src/glsl/brick.c

   1 /**
   2  * "Brick" shader demo.  Uses the example shaders from chapter 6 of
   3  * the OpenGL Shading Language "orange" book.
   4  * 10 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
  16
  17 static char *FragProgFile = "CH06-brick.frag";
  18 static char *VertProgFile = "CH06-brick.vert";
  19
  20 /* program/shader objects */
  21 static GLuint fragShader;
  22 static GLuint vertShader;
  23 static GLuint program;
  24
  25 static struct uniform_info Uniforms[] = {
  26    /* vert */
  27    { "LightPosition",     1, GL_FLOAT_VEC3, { 0.1, 0.1, 9.0, 0}, -1 },
  28    /* frag */
  29    { "BrickColor",        1, GL_FLOAT_VEC3, { 0.8, 0.2, 0.2, 0 }, -1 },
  30    { "MortarColor",       1, GL_FLOAT_VEC3, { 0.6, 0.6, 0.6, 0 }, -1 },
  31    { "BrickSize",         1, GL_FLOAT_VEC2, { 1.0, 0.3, 0, 0 }, -1 },
  32    { "BrickPct",          1, GL_FLOAT_VEC2, { 0.9, 0.8, 0, 0 }, -1 },
  33    END_OF_UNIFORMS
  34 };
  35
  36 static GLint win = 0;
  37
  38
  39 static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f;
  40
  41
  42
  43
  44 static void
  45 Redisplay(void)
  46 {
  47    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  48
  49    glPushMatrix();
  50    glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  51    glRotatef(yRot, 0.0f, 1.0f, 0.0f);
  52    glRotatef(zRot, 0.0f, 0.0f, 1.0f);
  53
  54    glBegin(GL_POLYGON);
  55    glTexCoord2f(0, 0);   glVertex2f(-2, -2);
  56    glTexCoord2f(1, 0);   glVertex2f( 2, -2);
  57    glTexCoord2f(1, 1);   glVertex2f( 2,  2);
  58    glTexCoord2f(0, 1);   glVertex2f(-2,  2);
  59    glEnd();
  60
  61    glPopMatrix();
  62
  63    glutSwapBuffers();
  64 }
  65
  66
  67 static void
  68 Reshape(int width, int height)
  69 {
  70    glViewport(0, 0, width, height);
  71    glMatrixMode(GL_PROJECTION);
  72    glLoadIdentity();
  73    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  74    glMatrixMode(GL_MODELVIEW);
  75    glLoadIdentity();
  76    glTranslatef(0.0f, 0.0f, -15.0f);
  77 }
  78
  79
  80 static void
  81 CleanUp(void)
  82 {
  83    DeleteShader(fragShader);
  84    DeleteShader(vertShader);
  85    DeleteProgram(program);
  86    glutDestroyWindow(win);
  87 }
  88
  89
  90 static void
  91 Key(unsigned char key, int x, int y)
  92 {
  93   (void) x;
  94   (void) y;
  95
  96    switch(key) {
  97    case 'z':
  98       zRot -= 1.0;
  99       break;
 100    case 'Z':
 101       zRot += 1.0;
 102       break;
 103    case 27:
 104       CleanUp();
 105       exit(0);
 106       break;
 107    }
 108    glutPostRedisplay();
 109 }
 110
 111
 112 static void
 113 SpecialKey(int key, int x, int y)
 114 {
 115    const GLfloat step = 3.0f;
 116
 117   (void) x;
 118   (void) y;
 119
 120    switch(key) {
 121    case GLUT_KEY_UP:
 122       xRot -= step;
 123       break;
 124    case GLUT_KEY_DOWN:
 125       xRot += step;
 126       break;
 127    case GLUT_KEY_LEFT:
 128       yRot -= step;
 129       break;
 130    case GLUT_KEY_RIGHT:
 131       yRot += step;
 132       break;
 133    }
 134    glutPostRedisplay();
 135 }
 136
 137
 138
 139 static void
 140 Init(void)
 141 {
 142    if (!ShadersSupported())
 143       exit(1);
 144
 145    vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
 146    fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
 147    program = LinkShaders(vertShader, fragShader);
 148
 149    UseProgram(program);
 150
 151    SetUniformValues(program, Uniforms);
 152    PrintUniforms(Uniforms);
 153
 154    assert(glGetError() == 0);
 155
 156    glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
 157
 158    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 159
 160    if (GLEW_VERSION_2_0) {
 161       assert(glIsProgram(program));
 162       assert(glIsShader(fragShader));
 163       assert(glIsShader(vertShader));
 164    }
 165
 166    glColor3f(1, 0, 0);
 167 }
 168
 169
 170 static void
 171 ParseOptions(int argc, char *argv[])
 172 {
 173    int i;
 174    for (i = 1; i < argc; i++) {
 175       if (strcmp(argv[i], "-fs") == 0) {
 176          FragProgFile = argv[i+1];
 177       }
 178       else if (strcmp(argv[i], "-vs") == 0) {
 179          VertProgFile = argv[i+1];
 180       }
 181    }
 182 }
 183
 184
 185 int
 186 main(int argc, char *argv[])
 187 {
 188    glutInit(&argc, argv);
 189    glutInitWindowSize(400, 400);
 190    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 191    win = glutCreateWindow(argv[0]);
 192    glewInit();
 193    glutReshapeFunc(Reshape);
 194    glutKeyboardFunc(Key);
 195    glutSpecialFunc(SpecialKey);
 196    glutDisplayFunc(Redisplay);
 197    ParseOptions(argc, argv);
 198    Init();
 199    glutMainLoop();
 200    return 0;
 201 }
 202