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#include "common_buffers.hlsl"
static const float att_c = 1.0f;
static const float att_l = 0.014f;
static const float att_q = 0.0007f;
float CalcAttenuation(float distance)
{
return 1 / (att_c + att_l * distance + att_q * distance * distance);
};
float3 CalcLight(float3 textureColor, float3 lightDir, float3 viewDir, float3 normal, float3 lightColor, float specPower, float specIntensity, float attenuation)
{
normal = normalize(normal);
// diffuse
float3 dirToLight = normalize(-lightDir);
float diffuseFactor = max(dot(normal, dirToLight), 0.0);
float3 diffuse = lightColor * textureColor * diffuseFactor * attenuation;
// specular (Blinn-Phong)
float3 halfwayDir = normalize(dirToLight + viewDir);
float specFactor = pow(max(dot(viewDir, halfwayDir), 0.0), specPower);
float3 spec = lightColor * specFactor * attenuation * specIntensity;
return diffuse + spec;
};
float3 CalcPixelLight(float3 diffuseColor, float3 worldPos, float3 normal)
{
float3 viewDir = normalize(viewPos - worldPos);
// ambient
float3 ambient = ambientColor * diffuseColor;
// dir light
float3 dirLight = CalcLight(diffuseColor, dirLightDir, viewDir, normal, dirLightColor, specularPower, specularIntensity, 1);
// point light
float3 pointLightDir = worldPos - pointLightPos;
float distance = length(pointLightDir);
float attenuation = CalcAttenuation(distance);
float3 pointLight = CalcLight(diffuseColor, pointLightDir, viewDir, normal, pointLightColor, specularPower, specularIntensity, attenuation);
// hacky hack: ambient attenuates within point light distance
ambient *= attenuation;
return ambient + dirLight + pointLight;
};
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