#define CSM_MAXSPLITS 8
SamplerState shadowMapSampler
{
Filter = MIN_MAG_MIP_POINT;
AddressU = BORDER;
AddressV = BORDER;
BorderCOLOR = float4(1.0f,1.0f,1.0f,1.0f);
};
bool getSplitUV(in float posProjZ,in float3 posWorld,out uint split,out float2 uv,out float posLightZ)
{
split=1;
uv=0;
posLightZ=0;
[unroll (CSM_MAXSPLITS)]
for (;split<=g_CSM_nbSplits;split++)
if (posProjZ<g_CSM_depths[split].x) break;
split--;
if (split==g_CSM_nbSplits) return false;
float4 posLight=mul(float4(posWorld,1.0f),g_CSM_VP[split]);
posLight/=posLight.w;
posLightZ=posLight.z;
uv=(posLight.xy)*float2(0.5f,-0.5f)+0.5f;
return true;
}
float3 sampleColorCSM(in float posProjZ,in float3 posWorld,in float3 normalWorld)
{
uint split;
float2 uv;
float posLightZ,factor;
if (getSplitUV(posProjZ,posWorld,split,uv,posLightZ))
{
factor=saturate(dot(normalWorld,g_vDirectionalLightDirection));
factor=saturate(sqrt(1.0f-factor*factor)/factor)*g_CSM_depths[split].y;
factor=(g_CSMMaps.Sample(shadowMapSampler,float3(uv,split)).x+factor<posLightZ) ? 0.0f : 1.0f;
}
else
factor=1.0f;
return factor*g_ColorCSMMaps.Sample(shadowMapSampler,float3(uv,split)).xyz;
}
Thanks, it solved the problem
If you want to have a look on my HLSL colored csm sampling functions that use it :
....
PS :
[font=courier new,courier,monospace]g_CSM_depths[split].x[/font] is the minimal depth of the [font=courier new,courier,monospace]#split[/font] map, [font=courier new,courier,monospace]g_CSM_depths[split+1].x[/font] is the maximal depth of the [font=courier new,courier,monospace]#split[/font] map.
[font=courier new,courier,monospace]g_CSM_depths[split].y[/font] is the depth bias of the [font=courier new,courier,monospace]#split[/font] map
Any suggestion or improvement is welcome
cascadeDistances[NUM_CASCADES];
// In the pixel shader
splitIndex = 0;
for (int i = 0; i < NUM_CASCADES; i++)
splitIndex += (linearZ > cascadeDistances);
// Get shadow map position projected in light view
float4 shadowMapPos = mul(position, lightViewProj[splitIndex]);
Instead of using if statements while looping through split indices get the correct split index by adding up conditional statements for all the split tests. This does away with the need for branching.
...
[/quote]
thanks
So here's my last version [EDITED] :
#define CSM_MAXSPLITS 8
SamplerState shadowMapSampler
{
Filter = MIN_MAG_MIP_POINT;
AddressU = BORDER;
AddressV = BORDER;
BorderCOLOR = float4(1.0f,1.0f,1.0f,1.0f);
};
float3 sampleColorCSM(in float posProjZ,in float3 posWorld,in float3 normalWorld)
{
float3 uv;
float bias;
uint split=0;
float4 posLight;
if (posProjZ<g_CSM_depths[0].x || posProjZ>g_CSM_depths[g_CSM_nbSplits].x) return float3(1.0,1.0f,1.0f);
[unroll (CSM_MAXSPLITS)]
for (uint i=1;i<=g_CSM_nbSplits;i++)
split+=posProjZ>g_CSM_depths.x;
posLight=mul(float4(posWorld,1.0f),g_CSM_VP[split]);
posLight/=posLight.w;
bias=dot(normalWorld,-g_vDirectionalLightDirection);
bias=clamp(g_CSM_depths[split].y*sqrt(1.0f-bias*bias)/bias,g_CSM_depths[split].y,g_CSM_depths[split].z);
uv=float3(posLight.xy*float2(0.5f,-0.5f)+0.5f,split);
return (g_CSMMaps.Sample(shadowMapSampler,uv).x+bias>posLight.z)*g_ColorCSMMaps.Sample(shadowMapSampler,uv).xyz;
}
float sampleCSM(in float posProjZ,in float3 posWorld,in float3 normalWorld)
{
float3 uv;
float bias;
uint split=0;
float4 posLight;
if (posProjZ<g_CSM_depths[0].x || posProjZ>g_CSM_depths[g_CSM_nbSplits].x) return 1.0f;
[unroll (CSM_MAXSPLITS)]
for (uint i=1;i<=g_CSM_nbSplits;i++)
split+=posProjZ>g_CSM_depths.x;
posLight=mul(float4(posWorld,1.0f),g_CSM_VP[split]);
posLight/=posLight.w;
bias=dot(normalWorld,-g_vDirectionalLightDirection);
bias=clamp(g_CSM_depths[split].y*sqrt(1.0f-bias*bias)/bias,g_CSM_depths[split].y,g_CSM_depths[split].z);
uv=float3(posLight.xy*float2(0.5f,-0.5f)+0.5f,split);
return g_CSMMaps.Sample(shadowMapSampler,uv).x+bias>posLight.z;
}
[font=courier new,courier,monospace]g_CSM_depths[split].x[/font] is the minimal depth of the #split map, [font=courier new,courier,monospace]g_CSM_depths[split+1].x[/font] is the maximal depth of the #split map.
[font=courier new,courier,monospace]g_CSM_depths[split].y[/font] is the minimal depth bias of the #split map (remove acne on flat surfaces)
[font=courier new,courier,monospace]g_CSM_depths[split].z[/font] is the maximal depth bias of the #split map (remove acne on bumped surfaces)
Thanks for reading
The splitIndex is determined by the distance of the pixel in the depth map, which then is used to choose what cascade to sample from and what transformation matrix to use for the cascade. No if statements needed for that, just begin with splitIndex at 0 and increase it (if necessary) through comparison statements.
[/font][/font][/font][/font]
[font=arial, helvetica, sans-serif][font=courier new,courier,monospace][font=arial,helvetica,sans-serif]Well the way I see it, you should always be sampling from a shadow map because as long as you transform your view-projection matrices correctly, all visible pixels will be overlapped with it.
factor=(g_CSMMaps.Sample(shadowMapSampler,float3(uv,split)).x+factor<posLightZ) ? 0.0f : 1.0f;
