Framebuffer Objects - Praise for OpenGL ES 30 Programming Guide - page 353

Example 12-3 Render to Depth Texture (continued)

glClearColor ( 0.0f, 0.0f, 0.0f, 1.0f );
glClear ( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

// Load uniforms for vertex and fragment shaders
// used to render to FBO. The vertex shader is the
// ES 1.1 vertex shader described in Example 8-8 in
// Chapter 8. The fragment shader outputs the color
// computed by vertex shader as fragment color and
// is described in Example 1-2 in Chapter 1.
set_fbo_texture_shader_and_uniforms( );

// drawing commands to the framebuffer object
draw_teapot( );

// render to window system-provided framebuffer
glBindFramebuffer ( GL_FRAMEBUFFER, 0 );

// Use depth texture to draw to window system framebuffer.
// We draw a quad that is the size of the viewport.
//
// The vertex shader outputs the vertex position and texture
// coordinates passed as inputs.
//
// The fragment shader uses the texture coordinate to sample
// the texture and uses this as the per-fragment color value.
set_screen_shader_and_uniforms( );
draw_screen_quad( );
}

// clean up
glDeleteFramebuffers ( l, &framebuffer );
glDeleteTextures ( 2, textures );

Figure 12-3 Render to Depth Texture