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
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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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  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 #include "glformats.h"
  44
  45 #include "st_context.h"
  46 #include "st_atom.h"
  47 #include "st_draw.h"
  48 #include "st_program.h"
  49 #include "st_cb_rasterpos.h"
  50 #include "draw/draw_context.h"
  51 #include "draw/draw_pipe.h"
  52 #include "vbo/vbo.h"
  53
  54
  55 /**
  56  * Our special drawing pipeline stage (replaces rasterization).
  57  */
  58 struct rastpos_stage
  59 {
  60    struct draw_stage stage;   /**< Base class */
  61    struct gl_context *ctx;            /**< Rendering context */
  62
  63    /* vertex attrib info we can setup once and re-use */
  64    struct gl_vertex_buffer_binding binding;
  65    struct gl_array_attributes attrib[VERT_ATTRIB_MAX];
  66    struct gl_vertex_array array[VERT_ATTRIB_MAX];
  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    free(stage);
 107 }
 108
 109
 110 /**
 111  * Update a raster pos attribute from the vertex result if it's present,
 112  * else copy the current attrib.
 113  */
 114 static void
 115 update_attrib(struct gl_context *ctx, const ubyte *outputMapping,
 116               const struct vertex_header *vert,
 117               GLfloat *dest,
 118               GLuint result, GLuint defaultAttrib)
 119 {
 120    const GLfloat *src;
 121    const GLuint k = outputMapping[result];
 122    if (k != ~0U)
 123       src = vert->data[k];
 124    else
 125       src = ctx->Current.Attrib[defaultAttrib];
 126    COPY_4V(dest, src);
 127 }
 128
 129
 130 /**
 131  * Normally, this function would render a GL_POINT.
 132  */
 133 static void
 134 rastpos_point(struct draw_stage *stage, struct prim_header *prim)
 135 {
 136    struct rastpos_stage *rs = rastpos_stage(stage);
 137    struct gl_context *ctx = rs->ctx;
 138    struct st_context *st = st_context(ctx);
 139    const GLfloat height = (GLfloat) ctx->DrawBuffer->Height;
 140    const ubyte *outputMapping = st->vp->result_to_output;
 141    const GLfloat *pos;
 142    GLuint i;
 143
 144    /* if we get here, we didn't get clipped */
 145    ctx->Current.RasterPosValid = GL_TRUE;
 146
 147    /* update raster pos */
 148    pos = prim->v[0]->data[0];
 149    ctx->Current.RasterPos[0] = pos[0];
 150    if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP)
 151       ctx->Current.RasterPos[1] = height - pos[1]; /* invert Y */
 152    else
 153       ctx->Current.RasterPos[1] = pos[1];
 154    ctx->Current.RasterPos[2] = pos[2];
 155    ctx->Current.RasterPos[3] = pos[3];
 156
 157    /* update other raster attribs */
 158    update_attrib(ctx, outputMapping, prim->v[0],
 159                  ctx->Current.RasterColor,
 160                  VARYING_SLOT_COL0, VERT_ATTRIB_COLOR0);
 161
 162    update_attrib(ctx, outputMapping, prim->v[0],
 163                  ctx->Current.RasterSecondaryColor,
 164                  VARYING_SLOT_COL1, VERT_ATTRIB_COLOR1);
 165
 166    for (i = 0; i < ctx->Const.MaxTextureCoordUnits; i++) {
 167       update_attrib(ctx, outputMapping, prim->v[0],
 168                     ctx->Current.RasterTexCoords[i],
 169                     VARYING_SLOT_TEX0 + i, VERT_ATTRIB_TEX0 + i);
 170    }
 171
 172    if (ctx->RenderMode == GL_SELECT) {
 173       _mesa_update_hitflag( ctx, ctx->Current.RasterPos[2] );
 174    }
 175 }
 176
 177
 178 /**
 179  * Create rasterpos "drawing" stage.
 180  */
 181 static struct rastpos_stage *
 182 new_draw_rastpos_stage(struct gl_context *ctx, struct draw_context *draw)
 183 {
 184    struct rastpos_stage *rs = ST_CALLOC_STRUCT(rastpos_stage);
 185    GLuint i;
 186    GLuint elementSize;
 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->binding.Stride = 0;
 200    rs->binding.BufferObj = NULL;
 201
 202    elementSize = _mesa_bytes_per_vertex_attrib(4, GL_FLOAT);
 203    for (i = 0; i < ARRAY_SIZE(rs->array); i++) {
 204       rs->attrib[i].Size = 4;
 205       rs->attrib[i].Type = GL_FLOAT;
 206       rs->attrib[i].Format = GL_RGBA;
 207       rs->attrib[i].Ptr = (GLubyte *) ctx->Current.Attrib[i];
 208       rs->attrib[i].Normalized = GL_TRUE;
 209       rs->attrib[i]._ElementSize = elementSize;
 210       rs->array[i].BufferBinding = &rs->binding;
 211       rs->array[i].VertexAttrib = &rs->attrib[i];
 212    }
 213
 214    rs->prim.mode = GL_POINTS;
 215    rs->prim.indexed = 0;
 216    rs->prim.begin = 1;
 217    rs->prim.end = 1;
 218    rs->prim.weak = 0;
 219    rs->prim.start = 0;
 220    rs->prim.count = 1;
 221
 222    return rs;
 223 }
 224
 225
 226 static void
 227 st_RasterPos(struct gl_context *ctx, const GLfloat v[4])
 228 {
 229    struct st_context *st = st_context(ctx);
 230    struct draw_context *draw = st_get_draw_context(st);
 231    struct rastpos_stage *rs;
 232    const struct gl_vertex_array *saved_arrays = ctx->Array._DrawArrays;
 233
 234    if (!st->draw)
 235       return;
 236
 237    if (ctx->VertexProgram._Current == NULL ||
 238        ctx->VertexProgram._Current == ctx->VertexProgram._TnlProgram) {
 239       /* No vertex shader/program is enabled, used the simple/fast fixed-
 240        * function implementation of RasterPos.
 241        */
 242       _mesa_RasterPos(ctx, v);
 243       return;
 244    }
 245
 246    if (st->rastpos_stage) {
 247       /* get rastpos stage info */
 248       rs = rastpos_stage(st->rastpos_stage);
 249    }
 250    else {
 251       /* create rastpos draw stage */
 252       rs = new_draw_rastpos_stage(ctx, draw);
 253       st->rastpos_stage = &rs->stage;
 254    }
 255
 256    /* plug our rastpos stage into the draw module */
 257    draw_set_rasterize_stage(st->draw, st->rastpos_stage);
 258
 259    /* make sure everything's up to date */
 260    st_validate_state(st, ST_PIPELINE_RENDER);
 261
 262    /* This will get set only if rastpos_point(), above, gets called */
 263    ctx->Current.RasterPosValid = GL_FALSE;
 264
 265    /* All vertex attribs but position were previously initialized above.
 266     * Just plug in position pointer now.
 267     */
 268    rs->attrib[0].Ptr = (GLubyte *) v;
 269
 270    /* Draw the point.
 271     *
 272     * Don't set DriverFlags.NewArray.
 273     * st_feedback_draw_vbo doesn't check for that flag. */
 274    ctx->Array._DrawArrays = rs->array;
 275    st_feedback_draw_vbo(ctx, &rs->prim, 1, NULL, GL_TRUE, 0, 1,
 276                         NULL, 0, NULL);
 277    ctx->Array._DrawArrays = saved_arrays;
 278
 279    /* restore draw's rasterization stage depending on rendermode */
 280    if (ctx->RenderMode == GL_FEEDBACK) {
 281       draw_set_rasterize_stage(draw, st->feedback_stage);
 282    }
 283    else if (ctx->RenderMode == GL_SELECT) {
 284       draw_set_rasterize_stage(draw, st->selection_stage);
 285    }
 286 }
 287
 288
 289
 290 void st_init_rasterpos_functions(struct dd_function_table *functions)
 291 {
 292    functions->RasterPos = st_RasterPos;
 293 }