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 Win;
  17 static int Width = 400, Height = 400;
  18 static GLuint MyFB, MyRB;
  19
  20
  21 static void
  22 CheckError(int line)
  23 {
  24    GLenum err = glGetError();
  25    if (err) {
  26       printf("GL Error 0x%x at line %d\n", (int) err, line);
  27    }
  28 }
  29
  30
  31 static void
  32 Display( void )
  33 {
  34    GLubyte *buffer = malloc(Width * Height * 4);
  35    GLenum status;
  36
  37    /* draw to user framebuffer */
  38    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
  39    glDrawBuffer(GL_COLOR_ATTACHMENT1_EXT);
  40    glReadBuffer(GL_COLOR_ATTACHMENT1_EXT);
  41
  42    status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
  43    if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
  44       printf("Framebuffer incomplete!!!\n");
  45    }
  46
  47    glClearColor(0.5, 0.5, 1.0, 0.0);
  48    glClear( GL_COLOR_BUFFER_BIT );
  49
  50    glBegin(GL_POLYGON);
  51    glColor3f(1, 0, 0);
  52    glVertex2f(-1, -1);
  53    glColor3f(0, 1, 0);
  54    glVertex2f(1, -1);
  55    glColor3f(0, 0, 1);
  56    glVertex2f(0, 1);
  57    glEnd();
  58
  59    /* read from user framebuffer */
  60    glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
  61
  62    /* draw to window */
  63    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
  64    glWindowPos2iARB(0, 0);
  65    glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
  66
  67    free(buffer);
  68    glutSwapBuffers();
  69    CheckError(__LINE__);
  70 }
  71
  72
  73 static void
  74 Reshape( int width, int height )
  75 {
  76 #if 0
  77    float ar = (float) width / (float) height;
  78 #endif
  79    glViewport( 0, 0, width, height );
  80    glMatrixMode( GL_PROJECTION );
  81    glLoadIdentity();
  82 #if 0
  83    glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
  84 #else
  85    glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
  86 #endif
  87    glMatrixMode( GL_MODELVIEW );
  88    glLoadIdentity();
  89    glTranslatef( 0.0, 0.0, -15.0 );
  90    Width = width;
  91    Height = height;
  92    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
  93 }
  94
  95
  96 static void
  97 CleanUp(void)
  98 {
  99    glDeleteFramebuffersEXT(1, &MyFB);
 100    glDeleteRenderbuffersEXT(1, &MyRB);
 101    assert(!glIsFramebufferEXT(MyFB));
 102    assert(!glIsRenderbufferEXT(MyRB));
 103    glutDestroyWindow(Win);
 104    exit(0);
 105 }
 106
 107
 108 static void
 109 Key( unsigned char key, int x, int y )
 110 {
 111    (void) x;
 112    (void) y;
 113    switch (key) {
 114       case 27:
 115          CleanUp();
 116          break;
 117    }
 118    glutPostRedisplay();
 119 }
 120
 121
 122 static void
 123 Init( void )
 124 {
 125    GLint i;
 126
 127    if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
 128       printf("GL_EXT_framebuffer_object not found!\n");
 129       /*exit(0);*/
 130    }
 131    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 132
 133    glGenFramebuffersEXT(1, &MyFB);
 134    assert(MyFB);
 135    assert(!glIsFramebufferEXT(MyFB));
 136    glDeleteFramebuffersEXT(1, &MyFB);
 137    assert(!glIsFramebufferEXT(MyFB));
 138    /* Note, continue to use MyFB below */
 139
 140    glGenRenderbuffersEXT(1, &MyRB);
 141    assert(MyRB);
 142    assert(!glIsRenderbufferEXT(MyRB));
 143    glDeleteRenderbuffersEXT(1, &MyRB);
 144    assert(!glIsRenderbufferEXT(MyRB));
 145    MyRB = 42; /* an arbitrary ID */
 146
 147    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
 148    assert(glIsFramebufferEXT(MyFB));
 149    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, MyRB);
 150    assert(glIsRenderbufferEXT(MyRB));
 151
 152    glGetIntegerv(GL_RENDERBUFFER_BINDING_EXT, &i);
 153    assert(i == MyRB);
 154
 155    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
 156    assert(i == MyFB);
 157
 158    CheckError(__LINE__);
 159    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT1_EXT,
 160                                 GL_RENDERBUFFER_EXT, MyRB);
 161
 162    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGB, Width, Height);
 163
 164    CheckError(__LINE__);
 165
 166    {
 167       GLint r, g, b, a;
 168       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 169                                       GL_RENDERBUFFER_RED_SIZE_EXT, &r);
 170       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 171                                       GL_RENDERBUFFER_GREEN_SIZE_EXT, &g);
 172       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 173                                       GL_RENDERBUFFER_BLUE_SIZE_EXT, &b);
 174       glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
 175                                       GL_RENDERBUFFER_ALPHA_SIZE_EXT, &a);
 176       CheckError(__LINE__);
 177       printf("renderbuffer RGBA sizes = %d %d %d %d\n", r, g, b, a);
 178
 179       glGetIntegerv(GL_RED_BITS, &r);
 180       glGetIntegerv(GL_GREEN_BITS, &g);
 181       glGetIntegerv(GL_BLUE_BITS, &b);
 182       glGetIntegerv(GL_ALPHA_BITS, &a);
 183       printf("Visual RGBA sizes = %d %d %d %d\n", r, g, b, a);
 184    }
 185
 186    /* restore to default */
 187    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
 188    CheckError(__LINE__);
 189 }
 190
 191
 192 int
 193 main( int argc, char *argv[] )
 194 {
 195    glutInit( &argc, argv );
 196    glutInitWindowPosition( 0, 0 );
 197    glutInitWindowSize(Width, Height);
 198    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 199    Win = glutCreateWindow(argv[0]);
 200    glutReshapeFunc( Reshape );
 201    glutKeyboardFunc( Key );
 202    glutDisplayFunc( Display );
 203    Init();
 204    glutMainLoop();
 205    return 0;
 206 }