src/mesa/state_tracker/st_atom_clip.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 VMware, Inc.
   4  * All Rights Reserved.
   5  *
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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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  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
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  26  **************************************************************************/
  27
  28  /*
  29   * Authors:
  30   *   Keith Whitwell <keithw@vmware.com>
  31   */
  32
  33
  34 #include "st_context.h"
  35 #include "pipe/p_context.h"
  36 #include "st_atom.h"
  37 #include "st_program.h"
  38 #include "util/u_debug.h"
  39 #include "cso_cache/cso_context.h"
  40
  41
  42 /* Second state atom for user clip planes:
  43  */
  44 void st_update_clip( struct st_context *st )
  45 {
  46    struct pipe_clip_state clip;
  47    const struct gl_context *ctx = st->ctx;
  48    bool use_eye = FALSE;
  49
  50    STATIC_ASSERT(sizeof(clip.ucp) <= sizeof(ctx->Transform._ClipUserPlane));
  51
  52    /* if we have a vertex shader that writes clip vertex we need to pass
  53       the pre-projection transformed coordinates into the driver. */
  54    if (ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX])
  55       use_eye = TRUE;
  56
  57    /* _ClipUserPlane = _NEW_TRANSFORM | _NEW_PROJECTION
  58     * EyeUserPlane = _NEW_TRANSFORM
  59     */
  60    memcpy(clip.ucp,
  61           use_eye ? ctx->Transform.EyeUserPlane
  62                   : ctx->Transform._ClipUserPlane, sizeof(clip.ucp));
  63
  64    if (memcmp(&st->state.clip, &clip, sizeof(clip)) != 0) {
  65       st->state.clip = clip;
  66       st->pipe->set_clip_state(st->pipe, &clip);
  67    }
  68 }