Hello.
To create active water reflection, which reflects in-game objects, I am using a technique like Yann Lonbard's article on GameDev.
I never understood how he created the ripples, so instead I used a bumpMap. This works well, except I have ragged edges appearing around the edge of the screen:
I think this is because I am wobbling the projected texture coords. Heres my effect file:
float4x4 WorldView : WORLDVIEW;
float4x4 Projection : PROJECTION;
float4x4 TexProj;
float bumpHeight = 10.0;
float2 textureScale = { 8.0, 4.0 };
float2 bumpSpeed = { -0.002, 0.000 };
float time = 0.0f;
texture reflectMap;
texture normalMap;
sampler2D reflectMapSampler = sampler_state
{
Texture = <reflectMap>;
#if 0
// this is a trick from Halo - use point sampling for sparkles
MagFilter = Linear;
MinFilter = Point;
MipFilter = None;
#else
MagFilter = Linear;
MinFilter = Linear;
MipFilter = Linear;
#endif
};
sampler2D normalMapSampler = sampler_state
{
Texture = <normalMap>;
#if 0
// this is a trick from Halo - use point sampling for sparkles
MagFilter = Linear;
MinFilter = Point;
MipFilter = None;
#else
MagFilter = Linear;
MinFilter = Linear;
MipFilter = Linear;
#endif
};
////////////////////////////////////////////////////////////////////////////
struct VS_INPUT {
float3 Position : POSITION;
float3 Normal : NORMAL;
float2 Tex : TEXCOORD0;
};
struct VS_OUTPUT {
float4 Position : POSITION;
float4 TexProj : TEXCOORD0;
float2 Tex : TEXCOORD1;
float2 bumpCoord0 : TEXCOORD2;
float2 bumpCoord1 : TEXCOORD3;
// float2 bumpCoord2 : TEXCOORD4;
};
/////////////////////////////////////////////////////////////////////////////////
VS_OUTPUT reflectVS( VS_INPUT IN )
{
VS_OUTPUT OUT = (VS_OUTPUT)0;
float3 Pwv = mul(float4(IN.Position, 1), (float4x3)WorldView); // position (view space)
// float3 N = normalize(mul(IN.Normal, (float3x3)WorldView)); // normal (view space)
float4 Pwvp = mul(float4(Pwv, 1), Projection); // position (projected)
OUT.Position = Pwvp;
OUT.TexProj = mul(TexProj, Pwvp);
// pass texture coordinates for fetching the normal map
OUT.Tex.xy = IN.Tex*textureScale;
time = fmod(time, 100.0);
OUT.bumpCoord0.xy = IN.Tex*textureScale* + time*bumpSpeed;
OUT.bumpCoord1.yx = IN.Tex*-textureScale*2.0 + time*bumpSpeed*4.0;
//OUT.bumpCoord2.xy = IN.Tex*textureScale*4.0 + time*bumpSpeed*8.0;
return OUT;
}
float4 reflectPS( VS_OUTPUT IN ) : COLOR
{
float4 Color = (float4)0;
half4 t0 = tex2D(normalMapSampler, IN.bumpCoord0.xy)*2.0-1.0;
half4 t1 = tex2D(normalMapSampler, IN.bumpCoord1.xy)*2.0-1.0;
// half4 t2 = tex2D(normalMapSampler, IN.bumpCoord2.xy)*2.0-1.0;
half4 N = t0 + t1;// + t2;
N = normalize(N) * bumpHeight;
// projectively sample the 2D reflection texture
Color.rgb = tex2Dproj(reflectMapSampler, IN.TexProj + N ).rgb + 0.1;
Color.a = 1.0;
return Color;
}
technique t0
{
pass p0
{
VertexShader = compile vs_2_0 reflectVS();
Zenable = true;
ZWriteEnable = true;
// AlphaBlendEnable = true;
PixelShader = compile ps_2_0 reflectPS();
}
}
Can anyone suggest an alternative way to do this? I am not calculating any waves with the vertex shader.
Thank you.
Simon
