1 files changed, 111 insertions, 0 deletions
diff --git a/indra/newview/app_settings/shaders/class3/deferred/genSkyShF.glsl b/indra/newview/app_settings/shaders/class3/deferred/genSkyShF.glsl
new file mode 100644
index 0000000000..d5d91c88f0
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+++ b/indra/newview/app_settings/shaders/class3/deferred/genSkyShF.glsl
@@ -0,0 +1,111 @@
+/** 
+ * @file class3/deferred/genSkyShF.glsl
+ *
+ * $LicenseInfo:firstyear=2005&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2005, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+ 
+#ifdef DEFINE_GL_FRAGCOLOR
+out vec4 frag_data[3];
+#else
+#define frag_data gl_FragData
+#endif
+
+VARYING vec2 vary_frag;
+
+uniform vec3 sun_dir;
+
+uniform sampler2D transmittance_texture;
+uniform sampler3D scattering_texture;
+uniform sampler3D single_mie_scattering_texture;
+uniform sampler2D irradiance_texture;
+
+vec3 GetSkyLuminance(vec3 camPos, vec3 view_dir, float shadow_length, vec3 dir, out vec3 transmittance);
+
+vec3 calcDirection(vec2 tc)
+{
+     float phi = tc.y * 2.0 * 3.14159265;
+     float cosTheta = sqrt(1.0 - tc.x);
+     float sinTheta = sqrt(1.0 - cosTheta * cosTheta);
+     return vec3(cos(phi) * sinTheta, sin(phi) * sinTheta, cosTheta);
+}
+
+// reverse mapping above to convert a hemisphere direction into phi/theta values
+void getPhiAndThetaFromDirection(vec3 dir, out float phi, out float theta)
+{
+     float sin_theta;
+     float cos_theta;
+     cos_theta = dir.z;
+     theta     = acos(cos_theta);
+     sin_theta = sin(theta);
+     phi       = abs(sin_theta) > 0.0001 ? acos(dir.x / sin_theta) : 1.0;
+}
+
+// reverse mapping above to convert a hemisphere direction into an SH texture sample pos
+vec2 calcShUvFromDirection(vec3 dir)
+{
+    vec2 uv;
+    float phi;
+    float theta;
+    getPhiAndThetaFromDirection(dir, phi, theta);
+    uv.y = phi   / 2.0 * 3.14159265;
+    uv.x = theta / 2.0 * 3.14159265;
+    return uv;
+}
+
+void projectToL1(vec3 n, vec3 c, vec4 basis, out vec4 coeffs[3])
+{
+    coeffs[0] = vec4(basis.x, n * basis.yzw * c.r);
+    coeffs[1] = vec4(basis.x, n * basis.yzw * c.g);
+    coeffs[2] = vec4(basis.x, n * basis.yzw * c.b);
+}
+
+void main()
+{
+    float Y00 = sqrt(1.0 / 3.14159265) * 0.5;
+    float Y1x = sqrt(3.0 / 3.14159265) * 0.5;
+    float Y1y = Y1x;
+    float Y1z = Y1x;
+
+    vec4 L1 = vec4(Y00, Y1x, Y1y, Y1z);
+
+    vec3 view_direction = calcDirection(vary_frag);
+    vec3 sun_direction  = normalize(sun_dir);
+    vec3 cam_pos        = vec3(0, 0, 6360);
+
+    vec3 transmittance;
+    vec3 radiance = GetSkyLuminance(cam_pos, view_direction, 0.0f, sun_direction, transmittance);
+
+    vec3 color = vec3(1.0) - exp(-radiance * 0.0001);
+
+    color = pow(color, vec3(1.0/2.2));
+
+    vec4 coeffs[3];
+    coeffs[0] = vec4(0);
+    coeffs[1] = vec4(0);
+    coeffs[2] = vec4(0);
+
+    projectToL1(view_direction, color.rgb, L1, coeffs);
+
+    frag_data[0] = coeffs[0];
+    frag_data[1] = coeffs[1];
+    frag_data[2] = coeffs[2];
+}