259
 260    /* restore draw's rasterization stage depending on rendermode */
 261    if (ctx->RenderMode == GL_FEEDBACK) {
 262       draw_set_rasterize_stage(draw, st->feedback_stage);
 263    }
 264    else if (ctx->RenderMode == GL_SELECT) {
 265       draw_set_rasterize_stage(draw, st->selection_stage);
 266    }
 267 }
 268
 269
 270
 271 void st_init_rasterpos_functions(struct dd_function_table *functions)
 272 {
 273    functions->RasterPos = st_RasterPos;
 274 }