Update Files

leenkx/Shaders/std/ies.glsl

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+
+uniform sampler2D texIES;
+
+float iesAttenuation(vec3 l) {
+
+	const float PI = 3.1415926535;
+	// https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf
+	// Sample direction into light space
+	// vec3 iesSampleDirection = mul(light.worldToLight , -L);
+	// Cartesian to spherical
+	// Texture encoded with cos( phi ), scale from -1 - >1 to 0 - >1
+	// float phiCoord = (iesSampleDirection.z * 0.5f) + 0.5f;
+	// float theta = atan2 (iesSampleDirection.y , iesSampleDirection .x);
+	// float thetaCoord = theta * (1.0 / (PI * 2.0));
+	// float iesProfileScale = texture(texIES, vec2(thetaCoord, phiCoord)).r;
+	// return iesProfileScale;
+
+	// 1D texture
+	// vec3 pl = normalize(p - lightPos);
+	// float f = asin(dot(pl, l)) / PI + 0.5;
+	// return texture(texIES, vec2(f, 0.0)).r;
+
+	// 1D texture
+	// float cosTheta = dot(lightToPos, lightDir);
+	// float angle = acos(cosTheta) * (1.0 / PI);
+	// return texture(texIES, vec2(angle, 0.0), 0.0).r;
+
+	// Based on https://github.com/tobspr/RenderPipeline
+	float hor = acos(l.z) / PI;
+	float vert = atan(l.x, l.y) * (1.0 / (PI * 2.0)) + 0.5;
+	return texture(texIES, vec2(hor, vert)).r;
+}