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annotate examples/volume/src/sdr.c @ 3:52664d3451ad

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added volume rendering example
author John Tsiombikas <nuclear@member.fsf.org>
date Tue, 25 Oct 2011 13:30:03 +0300
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nuclear@3 1 #ifndef NO_SHADERS
nuclear@3 2
nuclear@3 3 #include <stdio.h>
nuclear@3 4 #include <stdlib.h>
nuclear@3 5 #include <string.h>
nuclear@3 6 #include <errno.h>
nuclear@3 7 #include <assert.h>
nuclear@3 8 #include <GL/glew.h>
nuclear@3 9
nuclear@3 10 #if defined(unix) || defined(__unix__)
nuclear@3 11 #include <unistd.h>
nuclear@3 12 #include <sys/stat.h>
nuclear@3 13 #endif /* unix */
nuclear@3 14
nuclear@3 15 #include "sdr.h"
nuclear@3 16
nuclear@3 17 unsigned int create_vertex_shader(const char *src)
nuclear@3 18 {
nuclear@3 19 return create_shader(src, GL_VERTEX_SHADER);
nuclear@3 20 }
nuclear@3 21
nuclear@3 22 unsigned int create_pixel_shader(const char *src)
nuclear@3 23 {
nuclear@3 24 return create_shader(src, GL_FRAGMENT_SHADER);
nuclear@3 25 }
nuclear@3 26
nuclear@3 27 unsigned int create_shader(const char *src, unsigned int sdr_type)
nuclear@3 28 {
nuclear@3 29 unsigned int sdr;
nuclear@3 30 int success, info_len;
nuclear@3 31 char *info_str = 0;
nuclear@3 32 GLenum err;
nuclear@3 33
nuclear@3 34 sdr = glCreateShader(sdr_type);
nuclear@3 35 assert(glGetError() == GL_NO_ERROR);
nuclear@3 36 glShaderSource(sdr, 1, &src, 0);
nuclear@3 37 err = glGetError();
nuclear@3 38 assert(err == GL_NO_ERROR);
nuclear@3 39 glCompileShader(sdr);
nuclear@3 40 assert(glGetError() == GL_NO_ERROR);
nuclear@3 41
nuclear@3 42 glGetShaderiv(sdr, GL_COMPILE_STATUS, &success);
nuclear@3 43 assert(glGetError() == GL_NO_ERROR);
nuclear@3 44 glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &info_len);
nuclear@3 45 assert(glGetError() == GL_NO_ERROR);
nuclear@3 46
nuclear@3 47 if(info_len) {
nuclear@3 48 if((info_str = malloc(info_len + 1))) {
nuclear@3 49 glGetShaderInfoLog(sdr, info_len, 0, info_str);
nuclear@3 50 assert(glGetError() == GL_NO_ERROR);
nuclear@3 51 }
nuclear@3 52 }
nuclear@3 53
nuclear@3 54 if(success) {
nuclear@3 55 fprintf(stderr, info_str ? "done: %s\n" : "done\n", info_str);
nuclear@3 56 } else {
nuclear@3 57 fprintf(stderr, info_str ? "failed: %s\n" : "failed\n", info_str);
nuclear@3 58 glDeleteShader(sdr);
nuclear@3 59 sdr = 0;
nuclear@3 60 }
nuclear@3 61
nuclear@3 62 free(info_str);
nuclear@3 63 return sdr;
nuclear@3 64 }
nuclear@3 65
nuclear@3 66 void free_shader(unsigned int sdr)
nuclear@3 67 {
nuclear@3 68 glDeleteShader(sdr);
nuclear@3 69 }
nuclear@3 70
nuclear@3 71 unsigned int load_vertex_shader(const char *fname)
nuclear@3 72 {
nuclear@3 73 return load_shader(fname, GL_VERTEX_SHADER);
nuclear@3 74 }
nuclear@3 75
nuclear@3 76 unsigned int load_pixel_shader(const char *fname)
nuclear@3 77 {
nuclear@3 78 return load_shader(fname, GL_FRAGMENT_SHADER);
nuclear@3 79 }
nuclear@3 80
nuclear@3 81 unsigned int load_shader(const char *fname, unsigned int sdr_type)
nuclear@3 82 {
nuclear@3 83 #if defined(unix) || defined(__unix__)
nuclear@3 84 struct stat st;
nuclear@3 85 #endif
nuclear@3 86 unsigned int sdr;
nuclear@3 87 size_t filesize;
nuclear@3 88 FILE *fp;
nuclear@3 89 char *src;
nuclear@3 90
nuclear@3 91 if(!(fp = fopen(fname, "r"))) {
nuclear@3 92 fprintf(stderr, "failed to open shader %s: %s\n", fname, strerror(errno));
nuclear@3 93 return 0;
nuclear@3 94 }
nuclear@3 95
nuclear@3 96 #if defined(unix) || defined(__unix__)
nuclear@3 97 fstat(fileno(fp), &st);
nuclear@3 98 filesize = st.st_size;
nuclear@3 99 #else
nuclear@3 100 fseek(fp, 0, SEEK_END);
nuclear@3 101 filesize = ftell(fp);
nuclear@3 102 fseek(fp, 0, SEEK_SET);
nuclear@3 103 #endif /* unix */
nuclear@3 104
nuclear@3 105 if(!(src = malloc(filesize + 1))) {
nuclear@3 106 fclose(fp);
nuclear@3 107 return 0;
nuclear@3 108 }
nuclear@3 109 fread(src, 1, filesize, fp);
nuclear@3 110 src[filesize] = 0;
nuclear@3 111 fclose(fp);
nuclear@3 112
nuclear@3 113 fprintf(stderr, "compiling %s shader: %s... ", (sdr_type == GL_VERTEX_SHADER ? "vertex" : "pixel"), fname);
nuclear@3 114 sdr = create_shader(src, sdr_type);
nuclear@3 115
nuclear@3 116 free(src);
nuclear@3 117 return sdr;
nuclear@3 118 }
nuclear@3 119
nuclear@3 120
nuclear@3 121 unsigned int get_vertex_shader(const char *fname)
nuclear@3 122 {
nuclear@3 123 return get_shader(fname, GL_VERTEX_SHADER);
nuclear@3 124 }
nuclear@3 125
nuclear@3 126 unsigned int get_pixel_shader(const char *fname)
nuclear@3 127 {
nuclear@3 128 return get_shader(fname, GL_FRAGMENT_SHADER);
nuclear@3 129 }
nuclear@3 130
nuclear@3 131 unsigned int get_shader(const char *fname, unsigned int sdr_type)
nuclear@3 132 {
nuclear@3 133 unsigned int sdr;
nuclear@3 134
nuclear@3 135 if(!(sdr = load_shader(fname, sdr_type))) {
nuclear@3 136 return 0;
nuclear@3 137 }
nuclear@3 138 return sdr;
nuclear@3 139 }
nuclear@3 140
nuclear@3 141
nuclear@3 142 /* ---- gpu programs ---- */
nuclear@3 143
nuclear@3 144 unsigned int create_program(void)
nuclear@3 145 {
nuclear@3 146 unsigned int prog = glCreateProgram();
nuclear@3 147 assert(glGetError() == GL_NO_ERROR);
nuclear@3 148 return prog;
nuclear@3 149 }
nuclear@3 150
nuclear@3 151 unsigned int create_program_link(unsigned int vs, unsigned int ps)
nuclear@3 152 {
nuclear@3 153 unsigned int prog;
nuclear@3 154
nuclear@3 155 if(!(prog = create_program())) {
nuclear@3 156 return 0;
nuclear@3 157 }
nuclear@3 158
nuclear@3 159 if(vs) {
nuclear@3 160 attach_shader(prog, vs);
nuclear@3 161 assert(glGetError() == GL_NO_ERROR);
nuclear@3 162 }
nuclear@3 163 if(ps) {
nuclear@3 164 attach_shader(prog, ps);
nuclear@3 165 assert(glGetError() == GL_NO_ERROR);
nuclear@3 166 }
nuclear@3 167
nuclear@3 168 if(link_program(prog) == -1) {
nuclear@3 169 free_program(prog);
nuclear@3 170 return 0;
nuclear@3 171 }
nuclear@3 172 return prog;
nuclear@3 173 }
nuclear@3 174
nuclear@3 175 unsigned int create_program_load(const char *vfile, const char *pfile)
nuclear@3 176 {
nuclear@3 177 unsigned int vs = 0, ps = 0;
nuclear@3 178
nuclear@3 179 if(vfile && !(vs = get_vertex_shader(vfile))) {
nuclear@3 180 return 0;
nuclear@3 181 }
nuclear@3 182 if(pfile && !(ps = get_pixel_shader(pfile))) {
nuclear@3 183 return 0;
nuclear@3 184 }
nuclear@3 185 return create_program_link(vs, ps);
nuclear@3 186 }
nuclear@3 187
nuclear@3 188 void free_program(unsigned int sdr)
nuclear@3 189 {
nuclear@3 190 glDeleteProgram(sdr);
nuclear@3 191 }
nuclear@3 192
nuclear@3 193 void attach_shader(unsigned int prog, unsigned int sdr)
nuclear@3 194 {
nuclear@3 195 glAttachShader(prog, sdr);
nuclear@3 196 assert(glGetError() == GL_NO_ERROR);
nuclear@3 197 }
nuclear@3 198
nuclear@3 199 int link_program(unsigned int prog)
nuclear@3 200 {
nuclear@3 201 int linked, info_len, retval = 0;
nuclear@3 202 char *info_str = 0;
nuclear@3 203
nuclear@3 204 glLinkProgram(prog);
nuclear@3 205 assert(glGetError() == GL_NO_ERROR);
nuclear@3 206 glGetProgramiv(prog, GL_LINK_STATUS, &linked);
nuclear@3 207 assert(glGetError() == GL_NO_ERROR);
nuclear@3 208 glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &info_len);
nuclear@3 209 assert(glGetError() == GL_NO_ERROR);
nuclear@3 210
nuclear@3 211 if(info_len) {
nuclear@3 212 if((info_str = malloc(info_len + 1))) {
nuclear@3 213 glGetProgramInfoLog(prog, info_len, 0, info_str);
nuclear@3 214 assert(glGetError() == GL_NO_ERROR);
nuclear@3 215 }
nuclear@3 216 }
nuclear@3 217
nuclear@3 218 if(linked) {
nuclear@3 219 fprintf(stderr, info_str ? "linking done: %s\n" : "linking done\n", info_str);
nuclear@3 220 } else {
nuclear@3 221 fprintf(stderr, info_str ? "linking failed: %s\n" : "linking failed\n", info_str);
nuclear@3 222 retval = -1;
nuclear@3 223 }
nuclear@3 224
nuclear@3 225 free(info_str);
nuclear@3 226 return retval;
nuclear@3 227 }
nuclear@3 228
nuclear@3 229 int bind_program(unsigned int prog)
nuclear@3 230 {
nuclear@3 231 GLenum err;
nuclear@3 232
nuclear@3 233 glUseProgram(prog);
nuclear@3 234 if(prog && (err = glGetError()) != GL_NO_ERROR) {
nuclear@3 235 /* maybe the program is not linked, try linking first */
nuclear@3 236 if(err == GL_INVALID_OPERATION) {
nuclear@3 237 if(link_program(prog) == -1) {
nuclear@3 238 return -1;
nuclear@3 239 }
nuclear@3 240 glUseProgram(prog);
nuclear@3 241 return glGetError() == GL_NO_ERROR ? 0 : -1;
nuclear@3 242 }
nuclear@3 243 return -1;
nuclear@3 244 }
nuclear@3 245 return 0;
nuclear@3 246 }
nuclear@3 247
nuclear@3 248 /* ugly but I'm not going to write the same bloody code over and over */
nuclear@3 249 #define BEGIN_UNIFORM_CODE \
nuclear@3 250 int loc, curr_prog; \
nuclear@3 251 glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog); \
nuclear@3 252 if(curr_prog != prog && bind_program(prog) == -1) { \
nuclear@3 253 return -1; \
nuclear@3 254 } \
nuclear@3 255 if((loc = glGetUniformLocation(prog, name)) != -1)
nuclear@3 256
nuclear@3 257 #define END_UNIFORM_CODE \
nuclear@3 258 if(curr_prog != prog) { \
nuclear@3 259 bind_program(curr_prog); \
nuclear@3 260 } \
nuclear@3 261 return loc == -1 ? -1 : 0
nuclear@3 262
nuclear@3 263 int set_uniform_int(unsigned int prog, const char *name, int val)
nuclear@3 264 {
nuclear@3 265 BEGIN_UNIFORM_CODE {
nuclear@3 266 glUniform1i(loc, val);
nuclear@3 267 }
nuclear@3 268 END_UNIFORM_CODE;
nuclear@3 269 }
nuclear@3 270
nuclear@3 271 int set_uniform_float(unsigned int prog, const char *name, float val)
nuclear@3 272 {
nuclear@3 273 BEGIN_UNIFORM_CODE {
nuclear@3 274 glUniform1f(loc, val);
nuclear@3 275 }
nuclear@3 276 END_UNIFORM_CODE;
nuclear@3 277 }
nuclear@3 278
nuclear@3 279 int set_uniform_float3(unsigned int prog, const char *name, float x, float y, float z)
nuclear@3 280 {
nuclear@3 281 BEGIN_UNIFORM_CODE {
nuclear@3 282 glUniform3f(loc, x, y, z);
nuclear@3 283 }
nuclear@3 284 END_UNIFORM_CODE;
nuclear@3 285 }
nuclear@3 286
nuclear@3 287 int set_uniform_float4(unsigned int prog, const char *name, float x, float y, float z, float w)
nuclear@3 288 {
nuclear@3 289 BEGIN_UNIFORM_CODE {
nuclear@3 290 glUniform4f(loc, x, y, z, w);
nuclear@3 291 }
nuclear@3 292 END_UNIFORM_CODE;
nuclear@3 293 }
nuclear@3 294
nuclear@3 295 int set_uniform_matrix4(unsigned int prog, const char *name, float *mat)
nuclear@3 296 {
nuclear@3 297 BEGIN_UNIFORM_CODE {
nuclear@3 298 glUniformMatrix4fv(loc, 1, GL_FALSE, mat);
nuclear@3 299 }
nuclear@3 300 END_UNIFORM_CODE;
nuclear@3 301 }
nuclear@3 302
nuclear@3 303 int set_uniform_matrix4_transposed(unsigned int prog, const char *name, float *mat)
nuclear@3 304 {
nuclear@3 305 BEGIN_UNIFORM_CODE {
nuclear@3 306 glUniformMatrix4fv(loc, 1, GL_TRUE, mat);
nuclear@3 307 }
nuclear@3 308 END_UNIFORM_CODE;
nuclear@3 309 }
nuclear@3 310
nuclear@3 311 int get_attrib_loc(unsigned int prog, const char *name)
nuclear@3 312 {
nuclear@3 313 int loc, curr_prog;
nuclear@3 314
nuclear@3 315 glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
nuclear@3 316 if(curr_prog != prog && bind_program(prog) == -1) {
nuclear@3 317 return -1;
nuclear@3 318 }
nuclear@3 319
nuclear@3 320 loc = glGetAttribLocation(prog, (char*)name);
nuclear@3 321
nuclear@3 322 if(curr_prog != prog) {
nuclear@3 323 bind_program(curr_prog);
nuclear@3 324 }
nuclear@3 325 return loc;
nuclear@3 326 }
nuclear@3 327
nuclear@3 328 void set_attrib_float3(int attr_loc, float x, float y, float z)
nuclear@3 329 {
nuclear@3 330 glVertexAttrib3f(attr_loc, x, y, z);
nuclear@3 331 }
nuclear@3 332
nuclear@3 333 #endif /* !NO_SHADERS */