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add normal map sampling

PBR
cosmonaut 2020-08-03 16:47:08 -07:00
parent 5465b13b9d
commit 75114d77ef
3 changed files with 83 additions and 17 deletions
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74
Effects/PBREffect.fx
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@ -57,7 +57,7 @@ PixelShaderInput main_vs(VertexShaderInput input)
output.TexCoord = input.TexCoord;
output.PositionWS = mul(input.Position, World).xyz;
output.NormalWS = mul(input.Normal, WorldInverseTranspose);
output.NormalWS = mul(input.Normal, (float3x3)WorldInverseTranspose).xyz;
output.Position = mul(input.Position, WorldViewProjection);
return output;
@ -103,6 +103,24 @@ float GeometrySmith(float3 N, float3 V, float3 L, float roughness)
return ggx1 * ggx2;
}
// Easy trick to get tangent-normals to world-space to keep PBR code simplified.
float3 GetNormalFromMap(float3 worldPos, float2 texCoords, float3 normal)
{
float3 tangentNormal = SAMPLE_TEXTURE(NormalTexture, texCoords).xyz * 2.0 - 1.0;
float3 Q1 = ddx(worldPos);
float3 Q2 = ddy(worldPos);
float2 st1 = ddx(texCoords);
float2 st2 = ddy(texCoords);
float3 N = normalize(normal);
float3 T = normalize(Q1*st2.y - Q2*st1.y);
float3 B = -normalize(cross(N, T));
float3x3 TBN = float3x3(T, B, N);
return normalize(mul(tangentNormal, TBN));
}
// The case where we have no texture maps for any PBR data
float4 None(PixelShaderInput input) : SV_TARGET0
{
@ -258,11 +276,63 @@ float4 AlbedoMetallicRoughnessMapPS(PixelShaderInput input) : SV_TARGET
return float4(color, 1.0);
}
float4 AlbedoMetallicRoughnessNormalMapPS(PixelShaderInput input) : SV_TARGET
{
float3 albedo = pow(SAMPLE_TEXTURE(AlbedoTexture, input.TexCoord), 2.2).rgb;
float2 metallicRoughness = SAMPLE_TEXTURE(MetallicRoughnessTexture, input.TexCoord).rg;
float metallic = metallicRoughness.r;
float roughness = metallicRoughness.g;
float3 N = GetNormalFromMap(input.PositionWS, input.TexCoord, input.NormalWS);
float3 V = normalize(EyePosition - input.PositionWS);
float3 F0 = float3(0.04, 0.04, 0.04);
F0 = lerp(F0, albedo, metallic);
float3 Lo = float3(0.0, 0.0, 0.0);
for (int i = 0; i < 4; i++)
{
float3 lightDir = LightPositions[i] - input.PositionWS;
float3 L = normalize(lightDir);
float3 H = normalize(V + L);
float distance = length(lightDir);
float attenuation = 1.0 / (distance * distance);
float3 radiance = LightColors[i] * attenuation;
float NDF = DistributionGGX(N, H, roughness);
float G = GeometrySmith(N, V, L, roughness);
float3 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
float3 numerator = NDF * G * F;
float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
float3 specular = numerator / max(denominator, 0.001);
float3 kS = F;
float3 kD = float3(1.0, 1.0, 1.0) - kS;
kD *= 1.0 - metallic;
float NdotL = max(dot(N, L), 0.0);
Lo += (kD * albedo / PI + specular) * radiance * NdotL;
}
float3 ambient = float3(0.03, 0.03, 0.03) * albedo * AO;
float3 color = ambient + Lo;
color = color / (color + float3(1.0, 1.0, 1.0));
float exposureConstant = 1.0 / 2.2;
color = pow(color, float3(exposureConstant, exposureConstant, exposureConstant));
return float4(color, 1.0);
}
Technique PBR
{
Pass Pass1
{
VertexShader = compile vs_3_0 main_vs();
PixelShader = compile ps_3_0 AlbedoMetallicRoughnessMapPS();
PixelShader = compile ps_3_0 AlbedoMetallicRoughnessNormalMapPS();
}
}

BIN
Effects/PBREffect.fxb
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26
Importer.cs
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@ -141,19 +141,17 @@ namespace Smuggler
if (primitive.Material != null)
{
//var normalChannel = primitive.Material.FindChannel("Normal");
//if (normalChannel.HasValue)
//{
// if (normalChannel.Value.Texture != null)
// {
// effect.NormalTexture = Texture2D.FromStream(
// graphicsDevice,
// normalChannel.Value.Texture.PrimaryImage.Content.Open()
// );
// }
// effect.NormalScale = normalChannel.Value.Parameter.X;
//}
var normalChannel = primitive.Material.FindChannel("Normal");
if (normalChannel.HasValue)
{
if (normalChannel.Value.Texture != null)
{
effect.NormalTexture = Texture2D.FromStream(
graphicsDevice,
normalChannel.Value.Texture.PrimaryImage.Content.Open()
);
}
}
//var occlusionChannel = primitive.Material.FindChannel("Occlusion");
//if (occlusionChannel.HasValue)
@ -218,7 +216,6 @@ namespace Smuggler
graphicsDevice,
metallicRoughnessChannel.Value.Texture.PrimaryImage.Content.Open()
);
System.Console.WriteLine(effect.MetallicRoughnessTexture.Width);
}
var parameter = metallicRoughnessChannel.Value.Parameter;
@ -416,7 +413,6 @@ namespace Smuggler
uint[] indices,
Vector3[] positions
) {
System.Console.WriteLine("normals");
var normals = Normals(primitive);
var texcoords = TexCoords(primitive);