goat3dgfx: 1873dfd13f2d src/meshgen.cc

goat3dgfx

view src/meshgen.cc @ 0:1873dfd13f2d

initial commit

author	John Tsiombikas <nuclear@member.fsf.org>
date	Thu, 14 Nov 2013 05:27:09 +0200
parents
children	7d6b667821cf

line source

1 #include "meshgen.h"

2 #include "mesh.h"

3 #include "logger.h"

5 // -------- sphere --------

7 #define SURAD(u) ((u) * 2.0 * M_PI)

8 #define SVRAD(v) ((v) * M_PI)

10 static Vector3 sphvec(float theta, float phi)

11 {

12 return Vector3(sin(theta) * sin(phi),

13 cos(phi),

14 cos(theta) * sin(phi));

15 }

17 void gen_sphere(Mesh *mesh, float rad, int usub, int vsub, float urange, float vrange)

18 {

19 if(usub < 4) usub = 4;

20 if(vsub < 2) vsub = 2;

22 int uverts = usub + 1;

23 int vverts = vsub + 1;

25 int num_verts = uverts * vverts;

26 int num_quads = usub * vsub;

27 int num_tri = num_quads * 2;

29 mesh->clear();

30 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

31 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

32 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

33 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

34 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

36 float du = urange / (float)(uverts - 1);

37 float dv = vrange / (float)(vverts - 1);

39 float u = 0.0;

40 for(int i=0; i<uverts; i++) {

41 float theta = SURAD(u * urange);

43 float v = 0.0;

44 for(int j=0; j<vverts; j++) {

45 float phi = SVRAD(v * vrange);

47 Vector3 pos = sphvec(theta, phi);

49 *varr++ = pos * rad;

50 *narr++ = pos;

51 *tarr++ = (sphvec(theta + 0.1, M_PI / 2.0) - sphvec(theta - 0.1, M_PI / 2.0)).normalized();

52 *uvarr++ = Vector2(u * urange, v * vrange);

54 if(i < usub && j < vsub) {

55 int idx = i * vverts + j;

56 *idxarr++ = idx;

57 *idxarr++ = idx + 1;

58 *idxarr++ = idx + vverts + 1;

60 *idxarr++ = idx;

61 *idxarr++ = idx + vverts + 1;

62 *idxarr++ = idx + vverts;

63 }

65 v += dv;

66 }

67 u += du;

68 }

69 }

72 // -------- cylinder --------

74 static Vector3 cylvec(float theta, float height)

75 {

76 return Vector3(sin(theta), height, cos(theta));

77 }

79 void gen_cylinder(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub, float urange, float vrange)

80 {

81 if(usub < 4) usub = 4;

82 if(vsub < 1) vsub = 1;

84 int uverts = usub + 1;

85 int vverts = vsub + 1;

87 int num_body_verts = uverts * vverts;

88 int num_body_quads = usub * vsub;

89 int num_body_tri = num_body_quads * 2;

91 int capvverts = capsub ? capsub + 1 : 0;

92 int num_cap_verts = uverts * capvverts;

93 int num_cap_quads = usub * capsub;

94 int num_cap_tri = num_cap_quads * 2;

96 int num_verts = num_body_verts + num_cap_verts * 2;

97 int num_tri = num_body_tri + num_cap_tri * 2;

99 mesh->clear();

100 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

101 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

102 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

103 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

104 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

105

106 float du = urange / (float)(uverts - 1);

107 float dv = vrange / (float)(vverts - 1);

108

109 float u = 0.0;

110 for(int i=0; i<uverts; i++) {

111 float theta = SURAD(u);

112

113 float v = 0.0;

114 for(int j=0; j<vverts; j++) {

115 float y = (v - 0.5) * height;

116 Vector3 pos = cylvec(theta, y);

117

118 *varr++ = Vector3(pos.x * rad, pos.y, pos.z * rad);

119 *narr++ = Vector3(pos.x, 0.0, pos.z);

120 *tarr++ = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

121 *uvarr++ = Vector2(u * urange, v * vrange);

122

123 if(i < usub && j < vsub) {

124 int idx = i * vverts + j;

125

126 *idxarr++ = idx;

127 *idxarr++ = idx + vverts + 1;

128 *idxarr++ = idx + 1;

129

130 *idxarr++ = idx;

131 *idxarr++ = idx + vverts;

132 *idxarr++ = idx + vverts + 1;

133 }

134

135 v += dv;

136 }

137 u += du;

138 }

139

140

141 // now the cap!

142 if(!capsub) {

143 return;

144 }

145

146 dv = 1.0 / (float)(capvverts - 1);

147

148 u = 0.0;

149 for(int i=0; i<uverts; i++) {

150 float theta = SURAD(u);

151

152 float v = 0.0;

153 for(int j=0; j<capvverts; j++) {

154 float r = v * rad;

155

156 Vector3 pos = cylvec(theta, height / 2.0) * r;

157 pos.y = height / 2.0;

158 Vector3 tang = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

159

160 *varr++ = pos;

161 *narr++ = Vector3(0, 1, 0);

162 *tarr++ = tang;

163 *uvarr++ = Vector2(u * urange, v);

164

165 pos.y = -height / 2.0;

166 *varr++ = pos;

167 *narr++ = Vector3(0, -1, 0);

168 *tarr++ = -tang;

169 *uvarr++ = Vector2(u * urange, v);

170

171 if(i < usub && j < capsub) {

172 unsigned int idx = num_body_verts + (i * capvverts + j) * 2;

173

174 unsigned int vidx[4] = {

175 idx,

176 idx + capvverts * 2,

177 idx + (capvverts + 1) * 2,

178 idx + 2

179 };

180

181 *idxarr++ = vidx[0];

182 *idxarr++ = vidx[2];

183 *idxarr++ = vidx[1];

184 *idxarr++ = vidx[0];

185 *idxarr++ = vidx[3];

186 *idxarr++ = vidx[2];

187

188 *idxarr++ = vidx[0] + 1;

189 *idxarr++ = vidx[1] + 1;

190 *idxarr++ = vidx[2] + 1;

191 *idxarr++ = vidx[0] + 1;

192 *idxarr++ = vidx[2] + 1;

193 *idxarr++ = vidx[3] + 1;

194 }

195

196 v += dv;

197 }

198 u += du;

199 }

200 }

201

202 // -------- cone --------

203

204 static Vector3 conevec(float theta, float y, float height)

205 {

206 float scale = 1.0 - y / height;

207 return Vector3(sin(theta) * scale, y, cos(theta) * scale);

208 }

209

210 void gen_cone(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub, float urange, float vrange)

211 {

212 if(usub < 4) usub = 4;

213 if(vsub < 1) vsub = 1;

214

215 int uverts = usub + 1;

216 int vverts = vsub + 1;

217

218 int num_body_verts = uverts * vverts;

219 int num_body_quads = usub * vsub;

220 int num_body_tri = num_body_quads * 2;

221

222 int capvverts = capsub ? capsub + 1 : 0;

223 int num_cap_verts = uverts * capvverts;

224 int num_cap_quads = usub * capsub;

225 int num_cap_tri = num_cap_quads * 2;

226

227 int num_verts = num_body_verts + num_cap_verts;

228 int num_tri = num_body_tri + num_cap_tri;

229

230 mesh->clear();

231 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

232 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

233 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

234 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

235 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

236

237 float du = urange / (float)(uverts - 1);

238 float dv = vrange / (float)(vverts - 1);

239

240 float u = 0.0;

241 for(int i=0; i<uverts; i++) {

242 float theta = SURAD(u);

243

244 float v = 0.0;

245 for(int j=0; j<vverts; j++) {

246 float y = v * height;

247 Vector3 pos = conevec(theta, y, height);

248

249 Vector3 tang = (conevec(theta + 0.1, 0.0, height) - conevec(theta - 0.1, 0.0, height)).normalized();

250 Vector3 bitang = (conevec(theta, y + 0.1, height) - pos).normalized();

251

252 *varr++ = Vector3(pos.x * rad, pos.y, pos.z * rad);

253 *narr++ = cross_product(tang, bitang);

254 *tarr++ = tang;

255 *uvarr++ = Vector2(u * urange, v * vrange);

256

257 if(i < usub && j < vsub) {

258 int idx = i * vverts + j;

259

260 *idxarr++ = idx;

261 *idxarr++ = idx + vverts + 1;

262 *idxarr++ = idx + 1;

263

264 *idxarr++ = idx;

265 *idxarr++ = idx + vverts;

266 *idxarr++ = idx + vverts + 1;

267 }

268

269 v += dv;

270 }

271 u += du;

272 }

273

274

275 // now the bottom cap!

276 if(!capsub) {

277 return;

278 }

279

280 dv = 1.0 / (float)(capvverts - 1);

281

282 u = 0.0;

283 for(int i=0; i<uverts; i++) {

284 float theta = SURAD(u);

285

286 float v = 0.0;

287 for(int j=0; j<capvverts; j++) {

288 float r = v * rad;

289

290 Vector3 pos = conevec(theta, 0.0, height) * r;

291 Vector3 tang = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

292

293 *varr++ = pos;

294 *narr++ = Vector3(0, -1, 0);

295 *tarr++ = tang;

296 *uvarr++ = Vector2(u * urange, v);

297

298 if(i < usub && j < capsub) {

299 unsigned int idx = num_body_verts + i * capvverts + j;

300

301 unsigned int vidx[4] = {

302 idx,

303 idx + capvverts,

304 idx + (capvverts + 1),

305 idx + 1

306 };

307

308 *idxarr++ = vidx[0];

309 *idxarr++ = vidx[1];

310 *idxarr++ = vidx[2];

311 *idxarr++ = vidx[0];

312 *idxarr++ = vidx[2];

313 *idxarr++ = vidx[3];

314 }

315

316 v += dv;

317 }

318 u += du;

319 }

320 }

321

322

323 // -------- plane --------

324

325 void gen_plane(Mesh *mesh, float width, float height, int usub, int vsub)

326 {

327 if(usub < 1) usub = 1;

328 if(vsub < 1) vsub = 1;

329

330 mesh->clear();

331

332 int uverts = usub + 1;

333 int vverts = vsub + 1;

334 int num_verts = uverts * vverts;

335

336 int num_quads = usub * vsub;

337 int num_tri = num_quads * 2;

338

339 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

340 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

341 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

342 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

343 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

344

345 float du = 1.0 / (float)usub;

346 float dv = 1.0 / (float)vsub;

347

348 float u = 0.0;

349 for(int i=0; i<uverts; i++) {

350 float v = 0.0;

351 for(int j=0; j<vverts; j++) {

352 *varr++ = Vector3((u - 0.5) * width, (v - 0.5) * height, 0.0);

353 *narr++ = Vector3(0, 0, 1);

354 *tarr++ = Vector3(1, 0, 0);

355 *uvarr++ = Vector2(u, v);

356

357 if(i < usub && j < vsub) {

358 int idx = i * vverts + j;

359

360 *idxarr++ = idx;

361 *idxarr++ = idx + vverts + 1;

362 *idxarr++ = idx + 1;

363

364 *idxarr++ = idx;

365 *idxarr++ = idx + vverts;

366 *idxarr++ = idx + vverts + 1;

367 }

368

369 v += dv;

370 }

371 u += du;

372 }

373 }