Imported existing code

indra/newview/app_settings/shaders/class2/windlight/cloudsF.glsl

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+/** 
+ * @file WLCloudsF.glsl
+ *
+ * Copyright (c) 2005-$CurrentYear$, Linden Research, Inc.
+ * $License$
+ */
+
+/////////////////////////////////////////////////////////////////////////
+// The fragment shader for the sky
+/////////////////////////////////////////////////////////////////////////
+
+varying vec4 vary_CloudColorSun;
+varying vec4 vary_CloudColorAmbient;
+varying float vary_CloudDensity;
+
+uniform sampler2D cloud_noise_texture;
+uniform vec4 cloud_pos_density1;
+uniform vec4 cloud_pos_density2;
+uniform vec4 gamma;
+
+/// Soft clips the light with a gamma correction
+vec3 scaleSoftClip(vec3 light) {
+	//soft clip effect:
+	light = 1. - clamp(light, vec3(0.), vec3(1.));
+	light = 1. - pow(light, gamma.xxx);
+
+	return light;
+}
+
+void main()
+{
+	// Set variables
+	vec2 uv1 = gl_TexCoord[0].xy;
+	vec2 uv2 = gl_TexCoord[1].xy;
+
+	vec4 cloudColorSun = vary_CloudColorSun;
+	vec4 cloudColorAmbient = vary_CloudColorAmbient;
+	float cloudDensity = vary_CloudDensity;
+	vec2 uv3 = gl_TexCoord[2].xy;
+	vec2 uv4 = gl_TexCoord[3].xy;
+
+	// Offset texture coords
+	uv1 += cloud_pos_density1.xy;	//large texture, visible density
+	uv2 += cloud_pos_density1.xy;	//large texture, self shadow
+	uv3 += cloud_pos_density2.xy;	//small texture, visible density
+	uv4 += cloud_pos_density2.xy;	//small texture, self shadow
+
+
+	// Compute alpha1, the main cloud opacity
+	float alpha1 = (texture2D(cloud_noise_texture, uv1).x - 0.5) + (texture2D(cloud_noise_texture, uv3).x - 0.5) * cloud_pos_density2.z;
+	alpha1 = min(max(alpha1 + cloudDensity, 0.) * 10. * cloud_pos_density1.z, 1.);
+
+	// And smooth
+	alpha1 = 1. - alpha1 * alpha1;
+	alpha1 = 1. - alpha1 * alpha1;	
+
+
+	// Compute alpha2, for self shadowing effect
+	// (1 - alpha2) will later be used as percentage of incoming sunlight
+	float alpha2 = (texture2D(cloud_noise_texture, uv2).x - 0.5);
+	alpha2 = min(max(alpha2 + cloudDensity, 0.) * 2.5 * cloud_pos_density1.z, 1.);
+
+	// And smooth
+	alpha2 = 1. - alpha2;
+	alpha2 = 1. - alpha2 * alpha2;	
+
+	// Combine
+	vec4 color;
+	color = (cloudColorSun*(1.-alpha2) + cloudColorAmbient);
+	color *= 2.;
+
+	/// Gamma correct for WL (soft clip effect).
+	gl_FragColor.rgb = scaleSoftClip(color.rgb);
+	gl_FragColor.a = alpha1;
+}
+