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/gl.h>
  14 #include <GL/glut.h>
  15 #include <GL/glext.h>
  16 #include "extfuncs.h"
  17 #include "shaderutil.h"
  18
  19
  20 static char *FragProgFile = NULL;
  21 static char *VertProgFile = NULL;
  22 static GLuint fragShader;
  23 static GLuint vertShader;
  24 static GLuint program;
  25 static GLint win = 0;
  26 static GLboolean anim = GL_FALSE;
  27 static GLfloat xRot = 0.0f, yRot = 0.0f;
  28 static int w,h;
  29
  30
  31 static void
  32 Redisplay(void)
  33 {
  34    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  35
  36    glBegin(GL_TRIANGLES);
  37    glColor3f(.8,0,0);
  38    glVertex3f(-0.9, -0.9, 0.0);
  39    glColor3f(0,.9,0);
  40    glVertex3f( 0.9, -0.9, 0.0);
  41    glColor3f(0,0,.7);
  42    glVertex3f( 0.0,  0.9, 0.0);
  43    glEnd();
  44
  45    glutSwapBuffers();
  46 }
  47
  48
  49 static void
  50 Idle(void)
  51 {
  52    yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
  53    glutPostRedisplay();
  54 }
  55
  56
  57 static void
  58 Reshape(int width, int height)
  59 {
  60    glViewport(0, 0, width, height);
  61    glMatrixMode(GL_PROJECTION);
  62    glLoadIdentity();
  63    glMatrixMode(GL_MODELVIEW);
  64    glLoadIdentity();
  65    w = width;
  66    h = height;
  67 }
  68
  69
  70 static void
  71 CleanUp(void)
  72 {
  73    glDeleteShader_func(fragShader);
  74    glDeleteShader_func(vertShader);
  75    glDeleteProgram_func(program);
  76    glutDestroyWindow(win);
  77 }
  78
  79
  80 static void
  81 Key(unsigned char key, int x, int y)
  82 {
  83   (void) x;
  84   (void) y;
  85
  86    switch(key) {
  87    case ' ':
  88    case 'a':
  89       anim = !anim;
  90       if (anim)
  91          glutIdleFunc(Idle);
  92       else
  93          glutIdleFunc(NULL);
  94       break;
  95    case 27:
  96       CleanUp();
  97       exit(0);
  98       break;
  99    }
 100    glutPostRedisplay();
 101 }
 102
 103
 104 static void
 105 SpecialKey(int key, int x, int y)
 106 {
 107    const GLfloat step = 3.0f;
 108
 109   (void) x;
 110   (void) y;
 111
 112    switch(key) {
 113    case GLUT_KEY_UP:
 114       xRot -= step;
 115       break;
 116    case GLUT_KEY_DOWN:
 117       xRot += step;
 118       break;
 119    case GLUT_KEY_LEFT:
 120       yRot -= step;
 121       break;
 122    case GLUT_KEY_RIGHT:
 123       yRot += step;
 124       break;
 125    }
 126    glutPostRedisplay();
 127 }
 128
 129
 130 static void
 131 Init(void)
 132 {
 133    static const char *fragShaderText =
 134       "void main() {\n"
 135       "   gl_FragColor = vec4(1.0,0.0,0.0,1.0);\n"
 136       "}\n";
 137    static const char *vertShaderText =
 138       "void main() {\n"
 139       "   gl_Position = gl_Vertex;\n"
 140       "}\n";
 141
 142    if (!ShadersSupported())
 143       exit(1);
 144
 145    GetExtensionFuncs();
 146
 147    if (FragProgFile)
 148       fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
 149    else
 150       fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
 151
 152    if (VertProgFile)
 153       vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
 154    else
 155       vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
 156
 157    program = LinkShaders(vertShader, fragShader);
 158
 159    glUseProgram_func(program);
 160
 161    /*assert(glGetError() == 0);*/
 162
 163    glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
 164    glEnable(GL_DEPTH_TEST);
 165
 166    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 167
 168    assert(glIsProgram_func(program));
 169    assert(glIsShader_func(fragShader));
 170    assert(glIsShader_func(vertShader));
 171
 172    glColor3f(1, 0, 0);
 173 }
 174
 175
 176 static void
 177 ParseOptions(int argc, char *argv[])
 178 {
 179    int i;
 180    for (i = 1; i < argc; i++) {
 181       if (strcmp(argv[i], "-fs") == 0) {
 182          FragProgFile = argv[i+1];
 183       }
 184       else if (strcmp(argv[i], "-vs") == 0) {
 185          VertProgFile = argv[i+1];
 186       }
 187    }
 188 }
 189
 190
 191 int
 192 main(int argc, char *argv[])
 193 {
 194    glutInit(&argc, argv);
 195    glutInitWindowPosition( 0, 0);
 196    glutInitWindowSize(200, 200);
 197    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 198    win = glutCreateWindow(argv[0]);
 199    glewInit();
 200    glutReshapeFunc(Reshape);
 201    glutKeyboardFunc(Key);
 202    glutSpecialFunc(SpecialKey);
 203    glutDisplayFunc(Redisplay);
 204    if (anim)
 205       glutIdleFunc(Idle);
 206    ParseOptions(argc, argv);
 207    Init();
 208    glutMainLoop();
 209    return 0;
 210 }