path: root/src/mesa/state_tracker/st_cb_rasterpos.c

/**************************************************************************
 * 
 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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 **************************************************************************/

/**
 * glRasterPos implementation.  Basically render a GL_POINT with our
 * private draw module.  Plug in a special "rasterpos" stage at the end
 * of the 'draw' pipeline to capture the results and update the current
 * raster pos attributes.
 *
 * Authors:
 *   Brian Paul
 */


#include "main/imports.h"
#include "main/macros.h"

#include "st_context.h"
#include "st_atom.h"
#include "st_draw.h"
#include "st_cb_rasterpos.h"
#include "st_draw.h"
#include "pipe/draw/draw_context.h"
#include "pipe/draw/draw_private.h"
#include "shader/prog_instruction.h"
#include "vbo/vbo.h"



/**
 * Our special drawing pipeline stage (replaces rasterization).
 */
struct rastpos_stage
{
   struct draw_stage stage;   /**< Base class */
   GLcontext *ctx;            /**< Rendering context */

   /* vertex attrib info we can setup once and re-use */
   struct gl_client_array array[VERT_ATTRIB_MAX];
   const struct gl_client_array *arrays[VERT_ATTRIB_MAX];
   struct _mesa_prim prim;
};


static INLINE struct rastpos_stage *
rastpos_stage( struct draw_stage *stage )
{
   return (struct rastpos_stage *) stage;
}

static void
rastpos_begin( struct draw_stage *stage )
{
   /* no-op */
}

static void
rastpos_end( struct draw_stage *stage )
{
   /* no-op */
}

static void
rastpos_reset_stipple_counter( struct draw_stage *stage )
{
   /* no-op */
}

static void
rastpos_tri( struct draw_stage *stage, struct prim_header *prim )
{
   /* should never get here */
   assert(0);
}

static void
rastpos_line( struct draw_stage *stage, struct prim_header *prim )
{
   /* should never get here */
   assert(0);
}


/**
 * Update a raster pos attribute from the vertex result if it's present,
 * else copy the current attrib.
 */
static void
update_attrib(GLcontext *ctx, const GLuint *outputMapping,
              const struct vertex_header *vert,
              GLfloat *dest,
              GLuint result, GLuint defaultAttrib)
{
   const GLfloat *src;
   const GLuint k = outputMapping[result];
   if (k != ~0)
      src = vert->data[k];
   else
      src = ctx->Current.Attrib[defaultAttrib];
   COPY_4V(dest, src);
}


/**
 * Normally, this function would render a GL_POINT.
 */
static void
rastpos_point(struct draw_stage *stage, struct prim_header *prim)
{
   struct rastpos_stage *rs = rastpos_stage(stage);
   GLcontext *ctx = rs->ctx;
   struct st_context *st = ctx->st;
   const GLfloat height = ctx->DrawBuffer->Height;
   const GLuint *outputMapping = st->vertex_result_to_slot;
   const GLfloat *pos;
   GLuint i;

   /* if we get here, we didn't get clipped */
   ctx->Current.RasterPosValid = GL_TRUE;

   /* update raster pos */
   pos = prim->v[0]->data[0];
   ctx->Current.RasterPos[0] = pos[0];
   ctx->Current.RasterPos[1] = height - 1 - pos[1];
   ctx->Current.RasterPos[2] = pos[2];
   ctx->Current.RasterPos[3] = pos[3];

   /* update other raster attribs */
   update_attrib(ctx, outputMapping, prim->v[0],
                 ctx->Current.RasterColor,
                 VERT_RESULT_COL0, VERT_ATTRIB_COLOR0);

   update_attrib(ctx, outputMapping, prim->v[0],
                 ctx->Current.RasterSecondaryColor,
                 VERT_RESULT_COL1, VERT_ATTRIB_COLOR1);

   for (i = 0; i < MAX_TEXTURE_UNITS; i++) {
      update_attrib(ctx, outputMapping, prim->v[0],
                    ctx->Current.RasterTexCoords[i],
                    VERT_RESULT_TEX0 + i, VERT_ATTRIB_TEX0 + i);
   }
}


/**
 * Create rasterpos "drawing" stage.
 */
static struct rastpos_stage *
new_draw_rastpos_stage(GLcontext *ctx, struct draw_context *draw)
{
   struct rastpos_stage *rs = CALLOC_STRUCT(rastpos_stage);
   GLuint i;

   rs->stage.draw = draw;
   rs->stage.next = NULL;
   rs->stage.begin = rastpos_begin;
   rs->stage.point = rastpos_point;
   rs->stage.line = rastpos_line;
   rs->stage.tri = rastpos_tri;
   rs->stage.end = rastpos_end;
   rs->stage.reset_stipple_counter = rastpos_reset_stipple_counter;
   rs->ctx = ctx;

   for (i = 0; i < VERT_ATTRIB_MAX; i++) {
      rs->array[i].Size = 4;
      rs->array[i].Type = GL_FLOAT;
      rs->array[i].Stride = 0;
      rs->array[i].StrideB = 0;
      rs->array[i].Ptr = (GLubyte *) ctx->Current.Attrib[i];
      rs->array[i].Enabled = GL_TRUE;
      rs->array[i].Normalized = GL_TRUE;
      rs->array[i].BufferObj = NULL;
      rs->arrays[i] = &rs->array[i];
   }

   rs->prim.mode = GL_POINTS;
   rs->prim.indexed = 0;
   rs->prim.begin = 1;
   rs->prim.end = 1;
   rs->prim.weak = 0;
   rs->prim.start = 0;
   rs->prim.count = 1;

   return rs;
}


static void
st_RasterPos(GLcontext *ctx, const GLfloat v[4])
{
   struct st_context *st = ctx->st;
   struct draw_context *draw = st->draw;
   struct rastpos_stage *rs;

   if (st->rastpos_stage) {
      /* get rastpos stage info */
      rs = rastpos_stage(st->rastpos_stage);
   }
   else {
      /* create rastpos draw stage */
      rs = new_draw_rastpos_stage(ctx, draw);
      st->rastpos_stage = &rs->stage;
   }

   /* plug our rastpos stage into the draw module */
   draw_set_rasterize_stage(st->draw, st->rastpos_stage);

   /* make sure everything's up to date */
   st_validate_state(ctx->st);

   /* This will get set only if rastpos_point(), above, gets called */
   ctx->Current.RasterPosValid = GL_FALSE;

   /* All vertex attribs but position were previously initialized above.
    * Just plug in position pointer now.
    */
   rs->array[0].Ptr = (GLubyte *) v;

   /* draw the point */
   st_feedback_draw_vbo(ctx, rs->arrays, &rs->prim, 1, NULL, 0, 1);
}



void st_init_rasterpos_functions(struct dd_function_table *functions)
{
   functions->RasterPos = st_RasterPos;
}