1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
/* -----------------------------------------------------------------------------
Copyright (c) 2006 Simon Brown si@sjbrown.co.uk
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 THE AUTHORS OR COPYRIGHT HOLDERS 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.
-------------------------------------------------------------------------- */
#include "colourset.h"
namespace squish {
ColourSet::ColourSet( u8 const* rgba, int mask, int flags )
: m_count( 0 ),
m_transparent( false )
{
// check the compression mode for dxt1
bool isDxt1 = ( ( flags & kDxt1 ) != 0 );
bool weightByAlpha = ( ( flags & kWeightColourByAlpha ) != 0 );
// create the minimal set
for( int i = 0; i < 16; ++i )
{
// check this pixel is enabled
int bit = 1 << i;
if( ( mask & bit ) == 0 )
{
m_remap[i] = -1;
continue;
}
// check for transparent pixels when using dxt1
if( isDxt1 && rgba[4*i + 3] < 128 )
{
m_remap[i] = -1;
m_transparent = true;
continue;
}
// loop over previous points for a match
for( int j = 0;; ++j )
{
// allocate a new point
if( j == i )
{
// normalise coordinates to [0,1]
float x = ( float )rgba[4*i] / 255.0f;
float y = ( float )rgba[4*i + 1] / 255.0f;
float z = ( float )rgba[4*i + 2] / 255.0f;
// ensure there is always non-zero weight even for zero alpha
float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f;
// add the point
m_points[m_count] = Vec3( x, y, z );
m_weights[m_count] = ( weightByAlpha ? w : 1.0f );
m_remap[i] = m_count;
// advance
++m_count;
break;
}
// check for a match
int oldbit = 1 << j;
bool match = ( ( mask & oldbit ) != 0 )
&& ( rgba[4*i] == rgba[4*j] )
&& ( rgba[4*i + 1] == rgba[4*j + 1] )
&& ( rgba[4*i + 2] == rgba[4*j + 2] )
&& ( rgba[4*j + 3] >= 128 || !isDxt1 );
if( match )
{
// get the index of the match
int index = m_remap[j];
// ensure there is always non-zero weight even for zero alpha
float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f;
// map to this point and increase the weight
m_weights[index] += ( weightByAlpha ? w : 1.0f );
m_remap[i] = index;
break;
}
}
}
// square root the weights
for( int i = 0; i < m_count; ++i )
m_weights[i] = std::sqrt( m_weights[i] );
}
void ColourSet::RemapIndices( u8 const* source, u8* target ) const
{
for( int i = 0; i < 16; ++i )
{
int j = m_remap[i];
if( j == -1 )
target[i] = 3;
else
target[i] = source[j];
}
}
} // namespace squish
|