src/mesa/state_tracker/st_cb_rasterpos.c

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