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      1 /*
      2  * Mesa 3-D graphics library
      3  *
      4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included
     14  * in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 
     26 #ifndef _M_XFORM_H
     27 #define _M_XFORM_H
     28 
     29 
     30 #include "main/compiler.h"
     31 #include "main/glheader.h"
     32 #include "math/m_matrix.h"
     33 #include "math/m_vector.h"
     34 
     35 
     36 extern void
     37 _math_init_transformation(void);
     38 extern void
     39 init_c_cliptest(void);
     40 
     41 /* KW: Clip functions now do projective divide as well.  The projected
     42  * coordinates are very useful to us because they let us cull
     43  * backfaces and eliminate vertices from lighting, fogging, etc
     44  * calculations.  Despite the fact that this divide could be done one
     45  * day in hardware, we would still have a reason to want to do it here
     46  * as long as those other calculations remain in software.
     47  *
     48  * Clipping is a convenient place to do the divide on x86 as it should be
     49  * possible to overlap with integer outcode calculations.
     50  *
     51  * There are two cases where we wouldn't want to do the divide in cliptest:
     52  *    - When we aren't clipping.  We still might want to cull backfaces
     53  *      so the divide should be done elsewhere.  This currently never
     54  *      happens.
     55  *
     56  *    - When culling isn't likely to help us, such as when the GL culling
     57  *      is disabled and we not lighting or are only lighting
     58  *      one-sided.  In this situation, backface determination provides
     59  *      us with no useful information.  A tricky case to detect is when
     60  *      all input data is already culled, although hopefully the
     61  *      application wouldn't turn on culling in such cases.
     62  *
     63  * We supply a buffer to hold the [x/w,y/w,z/w,1/w] values which
     64  * are the result of the projection.  This is only used in the
     65  * 4-vector case - in other cases, we just use the clip coordinates
     66  * as the projected coordinates - they are identical.
     67  *
     68  * This is doubly convenient because it means the Win[] array is now
     69  * of the same stride as all the others, so I can now turn map_vertices
     70  * into a straight-forward matrix transformation, with asm acceleration
     71  * automatically available.
     72  */
     73 
     74 /* Vertex buffer clipping flags
     75  */
     76 #define CLIP_RIGHT_SHIFT 	0
     77 #define CLIP_LEFT_SHIFT 	1
     78 #define CLIP_TOP_SHIFT  	2
     79 #define CLIP_BOTTOM_SHIFT       3
     80 #define CLIP_NEAR_SHIFT  	4
     81 #define CLIP_FAR_SHIFT  	5
     82 
     83 #define CLIP_RIGHT_BIT   0x01
     84 #define CLIP_LEFT_BIT    0x02
     85 #define CLIP_TOP_BIT     0x04
     86 #define CLIP_BOTTOM_BIT  0x08
     87 #define CLIP_NEAR_BIT    0x10
     88 #define CLIP_FAR_BIT     0x20
     89 #define CLIP_USER_BIT    0x40
     90 #define CLIP_CULL_BIT    0x80
     91 #define CLIP_FRUSTUM_BITS    0x3f
     92 
     93 
     94 typedef GLvector4f * (*clip_func)(GLvector4f *vClip,
     95                                   GLvector4f *vProj,
     96                                   GLubyte clipMask[],
     97                                   GLubyte *orMask,
     98                                   GLubyte *andMask,
     99                                   GLboolean viewport_z_clip);
    100 
    101 typedef void (*dotprod_func)( GLfloat *out,
    102 			      GLuint out_stride,
    103 			      const GLvector4f *coord_vec,
    104 			      const GLfloat plane[4] );
    105 
    106 typedef void (*vec_copy_func)( GLvector4f *to,
    107 			       const GLvector4f *from );
    108 
    109 
    110 
    111 /*
    112  * Functions for transformation of normals in the VB.
    113  */
    114 typedef void (*normal_func)(const GLmatrix *mat,
    115                             GLfloat scale,
    116                             const GLvector4f *in,
    117                             const GLfloat lengths[],
    118                             GLvector4f *dest);
    119 
    120 
    121 /* Flags for selecting a normal transformation function.
    122  */
    123 #define NORM_RESCALE   0x1		/* apply the scale factor */
    124 #define NORM_NORMALIZE 0x2		/* normalize */
    125 #define NORM_TRANSFORM 0x4		/* apply the transformation matrix */
    126 #define NORM_TRANSFORM_NO_ROT 0x8	/* apply the transformation matrix */
    127 
    128 
    129 
    130 
    131 /* KW: New versions of the transform function allow a mask array
    132  *     specifying that individual vector transform should be skipped
    133  *     when the mask byte is zero.  This is always present as a
    134  *     parameter, to allow a unified interface.
    135  */
    136 typedef void (*transform_func)(GLvector4f *to_vec,
    137                                const GLfloat m[16],
    138                                const GLvector4f *from_vec);
    139 
    140 
    141 extern dotprod_func  _mesa_dotprod_tab[5];
    142 extern vec_copy_func _mesa_copy_tab[0x10];
    143 extern vec_copy_func _mesa_copy_clean_tab[5];
    144 extern clip_func     _mesa_clip_tab[5];
    145 extern clip_func     _mesa_clip_np_tab[5];
    146 extern normal_func   _mesa_normal_tab[0xf];
    147 
    148 /* Use of 2 layers of linked 1-dimensional arrays to reduce
    149  * cost of lookup.
    150  */
    151 extern transform_func *_mesa_transform_tab[5];
    152 
    153 
    154 
    155 #define TransformRaw( to, mat, from ) \
    156    ( _mesa_transform_tab[(from)->size][(mat)->type]( to, (mat)->m, from ), \
    157      (to) )
    158 
    159 
    160 #endif
    161