progs/glsl/toyball.c

   1 /**
   2  * "Toy Ball" shader 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/gl.h>
  13 #include <GL/glut.h>
  14 #include <GL/glext.h>
  15 #include "extfuncs.h"
  16
  17
  18 static char *FragProgFile = "CH11-toyball.frag.txt";
  19 static char *VertProgFile = "CH11-toyball.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    { "LightDir",       4, -1, { 0.57737, 0.57735, 0.57735, 0.0 } },
  36    { "HVector",        4, -1, { 0.32506, 0.32506, 0.88808, 0.0 } },
  37    { "BallCenter",     4, -1, { 0.0, 0.0, 0.0, 1.0 } },
  38    { "SpecularColor",  4, -1, { 0.4, 0.4, 0.4, 60.0 } },
  39    { "Red",            4, -1, { 0.6, 0.0, 0.0, 1.0 } },
  40    { "Blue",           4, -1, { 0.0, 0.3, 0.6, 1.0 } },
  41    { "Yellow",         4, -1, { 0.6, 0.5, 0.0, 1.0 } },
  42    { "HalfSpace0",     4, -1, { 1.0, 0.0, 0.0, 0.2 } },
  43    { "HalfSpace1",     4, -1, { 0.309016994, 0.951056516, 0.0, 0.2 } },
  44    { "HalfSpace2",     4, -1, { -0.809016994, 0.587785252, 0.0, 0.2 } },
  45    { "HalfSpace3",     4, -1, { -0.809016994, -0.587785252, 0.0, 0.2 } },
  46    { "HalfSpace4",     4, -1, { 0.309116994, -0.951056516, 0.0, 0.2 } },
  47    { "InOrOutInit",    1, -1, { -3.0, 0, 0, 0 } },
  48    { "StripeWidth",    1, -1, {  0.3, 0, 0, 0 } },
  49    { "FWidth",         1, -1, { 0.005, 0, 0, 0 } },
  50    { NULL, 0, 0, { 0, 0, 0, 0 } }
  51 };
  52
  53 static GLint win = 0;
  54 static GLboolean Anim = GL_FALSE;
  55 static GLfloat TexRot = 0.0;
  56 static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f;
  57
  58
  59 static void
  60 Idle(void)
  61 {
  62    TexRot += 2.0;
  63    if (TexRot > 360.0)
  64       TexRot -= 360.0;
  65    glutPostRedisplay();
  66 }
  67
  68
  69 static void
  70 Redisplay(void)
  71 {
  72    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  73
  74    glPushMatrix();
  75    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  76    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
  77    glRotatef(zRot, 0.0f, 0.0f, 1.0f);
  78
  79    glMatrixMode(GL_TEXTURE);
  80    glLoadIdentity();
  81    glRotatef(TexRot, 0.0f, 1.0f, 0.0f);
  82    glMatrixMode(GL_MODELVIEW);
  83
  84    glutSolidSphere(2.0, 20, 10);
  85
  86    glPopMatrix();
  87
  88    glFinish();
  89    glFlush();
  90    glutSwapBuffers();
  91 }
  92
  93
  94 static void
  95 Reshape(int width, int height)
  96 {
  97    glViewport(0, 0, width, height);
  98    glMatrixMode(GL_PROJECTION);
  99    glLoadIdentity();
 100    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
 101    glMatrixMode(GL_MODELVIEW);
 102    glLoadIdentity();
 103    glTranslatef(0.0f, 0.0f, -15.0f);
 104 }
 105
 106
 107 static void
 108 CleanUp(void)
 109 {
 110    glDeleteShader_func(fragShader);
 111    glDeleteShader_func(vertShader);
 112    glDeleteProgram_func(program);
 113    glutDestroyWindow(win);
 114 }
 115
 116
 117 static void
 118 Key(unsigned char key, int x, int y)
 119 {
 120    const GLfloat step = 2.0;
 121   (void) x;
 122   (void) y;
 123
 124    switch(key) {
 125    case 'a':
 126       Anim = !Anim;
 127       if (Anim)
 128          glutIdleFunc(Idle);
 129       else
 130          glutIdleFunc(NULL);
 131       break;
 132    case 'z':
 133       zRot += step;
 134       break;
 135    case 'Z':
 136       zRot -= step;
 137       break;
 138    case 27:
 139       CleanUp();
 140       exit(0);
 141       break;
 142    }
 143    glutPostRedisplay();
 144 }
 145
 146
 147 static void
 148 SpecialKey(int key, int x, int y)
 149 {
 150    const GLfloat step = 2.0;
 151
 152   (void) x;
 153   (void) y;
 154
 155    switch(key) {
 156    case GLUT_KEY_UP:
 157       xRot += step;
 158       break;
 159    case GLUT_KEY_DOWN:
 160       xRot -= step;
 161       break;
 162    case GLUT_KEY_LEFT:
 163       yRot -= step;
 164       break;
 165    case GLUT_KEY_RIGHT:
 166       yRot += step;
 167       break;
 168    }
 169    glutPostRedisplay();
 170 }
 171
 172
 173
 174 static void
 175 LoadAndCompileShader(GLuint shader, const char *text)
 176 {
 177    GLint stat;
 178
 179    glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
 180
 181    glCompileShader_func(shader);
 182
 183    glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
 184    if (!stat) {
 185       GLchar log[1000];
 186       GLsizei len;
 187       glGetShaderInfoLog_func(shader, 1000, &len, log);
 188       fprintf(stderr, "toyball: problem compiling shader: %s\n", log);
 189       exit(1);
 190    }
 191    else {
 192       printf("Shader compiled OK\n");
 193    }
 194 }
 195
 196
 197 /**
 198  * Read a shader from a file.
 199  */
 200 static void
 201 ReadShader(GLuint shader, const char *filename)
 202 {
 203    const int max = 100*1000;
 204    int n;
 205    char *buffer = (char*) malloc(max);
 206    FILE *f = fopen(filename, "r");
 207    if (!f) {
 208       fprintf(stderr, "toyball: Unable to open shader file %s\n", filename);
 209       exit(1);
 210    }
 211
 212    n = fread(buffer, 1, max, f);
 213    printf("toyball: read %d bytes from shader file %s\n", n, filename);
 214    if (n > 0) {
 215       buffer[n] = 0;
 216       LoadAndCompileShader(shader, buffer);
 217    }
 218
 219    fclose(f);
 220    free(buffer);
 221 }
 222
 223
 224 static void
 225 CheckLink(GLuint prog)
 226 {
 227    GLint stat;
 228    glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
 229    if (!stat) {
 230       GLchar log[1000];
 231       GLsizei len;
 232       glGetProgramInfoLog_func(prog, 1000, &len, log);
 233       fprintf(stderr, "Linker error:\n%s\n", log);
 234    }
 235    else {
 236       fprintf(stderr, "Link success!\n");
 237    }
 238 }
 239
 240
 241 static void
 242 Init(void)
 243 {
 244    const char *version;
 245    GLint i;
 246
 247    version = (const char *) glGetString(GL_VERSION);
 248    if (version[0] != '2' || version[1] != '.') {
 249       printf("Warning: this program expects OpenGL 2.0\n");
 250       /*exit(1);*/
 251    }
 252    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 253
 254    GetExtensionFuncs();
 255
 256    vertShader = glCreateShader_func(GL_VERTEX_SHADER);
 257    ReadShader(vertShader, VertProgFile);
 258
 259    fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
 260    ReadShader(fragShader, FragProgFile);
 261
 262    program = glCreateProgram_func();
 263    glAttachShader_func(program, fragShader);
 264    glAttachShader_func(program, vertShader);
 265    glLinkProgram_func(program);
 266    CheckLink(program);
 267    glUseProgram_func(program);
 268
 269    assert(glIsProgram_func(program));
 270    assert(glIsShader_func(fragShader));
 271    assert(glIsShader_func(vertShader));
 272
 273
 274    for (i = 0; Uniforms[i].name; i++) {
 275       Uniforms[i].location
 276          = glGetUniformLocation_func(program, Uniforms[i].name);
 277       printf("Uniform %s location: %d\n", Uniforms[i].name,
 278              Uniforms[i].location);
 279       switch (Uniforms[i].size) {
 280       case 1:
 281          glUniform1fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 282          break;
 283       case 2:
 284          glUniform2fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 285          break;
 286       case 3:
 287          glUniform3fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 288          break;
 289       case 4:
 290          glUniform4fv_func(Uniforms[i].location, 1, Uniforms[i].value);
 291          break;
 292       default:
 293          abort();
 294       }
 295    }
 296
 297    assert(glGetError() == 0);
 298
 299    glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
 300
 301    glEnable(GL_DEPTH_TEST);
 302
 303    glColor3f(1, 0, 0);
 304 }
 305
 306
 307 static void
 308 ParseOptions(int argc, char *argv[])
 309 {
 310    int i;
 311    for (i = 1; i < argc; i++) {
 312       if (strcmp(argv[i], "-fs") == 0) {
 313          FragProgFile = argv[i+1];
 314       }
 315       else if (strcmp(argv[i], "-vs") == 0) {
 316          VertProgFile = argv[i+1];
 317       }
 318    }
 319 }
 320
 321
 322 int
 323 main(int argc, char *argv[])
 324 {
 325    glutInit(&argc, argv);
 326    glutInitWindowPosition( 0, 0);
 327    glutInitWindowSize(400, 400);
 328    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 329    win = glutCreateWindow(argv[0]);
 330    glutReshapeFunc(Reshape);
 331    glutKeyboardFunc(Key);
 332    glutSpecialFunc(SpecialKey);
 333    glutDisplayFunc(Redisplay);
 334    ParseOptions(argc, argv);
 335    Init();
 336    glutMainLoop();
 337    return 0;
 338 }
 339