Hi,
I've been playing around with point lights in my d3d engine and got one working using my shader.
Although on the 'attenuation' side I have a challenge:
- I can now only control attenuation by changing "lightRange" from a range of 0.0 to 1.0 (0.1 being a 'big' range, 0.9 being a 'small' range), and with this, the range is far to high, meaning that meshes far away are also lit (a little).
What I want to achieve is that I can use "lightRange" to pass in a value/range in 'units' in my scene, up to which the light falls of and at 'lightRange' also ends. For now linear falloff is fine (or another falloff calculation which is relatively easiest).
Can someone help me in the right direction?
/***********************************************************/
/** VARS NOT CONTROLLED BY ENGINE YET *********/
/***********************************************************/
float4 diffuseColor = { 0.8f, 0.8f, 0.8f, 0.0f }; // NEW
float3 lightPosition = { 0.0f, 2.0f, 0.0f }; // NEW
float lightRange = 0.9f; // NEW
// modelfile, just for effectedit
string XFile = "paving.x"; // model
/***********************************************************/
/** VARS CONTROLLED BY ENGINE *********/
/***********************************************************/
float4x4 World : WORLD;
float4x4 WorldInvTransp: WORLDINVTRANSP;
float4x4 ViewProj : VIEWPROJECTION;
float4 AmbientColor;
float AmbientIntensity;
float4 MatAmb : MATERIALAMBIENT;
float4 MatDiff: MATERIALDIFFUSE;
texture Tex0 < string name = "hungary009.jpg"; >;
/***********************************************************/
/** SAMPLER STATES FOR TEXTURING *********/
/***********************************************************/
sampler2D textureSampler = sampler_state
{
Texture = (Tex0);
MinFilter = ANISOTROPIC;
MagFilter = LINEAR;
MipFilter = LINEAR;
MaxAnisotropy = 4;
};
struct VS_INPUT
{
float4 Pos : POSITION0;
float4 Normal : NORMAL0;
float2 TexCoord : TEXCOORD0;
};
struct VS_OUTPUT
{
float4 Pos : POSITION;
float3 Normal : TEXCOORD1;
float2 TexCoord: TEXCOORD2;
float3 LightPos: TEXCOORD3;
float3 Att : TEXCOORD4;
};
/***********************************************************/
/** THE VERTEXSHADER PROGRAM *********/
/***********************************************************/
VS_OUTPUT VS_function(VS_INPUT input)
{
VS_OUTPUT Out = (VS_OUTPUT)0;
float4 worldPosition = mul(input.Pos, World);
Out.Pos = mul(worldPosition, ViewProj);
float4 normal = mul(input.Normal, WorldInvTransp);
Out.Normal = normal;
Out.TexCoord = input.TexCoord;
Out.LightPos = lightPosition.xyz - worldPosition;
Out.LightPos = normalize(Out.LightPos);
Out.Att = Out.LightPos * lightRange;
return Out;
}
/***********************************************************/
/** THE PIXELSHADER PROGRAM *********/
/***********************************************************/
float4 PS_function(VS_OUTPUT input): COLOR0
{
float4 textureColor = tex2D(textureSampler, input.TexCoord);
float lightIntensity = saturate(dot(input.Normal, input.LightPos));
float4 color = diffuseColor * lightIntensity;
float4 amb = AmbientColor * AmbientIntensity * MatAmb;
float4 attenuation = mul(input.Att, input.Att);
return saturate((color + amb) * textureColor) * MatDiff * (1-attenuation);
}
/***********************************************************/
/** OPAUQE SHADER, REGULAR MESHES *********/
/***********************************************************/
technique OpaqueShader
{
pass P0
{
AlphaBlendEnable = FALSE;
VertexShader = compile vs_2_0 VS_function();
PixelShader = compile ps_2_0 PS_function();
}
}
/***********************************************************/
/** BLENDING SHADER, MESHES WITH BLENDED TEXTURES *******/
/***********************************************************/
technique BlendingShader
{
pass P0
{
AlphaBlendEnable = TRUE;
SrcBlend = SRCALPHA;
DestBlend = INVSRCALPHA;
AlphaOp[0] = SelectArg1;
AlphaArg1[0] = Texture;
VertexShader = compile vs_2_0 VS_function();
PixelShader = compile ps_2_0 PS_function();
}
}
