Kav/Effects/HLSL/DiffuseLitSpriteEffect.fx

141 lines
3.4 KiB
HLSL

#include "Macros.fxh" //from FNA
// Effect applies normalmapped lighting to a 2D sprite.
DECLARE_TEXTURE(Texture, 0);
DECLARE_TEXTURE(Normal, 1);
float3 AmbientColor;
float3 PointLightPositions[8];
float3 PointLightColors[8];
float3 DirectionalLightDirection;
float3 DirectionalLightColor;
float4 UVOffsetAndDimensions;
float4x4 WorldInverseTranspose;
float4x4 World;
float4x4 WorldViewProjection;
struct VertexShaderInput
{
float4 Position : POSITION;
float3 Normal : NORMAL;
float2 TexCoord : TEXCOORD0;
};
struct PixelShaderInput
{
float4 Position : SV_Position;
float2 TexCoord : TEXCOORD0;
float3 NormalWS : TEXCOORD1;
float3 PositionWS : TEXCOORD2;
};
PixelShaderInput main_vs(VertexShaderInput input)
{
PixelShaderInput output;
output.Position = mul(input.Position, WorldViewProjection);
output.NormalWS = normalize(mul(input.Normal, (float3x3)WorldInverseTranspose));
output.PositionWS = mul(input.Position, World).xyz;
float2 texCoord;
texCoord.x = (input.TexCoord.x * UVOffsetAndDimensions.z) + UVOffsetAndDimensions.x;
texCoord.y = (input.TexCoord.y * UVOffsetAndDimensions.w) + UVOffsetAndDimensions.y;
output.TexCoord = texCoord;
return output;
}
// 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(Normal, 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));
}
float4 LightColor(float3 worldPosition, float3 worldNormal)
{
float3 lightColor = float3(0.0, 0.0, 0.0);
// point lights
for (int i = 0; i < 8; i++)
{
float3 lightVec = PointLightPositions[i] - worldPosition;
float distance = length(lightVec);
float3 lightDir = normalize(lightVec);
float diffuse = max(dot(worldNormal, lightDir), 0.0);
float3 attenuation = 1.0 / (distance * distance);
lightColor += diffuse * attenuation * PointLightColors[i];
}
// directional light
float directionalDiffuse = max(dot(worldNormal, DirectionalLightDirection), 0.0);
lightColor += directionalDiffuse * DirectionalLightColor;
// ambient light
lightColor += AmbientColor;
return float4(lightColor, 1.0);
}
float4 WithoutNormalMap(PixelShaderInput input) : COLOR0
{
float4 tex = SAMPLE_TEXTURE(Texture, input.TexCoord);
if (tex.a == 0.0) { discard; }
float3 normalWS = normalize(input.NormalWS);
return tex * LightColor(input.PositionWS, normalWS);
}
float4 WithNormalMap(PixelShaderInput input) : COLOR0
{
float4 tex = SAMPLE_TEXTURE(Texture, input.TexCoord);
if (tex.a == 0.0) { discard; }
float3 normalWS = GetNormalFromMap(input.PositionWS, input.TexCoord, input.NormalWS);
return tex * LightColor(input.PositionWS, normalWS);
}
PixelShader PSArray[2] =
{
compile ps_3_0 WithoutNormalMap(),
compile ps_3_0 WithNormalMap()
};
int PSIndices[2] =
{
0, 1
};
int ShaderIndex = 0;
Technique DiffuseLitSprite
{
pass
{
VertexShader = compile vs_3_0 main_vs();
PixelShader = (PSArray[PSIndices[ShaderIndex]]);
}
}