shadowgen.nvv

游戏编程精华02－含有几十个游戏编程例子

/************************************************************************
ShadowGen.nvv

Implements per-pixel shadow buffers

    Using a special 2048x256 texture, we are able to achieve 11 bit per-
    object shdow depth buffers as well as 8 bit object IDs.

    This shader is designed to set up the TSS or pixel shader pipeline to
    test the generated shadow coordinates versus the shadow map's depth

Copyright (C) 1999, 2000 NVIDIA Corporation
*************************************************************************/

#include "Constants.h"

#define  ZERO           c[CV_CONSTANTS].x
#define  ONE            c[CV_CONSTANTS].y
#define  HALF           c[CV_CONSTANTS].z

vs.1.1

; Transform from model space into light space, and then
;  squish along light space Z so that 0 to 1 maps to texture

; oT0.x is both the Green & Blue distance dimensions
; oT0.y is the Red ObjectID Dimension

; initialize Z & W to 1
mov oT0, ONE

// Don't want or need W component of matrix b/c I'm using Z and projecting by W would just give me 1 for Z...
mov oT0.y, c[ CV_CURR_OBJECTID_IN_TEXELS ].x

dp4 oT0.x, v0, c[ CV_CURR_SQUISH_TXF_2 ].xyzw


; Transform position into clip space

dp4 oPos.x, v0, c[ CV_MVP_TXF_0 ];
dp4 oPos.y, v0, c[ CV_MVP_TXF_1 ];
dp4 oPos.z, v0, c[ CV_MVP_TXF_2 ];
dp4 oPos.w, v0, c[ CV_MVP_TXF_3 ];


// T1 contains the shadow map's distance to the light

dp4 oT1.x, v0, c[ CV_CURR_WORLD2LIGHT_TXF_0 ]
dp4 oT1.y, v0, c[ CV_CURR_WORLD2LIGHT_TXF_1 ]
dp4 oT1.z, v0, c[ CV_CURR_WORLD2LIGHT_TXF_2 ]
dp4 oT1.w, v0, c[ CV_CURR_WORLD2LIGHT_TXF_3 ]