一个HLSL的常量数组问题

 

在RenderMonkey里写了RNM的demo:

 float fUvScale; sampler2D diffuseMap; sampler2D normalMap; sampler2D lightMap1; sampler2D lightMap2; sampler2D lightMap3; const float3 bumpBasis[3] = { {sqrt(2.0 / 3.0), 0.0, 1.0 / sqrt(3.0)}, {-1.0 / sqrt(6.0), -1.0 / sqrt(2.0), 1.0 / sqrt(3.0)}, {-1.0 / sqrt(6.0), 1.0 / sqrt(2.0), 1.0 / sqrt(3.0)}, }; struct PS_INPUT { float2 Texcoord0 : TEXCOORD0; float3 Texcoord1 : TEXCOORD1; }; float4 ps_main( PS_INPUT Input ) : COLOR0 { float3 normal = normalize((tex2D(normalMap, Input.Texcoord0).xyz * 2.0f) - 1.0f ); normal.y = -normal.y; float3 dp; dp.x = saturate(dot(normal, bumpBasis[0])); dp.y = saturate(dot(normal, bumpBasis[1])); dp.z = saturate(dot(normal, bumpBasis[2])); dp *= dp; float sum = dot(dp, float3(1.0, 1.0, 1.0)); dp *= 2.0; Input.Texcoord1 *= fUvScale; float3 diffuseLighting = dp.x * tex2D(lightMap1, Input.Texcoord1) + dp.y * tex2D(lightMap2, Input.Texcoord1) + dp.z * tex2D(lightMap3, Input.Texcoord1); diffuseLighting /= sum; float4 diffuse = tex2D(diffuseMap, Input.Texcoord0); diffuse.xyz = diffuseLighting; return diffuse; }

效果在这里面是正确的. 然后转到引擎里发现竟然变成这样了:

 

 

 

 

检查了贴图没问题, 那么只可能是bumpBasis的问题了. 把下面的引用换成float3(...)这种写死的表达式, 果然效果正确了:

要说环境有什么不同, 引擎里是写在.fx文件里的. 难道编译的时候被当成了外部传入的参数? 查了一下HLSL的说明, 发现有个修饰词:

static

Mark a local variable so that it is initialized one time and persists between function calls. If the declaration does not include an initializer, the value is set to zero. A global variable marked static is not visible to an application.

把const float3 bumpBasis[3]改成static const float3 bumpBasis[3], 果然问题没有了!

问题又来了, 为啥在RM里就是好的....而且以前我自己写类似功能时候也没有加static啊-_-