src/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/glew.h>
  13 #include "glut_wrap.h"
  14 #include "shaderutil.h"
  15 #include "readtex.h"
  16
  17
  18 static char *FragProgFile = "CH11-bumpmap.frag";
  19 static char *FragTexProgFile = "CH11-bumpmaptex.frag";
  20 static char *VertProgFile = "CH11-bumpmap.vert";
  21 static char *TextureFile = DEMOS_DATA_DIR "tile.rgb";
  22
  23 /* program/shader objects */
  24 static GLuint fragShader;
  25 static GLuint fragTexShader;
  26 static GLuint vertShader;
  27 static GLuint program;
  28 static GLuint texProgram;
  29
  30
  31 static struct uniform_info Uniforms[] = {
  32    { "LightPosition",  1, GL_FLOAT_VEC3, { 0.57737, 0.57735, 0.57735, 0.0 }, -1 },
  33    { "SurfaceColor",   1, GL_FLOAT_VEC3, { 0.8, 0.8, 0.2, 0 }, -1 },
  34    { "BumpDensity",    1, GL_FLOAT, { 10.0, 0, 0, 0 }, -1 },
  35    { "BumpSize",       1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 },
  36    { "SpecularFactor", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
  37    END_OF_UNIFORMS
  38 };
  39
  40 static struct uniform_info TexUniforms[] = {
  41    { "LightPosition",  1, GL_FLOAT_VEC3, { 0.57737, 0.57735, 0.57735, 0.0 }, -1 },
  42    { "Tex",            1, GL_INT,   { 0, 0, 0, 0 }, -1 },
  43    { "BumpDensity",    1, GL_FLOAT, { 10.0, 0, 0, 0 }, -1 },
  44    { "BumpSize",       1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 },
  45    { "SpecularFactor", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
  46    END_OF_UNIFORMS
  47 };
  48
  49 static GLint win = 0;
  50
  51 static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
  52
  53 static GLint tangentAttrib;
  54
  55 static GLuint Texture;
  56
  57 static GLboolean Anim = GL_FALSE;
  58 static GLboolean Textured = GL_FALSE;
  59
  60
  61 static void
  62 CheckError(int line)
  63 {
  64    GLenum err = glGetError();
  65    if (err) {
  66       printf("GL Error %s (0x%x) at line %d\n",
  67              gluErrorString(err), (int) err, line);
  68    }
  69 }
  70
  71 /*
  72  * Draw a square, specifying normal and tangent vectors.
  73  */
  74 static void
  75 Square(GLfloat size)
  76 {
  77    glNormal3f(0, 0, 1);
  78    glVertexAttrib3f(tangentAttrib, 1, 0, 0);
  79    glBegin(GL_POLYGON);
  80    glTexCoord2f(0, 0);  glVertex2f(-size, -size);
  81    glTexCoord2f(1, 0);  glVertex2f( size, -size);
  82    glTexCoord2f(1, 1);  glVertex2f( size,  size);
  83    glTexCoord2f(0, 1);  glVertex2f(-size,  size);
  84    glEnd();
  85 }
  86
  87
  88 static void
  89 Cube(GLfloat size)
  90 {
  91    /* +X */
  92    glPushMatrix();
  93    glRotatef(90, 0, 1, 0);
  94    glTranslatef(0, 0, size);
  95    Square(size);
  96    glPopMatrix();
  97
  98    /* -X */
  99    glPushMatrix();
 100    glRotatef(-90, 0, 1, 0);
 101    glTranslatef(0, 0, size);
 102    Square(size);
 103    glPopMatrix();
 104
 105    /* +Y */
 106    glPushMatrix();
 107    glRotatef(90, 1, 0, 0);
 108    glTranslatef(0, 0, size);
 109    Square(size);
 110    glPopMatrix();
 111
 112    /* -Y */
 113    glPushMatrix();
 114    glRotatef(-90, 1, 0, 0);
 115    glTranslatef(0, 0, size);
 116    Square(size);
 117    glPopMatrix();
 118
 119
 120    /* +Z */
 121    glPushMatrix();
 122    glTranslatef(0, 0, size);
 123    Square(size);
 124    glPopMatrix();
 125
 126    /* -Z */
 127    glPushMatrix();
 128    glRotatef(180, 0, 1, 0);
 129    glTranslatef(0, 0, size);
 130    Square(size);
 131    glPopMatrix();
 132
 133 }
 134
 135
 136 static void
 137 Idle(void)
 138 {
 139    GLint t = glutGet(GLUT_ELAPSED_TIME);
 140    yRot  = t * 0.05;
 141    glutPostRedisplay();
 142 }
 143
 144
 145 static void
 146 Redisplay(void)
 147 {
 148    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 149
 150    glPushMatrix();
 151    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
 152    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
 153    glRotatef(zRot, 0.0f, 0.0f, 1.0f);
 154
 155    if (Textured)
 156       glUseProgram(texProgram);
 157    else
 158       glUseProgram(program);
 159
 160    Cube(1.5);
 161
 162    glPopMatrix();
 163
 164    CheckError(__LINE__);
 165
 166    glutSwapBuffers();
 167 }
 168
 169
 170 static void
 171 Reshape(int width, int height)
 172 {
 173    float ar = (float) width / (float) height;
 174    glViewport(0, 0, width, height);
 175    glMatrixMode(GL_PROJECTION);
 176    glLoadIdentity();
 177    glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
 178    glMatrixMode(GL_MODELVIEW);
 179    glLoadIdentity();
 180    glTranslatef(0.0f, 0.0f, -15.0f);
 181 }
 182
 183
 184 static void
 185 CleanUp(void)
 186 {
 187    glDeleteShader(fragShader);
 188    glDeleteShader(fragTexShader);
 189    glDeleteShader(vertShader);
 190    glDeleteProgram(program);
 191    glDeleteProgram(texProgram);
 192    glutDestroyWindow(win);
 193 }
 194
 195
 196 static void
 197 Key(unsigned char key, int x, int y)
 198 {
 199    const GLfloat step = 2.0;
 200   (void) x;
 201   (void) y;
 202
 203    switch(key) {
 204    case 'a':
 205       Anim = !Anim;
 206       glutIdleFunc(Anim ? Idle : NULL);
 207       break;
 208    case 't':
 209       Textured = !Textured;
 210       break;
 211    case 'z':
 212       zRot += step;
 213       break;
 214    case 'Z':
 215       zRot -= step;
 216       break;
 217    case 27:
 218       CleanUp();
 219       exit(0);
 220       break;
 221    }
 222    glutPostRedisplay();
 223 }
 224
 225
 226 static void
 227 SpecialKey(int key, int x, int y)
 228 {
 229    const GLfloat step = 2.0;
 230
 231   (void) x;
 232   (void) y;
 233
 234    switch(key) {
 235    case GLUT_KEY_UP:
 236       xRot += step;
 237       break;
 238    case GLUT_KEY_DOWN:
 239       xRot -= step;
 240       break;
 241    case GLUT_KEY_LEFT:
 242       yRot -= step;
 243       break;
 244    case GLUT_KEY_RIGHT:
 245       yRot += step;
 246       break;
 247    }
 248    glutPostRedisplay();
 249 }
 250
 251
 252 static void
 253 Init(void)
 254 {
 255    if (!ShadersSupported())
 256       exit(1);
 257
 258    vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
 259    fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
 260    program = LinkShaders(vertShader, fragShader);
 261
 262    glUseProgram(program);
 263
 264    assert(glIsProgram(program));
 265    assert(glIsShader(fragShader));
 266    assert(glIsShader(vertShader));
 267
 268    assert(glGetError() == 0);
 269
 270    CheckError(__LINE__);
 271
 272    SetUniformValues(program, Uniforms);
 273    PrintUniforms(Uniforms);
 274
 275    CheckError(__LINE__);
 276
 277    tangentAttrib = glGetAttribLocation(program, "Tangent");
 278    printf("Tangent Attrib: %d\n", tangentAttrib);
 279
 280    assert(tangentAttrib >= 0);
 281
 282    CheckError(__LINE__);
 283
 284
 285    /*
 286     * As above, but fragment shader also uses a texture map.
 287     */
 288    fragTexShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragTexProgFile);
 289    texProgram = LinkShaders(vertShader, fragTexShader);
 290    glUseProgram(texProgram);
 291    assert(glIsProgram(texProgram));
 292    assert(glIsShader(fragTexShader));
 293    SetUniformValues(texProgram, TexUniforms);
 294    PrintUniforms(TexUniforms);
 295
 296    /*
 297     * Load tex image.
 298     */
 299    glGenTextures(1, &Texture);
 300    glBindTexture(GL_TEXTURE_2D, Texture);
 301    LoadRGBMipmaps(TextureFile, GL_RGB);
 302
 303
 304    glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
 305
 306    glEnable(GL_DEPTH_TEST);
 307
 308    glColor3f(1, 0, 0);
 309 }
 310
 311
 312 static void
 313 ParseOptions(int argc, char *argv[])
 314 {
 315    int i;
 316    for (i = 1; i < argc; i++) {
 317       if (strcmp(argv[i], "-fs") == 0) {
 318          FragProgFile = argv[++i];
 319       }
 320       else if (strcmp(argv[i], "-vs") == 0) {
 321          VertProgFile = argv[++i];
 322       }
 323       else if (strcmp(argv[i], "-t") == 0) {
 324          TextureFile = argv[++i];
 325       }
 326    }
 327 }
 328
 329
 330 int
 331 main(int argc, char *argv[])
 332 {
 333    glutInit(&argc, argv);
 334    glutInitWindowSize(400, 400);
 335    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 336    win = glutCreateWindow(argv[0]);
 337    glewInit();
 338    glutReshapeFunc(Reshape);
 339    glutKeyboardFunc(Key);
 340    glutSpecialFunc(SpecialKey);
 341    glutDisplayFunc(Redisplay);
 342    ParseOptions(argc, argv);
 343    Init();
 344    glutMainLoop();
 345    return 0;
 346 }
 347