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