GPU Pro 4

142 II Rendering

// Vertex -Shader Stage

flat out vec2 tex_coord;

uniform sampler2D zbuffer ;

void main ( void)

{

tex_coord = gl_Vertex.xy;

float depth = SampleBuf (zbuffer , tex_coord).x;

// screen space --> canonical screen space

vec3 pos_css = MAP_0To1_ -1To1 ( vec3 ( gl_Vertex.xy, depth ));

// canonical screen space --> object space

vec3 pos_wcs = PointCSS2WCS ( zbuffer_css);

// world space --> clip space

gl_Position = gl_ModelViewProjectionMatrix *

vec4 (pos_wcs , 1.0);

}

// Geometry - Shader Stage

layout (points ) in;

layout (points , max_vertices = 1) out;

uniform int vol_depth;

flat in vec2 tex_coord[];

flat out vec2 gtex_coord;

void main ( void)

{

gtex_coord ...