glFramebufferTexture2D example c c++ java objc

Name

glFramebufferTexture2D — attach a level of a texture object as a logical buffer to the currently bound framebuffer object

C Specification

void glFramebufferTexture(	GLenum target,
	GLenum attachment,
	GLuint texture,
	GLint level);

void glFramebufferTexture1D(	GLenum target,
	GLenum attachment,
	GLenum textarget,
	GLuint texture,
	GLint level);

void glFramebufferTexture2D(	GLenum target,
	GLenum attachment,
	GLenum textarget,
	GLuint texture,
	GLint level);

void glFramebufferTexture3D(	GLenum target,
	GLenum attachment,
	GLenum textarget,
	GLuint texture,
	GLint level,
	GLint layer);

Parameters

target

Specifies the framebuffer target. target must be GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER, or GL_FRAMEBUFFER. GL_FRAMEBUFFER is equivalent to GL_DRAW_FRAMEBUFFER.

attachment

Specifies the attachment point of the framebuffer. attachment must be GL_COLOR_ATTACHMENTi, GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT or GL_DEPTH_STENCIL_ATTACHMMENT.

textarget

For glFramebufferTexture1D, glFramebufferTexture2D and glFramebufferTexture3D, specifies what type of texture is expected in the texture parameter, or for cube map textures, which face is to be attached.

texture

Specifies the texture object to attach to the framebuffer attachment point named by attachment.

level

Specifies the mipmap level of texture to attach.

Description

glFramebufferTexture, glFramebufferTexture1D, glFramebufferTexture2D, and glFramebufferTexture attach a selected mipmap level or image of a texture object as one of the logical buffers of the framebuffer object currently bound to target. target must be GL_DRAW_FRAMEBUFFER, GL_READ_FRAMEBUFFER, or GL_FRAMEBUFFER. GL_FRAMEBUFFER is equivalent to GL_DRAW_FRAMEBUFFER.
attachment specifies the logical attachment of the framebuffer and must be GL_COLOR_ATTACHMENTi, GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT or GL_DEPTH_STENCIL_ATTACHMMENT. i inGL_COLOR_ATTACHMENTi may range from zero to the value of GL_MAX_COLOR_ATTACHMENTS - 1. Attaching a level of a texture to GL_DEPTH_STENCIL_ATTACHMENT is equivalent to attaching that level to both the GL_DEPTH_ATTACHMENT and the GL_STENCIL_ATTACHMENT attachment points simultaneously.
textarget specifies what type of texture is named by texture, and for cube map textures, specifies the face that is to be attached. If texture is not zero, it must be the name of an existing texture with typetextarget, unless it is a cube map texture, in which case textarget must be GL_TEXTURE_CUBE_MAP_POSITIVE_X GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.
If texture is non-zero, the specified level of the texture object named texture is attached to the framebfufer attachment point named by attachment. For glFramebufferTexture1D,glFramebufferTexture2D, and glFramebufferTexture3D, texture must be zero or the name of an existing texture with a target of textarget, or texture must be the name of an existing cube-map texture and textarget must be one of GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_X,GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.
If textarget is GL_TEXTURE_RECTANGLE, GL_TEXTURE_2D_MULTISAMPLE, or GL_TEXTURE_2D_MULTISAMPLE_ARRAY, then level must be zero. If textarget is GL_TEXTURE_3D, then level must be greater than or equal to zero and less than or equal to log₂ of the value of GL_MAX_3D_TEXTURE_SIZE. If textarget is one of GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y,GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_X, GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, or GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, then level must be greater than or equal to zero and less than or equal to log₂ of the value of GL_MAX_CUBE_MAP_TEXTURE_SIZE. For all other values of textarget, level must be greater than or equal to zero and no larger than log₂ of the value of GL_MAX_TEXTURE_SIZE.
layer specifies the layer of a 2-dimensional image within a 3-dimensional texture.
For glFramebufferTexture1D, if texture is not zero, then textarget must be GL_TEXTURE_1D. For glFramebufferTexture2D, if texture is not zero, textarget must be one of GL_TEXTURE_2D,GL_TEXTURE_RECTANGLE, GL_TEXTURE_CUBE_MAP_POSITIVE_X, GL_TEXTURE_CUBE_MAP_POSITIVE_Y, GL_TEXTURE_CUBE_MAP_POSITIVE_Z, GL_TEXTURE_CUBE_MAP_NEGATIVE_X,GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or GL_TEXTURE_2D_MULTISAMPLE. For glFramebufferTexture3D, if texture is not zero, then textarget must beGL_TEXTURE_3D.

Notes on glFramebufferTexture2D

glFramebufferTexture is available only if the GL version is 3.2 or greater.

Errors

GL_INVALID_ENUM is generated if target is not one of the accepted tokens.
GL_INVALID_ENUM is generated if renderbuffertarget is not GL_RENDERBUFFER.
GL_INVALID_OPERATION is generated if zero is bound to target.
GL_INVALID_OPERATION is generated if textarget and texture are not compatible.

See Also

glGenFramebuffers, glBindFramebuffer, glGenRenderbuffers, glFramebufferTexture, glFramebufferTexture1D, glFramebufferTexture2D, glFramebufferTexture3D

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 glFramebufferTexture2D

// 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);

    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);

    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);

}