1 files changed, 44 insertions, 0 deletions

diff --git a/src/extras/shaders/lighting.h b/src/extras/shaders/lighting.h
new file mode 100644
index 00000000..4b081962
--- /dev/null
+++ b/src/extras/shaders/lighting.h
@@ -0,0 +1,44 @@
+struct Light
+{
+	float4 color;	// and radius
+	float4 position;	// and -cos(angle)
+	float4 direction;	// and falloff clamp
+};
+
+float3 DoDirLight(Light L, float3 N)
+{
+	float l = max(0.0, dot(N, -L.direction.xyz));
+	return l*L.color.xyz;
+}
+
+float3 DoDirLightSpec(Light L, float3 N, float3 V, float power)
+{
+	return pow(saturate(dot(N, normalize(V + -L.direction.xyz))), power)*L.color.xyz;
+}
+
+float3 DoPointLight(Light L, float3 V, float3 N)
+{
+	// As on PS2
+	float3 dir = V - L.position.xyz;
+	float dist = length(dir);
+	float atten = max(0.0, (1.0 - dist/L.color.w));
+	float l = max(0.0, dot(N, -normalize(dir)));
+	return l*L.color.xyz*atten;
+}
+
+float3 DoSpotLight(Light L, float3 V, float3 N)
+{
+	// As on PS2
+	float3 dir = V - L.position.xyz;
+	float dist = length(dir);
+	float atten = max(0.0, (1.0 - dist/L.color.w));
+	dir /= dist;
+	float l = max(0.0, dot(N, -dir));
+	float pcos = dot(dir, L.direction.xyz);	// cos to point
+	float ccos = -L.position.w;	// cos of cone
+	float falloff = (pcos-ccos)/(1.0-ccos);
+	if(falloff < 0)	// outside of cone
+		l = 0;
+	l *= max(falloff, L.direction.w);	// falloff clamp
+	return l*L.color.xyz*atten;
+}