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Implement shadows rendering to direct light atlas (with Glboal SDF tracing)

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This commit is contained in:
Wojciech Figat
2022-04-14 16:26:45 +02:00
parent 0668a23167
commit d52e70af6c
4 changed files with 61 additions and 13 deletions
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5
Source/Shaders/GlobalSignDistanceField.hlsl
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@@ -6,6 +6,7 @@
#define GLOBAL_SDF_RASTERIZE_CHUNK_SIZE 32
#define GLOBAL_SDF_RASTERIZE_CHUNK_MARGIN 4
#define GLOBAL_SDF_MIP_FLOODS 5
#define GLOBAL_SDF_WORLD_SIZE 60000.0f
// Global SDF data for a constant buffer
struct GlobalSDFData
@@ -61,7 +62,7 @@ float SampleGlobalSDF(const GlobalSDFData data, Texture3D<float> tex[4], float3
{
float distance = data.CascadePosDistance[3].w * 2.0f;
if (distance <= 0.0f)
return 60000;
return GLOBAL_SDF_WORLD_SIZE;
UNROLL
for (uint cascade = 0; cascade < 4; cascade++)
{
@@ -83,7 +84,7 @@ float SampleGlobalSDF(const GlobalSDFData data, Texture3D<float> tex[4], float3
float3 SampleGlobalSDFGradient(const GlobalSDFData data, Texture3D<float> tex[4], float3 worldPosition, out float distance)
{
float3 gradient = float3(0, 0.00001f, 0);
distance = 60000;
distance = GLOBAL_SDF_WORLD_SIZE;
if (data.CascadePosDistance[3].w <= 0.0f)
return gradient;
UNROLL

44
Source/Shaders/GlobalSurfaceAtlas.shader
View File

@@ -12,7 +12,8 @@
META_CB_BEGIN(0, Data)
float3 ViewWorldPos;
float ViewNearPlane;
float3 Padding00;
float2 Padding00;
float LightShadowsStrengthOneMinus;
float ViewFarPlane;
float4 ViewFrustumWorldRays[4];
GlobalSDFData GlobalSDF;
@@ -66,6 +67,8 @@ void PS_Clear(out float4 Light : SV_Target0, out float4 RT0 : SV_Target1, out fl
// GBuffer+Depth at 0-3 slots
Buffer<float4> GlobalSurfaceAtlasObjects : register(t4);
Texture3D<float> GlobalSDFTex[4] : register(t5);
Texture3D<float> GlobalSDFMip[4] : register(t9);
// Pixel shader for Global Surface Atlas shading with direct light contribution
META_PS(true, FEATURE_LEVEL_SM5)
@@ -81,11 +84,10 @@ float4 PS_DirectLighting(AtlasVertexOutput input) : SV_Target
// Load GBuffer sample from atlas
GBufferData gBufferData = (GBufferData)0;
GBufferSample gBuffer = SampleGBuffer(gBufferData, atlasUV);
// Skip unlit pixels
BRANCH
if (gBuffer.ShadingModel == SHADING_MODEL_UNLIT)
{
// Skip unlit pixels
discard;
return 0;
}
@@ -102,11 +104,43 @@ float4 PS_DirectLighting(AtlasVertexOutput input) : SV_Target
float4x4 tileLocalToWorld = Inverse(tile.WorldToLocal);
gBuffer.WorldPos = mul(float4(gBufferTilePos, 1), tileLocalToWorld).xyz;
// Calculate shadowing
float3 L = Light.Direction;
#if RADIAL_LIGHT
float3 toLight = Light.Position - gBuffer.WorldPos;
float toLightDst = length(toLight);
if (toLightDst >= Light.Radius)
{
// Skip texels outside the light influence range
discard;
return 0;
}
L = toLight / toLightDst;
#else
float toLightDst = GLOBAL_SDF_WORLD_SIZE;
#endif
float4 shadowMask = 1;
BRANCH
if (Light.CastShadows > 0)
{
// TODO: calculate shadow for the light (use Global SDF)
float NoL = dot(gBuffer.Normal, L);
float shadowBias = 10.0f;
float bias = 2 * shadowBias * saturate(1 - NoL) + shadowBias;
BRANCH
if (NoL > 0)
{
// TODO: try using shadow map for on-screen pixels
// TODO: try using cone trace with Global SDF for smoother shadow (eg. for sun shadows or for area lights)
// Shot a ray from light into texel to see if there is any occluder
GlobalSDFTrace trace;
trace.Init(gBuffer.WorldPos + gBuffer.Normal * shadowBias, L, bias, toLightDst - bias);
GlobalSDFHit hit = RayTraceGlobalSDF(GlobalSDF, GlobalSDFTex, GlobalSDFMip, trace);
shadowMask = hit.IsHit() ? LightShadowsStrengthOneMinus : 1;
}
else
{
shadowMask = 0;
}
}
// Calculate lighting