Can you show us the code in question and tell what line triggers the error ?
Just a guess: SM 2 is rather restrictive in the pixel shader on what you can do with the texcoords before you sample. If hardware allows, check if you can run it with SM 3.
Here's my version of the entire shader, I've also highlighted the line that throws the error. I should also point out I've commented out the use of "* g_intensity; " and I still get the error, however commenting out "max1" instead and I don't get the error.
P.S. Please excuse the poor naming conventions, I've thrown a lot of temporary names around for the purposes of debugging.
texture normalTex;
texture positionTex;
texture randomTex;
float random_size;
float g_sample_rad;
float g_intensity;
float g_scale;
float g_bias;
float2 g_screen_size;
sampler g_buffer_norm : register(s0) = sampler_state
{
Texture = (normalTex);
MinFilter = Linear;
MagFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};
sampler g_buffer_pos: register(s0) = sampler_state
{
Texture = (positionTex);
MinFilter = Linear;
MagFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};
sampler g_random: register(s0) = sampler_state
{
Texture = (randomTex);
MinFilter = Linear;
MagFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};
struct PS_INPUT
{
float2 uv : TEXCOORD0;
};
struct PS_OUTPUT
{
float4 color : COLOR0;
};
float3 getPosition(in float2 uv)
{
return tex2D(g_buffer_pos,uv).xyz;
}
float3 getNormal(in float2 uv)
{
return normalize(tex2D(g_buffer_norm, uv).xyz * 2.0f - 1.0f);
}
float2 getRandom(in float2 uv)
{
return normalize(tex2D(g_random, g_screen_size * uv / random_size).xy * 2.0f - 1.0f);
}
float doAmbientOcclusion(in float2 tcoord , in float2 uv, in float3 p, in float3 cnorm)
{
float3 diff = getPosition(tcoord + uv) - p;
const float3 v = normalize(diff);
const float d = length(diff)*g_scale;
float dot1 = (dot(cnorm,v)-g_bias)*(1.0/(1.0+d));
float max1 = max(0.0, dot1);
return max1*g_intensity; ///<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
}
PS_OUTPUT main(PS_INPUT i)
{
PS_OUTPUT o = (PS_OUTPUT)0;
o.color.rgb = 1.0f;
const float2 vec[4] = {float2(1,0),float2(-1,0),
float2(0,1),float2(0,-1)};
float3 p = getPosition(i.uv);
float3 n = getNormal(i.uv);
float2 rand = getRandom(i.uv);
float ao = 0.0f;
float rad = g_sample_rad/p.z;
//**SSAO Calculation**//
int iterations = 4;
for (int j = 0; j < iterations; ++j)
{
float2 coord1 = reflect(vec[j],rand)*rad;
float2 coord2 = float2(coord1.x*0.707 - coord1.y*0.707,
coord1.x*0.707 + coord1.y*0.707);
ao += doAmbientOcclusion(i.uv,coord1*0.25, p, n);
ao += doAmbientOcclusion(i.uv,coord2*0.5, p, n);
ao += doAmbientOcclusion(i.uv,coord1*0.75, p, n);
ao += doAmbientOcclusion(i.uv,coord2, p, n);
}
ao/=(float)iterations*4.0;
//**END**//
o.color.rgb = ao;
//Do stuff here with your occlusion value “ao”: modulate ambient lighting, write it to a buffer for later //use, etc.
return o;
}
technique SSAO
{
pass P0
{
PixelShader = compile ps_3_0 main();
}
}
