progs/tests/fbotest1.c

   1 /*
   2  * Test GL_EXT_framebuffer_object
   3  *
   4  * Brian Paul
   5  * 7 Feb 2005
   6  */
   7
   8
   9 #define GL_GLEXT_PROTOTYPES
  10 #include <assert.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <math.h>
  14 #include <GL/glut.h>
  15
  16 static int Width = 400, Height = 400;
  17 static GLuint MyFB, MyRB;
  18
  19
  20 static void
  21 CheckError(int line)
  22 {
  23    GLenum err = glGetError();
  24    if (err) {
  25       printf("GL Error 0x%x at line %d\n", (int) err, line);
  26    }
  27 }
  28
  29
  30 static void
  31 Display( void )
  32 {
  33    GLubyte *buffer = malloc(Width * Height * 4);
  34    GLenum status;
  35
  36    /* draw to user framebuffer */
  37    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
  38    glDrawBuffer(GL_COLOR_ATTACHMENT1_EXT);
  39    glReadBuffer(GL_COLOR_ATTACHMENT1_EXT);
  40
  41    status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
  42    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
  43       printf("Framebuffer incomplete!!!\n");
  44    }
  45
  46    glClearColor(0.5, 0.5, 1.0, 0.0);
  47    glClear( GL_COLOR_BUFFER_BIT );
  48
  49    glBegin(GL_POLYGON);
  50    glColor3f(1, 0, 0);
  51    glVertex2f(-1, -1);
  52    glColor3f(0, 1, 0);
  53    glVertex2f(1, -1);
  54    glColor3f(0, 0, 1);
  55    glVertex2f(0, 1);
  56    glEnd();
  57
  58    /* read from user framebuffer */
  59    glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
  60
  61    /* draw to window */
  62    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
  63    glWindowPos2iARB(0, 0);
  64    glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
  65
  66    free(buffer);
  67    glutSwapBuffers();
  68    CheckError(__LINE__);
  69 }
  70
  71
  72 static void
  73 Reshape( int width, int height )
  74 {
  75 #if 0
  76    float ar = (float) width / (float) height;
  77 #endif
  78    glViewport( 0, 0, width, height );
  79    glMatrixMode( GL_PROJECTION );
  80    glLoadIdentity();
  81 #if 0
  82    glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
  83 #else
  84    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  85 #endif
  86    glMatrixMode( GL_MODELVIEW );
  87    glLoadIdentity();
  88    glTranslatef( 0.0, 0.0, -15.0 );
  89    Width = width;
  90    Height = height;
  91    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
  92 }
  93
  94
  95 static void
  96 CleanUp(void)
  97 {
  98    glDeleteFramebuffersEXT(1, &MyFB);
  99    glDeleteRenderbuffersEXT(1, &MyRB);
 100    assert(!glIsFramebufferEXT(MyFB));
 101    assert(!glIsRenderbufferEXT(MyRB));
 102    exit(0);
 103 }
 104
 105
 106 static void
 107 Key( unsigned char key, int x, int y )
 108 {
 109    (void) x;
 110    (void) y;
 111    switch (key) {
 112       case 27:
 113          CleanUp();
 114          break;
 115    }
 116    glutPostRedisplay();
 117 }
 118
 119
 120 static void
 121 Init( void )
 122 {
 123    GLint i;
 124
 125    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 126       printf("GL_EXT_framebuffer_object not found!\n");
 127       /*exit(0);*/
 128    }
 129    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 130
 131    glGenFramebuffersEXT(1, &MyFB);
 132    assert(MyFB);
 133    assert(!glIsFramebufferEXT(MyFB));
 134    glDeleteFramebuffersEXT(1, &MyFB);
 135    assert(!glIsFramebufferEXT(MyFB));
 136    /* Note, continue to use MyFB below */
 137
 138    glGenRenderbuffersEXT(1, &MyRB);
 139    assert(MyRB);
 140    assert(!glIsRenderbufferEXT(MyRB));
 141    glDeleteRenderbuffersEXT(1, &MyRB);
 142    assert(!glIsRenderbufferEXT(MyRB));
 143    MyRB = 42; /* an arbitrary ID */
 144
 145    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
 146    assert(glIsFramebufferEXT(MyFB));
 147    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, MyRB);
 148    assert(glIsRenderbufferEXT(MyRB));
 149
 150    glGetIntegerv(GL_RENDERBUFFER_BINDING_EXT, &i);
 151    assert(i == MyRB);
 152
 153    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
 154    assert(i == MyFB);
 155
 156    CheckError(__LINE__);
 157    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT1_EXT,
 158                                 GL_RENDERBUFFER_EXT, MyRB);
 159
 160    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
 161
 162    CheckError(__LINE__);
 163
 164    {
 165       GLint r, g, b, a;
 166       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 167                                       GL_RENDERBUFFER_RED_SIZE_EXT, &r);
 168       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 169                                       GL_RENDERBUFFER_GREEN_SIZE_EXT, &g);
 170       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 171                                       GL_RENDERBUFFER_BLUE_SIZE_EXT, &b);
 172       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 173                                       GL_RENDERBUFFER_ALPHA_SIZE_EXT, &a);
 174       CheckError(__LINE__);
 175       printf("renderbuffer RGBA sizes = %d %d %d %d\n", r, g, b, a);
 176
 177       glGetIntegerv(GL_RED_BITS, &r);
 178       glGetIntegerv(GL_GREEN_BITS, &g);
 179       glGetIntegerv(GL_BLUE_BITS, &b);
 180       glGetIntegerv(GL_ALPHA_BITS, &a);
 181       printf("Visual RGBA sizes = %d %d %d %d\n", r, g, b, a);
 182    }
 183
 184    /* restore to default */
 185    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
 186    CheckError(__LINE__);
 187 }
 188
 189
 190 int
 191 main( int argc, char *argv[] )
 192 {
 193    glutInit( &argc, argv );
 194    glutInitWindowPosition( 0, 0 );
 195    glutInitWindowSize(Width, Height);
 196    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 197    glutCreateWindow(argv[0]);
 198    glutReshapeFunc( Reshape );
 199    glutKeyboardFunc( Key );
 200    glutDisplayFunc( Display );
 201    Init();
 202    glutMainLoop();
 203    return 0;
 204 }