Im doing a water reflection shader and im getting a weird problem were as i decrease the height from the water or the plane its on. The water pulls sideways.
Im also seeing the bottom.
I checked the inflection point and it looks ok. But the behavior seems like it is that as i go to far down it flips.
So the back becomes the front. im not sure why its skewing like that either.
near the edge of the world
way down after i get the weird warping and then things seem to flip or something.
Maybe im not doing it right at all ?
My shader looks like this so far with comments.
//_______________________________________________________________
// technique
// ReflectionWaterShader.
//
// TextureCubeSampler
//_______________________________________________________________
// ToDo ....
//__________________________________________________________
struct VsInReflectionWater
{
float4 Position : POSITION0;
float3 Normal : NORMAL0;
float2 TexureCoordinateA : TEXCOORD0;
};
struct VsOutReflectionWater
{
float4 Position : SV_Position;
float2 TexureCoordinateA : TEXCOORD0;
float4 Position3D : TEXCOORD1;
float3 Normal : TEXCOORD2;
//float3 thisToPixel : TEXCOORD3;
};
// shaders
VsOutReflectionWater VsReflectionWater(VsInReflectionWater input)
{
VsOutReflectionWater output;
output.Position3D = mul(input.Position, World);
//output.thisToPixel = output.Position3D - World._m30_m31_m32;
float4x4 vp = mul(View, Projection);
output.Position = mul(output.Position3D, vp);
output.TexureCoordinateA = input.TexureCoordinateA;
output.Normal = normalize(mul(input.Normal, World)); // Reminder, if we want to rotate a scaled world normal we need to renormalize it.
return output;
}
float4 PsReflectionWater(VsOutReflectionWater input) : Color
{
float3 cubeDir = normalize(input.Position3D - InflectionOrReflectionVector);
float4 reflectionCubeColor = texCUBE(TextureCubeSampler, cubeDir); // -input.cubeDir
return float4(reflectionCubeColor.xyz, 1.0f);
}
technique ReflectionWaterShader
{
pass
{
VertexShader = compile VS_SHADERMODEL VsReflectionWater();
PixelShader = compile PS_SHADERMODEL PsReflectionWater();
}
}
Here my calculation for the inflected camera position under the water plane.
It looks like it works when i draw lines to see it.
Vector3 InflectionPositionFromPlane(Vector3 theCameraPostion, Vector3 thePlanesSurfaceNormal, Vector3 anyPositionOnThePlane)
{
var directionVector = thePlanesSurfaceNormal * -Vector3.Dot(thePlanesSurfaceNormal, (theCameraPostion - anyPositionOnThePlane));
var pointOnSurface = directionVector + theCameraPostion;
var surfaceDistance = Vector3.Distance(theCameraPostion, pointOnSurface);
return pointOnSurface - theCameraPostion;
}
