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 #include "shaderutil.h"
  17
  18
  19 static char *FragProgFile = "CH11-bumpmap.frag.txt";
  20 static char *VertProgFile = "CH11-bumpmap.vert.txt";
  21
  22 /* program/shader objects */
  23 static GLuint fragShader;
  24 static GLuint vertShader;
  25 static GLuint program;
  26
  27
  28 static struct uniform_info Uniforms[] = {
  29    { "LightPosition",    3, GL_FLOAT, { 0.57737, 0.57735, 0.57735, 0.0 }, -1 },
  30    { "SurfaceColor",     3, GL_FLOAT, { 0.8, 0.8, 0.2, 0 }, -1 },
  31    { "BumpDensity",      1, GL_FLOAT, { 10.0, 0, 0, 0 }, -1 },
  32    { "BumpSize",         1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 },
  33    { "SpecularFactor",   1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
  34    END_OF_UNIFORMS
  35 };
  36
  37 static GLint win = 0;
  38
  39 static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
  40
  41 static GLuint tangentAttrib;
  42
  43 static GLboolean Anim = GL_FALSE;
  44
  45
  46 static void
  47 CheckError(int line)
  48 {
  49    GLenum err = glGetError();
  50    if (err) {
  51       printf("GL Error %s (0x%x) at line %d\n",
  52              gluErrorString(err), (int) err, line);
  53    }
  54 }
  55
  56 /*
  57  * Draw a square, specifying normal and tangent vectors.
  58  */
  59 static void
  60 Square(GLfloat size)
  61 {
  62    glNormal3f(0, 0, 1);
  63    glVertexAttrib3f_func(tangentAttrib, 1, 0, 0);
  64    glBegin(GL_POLYGON);
  65    glTexCoord2f(0, 0);  glVertex2f(-size, -size);
  66    glTexCoord2f(1, 0);  glVertex2f( size, -size);
  67    glTexCoord2f(1, 1);  glVertex2f( size,  size);
  68    glTexCoord2f(0, 1);  glVertex2f(-size,  size);
  69    glEnd();
  70 }
  71
  72
  73 static void
  74 Cube(GLfloat size)
  75 {
  76    /* +X */
  77    glPushMatrix();
  78    glRotatef(90, 0, 1, 0);
  79    glTranslatef(0, 0, size);
  80    Square(size);
  81    glPopMatrix();
  82
  83    /* -X */
  84    glPushMatrix();
  85    glRotatef(-90, 0, 1, 0);
  86    glTranslatef(0, 0, size);
  87    Square(size);
  88    glPopMatrix();
  89
  90    /* +Y */
  91    glPushMatrix();
  92    glRotatef(90, 1, 0, 0);
  93    glTranslatef(0, 0, size);
  94    Square(size);
  95    glPopMatrix();
  96
  97    /* -Y */
  98    glPushMatrix();
  99    glRotatef(-90, 1, 0, 0);
 100    glTranslatef(0, 0, size);
 101    Square(size);
 102    glPopMatrix();
 103
 104
 105    /* +Z */
 106    glPushMatrix();
 107    glTranslatef(0, 0, size);
 108    Square(size);
 109    glPopMatrix();
 110
 111    /* -Z */
 112    glPushMatrix();
 113    glRotatef(180, 0, 1, 0);
 114    glTranslatef(0, 0, size);
 115    Square(size);
 116    glPopMatrix();
 117
 118 }
 119
 120
 121 static void
 122 Idle(void)
 123 {
 124    GLint t = glutGet(GLUT_ELAPSED_TIME);
 125    yRot  = t * 0.05;
 126    glutPostRedisplay();
 127 }
 128
 129
 130 static void
 131 Redisplay(void)
 132 {
 133    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 134
 135    glPushMatrix();
 136    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
 137    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
 138    glRotatef(zRot, 0.0f, 0.0f, 1.0f);
 139
 140    Cube(1.5);
 141
 142    glPopMatrix();
 143
 144    glFinish();
 145    glFlush();
 146
 147    CheckError(__LINE__);
 148
 149    glutSwapBuffers();
 150 }
 151
 152
 153 static void
 154 Reshape(int width, int height)
 155 {
 156    glViewport(0, 0, width, height);
 157    glMatrixMode(GL_PROJECTION);
 158    glLoadIdentity();
 159    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
 160    glMatrixMode(GL_MODELVIEW);
 161    glLoadIdentity();
 162    glTranslatef(0.0f, 0.0f, -15.0f);
 163 }
 164
 165
 166 static void
 167 CleanUp(void)
 168 {
 169    glDeleteShader_func(fragShader);
 170    glDeleteShader_func(vertShader);
 171    glDeleteProgram_func(program);
 172    glutDestroyWindow(win);
 173 }
 174
 175
 176 static void
 177 Key(unsigned char key, int x, int y)
 178 {
 179    const GLfloat step = 2.0;
 180   (void) x;
 181   (void) y;
 182
 183    switch(key) {
 184    case 'a':
 185       Anim = !Anim;
 186       glutIdleFunc(Anim ? Idle : NULL);
 187       break;
 188    case 'z':
 189       zRot += step;
 190       break;
 191    case 'Z':
 192       zRot -= step;
 193       break;
 194    case 27:
 195       CleanUp();
 196       exit(0);
 197       break;
 198    }
 199    glutPostRedisplay();
 200 }
 201
 202
 203 static void
 204 SpecialKey(int key, int x, int y)
 205 {
 206    const GLfloat step = 2.0;
 207
 208   (void) x;
 209   (void) y;
 210
 211    switch(key) {
 212    case GLUT_KEY_UP:
 213       xRot += step;
 214       break;
 215    case GLUT_KEY_DOWN:
 216       xRot -= step;
 217       break;
 218    case GLUT_KEY_LEFT:
 219       yRot -= step;
 220       break;
 221    case GLUT_KEY_RIGHT:
 222       yRot += step;
 223       break;
 224    }
 225    glutPostRedisplay();
 226 }
 227
 228
 229 static void
 230 Init(void)
 231 {
 232    if (!ShadersSupported())
 233       exit(1);
 234
 235    GetExtensionFuncs();
 236
 237    vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
 238    fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
 239    program = LinkShaders(vertShader, fragShader);
 240
 241    glUseProgram_func(program);
 242
 243    assert(glIsProgram_func(program));
 244    assert(glIsShader_func(fragShader));
 245    assert(glIsShader_func(vertShader));
 246
 247    assert(glGetError() == 0);
 248
 249    CheckError(__LINE__);
 250
 251    InitUniforms(program, Uniforms);
 252
 253    CheckError(__LINE__);
 254
 255    tangentAttrib = glGetAttribLocation_func(program, "Tangent");
 256    printf("Tangent Attrib: %d\n", tangentAttrib);
 257
 258    assert(tangentAttrib >= 0);
 259
 260    CheckError(__LINE__);
 261
 262    glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
 263
 264    glEnable(GL_DEPTH_TEST);
 265
 266    glColor3f(1, 0, 0);
 267 }
 268
 269
 270 static void
 271 ParseOptions(int argc, char *argv[])
 272 {
 273    int i;
 274    for (i = 1; i < argc; i++) {
 275       if (strcmp(argv[i], "-fs") == 0) {
 276          FragProgFile = argv[i+1];
 277       }
 278       else if (strcmp(argv[i], "-vs") == 0) {
 279          VertProgFile = argv[i+1];
 280       }
 281    }
 282 }
 283
 284
 285 int
 286 main(int argc, char *argv[])
 287 {
 288    glutInit(&argc, argv);
 289    glutInitWindowPosition( 0, 0);
 290    glutInitWindowSize(400, 400);
 291    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 292    win = glutCreateWindow(argv[0]);
 293    glutReshapeFunc(Reshape);
 294    glutKeyboardFunc(Key);
 295    glutSpecialFunc(SpecialKey);
 296    glutDisplayFunc(Redisplay);
 297    ParseOptions(argc, argv);
 298    Init();
 299    glutMainLoop();
 300    return 0;
 301 }
 302