GeneralsZeroHour/GeneralsMD/Code/GameEngineDevice/Source/W3DDevice/GameClient/Shaders/Trees.nvv

;
;	Command & Conquer Generals Zero Hour(tm)
;	Copyright 2025 Electronic Arts Inc.
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;	GNU General Public License for more details.
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//vertex shader for grass..
// v0   - Vertex Position
// v1   - Normal vector - used for other fun stuff.
//      - v1.x = index for the motion wave data 
//      - v1.y = color scale factor for darkening.
//      - v1.z = z coordinate value of the base of the tree/grass/bush.
// v2   - Diffuse color
// v7   - Vertex Texture Data u,v 
// c4-7  - Composite World-View-Projection Matrix
// c8  - Tilt vector.
// c32  - offset for shroud texture mapping
// c33  - scale for shroud texture mapping

vs.1.1


mov  r2, v1.wwzw    ; move the z value for the tree into r2
sub  r2, v0, r2     ; subtract the z from the base coordinate.
mov  a0.x, v1       ; get the index for the wave value.
mov  r0, c[a0.x+8]  ; load the correct wave entry for this tree/grass
mad  r1, r2.zzzw,r0,v0 ; multiply the z value by wave value to get the xy skew value for the wave motion
                    ; and add it to the coordinate value.
m4x4 oPos, r1, c4   ; Transform vertex to screen coords.
mov  r2, v1.yyyw    ; Get the color scale from v1.y
mul  oD0, v2,r2 	  ; Scale and move diffuse color into color register.
mov  oT0, v7			  ; Move texture coords into texture register.

add  r1, v0, c32    ; offset coordinate
mul  oT1, r1, c33    ;