progs/glsl/identity.c

   1 /**
   2  * Test very basic glsl functionality (identity vertex and fragment shaders).
   3  * Brian Paul & Stephane Marchesin
   4  */
   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 = NULL;
  18 static char *VertProgFile = NULL;
  19 static GLuint fragShader;
  20 static GLuint vertShader;
  21 static GLuint program;
  22 static GLint win = 0;
  23 static GLboolean anim = GL_FALSE;
  24 static GLfloat xRot = 0.0f, yRot = 0.0f;
  25 static int w,h;
  26
  27
  28 static void
  29 Redisplay(void)
  30 {
  31    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  32
  33    glBegin(GL_TRIANGLES);
  34    glColor3f(.8,0,0);
  35    glVertex3f(-0.9, -0.9, 0.0);
  36    glColor3f(0,.9,0);
  37    glVertex3f( 0.9, -0.9, 0.0);
  38    glColor3f(0,0,.7);
  39    glVertex3f( 0.0,  0.9, 0.0);
  40    glEnd();
  41
  42    glutSwapBuffers();
  43 }
  44
  45
  46 static void
  47 Idle(void)
  48 {
  49    yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
  50    glutPostRedisplay();
  51 }
  52
  53
  54 static void
  55 Reshape(int width, int height)
  56 {
  57    glViewport(0, 0, width, height);
  58    glMatrixMode(GL_PROJECTION);
  59    glLoadIdentity();
  60    glMatrixMode(GL_MODELVIEW);
  61    glLoadIdentity();
  62    w = width;
  63    h = height;
  64 }
  65
  66
  67 static void
  68 CleanUp(void)
  69 {
  70    glDeleteShader(fragShader);
  71    glDeleteShader(vertShader);
  72    glDeleteProgram(program);
  73    glutDestroyWindow(win);
  74 }
  75
  76
  77 static void
  78 Key(unsigned char key, int x, int y)
  79 {
  80   (void) x;
  81   (void) y;
  82
  83    switch(key) {
  84    case ' ':
  85    case 'a':
  86       anim = !anim;
  87       if (anim)
  88          glutIdleFunc(Idle);
  89       else
  90          glutIdleFunc(NULL);
  91       break;
  92    case 27:
  93       CleanUp();
  94       exit(0);
  95       break;
  96    }
  97    glutPostRedisplay();
  98 }
  99
 100
 101 static void
 102 SpecialKey(int key, int x, int y)
 103 {
 104    const GLfloat step = 3.0f;
 105
 106   (void) x;
 107   (void) y;
 108
 109    switch(key) {
 110    case GLUT_KEY_UP:
 111       xRot -= step;
 112       break;
 113    case GLUT_KEY_DOWN:
 114       xRot += step;
 115       break;
 116    case GLUT_KEY_LEFT:
 117       yRot -= step;
 118       break;
 119    case GLUT_KEY_RIGHT:
 120       yRot += step;
 121       break;
 122    }
 123    glutPostRedisplay();
 124 }
 125
 126
 127 static void
 128 Init(void)
 129 {
 130    static const char *fragShaderText =
 131       "void main() {\n"
 132       "   gl_FragColor = vec4(1.0,0.0,0.0,1.0);\n"
 133       "}\n";
 134    static const char *vertShaderText =
 135       "void main() {\n"
 136       "   gl_Position = gl_Vertex;\n"
 137       "}\n";
 138
 139    if (!ShadersSupported())
 140       exit(1);
 141
 142    if (FragProgFile)
 143       fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
 144    else
 145       fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
 146
 147    if (VertProgFile)
 148       vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
 149    else
 150       vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
 151
 152    program = LinkShaders(vertShader, fragShader);
 153
 154    glUseProgram(program);
 155
 156    /*assert(glGetError() == 0);*/
 157
 158    glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
 159    glEnable(GL_DEPTH_TEST);
 160
 161    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 162
 163    assert(glIsProgram(program));
 164    assert(glIsShader(fragShader));
 165    assert(glIsShader(vertShader));
 166
 167    glColor3f(1, 0, 0);
 168 }
 169
 170
 171 static void
 172 ParseOptions(int argc, char *argv[])
 173 {
 174    int i;
 175    for (i = 1; i < argc; i++) {
 176       if (strcmp(argv[i], "-fs") == 0) {
 177          FragProgFile = argv[i+1];
 178       }
 179       else if (strcmp(argv[i], "-vs") == 0) {
 180          VertProgFile = argv[i+1];
 181       }
 182    }
 183 }
 184
 185
 186 int
 187 main(int argc, char *argv[])
 188 {
 189    glutInit(&argc, argv);
 190    glutInitWindowSize(200, 200);
 191    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 192    win = glutCreateWindow(argv[0]);
 193    glewInit();
 194    glutReshapeFunc(Reshape);
 195    glutKeyboardFunc(Key);
 196    glutSpecialFunc(SpecialKey);
 197    glutDisplayFunc(Redisplay);
 198    if (anim)
 199       glutIdleFunc(Idle);
 200    ParseOptions(argc, argv);
 201    Init();
 202    glutMainLoop();
 203    return 0;
 204 }