Has anyone tried raytacing lighting in 2D using hlsl?
So far, I've come up with thhis
float4 RenderLightPS( float2 Tex : TEXCOORD0 ) : COLOR0
{
float2 pixelPos;
pixelPos.x = Tex.x * 800.0f;
pixelPos.y = Tex.y * 600.0f;
float2 lPos;
lPos.x = lightPos.x;
lPos.y = lightPos.y;
float att = lightRadius - distance(lPos, pixelPos);
att = clamp(att,0,lightRadius);
att = att / lightRadius;
int i;
float nx = lPos.x - pixelPos.x;
float ny = lPos.y - pixelPos.y;
float2 NYV;
NYV.x = nx;
NYV.y = ny;
float2 NEV;
NEV = 0.0f;
float dst = distance(NYV,NEV);
nx = nx / dst;
ny = ny / dst;
float lR = 256;
for(i=0; i<lR;i++);
{
float2 samPos;
samPos.x = pixelPos.x;
samPos.y = pixelPos.x;
samPos.x += nx * i;
samPos.y += ny * i;
float4 sam = tex2D(texSampler0, samPos);
att = att * sam.x;
}
return float4(att,att,att,1);
}
Where the texture in texture stage 0 contains a "depth" map, as in empty space is rgba(1,1,1,1) and fully opaque space is rgba(0,0,0,1), 800x600. This hlsl shader is run on a texture which is 800x600, with an additive pass(Source*One + Dest * One) for each light. The texture is multiplied by the scene to apply lighting to the scene.
When rendered, it looks like this
Looks a bit wierd, but the lights and objects were randomly positioned and colored. Note that the left-most light is a spotlight.
So,anyone else tried this?
