goat3d: fa5c52ea9d59 libs/openctm/compressMG1.c

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view libs/openctm/compressMG1.c @ 51:fa5c52ea9d59

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author	John Tsiombikas <nuclear@member.fsf.org>
date	Fri, 17 Jan 2014 18:16:09 +0200
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1 //-----------------------------------------------------------------------------

2 // Product: OpenCTM

3 // File: compressMG1.c

4 // Description: Implementation of the MG1 compression method.

5 //-----------------------------------------------------------------------------

7 //

8 // This software is provided 'as-is', without any express or implied

9 // warranty. In no event will the authors be held liable for any damages

10 // arising from the use of this software.

11 //

12 // Permission is granted to anyone to use this software for any purpose,

13 // including commercial applications, and to alter it and redistribute it

14 // freely, subject to the following restrictions:

15 //

16 // 1. The origin of this software must not be misrepresented; you must not

17 // claim that you wrote the original software. If you use this software

18 // in a product, an acknowledgment in the product documentation would be

19 // appreciated but is not required.

20 //

21 // 2. Altered source versions must be plainly marked as such, and must not

22 // be misrepresented as being the original software.

23 //

24 // 3. This notice may not be removed or altered from any source

25 // distribution.

26 //-----------------------------------------------------------------------------

28 #include <stdlib.h>

29 #include <math.h>

30 #include "openctm.h"

31 #include "internal.h"

33 #ifdef __DEBUG_

34 #include <stdio.h>

35 #endif

38 //-----------------------------------------------------------------------------

39 // _compareTriangle() - Comparator for the triangle sorting.

40 //-----------------------------------------------------------------------------

41 static int _compareTriangle(const void * elem1, const void * elem2)

42 {

43 CTMuint * tri1 = (CTMuint *) elem1;

44 CTMuint * tri2 = (CTMuint *) elem2;

45 if(tri1[0] != tri2[0])

46 return tri1[0] - tri2[0];

47 else

48 return tri1[1] - tri2[1];

49 }

51 //-----------------------------------------------------------------------------

52 // _ctmReArrangeTriangles() - Re-arrange all triangles for optimal

53 // compression.

54 //-----------------------------------------------------------------------------

55 static void _ctmReArrangeTriangles(_CTMcontext * self, CTMuint * aIndices)

56 {

57 CTMuint * tri, tmp, i;

59 // Step 1: Make sure that the first index of each triangle is the smallest

60 // one (rotate triangle nodes if necessary)

61 for(i = 0; i < self->mTriangleCount; ++ i)

62 {

63 tri = &aIndices[i * 3];

64 if((tri[1] < tri[0]) && (tri[1] < tri[2]))

65 {

66 tmp = tri[0];

67 tri[0] = tri[1];

68 tri[1] = tri[2];

69 tri[2] = tmp;

70 }

71 else if((tri[2] < tri[0]) && (tri[2] < tri[1]))

72 {

73 tmp = tri[0];

74 tri[0] = tri[2];

75 tri[2] = tri[1];

76 tri[1] = tmp;

77 }

78 }

80 // Step 2: Sort the triangles based on the first triangle index

81 qsort((void *) aIndices, self->mTriangleCount, sizeof(CTMuint) * 3, _compareTriangle);

82 }

84 //-----------------------------------------------------------------------------

85 // _ctmMakeIndexDeltas() - Calculate various forms of derivatives in order to

86 // reduce data entropy.

87 //-----------------------------------------------------------------------------

88 static void _ctmMakeIndexDeltas(_CTMcontext * self, CTMuint * aIndices)

89 {

90 CTMint i;

91 for(i = self->mTriangleCount - 1; i >= 0; -- i)

92 {

93 // Step 1: Calculate delta from second triangle index to the previous

94 // second triangle index, if the previous triangle shares the same first

95 // index, otherwise calculate the delta to the first triangle index

96 if((i >= 1) && (aIndices[i * 3] == aIndices[(i - 1) * 3]))

97 aIndices[i * 3 + 1] -= aIndices[(i - 1) * 3 + 1];

98 else

99 aIndices[i * 3 + 1] -= aIndices[i * 3];

100

101 // Step 2: Calculate delta from third triangle index to the first triangle

102 // index

103 aIndices[i * 3 + 2] -= aIndices[i * 3];

104

105 // Step 3: Calculate derivative of the first triangle index

106 if(i >= 1)

107 aIndices[i * 3] -= aIndices[(i - 1) * 3];

108 }

109 }

110

111 //-----------------------------------------------------------------------------

112 // _ctmRestoreIndices() - Restore original indices (inverse derivative

113 // operation).

114 //-----------------------------------------------------------------------------

115 static void _ctmRestoreIndices(_CTMcontext * self, CTMuint * aIndices)

116 {

117 CTMuint i;

118

119 for(i = 0; i < self->mTriangleCount; ++ i)

120 {

121 // Step 1: Reverse derivative of the first triangle index

122 if(i >= 1)

123 aIndices[i * 3] += aIndices[(i - 1) * 3];

124

125 // Step 2: Reverse delta from third triangle index to the first triangle

126 // index

127 aIndices[i * 3 + 2] += aIndices[i * 3];

128

129 // Step 3: Reverse delta from second triangle index to the previous

130 // second triangle index, if the previous triangle shares the same first

131 // index, otherwise reverse the delta to the first triangle index

132 if((i >= 1) && (aIndices[i * 3] == aIndices[(i - 1) * 3]))

133 aIndices[i * 3 + 1] += aIndices[(i - 1) * 3 + 1];

134 else

135 aIndices[i * 3 + 1] += aIndices[i * 3];

136 }

137 }

138

139 //-----------------------------------------------------------------------------

140 // _ctmCompressMesh_MG1() - Compress the mesh that is stored in the CTM

141 // context, and write it the the output stream in the CTM context.

142 //-----------------------------------------------------------------------------

143 int _ctmCompressMesh_MG1(_CTMcontext * self)

144 {

145 CTMuint * indices;

146 _CTMfloatmap * map;

147 CTMuint i;

148

149 #ifdef __DEBUG_

150 printf("COMPRESSION METHOD: MG1\n");

151 #endif

152

153 // Perpare (sort) indices

154 indices = (CTMuint *) malloc(sizeof(CTMuint) * self->mTriangleCount * 3);

155 if(!indices)

156 {

157 self->mError = CTM_OUT_OF_MEMORY;

158 return CTM_FALSE;

159 }

160 for(i = 0; i < self->mTriangleCount * 3; ++ i)

161 indices[i] = self->mIndices[i];

162 _ctmReArrangeTriangles(self, indices);

163

164 // Calculate index deltas (entropy-reduction)

165 _ctmMakeIndexDeltas(self, indices);

166

167 // Write triangle indices

168 #ifdef __DEBUG_

169 printf("Inidices: ");

170 #endif

171 _ctmStreamWrite(self, (void *) "INDX", 4);

172 if(!_ctmStreamWritePackedInts(self, (CTMint *) indices, self->mTriangleCount, 3, CTM_FALSE))

173 {

174 free((void *) indices);

175 return CTM_FALSE;

176 }

177

178 // Free temporary resources

179 free((void *) indices);

180

181 // Write vertices

182 #ifdef __DEBUG_

183 printf("Vertices: ");

184 #endif

185 _ctmStreamWrite(self, (void *) "VERT", 4);

186 if(!_ctmStreamWritePackedFloats(self, self->mVertices, self->mVertexCount * 3, 1))

187 {

188 free((void *) indices);

189 return CTM_FALSE;

190 }

191

192 // Write normals

193 if(self->mNormals)

194 {

195 #ifdef __DEBUG_

196 printf("Normals: ");

197 #endif

198 _ctmStreamWrite(self, (void *) "NORM", 4);

199 if(!_ctmStreamWritePackedFloats(self, self->mNormals, self->mVertexCount, 3))

200 return CTM_FALSE;

201 }

202

203 // Write UV maps

204 map = self->mUVMaps;

205 while(map)

206 {

207 #ifdef __DEBUG_

208 printf("UV coordinates (%s): ", map->mName ? map->mName : "no name");

209 #endif

210 _ctmStreamWrite(self, (void *) "TEXC", 4);

211 _ctmStreamWriteSTRING(self, map->mName);

212 _ctmStreamWriteSTRING(self, map->mFileName);

213 if(!_ctmStreamWritePackedFloats(self, map->mValues, self->mVertexCount, 2))

214 return CTM_FALSE;

215 map = map->mNext;

216 }

217

218 // Write attribute maps

219 map = self->mAttribMaps;

220 while(map)

221 {

222 #ifdef __DEBUG_

223 printf("Vertex attributes (%s): ", map->mName ? map->mName : "no name");

224 #endif

225 _ctmStreamWrite(self, (void *) "ATTR", 4);

226 _ctmStreamWriteSTRING(self, map->mName);

227 if(!_ctmStreamWritePackedFloats(self, map->mValues, self->mVertexCount, 4))

228 return CTM_FALSE;

229 map = map->mNext;

230 }

231

232 return CTM_TRUE;

233 }

234

235 //-----------------------------------------------------------------------------

236 // _ctmUncompressMesh_MG1() - Uncmpress the mesh from the input stream in the

237 // CTM context, and store the resulting mesh in the CTM context.

238 //-----------------------------------------------------------------------------

239 int _ctmUncompressMesh_MG1(_CTMcontext * self)

240 {

241 CTMuint * indices;

242 _CTMfloatmap * map;

243 CTMuint i;

244

245 // Allocate memory for the indices

246 indices = (CTMuint *) malloc(sizeof(CTMuint) * self->mTriangleCount * 3);

247 if(!indices)

248 {

249 self->mError = CTM_OUT_OF_MEMORY;

250 return CTM_FALSE;

251 }

252

253 // Read triangle indices

254 if(_ctmStreamReadUINT(self) != FOURCC("INDX"))

255 {

256 self->mError = CTM_BAD_FORMAT;

257 free(indices);

258 return CTM_FALSE;

259 }

260 if(!_ctmStreamReadPackedInts(self, (CTMint *) indices, self->mTriangleCount, 3, CTM_FALSE))

261 return CTM_FALSE;

262

263 // Restore indices

264 _ctmRestoreIndices(self, indices);

265 for(i = 0; i < self->mTriangleCount * 3; ++ i)

266 self->mIndices[i] = indices[i];

267

268 // Free temporary resources

269 free(indices);

270

271 // Read vertices

272 if(_ctmStreamReadUINT(self) != FOURCC("VERT"))

273 {

274 self->mError = CTM_BAD_FORMAT;

275 return CTM_FALSE;

276 }

277 if(!_ctmStreamReadPackedFloats(self, self->mVertices, self->mVertexCount * 3, 1))

278 return CTM_FALSE;

279

280 // Read normals

281 if(self->mNormals)

282 {

283 if(_ctmStreamReadUINT(self) != FOURCC("NORM"))

284 {

285 self->mError = CTM_BAD_FORMAT;

286 return CTM_FALSE;

287 }

288 if(!_ctmStreamReadPackedFloats(self, self->mNormals, self->mVertexCount, 3))

289 return CTM_FALSE;

290 }

291

292 // Read UV maps

293 map = self->mUVMaps;

294 while(map)

295 {

296 if(_ctmStreamReadUINT(self) != FOURCC("TEXC"))

297 {

298 self->mError = CTM_BAD_FORMAT;

299 return 0;

300 }

301 _ctmStreamReadSTRING(self, &map->mName);

302 _ctmStreamReadSTRING(self, &map->mFileName);

303 if(!_ctmStreamReadPackedFloats(self, map->mValues, self->mVertexCount, 2))

304 return CTM_FALSE;

305 map = map->mNext;

306 }

307

308 // Read vertex attribute maps

309 map = self->mAttribMaps;

310 while(map)

311 {

312 if(_ctmStreamReadUINT(self) != FOURCC("ATTR"))

313 {

314 self->mError = CTM_BAD_FORMAT;

315 return 0;

316 }

317 _ctmStreamReadSTRING(self, &map->mName);

318 if(!_ctmStreamReadPackedFloats(self, map->mValues, self->mVertexCount, 4))

319 return CTM_FALSE;

320 map = map->mNext;

321 }

322

323 return CTM_TRUE;

324 }