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