t_vb_vertex.c

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/*
 * Mesa 3-D graphics library
 * Version:  6.5
 *
 * Copyright (C) 1999-2006  Brian Paul   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, sublicense,
 * 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 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL 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.
 *
 * Authors:
 *    Keith Whitwell <keith@tungstengraphics.com>
 */


#include "main/glheader.h"
#include "main/colormac.h"
#include "main/context.h"
#include "main/macros.h"
#include "main/imports.h"
#include "main/mtypes.h"

#include "math/m_xform.h"

#include "t_context.h"
#include "t_pipeline.h"



struct vertex_stage_data {
   GLvector4f eye;
   GLvector4f clip;
   GLvector4f proj;
   GLubyte *clipmask;
   GLubyte ormask;
   GLubyte andmask;
};

#define VERTEX_STAGE_DATA(stage) ((struct vertex_stage_data *)stage->privatePtr)




/* This function implements cliptesting for user-defined clip planes.
 * The clipping of primitives to these planes is implemented in
 * t_render_clip.h.
 */
#define USER_CLIPTEST(NAME, SZ)                 \
static void NAME( GLcontext *ctx,               \
          GLvector4f *clip,             \
          GLubyte *clipmask,                \
          GLubyte *clipormask,              \
          GLubyte *clipandmask )            \
{                               \
   GLuint p;                            \
                                \
   for (p = 0; p < ctx->Const.MaxClipPlanes; p++)       \
      if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {    \
     GLuint nr, i;                      \
     const GLfloat a = ctx->Transform._ClipUserPlane[p][0]; \
     const GLfloat b = ctx->Transform._ClipUserPlane[p][1]; \
     const GLfloat c = ctx->Transform._ClipUserPlane[p][2]; \
     const GLfloat d = ctx->Transform._ClipUserPlane[p][3]; \
         GLfloat *coord = (GLfloat *)clip->data;        \
         GLuint stride = clip->stride;              \
         GLuint count = clip->count;                \
                                \
     for (nr = 0, i = 0 ; i < count ; i++) {        \
        GLfloat dp = coord[0] * a + coord[1] * b;       \
        if (SZ > 2) dp += coord[2] * c;         \
        if (SZ > 3) dp += coord[3] * d; else dp += d;   \
                                \
        if (dp < 0) {                   \
           nr++;                        \
           clipmask[i] |= CLIP_USER_BIT;            \
        }                           \
                                \
        STRIDE_F(coord, stride);                \
     }                          \
                                \
     if (nr > 0) {                      \
        *clipormask |= CLIP_USER_BIT;           \
        if (nr == count) {                  \
           *clipandmask |= CLIP_USER_BIT;           \
           return;                      \
        }                           \
     }                          \
      }                             \
}


USER_CLIPTEST(userclip2, 2)
USER_CLIPTEST(userclip3, 3)
USER_CLIPTEST(userclip4, 4)

static void (*(usercliptab[5]))( GLcontext *,
                 GLvector4f *, GLubyte *,
                 GLubyte *, GLubyte * ) =
{
   NULL,
   NULL,
   userclip2,
   userclip3,
   userclip4
};



static GLboolean run_vertex_stage( GLcontext *ctx,
                   struct tnl_pipeline_stage *stage )
{
   struct vertex_stage_data *store = (struct vertex_stage_data *)stage->privatePtr;
   TNLcontext *tnl = TNL_CONTEXT(ctx);
   struct vertex_buffer *VB = &tnl->vb;

   if (ctx->VertexProgram._Current) 
      return GL_TRUE;

   if (ctx->_NeedEyeCoords) {
      /* Separate modelview transformation:
       * Use combined ModelProject to avoid some depth artifacts
       */
      if (ctx->ModelviewMatrixStack.Top->type == MATRIX_IDENTITY)
     VB->EyePtr = VB->ObjPtr;
      else
     VB->EyePtr = TransformRaw( &store->eye,
                    ctx->ModelviewMatrixStack.Top,
                    VB->ObjPtr);
   }

   VB->ClipPtr = TransformRaw( &store->clip,
                   &ctx->_ModelProjectMatrix,
                   VB->ObjPtr );

   /* Drivers expect this to be clean to element 4...
    */
   switch (VB->ClipPtr->size) {
   case 1:          
      /* impossible */
   case 2:
      _mesa_vector4f_clean_elem( VB->ClipPtr, VB->Count, 2 );
      /* fall-through */
   case 3:
      _mesa_vector4f_clean_elem( VB->ClipPtr, VB->Count, 3 );
      /* fall-through */
   case 4:
      break;
   }


   /* Cliptest and perspective divide.  Clip functions must clear
    * the clipmask.
    */
   store->ormask = 0;
   store->andmask = CLIP_FRUSTUM_BITS;

   if (tnl->NeedNdcCoords) {
      VB->NdcPtr =
     _mesa_clip_tab[VB->ClipPtr->size]( VB->ClipPtr,
                        &store->proj,
                        store->clipmask,
                        &store->ormask,
                        &store->andmask );
   }
   else {
      VB->NdcPtr = NULL;
      _mesa_clip_np_tab[VB->ClipPtr->size]( VB->ClipPtr,
                        NULL,
                        store->clipmask,
                        &store->ormask,
                        &store->andmask );
   }

   if (store->andmask)
      return GL_FALSE;


   /* Test userclip planes.  This contributes to VB->ClipMask, so
    * is essentially required to be in this stage.
    */
   if (ctx->Transform.ClipPlanesEnabled) {
      usercliptab[VB->ClipPtr->size]( ctx,
                      VB->ClipPtr,
                      store->clipmask,
                      &store->ormask,
                      &store->andmask );

      if (store->andmask)
     return GL_FALSE;
   }

   VB->ClipAndMask = store->andmask;
   VB->ClipOrMask = store->ormask;
   VB->ClipMask = store->clipmask;

   return GL_TRUE;
}


static GLboolean init_vertex_stage( GLcontext *ctx,
                    struct tnl_pipeline_stage *stage )
{
   struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
   struct vertex_stage_data *store;
   GLuint size = VB->Size;

   stage->privatePtr = CALLOC(sizeof(*store));
   store = VERTEX_STAGE_DATA(stage);
   if (!store)
      return GL_FALSE;

   _mesa_vector4f_alloc( &store->eye, 0, size, 32 );
   _mesa_vector4f_alloc( &store->clip, 0, size, 32 );
   _mesa_vector4f_alloc( &store->proj, 0, size, 32 );

   store->clipmask = (GLubyte *) ALIGN_MALLOC(sizeof(GLubyte)*size, 32 );

   if (!store->clipmask ||
       !store->eye.data ||
       !store->clip.data ||
       !store->proj.data)
      return GL_FALSE;

   return GL_TRUE;
}

static void dtr( struct tnl_pipeline_stage *stage )
{
   struct vertex_stage_data *store = VERTEX_STAGE_DATA(stage);

   if (store) {
      _mesa_vector4f_free( &store->eye );
      _mesa_vector4f_free( &store->clip );
      _mesa_vector4f_free( &store->proj );
      ALIGN_FREE( store->clipmask );
      FREE(store);
      stage->privatePtr = NULL;
      stage->run = init_vertex_stage;
   }
}


const struct tnl_pipeline_stage _tnl_vertex_transform_stage =
{
   "modelview/project/cliptest/divide",
   NULL,            /* private data */
   init_vertex_stage,
   dtr,             /* destructor */
   NULL,
   run_vertex_stage     /* run -- initially set to init */
};