src/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;
  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 }
  69
  70
  71 static void
  72 Reshape( int width, int height )
  73 {
  74    float ar = (float) width / (float) height;
  75    glViewport( 0, 0, width, height );
  76    glMatrixMode( GL_PROJECTION );
  77    glLoadIdentity();
  78 #if 0
  79    glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
  80 #else
  81    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  82 #endif
  83    glMatrixMode( GL_MODELVIEW );
  84    glLoadIdentity();
  85    glTranslatef( 0.0, 0.0, -15.0 );
  86    Width = width;
  87    Height = height;
  88    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
  89 }
  90
  91
  92 static void
  93 Key( unsigned char key, int x, int y )
  94 {
  95    (void) x;
  96    (void) y;
  97    switch (key) {
  98       case 27:
  99          exit(0);
 100          break;
 101    }
 102    glutPostRedisplay();
 103 }
 104
 105
 106 static void
 107 Init( void )
 108 {
 109    GLuint rb;
 110    GLint i;
 111
 112    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 113       printf("GL_EXT_framebuffer_object not found!\n");
 114       /*exit(0);*/
 115    }
 116    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 117
 118    glGenFramebuffersEXT(1, &MyFB);
 119    assert(MyFB);
 120    assert(glIsFramebufferEXT(MyFB));
 121    glDeleteFramebuffersEXT(1, &MyFB);
 122    assert(!glIsFramebufferEXT(MyFB));
 123    /* Note, continue to use MyFB below */
 124
 125    glGenRenderbuffersEXT(1, &rb);
 126    assert(rb);
 127    assert(glIsRenderbufferEXT(rb));
 128    glDeleteRenderbuffersEXT(1, &rb);
 129    assert(!glIsRenderbufferEXT(rb));
 130    rb = 42; /* an arbitrary ID */
 131
 132    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
 133    assert(glIsFramebufferEXT(MyFB));
 134    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rb);
 135    assert(glIsRenderbufferEXT(rb));
 136
 137    glGetIntegerv(GL_RENDERBUFFER_BINDING_EXT, &i);
 138    assert(i == rb);
 139
 140    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
 141    assert(i == MyFB);
 142
 143    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT1_EXT,
 144                                 GL_RENDERBUFFER_EXT, rb);
 145
 146    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
 147
 148    {
 149       GLint r, g, b, a;
 150       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 151                                       GL_RENDERBUFFER_RED_SIZE_EXT, &r);
 152       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 153                                       GL_RENDERBUFFER_GREEN_SIZE_EXT, &g);
 154       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 155                                       GL_RENDERBUFFER_BLUE_SIZE_EXT, &b);
 156       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 157                                       GL_RENDERBUFFER_ALPHA_SIZE_EXT, &a);
 158       printf("renderbuffer RGBA sizes = %d %d %d %d\n", r, g, b, a);
 159    }
 160
 161    CheckError(__LINE__);
 162
 163    /* restore to default */
 164    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
 165 }
 166
 167
 168 int
 169 main( int argc, char *argv[] )
 170 {
 171    glutInit( &argc, argv );
 172    glutInitWindowPosition( 0, 0 );
 173    glutInitWindowSize(Width, Height);
 174    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 175    glutCreateWindow(argv[0]);
 176    glutReshapeFunc( Reshape );
 177    glutKeyboardFunc( Key );
 178    glutDisplayFunc( Display );
 179    Init();
 180    glutMainLoop();
 181    return 0;
 182 }