GL_FRAMEBUFFER example c c++ java

Name

glBindFramebuffer — bind a framebuffer to a framebuffer target - GL_FRAMEBUFFER

C Specification

void glBindFramebuffer(	GLenum	target,
	GLuint	framebuffer);

Parameters

target

Specifies the framebuffer target of the binding operation.

framebuffer

Specifies the name of the framebuffer object to bind.

Description

glBindFramebuffer binds the framebuffer object with name framebuffer to the framebuffer target specified by target. target must be either GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER or GL_FRAMEBUFFER. If a framebuffer object is bound to GL_DRAW_FRAMEBUFFER or GL_READ_FRAMEBUFFER, it becomes the target for rendering or readback operations, respectively, until it is deleted or another framebuffer is bound to the corresponding bind point. Calling glBindFramebuffer with target set to GL_FRAMEBUFFER binds framebuffer to both the read and draw framebuffer targets. framebuffer is the name of a framebuffer object previously returned from a call to glGenFramebuffers, or zero to break the existing binding of a framebuffer object to target.

Errors

GL_INVALID_ENUM is generated if target is not GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER or GL_FRAMEBUFFER.
GL_INVALID_OPERATION is generated if framebuffer is not zero or the name of a framebuffer previously returned from a call to glGenFramebuffers.

See Also

glGenFramebuffers, glDeleteFramebuffers, glFramebufferRenderbuffer, glFramebufferTexture, glFramebufferTexture1D, glFramebufferTexture2D, glFramebufferTexture3D,glFramebufferTextureFace, glFramebufferTextureLayer, glIsFramebuffer

Copyright

Copyright © 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.

Example of GL_FRAMEBUFFER

// This function does any needed initialization on the rendering

// context. 

void SetupRC()

{

    fprintf(stdout, "FBO Draw Buffers Demo\n\n");

    // Make sure required functionality is available: cube maps, auto mip gen, etc.

    if (!GLEE_VERSION_1_4)

    {

        fprintf(stderr, "OpenGL 1.4 is not available!\n");

        Sleep(2000);

        exit(0);

    }

    if (GLEE_ARB_texture_non_power_of_two)

    {

        npotTexturesAvailable = GL_TRUE;

    }

    else

    {

        fprintf(stderr, "GL_ARB_texture_non_power_of_two extension is not available!\n");

        fprintf(stderr, "Framebuffer effects will be lower resolution (lower quality).\n\n");

    }

    if (!GLEE_EXT_framebuffer_object)

    {

        fprintf(stderr, "GL_EXT_framebuffer_object extension is unavailable!\n");

        Sleep(2000);

        exit(0);

    }

    // we'll use up to 4 render targets if they're available

    glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxDrawBuffers);

    glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &maxColorAttachments);

    glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &maxTexUnits);

    maxDrawBuffers = (maxDrawBuffers > maxColorAttachments) ? maxColorAttachments : maxDrawBuffers;

    maxDrawBuffers = (maxDrawBuffers > (maxTexUnits-1)) ? (maxTexUnits-1) : maxDrawBuffers;

    maxDrawBuffers = (maxDrawBuffers > 4) ? 4 : maxDrawBuffers;

    if (((!GLEE_ARB_draw_buffers || !GLEE_ARB_fragment_shader || !GLEE_ARB_shader_objects) 

        && !GLEE_VERSION_2_0) || (maxDrawBuffers != 4))

    {

        fprintf(stderr, "Support for at least 4 draw buffers is unavailable!\n");

        Sleep(2000);

        exit(0);

    }

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTexSize);

    glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE_EXT, &maxRenderbufferSize);

    maxTexSize = (maxRenderbufferSize > maxTexSize) ? maxTexSize : maxRenderbufferSize;

    fprintf(stdout, "Controls:\n");

    fprintf(stdout, "\tRight-click for menu\n\n");

    fprintf(stdout, "\tx/X\t\tMove +/- in x direction\n");

    fprintf(stdout, "\ty/Y\t\tMove +/- in y direction\n");

    fprintf(stdout, "\tz/Z\t\tMove +/- in z direction\n\n");

    fprintf(stdout, "\td/D\t\tToggle use of draw buffers\n\n");

    fprintf(stdout, "\tq\t\tExit demo\n\n");

    

    // Black background

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f );

    // Hidden surface removal

    glEnable(GL_DEPTH_TEST);

    glDepthFunc(GL_LEQUAL);

    // Set up some lighting state that never changes

    glShadeModel(GL_SMOOTH);

    glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);

    glLightfv(GL_LIGHT0, GL_AMBIENT, ambientLight);

    glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);

    glLightfv(GL_LIGHT0, GL_SPECULAR, specularLight);

    glLightfv(GL_LIGHT0, GL_POSITION, lightPos);

    glMaterialfv(GL_FRONT, GL_SPECULAR, specularLight);

    glMateriali(GL_FRONT, GL_SHININESS, 128);

    glEnable(GL_LIGHTING);

    glEnable(GL_COLOR_MATERIAL);

    glEnable(GL_NORMALIZE);

    glEnable(GL_LIGHT0);

    // Set up textures & shaders

    SetupTextures();

    SetupShaders();

    // Set up some renderbuffer state

    glGenRenderbuffersEXT(1, &renderbufferID);

    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, renderbufferID);

    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT32, fboWidth, fboHeight);

    glGenFramebuffersEXT(2, framebufferID);

    //glBindFramebuffer(GL_FRAMEBUFFER, framebufferID[0]);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[0]);

    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, renderbufferID);

    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[0], 0);

    //glBindFramebuffer(GL_FRAMEBUFFER, framebufferID[1]);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[1]);

    for (int i = 0; i < maxDrawBuffers; i++)

    {

        glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT + i, GL_TEXTURE_2D, renderTextureID[i+1], 0);

    }

    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

}