t_vb_vertex.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * 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 <[e-mail]>
 */


#include "glheader.h"
#include "colormac.h"
#include "context.h"
#include "macros.h"
#include "imports.h"
#include "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 */
};