[852] | 1 | /*
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| 2 | glh - is a platform-indepenedent C++ OpenGL helper library
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| 3 |
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| 4 |
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| 5 | Copyright (c) 2000 Cass Everitt
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| 6 | Copyright (c) 2000, 2001 NVIDIA Corporation
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| 7 | All rights reserved.
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| 8 |
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| 9 | Redistribution and use in source and binary forms, with or
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| 10 | without modification, are permitted provided that the following
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| 11 | conditions are met:
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| 12 |
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| 13 | * Redistributions of source code must retain the above
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| 14 | copyright notice, this list of conditions and the following
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| 15 | disclaimer.
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| 16 |
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| 17 | * Redistributions in binary form must reproduce the above
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| 18 | copyright notice, this list of conditions and the following
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| 19 | disclaimer in the documentation and/or other materials
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| 20 | provided with the distribution.
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| 21 |
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| 22 | * The names of contributors to this software may not be used
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| 23 | to endorse or promote products derived from this software
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| 24 | without specific prior written permission.
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| 25 |
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| 26 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| 27 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| 28 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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| 29 | FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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| 30 | REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 31 | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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| 32 | BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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| 33 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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| 34 | CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 35 | LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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| 36 | ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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| 37 | POSSIBILITY OF SUCH DAMAGE.
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| 38 |
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| 39 |
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| 40 | Cass Everitt - cass@r3.nu
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| 41 | */
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| 42 |
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| 43 | /*
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| 44 | gluBuild2DMipmaps cannot build mipmaps for textures whose
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| 45 | "format" it does not recognize. This is primarily because
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| 46 | it infers the number of components and how to average them
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| 47 | from the format. This helper eliminates that problem by
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| 48 | factoring out that functionality.
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| 49 |
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| 50 | Cass Everitt
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| 51 | 1-9-01
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| 52 |
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| 53 | */
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| 54 |
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| 55 | #ifndef GLH_MIPMAPS_H
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| 56 | #define GLH_MIPMAPS_H
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| 57 |
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| 58 | #ifdef _WIN32
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| 59 | # include <windows.h>
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| 60 | #endif
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| 61 |
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| 62 | #ifdef MACOS
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| 63 | #include <OpenGL/gl.h>
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| 64 | #else
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| 65 | #include <GL/gl.h>
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| 66 | #endif
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| 67 |
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| 68 | namespace glh
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| 69 | {
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| 70 |
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| 71 | template <class T>
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| 72 | class tex_indexer2
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| 73 | {
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| 74 | public:
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| 75 | tex_indexer2(int width, int height, int tuple_size, T * data) :
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| 76 | w(width), h(height), n(tuple_size), d(data) {}
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| 77 |
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| 78 | T * operator()(int i, int j)
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| 79 | { return d + n * (w * j + i); }
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| 80 | private:
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| 81 | int w, h, n;
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| 82 | T * d;
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| 83 | };
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| 84 |
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| 85 | template <class T>
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| 86 | struct generic_filter
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| 87 | {
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| 88 | typedef T element_type;
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| 89 |
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| 90 | generic_filter(int tuplesize, GLenum gltype) :
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| 91 | gl_type(gltype), tuple_size(tuplesize) {}
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| 92 |
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| 93 | void average( T * out,
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| 94 | const T * a, const T * b,
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| 95 | const T * c, const T * d)
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| 96 | {
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| 97 | for(int i=0; i < tuple_size; i++)
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| 98 | {
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| 99 | double in = double(a[i]) + double(b[i]) + double(c[i]) + double(d[i]);
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| 100 | in /= 4;
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| 101 | out[i] = T(in);
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| 102 | }
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| 103 | }
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| 104 |
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| 105 | const GLenum gl_type;
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| 106 | const int tuple_size;
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| 107 | };
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| 108 |
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| 109 | // fixme: supports non-square textures!
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| 110 | template <class F>
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| 111 | void build_2D_mipmaps( GLenum target, GLenum internal_format,
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| 112 | GLsizei w, GLsizei h, GLenum format,
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| 113 | F filter, const void * vdata)
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| 114 | {
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| 115 |
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| 116 | typedef typename F::element_type DataType;
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| 117 | const DataType * in_data = (const DataType *)vdata;
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| 118 | DataType * data = new DataType [w * h * filter.tuple_size];
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| 119 |
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| 120 | glTexImage2D(target, 0, internal_format, w, h, 0, format, filter.gl_type, (const DataType *)vdata);
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| 121 |
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| 122 | int level = 1;
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| 123 | if( w >= 2 ) w /= 2;
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| 124 | if( h >= 2 ) h /= 2;
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| 125 | bool done = false;
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| 126 | while(! done)
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| 127 | {
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| 128 | tex_indexer2<const DataType> bg(w*2, h*2, filter.tuple_size, in_data);
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| 129 | tex_indexer2<DataType> sm(w , h , filter.tuple_size, data);
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| 130 | for(int j=0; j < h; j++)
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| 131 | {
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| 132 | int J = j * 2;
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| 133 | for(int i=0; i < w; i++)
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| 134 | {
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| 135 | int I = i*2;
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| 136 | filter.average( sm(i,j),
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| 137 | bg(I , J ), bg(I+1, J ),
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| 138 | bg(I , J+1), bg(I+1, J+1));
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| 139 | }
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| 140 | }
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| 141 |
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| 142 | glTexImage2D(target, level, internal_format, w, h, 0, format, filter.gl_type, data);
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| 143 |
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| 144 | if(w == 1 && h == 1) done = true;
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| 145 |
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| 146 | if( w >= 2 ) w /= 2;
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| 147 | if( h >= 2 ) h /= 2;
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| 148 | level++;
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| 149 | in_data = data;
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| 150 | }
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| 151 |
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| 152 | delete [] data;
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| 153 | }
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| 154 |
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| 155 | }
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| 156 |
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| 157 | #endif
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