progs/glsl/bump.c

   1 /**
   2  * Procedural Bump Mapping demo.  Uses the example shaders from
   3  * chapter 11 of the OpenGL Shading Language "orange" book.
   4  * 16 Jan 2007
   5  */
   6
   7 #include <assert.h>
   8 #include <string.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <math.h>
  12 #include <GL/glut.h>
  13 #include <GL/glu.h>
  14 #include <GL/glext.h>
  15 #include "extfuncs.h"
  16
  17
  18 static char *FragProgFile = "CH11-bumpmap.frag.txt";
  19 static char *VertProgFile = "CH11-bumpmap.vert.txt";
  20
  21 /* program/shader objects */
  22 static GLuint fragShader;
  23 static GLuint vertShader;
  24 static GLuint program;
  25
  26
  27 struct uniform_info {
  28    const char *name;
  29    GLuint size;
  30    GLint location;
  31    GLfloat value[4];
  32 };
  33
  34 static struct uniform_info Uniforms[] = {
  35    { "LightPosition",       3, -1, { 0.57737, 0.57735, 0.57735, 0.0 } },
  36    { "SurfaceColor",        3, -1, { 0.8, 0.8, 0.2, 0 } },
  37    { "BumpDensity",         1, -1, { 10.0, 0, 0, 0 } },
  38    { "BumpSize",            1, -1, { 0.125, 0, 0, 0 } },
  39    { "SpecularFactor",      1, -1, { 0.5, 0, 0, 0 } },
  40    { NULL, 0, 0, { 0, 0, 0, 0 } }
  41 };
  42
  43 static GLint win = 0;
  44
  45 static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
  46
  47 static GLuint tangentAttrib;
  48
  49 static GLboolean Anim = GL_FALSE;
  50
  51
  52 static void
  53 CheckError(int line)
  54 {
  55    GLenum err = glGetError();
  56    if (err) {
  57       printf("GL Error %s (0x%x) at line %d\n",
  58              gluErrorString(err), (int) err, line);
  59    }
  60 }
  61
  62 /*
  63  * Draw a square, specifying normal and tangent vectors.
  64  */
  65 static void
  66 Square(GLfloat size)
  67 {
  68    glNormal3f(0, 0, 1);
  69    glVertexAttrib3f_func(tangentAttrib, 1, 0, 0);
  70    glBegin(GL_POLYGON);
  71    glTexCoord2f(0, 0);  glVertex2f(-size, -size);
  72    glTexCoord2f(1, 0);  glVertex2f( size, -size);
  73    glTexCoord2f(1, 1);  glVertex2f( size,  size);
  74    glTexCoord2f(0, 1);  glVertex2f(-size,  size);
  75    glEnd();
  76 }
  77
  78
  79 static void
  80 Cube(GLfloat size)
  81 {
  82    /* +X */
  83    glPushMatrix();
  84    glRotatef(90, 0, 1, 0);
  85    glTranslatef(0, 0, size);
  86    Square(size);
  87    glPopMatrix();
  88
  89    /* -X */
  90    glPushMatrix();
  91    glRotatef(-90, 0, 1, 0);
  92    glTranslatef(0, 0, size);
  93    Square(size);
  94    glPopMatrix();
  95
  96    /* +Y */
  97    glPushMatrix();
  98    glRotatef(90, 1, 0, 0);
  99    glTranslatef(0, 0, size);
 100    Square(size);
 101    glPopMatrix();
 102
 103    /* -Y */
 104    glPushMatrix();
 105    glRotatef(-90, 1, 0, 0);
 106    glTranslatef(0, 0, size);
 107    Square(size);
 108    glPopMatrix();
 109
 110
 111    /* +Z */
 112    glPushMatrix();
 113    glTranslatef(0, 0, size);
 114    Square(size);
 115    glPopMatrix();
 116
 117    /* -Z */
 118    glPushMatrix();
 119    glRotatef(180, 0, 1, 0);
 120    glTranslatef(0, 0, size);
 121    Square(size);
 122    glPopMatrix();
 123
 124 }
 125
 126
 127 static void
 128 Idle(void)
 129 {
 130    GLint t = glutGet(GLUT_ELAPSED_TIME);
 131    yRot  = t * 0.05;
 132    glutPostRedisplay();
 133 }
 134
 135
 136 static void
 137 Redisplay(void)
 138 {
 139    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 140
 141    glPushMatrix();
 142    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
 143    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
 144    glRotatef(zRot, 0.0f, 0.0f, 1.0f);
 145
 146    Cube(1.5);
 147
 148    glPopMatrix();
 149
 150    glFinish();
 151    glFlush();
 152
 153    CheckError(__LINE__);
 154
 155    glutSwapBuffers();
 156 }
 157
 158
 159 static void
 160 Reshape(int width, int height)
 161 {
 162    glViewport(0, 0, width, height);
 163    glMatrixMode(GL_PROJECTION);
 164    glLoadIdentity();
 165    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
 166    glMatrixMode(GL_MODELVIEW);
 167    glLoadIdentity();
 168    glTranslatef(0.0f, 0.0f, -15.0f);
 169 }
 170
 171
 172 static void
 173 CleanUp(void)
 174 {
 175    glDeleteShader_func(fragShader);
 176    glDeleteShader_func(vertShader);
 177    glDeleteProgram_func(program);
 178    glutDestroyWindow(win);
 179 }
 180
 181
 182 static void
 183 Key(unsigned char key, int x, int y)
 184 {
 185    const GLfloat step = 2.0;
 186   (void) x;
 187   (void) y;
 188
 189    switch(key) {
 190    case 'a':
 191       Anim = !Anim;
 192       glutIdleFunc(Anim ? Idle : NULL);
 193       break;
 194    case 'z':
 195       zRot += step;
 196       break;
 197    case 'Z':
 198       zRot -= step;
 199       break;
 200    case 27:
 201       CleanUp();
 202       exit(0);
 203       break;
 204    }
 205    glutPostRedisplay();
 206 }
 207
 208
 209 static void
 210 SpecialKey(int key, int x, int y)
 211 {
 212    const GLfloat step = 2.0;
 213
 214   (void) x;
 215   (void) y;
 216
 217    switch(key) {
 218    case GLUT_KEY_UP:
 219       xRot += step;
 220       break;
 221    case GLUT_KEY_DOWN:
 222       xRot -= step;
 223       break;
 224    case GLUT_KEY_LEFT:
 225       yRot -= step;
 226       break;
 227    case GLUT_KEY_RIGHT:
 228       yRot += step;
 229       break;
 230    }
 231    glutPostRedisplay();
 232 }
 233
 234
 235
 236 static void
 237 LoadAndCompileShader(GLuint shader, const char *text)
 238 {
 239    GLint stat;
 240
 241    glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
 242
 243    glCompileShader_func(shader);
 244
 245    glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
 246    if (!stat) {
 247       GLchar log[1000];
 248       GLsizei len;
 249       glGetShaderInfoLog_func(shader, 1000, &len, log);
 250       fprintf(stderr, "brick: problem compiling shader: %s\n", log);
 251       exit(1);
 252    }
 253    else {
 254       printf("Shader compiled OK\n");
 255    }
 256 }
 257
 258
 259 /**
 260  * Read a shader from a file.
 261  */
 262 static void
 263 ReadShader(GLuint shader, const char *filename)
 264 {
 265    const int max = 100*1000;
 266    int n;
 267    char *buffer = (char*) malloc(max);
 268    FILE *f = fopen(filename, "r");
 269    if (!f) {
 270       fprintf(stderr, "brick: Unable to open shader file %s\n", filename);
 271       exit(1);
 272    }
 273
 274    n = fread(buffer, 1, max, f);
 275    printf("brick: read %d bytes from shader file %s\n", n, filename);
 276    if (n > 0) {
 277       buffer[n] = 0;
 278       LoadAndCompileShader(shader, buffer);
 279    }
 280
 281    fclose(f);
 282    free(buffer);
 283 }
 284
 285
 286 static void
 287 CheckLink(GLuint prog)
 288 {
 289    GLint stat;
 290    glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
 291    if (!stat) {
 292       GLchar log[1000];
 293       GLsizei len;
 294       glGetProgramInfoLog_func(prog, 1000, &len, log);
 295       fprintf(stderr, "Linker error:\n%s\n", log);
 296    }
 297    else {
 298       fprintf(stderr, "Link success!\n");
 299    }
 300 }
 301
 302
 303 static void
 304 Init(void)
 305 {
 306    const char *version;
 307    GLint i;
 308
 309    version = (const char *) glGetString(GL_VERSION);
 310    if (version[0] != '2' || version[1] != '.') {
 311       printf("Warning: this program expects OpenGL 2.0\n");
 312       /*exit(1);*/
 313    }
 314    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 315
 316    GetExtensionFuncs();
 317
 318    vertShader = glCreateShader_func(GL_VERTEX_SHADER);
 319    ReadShader(vertShader, VertProgFile);
 320
 321    fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
 322    ReadShader(fragShader, FragProgFile);
 323
 324    program = glCreateProgram_func();
 325    glAttachShader_func(program, fragShader);
 326    glAttachShader_func(program, vertShader);
 327    glLinkProgram_func(program);
 328    CheckLink(program);
 329    glUseProgram_func(program);
 330
 331    assert(glIsProgram_func(program));
 332    assert(glIsShader_func(fragShader));
 333    assert(glIsShader_func(vertShader));
 334
 335    assert(glGetError() == 0);
 336
 337    CheckError(__LINE__);
 338
 339    for (i = 0; Uniforms[i].name; i++) {
 340       Uniforms[i].location
 341          = glGetUniformLocation_func(program, Uniforms[i].name);
 342       printf("Uniform %s location: %d\n", Uniforms[i].name,
 343              Uniforms[i].location);
 344       switch (Uniforms[i].size) {
 345       case 1:
 346          glUniform1fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 347          break;
 348       case 2:
 349          glUniform2fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 350          break;
 351       case 3:
 352          glUniform3fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 353          break;
 354       case 4:
 355          glUniform4fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 356          break;
 357       default:
 358          abort();
 359       }
 360    }
 361
 362    CheckError(__LINE__);
 363
 364    tangentAttrib = glGetAttribLocation_func(program, "Tangent");
 365    printf("Tangent Attrib: %d\n", tangentAttrib);
 366
 367    assert(tangentAttrib >= 0);
 368
 369    CheckError(__LINE__);
 370
 371    glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
 372
 373    glEnable(GL_DEPTH_TEST);
 374
 375    glColor3f(1, 0, 0);
 376 }
 377
 378
 379 static void
 380 ParseOptions(int argc, char *argv[])
 381 {
 382    int i;
 383    for (i = 1; i < argc; i++) {
 384       if (strcmp(argv[i], "-fs") == 0) {
 385          FragProgFile = argv[i+1];
 386       }
 387       else if (strcmp(argv[i], "-vs") == 0) {
 388          VertProgFile = argv[i+1];
 389       }
 390    }
 391 }
 392
 393
 394 int
 395 main(int argc, char *argv[])
 396 {
 397    glutInit(&argc, argv);
 398    glutInitWindowPosition( 0, 0);
 399    glutInitWindowSize(400, 400);
 400    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 401    win = glutCreateWindow(argv[0]);
 402    glutReshapeFunc(Reshape);
 403    glutKeyboardFunc(Key);
 404    glutSpecialFunc(SpecialKey);
 405    glutDisplayFunc(Redisplay);
 406    ParseOptions(argc, argv);
 407    Init();
 408    glutMainLoop();
 409    return 0;
 410 }
 411