在上文中，会发现，调用3维柏林实现海水的波动效果，实在是难为CPU了，在这里，我们用着色器Cg语言来把相关计算过程移到GPU,看下效果。
先说下，原来纹理我们拿来只限于给模型着色，而在现代GPGPU中，有个比较重要的概念就是，纹理就是数组，想想也对，纹理原来我们放的是RGBA值，那么如果我们用来存取一些别的数据，而不是RGBA，在着色器中把纹理里数据取出来，而不是用于给模型着色,那能实现什么样的功能了。
本文中主要功能都在着色器中，故下面先给出着色器代码，包含原来的noise计算，还有动画与着色，可以对比上文F#代码来看。
1 //Fragment shader to write color for each pixel 2 3 #define ONE 0.00390625 4 #define ONEHALF 0.001953125 5 6 float fade(float t) { 7 //return t*t*(3.0-2.0*t); // Old fade 8 return t*t*t*(t*(t*6.0-15.0)+10.0); 9 // Improved fade 10 } 11 12 float noise(float3 P,sampler2D permTexture) 13 { 14 float3 Pi = ONE*floor(P)+ONEHALF; 15 float3 Pf = P-floor(P); 16 // Noise contributions from (x=0, y=0), z=0 and z=1 17 float perm00 = tex2D(permTexture, Pi.xy).a ; 18 float3 grad000 = tex2D(permTexture, float2(perm00, Pi.z)).rgb * 4.0 - 1.0; 19 float n000 = dot(grad000, Pf); 20 float3 grad001 = tex2D(permTexture, float2(perm00, Pi.z + ONE)).rgb * 4.0 - 1.0; 21 float n001 = dot(grad001, Pf - float3(0.0, 0.0, 1.0)); 22 // Noise contributions from (x=0, y=1), z=0 and z=1 23 float perm01 = tex2D(permTexture, Pi.xy + float2(0.0, ONE)).a ; 24 float3 grad010 = tex2D(permTexture, float2(perm01, Pi.z)).rgb * 4.0 - 1.0; 25 float n010 = dot(grad010, Pf - float3(0.0, 1.0, 0.0)); 26 float3 grad011 = tex2D(permTexture, float2(perm01, Pi.z + ONE)).rgb * 4.0 - 1.0; 27 float n011 = dot(grad011, Pf - float3(0.0, 1.0, 1.0)); 28 // Noise contributions from (x=1, y=0), z=0 and z=1 29 float perm10 = tex2D(permTexture, Pi.xy + float2(ONE, 0.0)).a ; 30 float3 grad100 = tex2D(permTexture, float2(perm10, Pi.z)).rgb * 4.0 - 1.0; 31 float n100 = dot(grad100, Pf - float3(1.0, 0.0, 0.0)); 32 float3 grad101 = tex2D(permTexture, float2(perm10, Pi.z + ONE)).rgb * 4.0 - 1.0; 33 float n101 = dot(grad101, Pf - float3(1.0, 0.0, 1.0)); 34 // Noise contributions from (x=1, y=1), z=0 and z=1 35 float perm11 = tex2D(permTexture, Pi.xy + float2(ONE, ONE)).a ; 36 float3 grad110 = tex2D(permTexture, float2(perm11, Pi.z)).rgb * 4.0 - 1.0; 37 float n110 = dot(grad110, Pf - float3(1.0, 1.0, 0.0)); 38 float3 grad111 = tex2D(permTexture, float2(perm11, Pi.z + ONE)).rgb * 4.0 - 1.0; 39 float n111 = dot(grad111, Pf - float3(1.0, 1.0, 1.0)); 40 // Blend contributions along x 41 float4 n_x = lerp(float4(n000, n001, n010, n011), float4(n100, n101, n110, n111), fade(Pf.x)); 42 // Blend contributions along y 43 float2 n_xy = lerp(n_x.xy, n_x.zw, fade(Pf.y)); 44 // Blend contributions along z 45 float n_xyz = lerp(n_xy.x, n_xy.y, fade(Pf.z)); 46 return n_xyz; 47 } 48 49 50 float turbulence(int octaves, float3 P, float lacunarity, float gain,sampler2D permTexture) 51 { 52 float sum = 0; 53 float scale = 1; 54 float totalgain = 1; 55 for(int i=0;i<octaves;i++){ 56 sum += totalgain*noise(P*scale,permTexture); 57 scale *= lacunarity; 58 totalgain *= gain; 59 } 60 61 return abs(sum); 62 } 63 64 65 struct v_Output { 66 float4 position : POSITION; 67 float pc : TEXCOORD0; 68 } 69 ; 70 v_Output main(float3 position : POSITION, 71 uniform float4x4 mvp, 72 uniform float time, 73 uniform sampler2D permTexture) 74 { 75 v_Output OUT; 76 float3 pf = float3(position.xz,time); 77 //float ty = noise(pf,permTexture); 78 //水 79 //float ty = turbulence(4,pf,2,0.5,permTexture); 80 //float yy = ty * 0.5 + 0.5; 81 //火 82 float ty = turbulence(4,pf,0.6,4,permTexture); 83 float yy = ty * 0.2 + 0.5; 84 float4 pos = float4(position.x,yy,position.z,1); 85 OUT.position = mul(mvp,pos); 86 OUT.pc = yy; 87 return OUT; 88 } 89 90 91 struct f_Output { 92 float4 color : COLOR; 93 } 94 ; 95 f_Output fragmentShader(v_Output vin) 96 { 97 f_Output OUT; 98 //水 99 //float3 color1 = float3(0.5*vin.pc, 0.8*vin.pc, 0.9*vin.pc); 100 //火 101 float3 color1 = float3(0.98*vin.pc, 0.6*vin.pc, 0.15*vin.pc); 102 OUT.color = float4(color1,1.0); 103 return OUT; 104 }