Name
glGenRenderbuffers — generate renderbuffer object names
C Specification
void glGenRenderbuffers( | GLsizei | n, |
| GLuint * | renderbuffers); |
Parameters
n- Specifies the number of renderbuffer object names to generate.
renderbuffers- Specifies an array in which the generated renderbuffer object names are stored.
Description
glGenRenderbuffers returns n renderbuffer object names in renderbuffers. There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to glGenRenderbuffers.Renderbuffer object names returned by a call to
glGenRenderbuffers are not returned by subsequent calls, unless they are first deleted with glDeleteRenderbuffers.The names returned in
renderbuffers are marked as used, for the purposes of glGenRenderbuffers only, but they acquire state and type only when they are first bound.Errors
GL_INVALID_VALUE is generated if n is negative.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 glGenRenderbuffers
// 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);
}
