[ІГРОГРАЙКО]

Да рах ты прав!
Запустилось у меня, но отрисовует только один шар:



Если:

float4 RayCastSimplePS(VertexShaderOutput input) : COLOR0
{ 
	//calculate projective texture coordinates
	//used to project the front and back position textures onto the cube
	float2 texC = input.pos.xy /= input.pos.w;
	texC.x =  0.5f*texC.x + 0.5f; 
	texC.y = -0.5f*texC.y + 0.5f;  
	
    float3 front = tex2D(FrontS, texC).xyz;
    float3 back = tex2D(BackS, texC).xyz;
    
    float3 dir = normalize(back - front);
    float4 pos = float4(input.texC, 0);
    
    float4 dst = float4(0, 0, 0, 0);
    float4 src = 0;
    
    float value = 0;
	
	float3 Step = dir * StepSize;
    
    for(int i = 0; i < 2; i++)
    {
		pos.w = 0;
		value = tex3D(VolumeS, pos).r;
				
		src = (float4)value;
		//src.a *= .1f; //reduce the alpha to have a more transparent result
					  //this needs to be adjusted based on the step size
					  //i.e. the more steps we take, the faster the alpha will grow	
			
		//Front to back blending
		// dst.rgb = dst.rgb + (1 - dst.a) * src.a * src.rgb
		// dst.a   = dst.a   + (1 - dst.a) * src.a		
		//src.rgb *= src.a;
		dst = (1.0f - dst.a)*src + dst;		
		
		//break from the loop when alpha gets high enough
		if(dst.a >= .9f)
			break;	
		
		//advance the current position
		pos.xyz += Step;
		
		//break if the position is greater than <1, 1, 1>
		if(pos.x > 1.0f || pos.y > 1.0f || pos.z > 1.0f)
			break;
    }
    
    return dst;
}

то вилетает:

Ошибка	2	E:\My Work\XNA to Silverlight\VolumeRayCasting_101\VolumeRayCasting\Content\Shaders\RayCasting.fx(112,8): error X5608: Compiled shader code uses too many arithmetic instruction slots (70). Max. allowed by the target (ps_2_0) is 64.
E:\My Work\XNA to Silverlight\VolumeRayCasting_101\VolumeRayCasting\Content\Shaders\RayCasting.fx(187,23): ID3DXEffectCompiler::CompileEffect: There was an error compiling expression
ID3DXEffectCompiler: Compilation failed

	E:\My Work\XNA to Silverlight\VolumeRayCasting_101\VolumeRayCasting\Content\Shaders\RayCasting.fx	VolumeRayCasting

Что с етим делать?
Как быть?