/// <summary>
/// Method for calculation the ambient lighting component.
/// </summary>
public static string AmbientComponent()
{
var methodBody = new List <string>
{
$"return vec3(color.xyz * ambientCoefficient);"
};
return(GLSL.CreateMethod(GLSL.Type.Vec3, "ambientLighting",
new[] { GLSL.CreateVar(GLSL.Type.Float, "ambientCoefficient"), GLSL.CreateVar(GLSL.Type.Vec4, "color") }, methodBody));
}
/// <summary>
/// Calculates the attenuation of a point light.
/// </summary>
/// <returns></returns>
public static string AttenuationPointComponent()
{
var methodBody = new List <string>
{
$"float distanceToLight = length(lightPos - fragPos);",
"float distance = pow(distanceToLight / lightMaxDistance, 2.0);",
"return (clamp(1.0 - pow(distance, 2.0), 0.0, 1.0)) / (pow(distance, 2.0) + 1.0);",
};
return(GLSL.CreateMethod(GLSL.Type.Float, "attenuationPointComponent",
new[] { GLSL.CreateVar(GLSL.Type.Vec3, "fragPos"), GLSL.CreateVar(GLSL.Type.Vec3, "lightPos"), GLSL.CreateVar(GLSL.Type.Float, "lightMaxDistance") }, methodBody));
}
//TODO: At the moment Blender's Principled BSDF material gets translated into a MaterialPBR and internally uses this lighting method for the specular component.
//This is not the same lighting method as is used in Blender and will therefor only produce approximately visually correct results.
/// <summary>
/// Method for calculation the specular lighting component.
/// Replaces the standard specular calculation with the Cook-Torrance-Shader
/// </summary>
public static string PbrSpecularComponent()
{
var methodBody = new List <string>
{
$"float roughnessValue = {UniformNameDeclarations.RoughnessValue}; // 0 : smooth, 1: rough", // roughness
$"float F0 = {UniformNameDeclarations.FresnelReflectance}; // fresnel reflectance at normal incidence", // fresnel => Specular from Blender
"float NdotL = max(dot(N, L), 0.0);",
"float specular = 0.0;",
"float BlinnSpecular = 0.0;",
"",
"if(dot(N, L) > 0.0)",
"{",
" // calculate intermediary values",
" vec3 H = normalize(L + V);",
" float NdotH = max(dot(N, H), 0.0); ",
" float NdotV = max(dot(N, L), 0.0); // note: this is NdotL, which is the same value",
" float VdotH = max(dot(V, H), 0.0);",
" float mSquared = roughnessValue * roughnessValue;",
"",
"",
"",
"",
" // -- geometric attenuation",
" //[Schlick's approximation of Smith's shadow equation]",
" float k= roughnessValue * sqrt(0.5 * 3.14159265);",
" float one_minus_k= 1.0 - k;",
" float geoAtt = ( NdotL / (NdotL * one_minus_k + k) ) * ( NdotV / (NdotV * one_minus_k + k) );",
"",
" // -- roughness (or: microfacet distribution function)",
" // Trowbridge-Reitz or GGX, GTR2",
" float a2 = mSquared * mSquared;",
" float d = (NdotH * a2 - NdotH) * NdotH + 1.0;",
" float roughness = a2 / (3.14 * d * d);",
"",
" // -- fresnel",
" // [Schlick 1994, An Inexpensive BRDF Model for Physically-Based Rendering]",
" float fresnel = pow(1.0 - VdotH, 5.0);",
$" fresnel = clamp((50.0 * {UniformNameDeclarations.SpecularColor}.y), 0.0, 1.0) * fresnel + (1.0 - fresnel);",
"",
$" specular = (fresnel * geoAtt * roughness) / (NdotV * NdotL * 3.14);",
" ",
"}",
"",
$"return (k + specular * (1.0-k));"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "specularLighting",
new[]
{
GLSL.CreateVar(GLSL.Type.Vec3, "N"), GLSL.CreateVar(GLSL.Type.Vec3, "L"), GLSL.CreateVar(GLSL.Type.Vec3, "V"),
GLSL.CreateVar(GLSL.Type.Float, "k")
}, methodBody));
}
/// <summary>
/// Method for calculation the diffuse lighting component.
/// </summary>
public static string DiffuseComponent()
{
var methodBody = new List <string>
{
"return max(dot(N, L), 0.0);"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "diffuseLighting",
new[]
{
GLSL.CreateVar(GLSL.Type.Vec3, "N"), GLSL.CreateVar(GLSL.Type.Vec3, "L")
}, methodBody));
}
/// <summary>
/// Creates the method for calculating whether a fragment is in shadow or not, by using a shadow map (sampler2DCube).
/// The cube map is used when calculating the shadows for a point light.
/// </summary>
/// <returns></returns>
public static string ShadowCalculationCubeMap()
{
var methodBody = new List <string>()
{
"float pcfKernelSize = pcfKernelHalfSize + pcfKernelHalfSize + 1.0;",
"pcfKernelSize *= pcfKernelSize;",
"vec3 sampleOffsetDirections[20] = vec3[]",
"(",
" vec3(pcfKernelHalfSize, pcfKernelHalfSize, pcfKernelHalfSize), vec3(pcfKernelHalfSize, -pcfKernelHalfSize, pcfKernelHalfSize), vec3(-pcfKernelHalfSize, -pcfKernelHalfSize, pcfKernelHalfSize), vec3(-pcfKernelHalfSize, pcfKernelHalfSize, pcfKernelHalfSize),",
" vec3(pcfKernelHalfSize, pcfKernelHalfSize, -pcfKernelHalfSize), vec3(pcfKernelHalfSize, -pcfKernelHalfSize, -pcfKernelHalfSize), vec3(-pcfKernelHalfSize, -pcfKernelHalfSize, -pcfKernelHalfSize), vec3(-pcfKernelHalfSize, pcfKernelHalfSize, -pcfKernelHalfSize),",
" vec3(pcfKernelHalfSize, pcfKernelHalfSize, 0), vec3(pcfKernelHalfSize, -pcfKernelHalfSize, 0), vec3(-pcfKernelHalfSize, -pcfKernelHalfSize, 0), vec3(-pcfKernelHalfSize, pcfKernelHalfSize, 0),",
" vec3(pcfKernelHalfSize, 0, pcfKernelHalfSize), vec3(-pcfKernelHalfSize, 0, pcfKernelHalfSize), vec3(pcfKernelHalfSize, 0, -pcfKernelHalfSize), vec3(-pcfKernelHalfSize, 0, -pcfKernelHalfSize),",
" vec3(0, pcfKernelHalfSize, pcfKernelHalfSize), vec3(0, -pcfKernelHalfSize, pcfKernelHalfSize), vec3(0, -pcfKernelHalfSize, -pcfKernelHalfSize), vec3(0, pcfKernelHalfSize, -pcfKernelHalfSize)",
");",
"// get vector between fragment position and light position",
"vec3 fragToLight = (fragPos - lightPos) * -1.0;",
"// now get current linear depth as the length between the fragment and light position",
"float currentDepth = length(fragToLight);",
"float shadow = 0.0;",
"float thisBias = max(bias * (1.0 - dot(normal, lightDir)), bias * 0.01);//0.15;",
"int samples = 20;",
$"vec3 camPos = {UniformNameDeclarations.IView}[3].xyz;",
"float viewDistance = length(camPos - fragPos);",
"float diskRadius = 0.5; //(1.0 + (viewDistance / farPlane)) / pcfKernelSize;",
"for (int i = 0; i < samples; ++i)",
"{",
" float closestDepth = texture(shadowMap, fragToLight + sampleOffsetDirections[i] * diskRadius).r;",
" closestDepth *= farPlane; // Undo mapping [0;1]",
" if (currentDepth - thisBias > closestDepth)",
" shadow += 1.0;",
"}",
"shadow /= float(samples);",
"return shadow;"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "ShadowCalculationCubeMap", new[]
{
GLSL.CreateVar(GLSL.Type.SamplerCube, "shadowMap"),
GLSL.CreateVar(GLSL.Type.Vec3, "fragPos"),
GLSL.CreateVar(GLSL.Type.Vec3, "lightPos"),
GLSL.CreateVar(GLSL.Type.Float, "farPlane"),
GLSL.CreateVar(GLSL.Type.Vec3, "normal"),
GLSL.CreateVar(GLSL.Type.Vec3, "lightDir"),
GLSL.CreateVar(GLSL.Type.Float, "bias"),
GLSL.CreateVar(GLSL.Type.Float, "pcfKernelHalfSize")
}, methodBody));
}
/// <summary>
/// Calculates the cone component of the attenuation of a spot light.
/// </summary>
/// <returns></returns>
public static string AttenuationConeComponent()
{
var methodBody = new List <string>
{
"vec3 coneDir = lightDir;",
"float lightToSurfaceAngleCos = dot(coneDir, -fragToLightDir);",
"float epsilon = cos(innerConeAngle) - cos(outerConeAngle);",
"float t = (lightToSurfaceAngleCos - cos(outerConeAngle)) / epsilon;",
"return clamp(t, 0.0, 1.0);"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "attenuationConeComponent",
new[] { GLSL.CreateVar(GLSL.Type.Vec3, "lightDir"), GLSL.CreateVar(GLSL.Type.Vec3, "fragToLightDir"), GLSL.CreateVar(GLSL.Type.Float, "innerConeAngle"), GLSL.CreateVar(GLSL.Type.Float, "outerConeAngle") }, methodBody));
}
/// <summary>
/// Creates the method for calculating whether a fragment is in shadow or not, by using a shadow map (sampler2D).
/// </summary>
/// <returns></returns>
public static string ShadowCalculation()
{
var methodBody = new List <string>()
{
"float shadow = 0.0;",
"int pcfLoop = int(pcfKernelHalfSize);",
"float pcfKernelSize = pcfKernelHalfSize + pcfKernelHalfSize + 1.0;",
"pcfKernelSize *= pcfKernelSize;",
"// perform perspective divide",
"vec4 projCoords = fragPosLightSpace / fragPosLightSpace.w;",
"projCoords = projCoords * 0.5 + 0.5;",
"//float closestDepth = texture(shadowMap, projCoords.xy).r;",
"float currentDepth = projCoords.z;",
"float thisBias = max(bias * (1.0 - dot(normal, lightDir)), bias / 100.0);",
"vec2 texelSize = 1.0 / vec2(textureSize(shadowMap, 0));",
"//use this for using sampler2DShadow (automatic PCF) instead of sampler2D",
"//float depth = texture(shadowMap, projCoords.xyz).r;",
"//shadow += (currentDepth - thisBias) > depth ? 1.0 : 0.0;",
"for (int x = -pcfLoop; x <= pcfLoop; ++x)",
"{",
"for (int y = -pcfLoop; y <= pcfLoop; ++y)",
"{",
"float pcfDepth = texture(shadowMap, projCoords.xy + vec2(x, y) * texelSize).r;",
"shadow += (currentDepth - thisBias) > pcfDepth ? 1.0 : 0.0;",
"}",
"}",
"shadow /= pcfKernelSize;",
"return shadow;"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "ShadowCalculation", new[]
{
GLSL.CreateVar(GLSL.Type.Sampler2D, "shadowMap"),
GLSL.CreateVar(GLSL.Type.Vec4, "fragPosLightSpace"),
GLSL.CreateVar(GLSL.Type.Vec3, "normal"),
GLSL.CreateVar(GLSL.Type.Vec3, "lightDir"),
GLSL.CreateVar(GLSL.Type.Float, "bias"),
GLSL.CreateVar(GLSL.Type.Float, "pcfKernelHalfSize")
}, methodBody));
}
/// <summary>
/// Method for calculation the specular lighting component.
/// </summary>
public static string SpecularComponent()
{
var methodBody = new List <string>
{
"float specularTerm = 0.0;",
"if(dot(N, L) > 0.0)",
"{",
" // half vector",
"vec3 reflectDir = reflect(-L, N);",
$" specularTerm = pow(max(0.0, dot(V, reflectDir)), shininess);",
"}",
"return specularTerm;"
};
return(GLSL.CreateMethod(GLSL.Type.Float, "specularLighting",
new[]
{
GLSL.CreateVar(GLSL.Type.Vec3, "N"), GLSL.CreateVar(GLSL.Type.Vec3, "L"), GLSL.CreateVar(GLSL.Type.Vec3, "V"),
GLSL.CreateVar(GLSL.Type.Float, "shininess")
}, methodBody));
}
/// <summary>
/// Wraps all the lighting methods into a single one.
/// </summary>
public static string ApplyLightForward(ShaderEffectProps effectProps)
{
var bumpNormals = new List <string>
{
"///////////////// Normal mapping, tangent space ///////////////////",
$"vec3 N = ((texture({UniformNameDeclarations.NormalMap}, {VaryingNameDeclarations.TextureCoordinates}).rgb * 2.0) - 1.0f) * vec3({UniformNameDeclarations.NormalMapIntensity}, {UniformNameDeclarations.NormalMapIntensity}, 1.0);",
$"N = (N.x * vec3({VaryingNameDeclarations.Tangent})) + (N.y * {VaryingNameDeclarations.Bitangent}) + (N.z * {VaryingNameDeclarations.Normal});",
"N = normalize(N);"
};
var normals = new List <string>
{
$"vec3 N = normalize({VaryingNameDeclarations.Normal});"
};
var fragToLightDirAndLightInit = new List <string>
{
"vec3 L = vec3(0.0, 0.0, 0.0);",
"if(lightType == 1){L = -normalize(direction);}",
"else",
"{",
$" L = normalize(position - {VaryingNameDeclarations.Position}.xyz);",
"}",
$"vec3 V = normalize(-{VaryingNameDeclarations.Position}.xyz);",
"if(lightType == 3) {",
" L = normalize(vec3(0.0,0.0,-1.0));",
"}",
$"vec2 o_texcoords = {VaryingNameDeclarations.TextureCoordinates};",
"",
"vec3 Idif = vec3(0);",
"vec3 Ispe = vec3(0);",
""
};
var applyLightParams = new List <string>();
applyLightParams.AddRange(effectProps.MatProbs.HasNormalMap ? bumpNormals : normals);
applyLightParams.AddRange(fragToLightDirAndLightInit);
if (effectProps.MatProbs.HasAlbedo)
{
//TODO: Test alpha blending between diffuse and texture
if (effectProps.MatProbs.HasAlbedoTexture)
{
applyLightParams.Add(
$"vec3 blendedCol = mix({UniformNameDeclarations.AlbedoColor}.rgb, texture({UniformNameDeclarations.AlbedoTexture}, {VaryingNameDeclarations.TextureCoordinates}).rgb, {UniformNameDeclarations.AlbedoMix});" +
$"Idif = blendedCol * diffuseLighting(N, L) * intensities.rgb;");
}
else
{
applyLightParams.Add($"Idif = vec3({UniformNameDeclarations.AlbedoColor}.rgb * intensities.rgb * diffuseLighting(N, L));");
}
}
if (effectProps.MatProbs.HasSpecular)
{
if (effectProps.MatType == MaterialType.Standard)
{
applyLightParams.Add($"float specularTerm = specularLighting(N, L, V, {UniformNameDeclarations.SpecularShininess});");
applyLightParams.Add($"Ispe = vec3(({ UniformNameDeclarations.SpecularColor}.rgb * { UniformNameDeclarations.SpecularIntensity} *intensities.rgb) *specularTerm);");
}
else if (effectProps.MatType == MaterialType.MaterialPbr)
{
applyLightParams.Add($"float k = 1.0 - {UniformNameDeclarations.DiffuseFraction};");
applyLightParams.Add("float specular = specularLighting(N, L, V, k);");
applyLightParams.Add($"Ispe = intensities.rgb * {UniformNameDeclarations.SpecularColor}.rgb * (k + specular * (1.0 - k));");
}
}
var pointLight = new List <string>
{
$"float att = attenuationPointComponent({VaryingNameDeclarations.Position}.xyz, position, maxDistance);",
"lighting = (Idif * att) + (Ispe * att);",
"lighting *= strength;"
};
//No attenuation!
var parallelLight = new List <string>
{
"lighting = Idif + Ispe;",
"lighting *= strength;"
};
var spotLight = new List <string>
{
$"float att = attenuationPointComponent({VaryingNameDeclarations.Position}.xyz, position, maxDistance) * attenuationConeComponent(direction, L, innerConeAngle, outerConeAngle);",
"lighting = (Idif * att) + (Ispe * att);",
"lighting *= strength;"
};
// - Disable GammaCorrection for better colors
/*var gammaCorrection = new List<string>()
* {
* "vec3 gamma = vec3(1.0/2.2);",
* "result = pow(result, gamma);"
* };*/
var methodBody = new List <string>();
methodBody.AddRange(applyLightParams);
methodBody.Add("vec3 lighting = vec3(0);");
methodBody.Add("");
//methodBody.AddRange(attenuation);
methodBody.Add("if(lightType == 0) // PointLight");
methodBody.Add("{");
methodBody.AddRange(pointLight);
methodBody.Add("}");
methodBody.Add("else if(lightType == 1 || lightType == 3) // ParallelLight or LegacyLight");
methodBody.Add("{");
methodBody.AddRange(parallelLight);
methodBody.Add("}");
methodBody.Add("else if(lightType == 2) // SpotLight");
methodBody.Add("{");
methodBody.AddRange(spotLight);
methodBody.Add("}");
methodBody.Add("");
//methodBody.AddRange(gammaCorrection); // - Disable GammaCorrection for better colors
methodBody.Add("");
methodBody.Add("return lighting;");
return(GLSL.CreateMethod(GLSL.Type.Vec3, "ApplyLight",
new[]
{
GLSL.CreateVar(GLSL.Type.Vec3, "position"), GLSL.CreateVar(GLSL.Type.Vec4, "intensities"),
GLSL.CreateVar(GLSL.Type.Vec3, "direction"), GLSL.CreateVar(GLSL.Type.Float, "maxDistance"),
GLSL.CreateVar(GLSL.Type.Float, "strength"), GLSL.CreateVar(GLSL.Type.Float, "outerConeAngle"),
GLSL.CreateVar(GLSL.Type.Float, "innerConeAngle"), GLSL.CreateVar(GLSL.Type.Int, "lightType"),
}, methodBody));
}
