Advanced Programming with OpenGL ES 3.0 - Praise for OpenGL ES 30 Programming Guide - page 416

Example 14-25 Create a Depth Texture and Attach It to a Framebuffer Object

int InitShadowMap ( ESContext *esContext )
{
UserData userData = (UserData) esContext−>userData;
GLenum none = GL_NONE;

// use 1K x 1K texture for shadow map
userData−>shadowMapTextureWidth = 1024;
userData−>shadowMapTextureHeight = 1024;

glGenTextures ( 1, &userData−>shadowMapTextureId );
glBindTexture ( GL_TEXTURE_2D, userData−>shadowMapTextureId);
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_NEAREST );
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR );
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
GL_CLAMP_TO_EDGE );
glTexParameteri ( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,
GL_CLAMP_TO_EDGE );

// set up hardware comparison
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
GL_COMPARE_REF_TO_TEXTURE );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC,
GL_LEQUAL );

glTexImage2D ( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT16,
userData−>shadowMapTextureWidth,
userData−>shadowMapTextureHeight,
0, GL_DEPTH_COMPONENT, GL_UNSIGNED_SHORT,
NULL );

glBindTexture ( GL_TEXTURE_2D, 0 );

GLint defaultFramebuffer = 0;
glGetIntegerv ( GL_FRAMEBUFFER_BINDING,
&defaultFramebuffer );

// set up fbo
glGenFramebuffers ( 1, &userData−>shadowMapBufferId );
glBindFramebuffer ( GL_FRAMEBUFFER,
userData−>shadowMapBufferId );

glDrawBuffers ( 1, &none );

glFramebufferTexture2D ( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_TEXTURE_2D,
userData−>shadowMapTextureId, 0 );