progs/demos/fslight.c

   1 /**
   2  * Test OpenGL 2.0 vertex/fragment shaders.
   3  * Brian Paul
   4  * 1 November 2006
   5  *
   6  * Based on ARB version by:
   7  * Michal Krol
   8  * 20 February 2006
   9  *
  10  * Based on the original demo by:
  11  * Brian Paul
  12  * 17 April 2003
  13  */
  14
  15 #include <assert.h>
  16 #include <string.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <math.h>
  20 #include <GL/gl.h>
  21 #include <GL/glut.h>
  22 #include <GL/glext.h>
  23 #include "extfuncs.h"
  24
  25 static char *FragProgFile = NULL;
  26 static char *VertProgFile = NULL;
  27
  28 static GLfloat diffuse[4] = { 0.5f, 0.5f, 1.0f, 1.0f };
  29 static GLfloat specular[4] = { 0.8f, 0.8f, 0.8f, 1.0f };
  30 static GLfloat lightPos[4] = { 0.0f, 10.0f, 20.0f, 1.0f };
  31 static GLfloat delta = 1.0f;
  32
  33 static GLuint fragShader;
  34 static GLuint vertShader;
  35 static GLuint program;
  36
  37 static GLint uLightPos;
  38 static GLint uDiffuse;
  39 static GLint uSpecular;
  40
  41 static GLint win = 0;
  42 static GLboolean anim = GL_FALSE;
  43 static GLboolean wire = GL_FALSE;
  44 static GLboolean pixelLight = GL_TRUE;
  45
  46 static GLint t0 = 0;
  47 static GLint frames = 0;
  48
  49 static GLfloat xRot = 0.0f, yRot = 0.0f;
  50
  51
  52 static void
  53 normalize(GLfloat *dst, const GLfloat *src)
  54 {
  55    GLfloat len = sqrtf(src[0] * src[0] + src[1] * src[1] + src[2] * src[2]);
  56    dst[0] = src[0] / len;
  57    dst[1] = src[1] / len;
  58    dst[2] = src[2] / len;
  59 }
  60
  61
  62 static void
  63 Redisplay(void)
  64 {
  65    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  66
  67    if (pixelLight) {
  68       GLfloat vec[3];
  69       glUseProgram_func(program);
  70       normalize(vec, lightPos);
  71       glUniform3fv_func(uLightPos, 1, vec);
  72       glDisable(GL_LIGHTING);
  73    }
  74    else {
  75       glUseProgram_func(0);
  76       glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
  77       glEnable(GL_LIGHTING);
  78    }
  79
  80    glPushMatrix();
  81    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  82    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
  83    glutSolidSphere(2.0, 10, 5);
  84    glPopMatrix();
  85
  86    glutSwapBuffers();
  87    frames++;
  88
  89    if (anim) {
  90       GLint t = glutGet(GLUT_ELAPSED_TIME);
  91       if (t - t0 >= 5000) {
  92          GLfloat seconds =(GLfloat)(t - t0) / 1000.0f;
  93          GLfloat fps = frames / seconds;
  94          printf("%d frames in %6.3f seconds = %6.3f FPS\n",
  95                 frames, seconds, fps);
  96          t0 = t;
  97          frames = 0;
  98       }
  99    }
 100 }
 101
 102
 103 static void
 104 Idle(void)
 105 {
 106    lightPos[0] += delta;
 107    if (lightPos[0] > 25.0f || lightPos[0] < -25.0f)
 108       delta = -delta;
 109    glutPostRedisplay();
 110 }
 111
 112
 113 static void
 114 Reshape(int width, int height)
 115 {
 116    glViewport(0, 0, width, height);
 117    glMatrixMode(GL_PROJECTION);
 118    glLoadIdentity();
 119    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
 120    glMatrixMode(GL_MODELVIEW);
 121    glLoadIdentity();
 122    glTranslatef(0.0f, 0.0f, -15.0f);
 123 }
 124
 125
 126 static void
 127 CleanUp(void)
 128 {
 129    glDeleteShader_func(fragShader);
 130    glDeleteShader_func(vertShader);
 131    glDeleteProgram_func(program);
 132    glutDestroyWindow(win);
 133 }
 134
 135
 136 static void
 137 Key(unsigned char key, int x, int y)
 138 {
 139   (void) x;
 140   (void) y;
 141
 142    switch(key) {
 143    case ' ':
 144    case 'a':
 145       anim = !anim;
 146       if (anim)
 147          glutIdleFunc(Idle);
 148       else
 149          glutIdleFunc(NULL);
 150       break;
 151    case 'x':
 152       lightPos[0] -= 1.0f;
 153       break;
 154    case 'X':
 155       lightPos[0] += 1.0f;
 156       break;
 157    case 'w':
 158       wire = !wire;
 159       if (wire)
 160          glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 161       else
 162          glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 163       break;
 164    case 'p':
 165       pixelLight = !pixelLight;
 166       if (pixelLight)
 167          printf("Per-pixel lighting\n");
 168       else
 169          printf("Conventional lighting\n");
 170       break;
 171    case 27:
 172       CleanUp();
 173       exit(0);
 174       break;
 175    }
 176    glutPostRedisplay();
 177 }
 178
 179
 180 static void
 181 SpecialKey(int key, int x, int y)
 182 {
 183    const GLfloat step = 3.0f;
 184
 185   (void) x;
 186   (void) y;
 187
 188    switch(key) {
 189    case GLUT_KEY_UP:
 190       xRot -= step;
 191       break;
 192    case GLUT_KEY_DOWN:
 193       xRot += step;
 194       break;
 195    case GLUT_KEY_LEFT:
 196       yRot -= step;
 197       break;
 198    case GLUT_KEY_RIGHT:
 199       yRot += step;
 200       break;
 201    }
 202    glutPostRedisplay();
 203 }
 204
 205
 206 static void
 207 TestFunctions(void)
 208 {
 209    printf("Error 0x%x at line %d\n", glGetError(), __LINE__);
 210    {
 211       GLfloat pos[3];
 212       glUniform3fv_func(uLightPos, 1, lightPos);
 213       glGetUniformfv_func(program, uLightPos, pos);
 214       printf("Error 0x%x at line %d\n", glGetError(), __LINE__);
 215       printf("Light pos %g %g %g\n", pos[0], pos[1], pos[2]);
 216    }
 217
 218
 219    {
 220       GLfloat m[16], result[16];
 221       GLint mPos;
 222       int i;
 223
 224       for (i = 0; i < 16; i++)
 225          m[i] = (float) i;
 226
 227       mPos = glGetUniformLocation_func(program, "m");
 228       printf("Error 0x%x at line %d\n", glGetError(), __LINE__);
 229       glUniformMatrix4fv_func(mPos, 1, GL_FALSE, m);
 230       printf("Error 0x%x at line %d\n", glGetError(), __LINE__);
 231
 232       glGetUniformfv_func(program, mPos, result);
 233       printf("Error 0x%x at line %d\n", glGetError(), __LINE__);
 234
 235       for (i = 0; i < 16; i++) {
 236          printf("%8g %8g\n", m[i], result[i]);
 237       }
 238    }
 239
 240    assert(glIsProgram_func(program));
 241    assert(glIsShader_func(fragShader));
 242    assert(glIsShader_func(vertShader));
 243
 244    /* attached shaders */
 245    {
 246       GLuint shaders[20];
 247       GLsizei count;
 248       int i;
 249       glGetAttachedShaders_func(program, 20, &count, shaders);
 250       for (i = 0; i < count; i++) {
 251          printf("Attached: %u\n", shaders[i]);
 252          assert(shaders[i] == fragShader ||
 253                 shaders[i] == vertShader);
 254       }
 255    }
 256
 257    {
 258       GLchar log[1000];
 259       GLsizei len;
 260       glGetShaderInfoLog_func(vertShader, 1000, &len, log);
 261       printf("Vert Shader Info Log: %s\n", log);
 262       glGetShaderInfoLog_func(fragShader, 1000, &len, log);
 263       printf("Frag Shader Info Log: %s\n", log);
 264       glGetProgramInfoLog_func(program, 1000, &len, log);
 265       printf("Program Info Log: %s\n", log);
 266    }
 267 }
 268
 269
 270 static void
 271 LoadAndCompileShader(GLuint shader, const char *text)
 272 {
 273    GLint stat;
 274
 275    glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
 276
 277    glCompileShader_func(shader);
 278
 279    glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
 280    if (!stat) {
 281       GLchar log[1000];
 282       GLsizei len;
 283       glGetShaderInfoLog_func(shader, 1000, &len, log);
 284       fprintf(stderr, "Problem compiling shader: %s\n", log);
 285       exit(1);
 286    }
 287 }
 288
 289
 290 /**
 291  * Read a shader from a file.
 292  */
 293 static void
 294 ReadShader(GLuint shader, const char *filename)
 295 {
 296    const int max = 100*1000;
 297    int n;
 298    char *buffer = (char*) malloc(max);
 299    FILE *f = fopen(filename, "r");
 300    if (!f) {
 301       fprintf(stderr, "Unable to open shader file %s\n", filename);
 302       exit(1);
 303    }
 304
 305    n = fread(buffer, 1, max, f);
 306    printf("Read %d bytes from shader file %s\n", n, filename);
 307    if (n > 0) {
 308       buffer[n] = 0;
 309       LoadAndCompileShader(shader, buffer);
 310    }
 311
 312    fclose(f);
 313    free(buffer);
 314 }
 315
 316
 317 static void
 318 CheckLink(GLuint prog)
 319 {
 320    GLint stat;
 321    glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
 322    if (!stat) {
 323       GLchar log[1000];
 324       GLsizei len;
 325       glGetProgramInfoLog_func(prog, 1000, &len, log);
 326       fprintf(stderr, "Linker error:\n%s\n", log);
 327    }
 328 }
 329
 330
 331 static void
 332 Init(void)
 333 {
 334    static const char *fragShaderText =
 335       "uniform vec3 lightPos;\n"
 336       "uniform vec4 diffuse;\n"
 337       "uniform vec4 specular;\n"
 338       "varying vec3 normal;\n"
 339       "void main() {\n"
 340       "   // Compute dot product of light direction and normal vector\n"
 341       "   float dotProd = max(dot(lightPos, normalize(normal)), 0.0);\n"
 342       "   // Compute diffuse and specular contributions\n"
 343       "   gl_FragColor = diffuse * dotProd + specular * pow(dotProd, 20.0);\n"
 344       "}\n";
 345    static const char *vertShaderText =
 346       "varying vec3 normal;\n"
 347       "void main() {\n"
 348       "   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
 349       "   normal = gl_NormalMatrix * gl_Normal;\n"
 350       "}\n";
 351    const char *version;
 352
 353    version = (const char *) glGetString(GL_VERSION);
 354    if (version[0] != '2' || version[1] != '.') {
 355       printf("Warning: this program expects OpenGL 2.0\n");
 356       /*exit(1);*/
 357    }
 358
 359    GetExtensionFuncs();
 360
 361    fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
 362    if (FragProgFile)
 363       ReadShader(fragShader, FragProgFile);
 364    else
 365       LoadAndCompileShader(fragShader, fragShaderText);
 366
 367
 368    vertShader = glCreateShader_func(GL_VERTEX_SHADER);
 369    if (VertProgFile)
 370       ReadShader(vertShader, VertProgFile);
 371    else
 372       LoadAndCompileShader(vertShader, vertShaderText);
 373
 374    program = glCreateProgram_func();
 375    glAttachShader_func(program, fragShader);
 376    glAttachShader_func(program, vertShader);
 377    glLinkProgram_func(program);
 378    CheckLink(program);
 379    glUseProgram_func(program);
 380
 381    uLightPos = glGetUniformLocation_func(program, "lightPos");
 382    uDiffuse = glGetUniformLocation_func(program, "diffuse");
 383    uSpecular = glGetUniformLocation_func(program, "specular");
 384    printf("LightPos %d  DiffusePos %d  SpecularPos %d\n",
 385           uLightPos, uDiffuse, uSpecular);
 386
 387    glUniform4fv_func(uDiffuse, 1, diffuse);
 388    glUniform4fv_func(uSpecular, 1, specular);
 389
 390    glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
 391    glEnable(GL_DEPTH_TEST);
 392    glEnable(GL_LIGHT0);
 393    glEnable(GL_LIGHTING);
 394    glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, diffuse);
 395    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, specular);
 396    glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 20.0f);
 397
 398    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 399    printf("Press p to toggle between per-pixel and per-vertex lighting\n");
 400
 401    /* test glGetShaderSource() */
 402    if (0) {
 403       GLsizei len = strlen(fragShaderText) + 1;
 404       GLsizei lenOut;
 405       GLchar *src =(GLchar *) malloc(len * sizeof(GLchar));
 406       glGetShaderSource_func(fragShader, 0, NULL, src);
 407       glGetShaderSource_func(fragShader, len, &lenOut, src);
 408       assert(len == lenOut + 1);
 409       assert(strcmp(src, fragShaderText) == 0);
 410       free(src);
 411    }
 412
 413    assert(glIsProgram_func(program));
 414    assert(glIsShader_func(fragShader));
 415    assert(glIsShader_func(vertShader));
 416
 417    glColor3f(1, 0, 0);
 418 #if 0
 419    TestFunctions();
 420 #endif
 421 }
 422
 423
 424 static void
 425 ParseOptions(int argc, char *argv[])
 426 {
 427    int i;
 428    for (i = 1; i < argc; i++) {
 429       if (strcmp(argv[i], "-fs") == 0) {
 430          FragProgFile = argv[i+1];
 431       }
 432       else if (strcmp(argv[i], "-vs") == 0) {
 433          VertProgFile = argv[i+1];
 434       }
 435    }
 436 }
 437
 438
 439 int
 440 main(int argc, char *argv[])
 441 {
 442    glutInit(&argc, argv);
 443    glutInitWindowPosition( 0, 0);
 444    glutInitWindowSize(100, 100);
 445    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 446    win = glutCreateWindow(argv[0]);
 447    glutReshapeFunc(Reshape);
 448    glutKeyboardFunc(Key);
 449    glutSpecialFunc(SpecialKey);
 450    glutDisplayFunc(Redisplay);
 451    if (anim)
 452       glutIdleFunc(Idle);
 453    ParseOptions(argc, argv);
 454    Init();
 455    glutMainLoop();
 456    return 0;
 457 }
 458