GPU Pro 6

320 IV Shadows

Face Horizontal FOV Vertical FOV

A 143.98570868 + α 125.26438968 + β

B 125.26438968 + β 143.98570868 + α

C 143.98570868 + α 125.26438968 + β

D 125.26438968 + β 143.98570868 + α

Table 2.2. Horizontal and vertical FOV in degrees to construct the perspective pro-

jection matrices for the four tetrahedron faces. As can be seen, faces A and C and,

respectively, faces B and D share the same values. In order to provide soft shadows, the

values from the original paper have to be adjusted by α and β.

vec3 centers [4] = { vec3 ( −1,0,−1) , vec3 (1 ,0 ,−1) , vec3 (0,−1,−1) ,

vec3 (0,1 ,−1) } ;

vec3 offsets [4] = { vec3(−r ,0 ,0) ,vec3 ( r ,0 ,0) ,