1 files changed, 100 insertions, 0 deletions
diff --git a/inscatterN.glsl b/inscatterN.glsl
new file mode 100644
index 0000000..c1d49c3
--- /dev/null
+++ b/inscatterN.glsl
@@ -0,0 +1,100 @@
+/**
+ * Precomputed Atmospheric Scattering
+ * Copyright (c) 2008 INRIA
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * Author: Eric Bruneton
+ */
+
+// computes higher order scattering (line 9 in algorithm 4.1)
+
+uniform float r;
+uniform vec4 dhdH;
+uniform int layer;
+
+uniform sampler3D deltaJSampler;
+
+#ifdef _VERTEX_
+
+void main() {
+    gl_Position = gl_Vertex;
+}
+
+#endif
+
+#ifdef _GEOMETRY_
+#extension GL_EXT_geometry_shader4 : enable
+
+void main() {
+    gl_Position = gl_PositionIn[0];
+    gl_Layer = layer;
+    EmitVertex();
+    gl_Position = gl_PositionIn[1];
+    gl_Layer = layer;
+    EmitVertex();
+    gl_Position = gl_PositionIn[2];
+    gl_Layer = layer;
+    EmitVertex();
+    EndPrimitive();
+}
+
+#endif
+
+#ifdef _FRAGMENT_
+
+vec3 integrand(float r, float mu, float muS, float nu, float t) {
+    float ri = sqrt(r * r + t * t + 2.0 * r * mu * t);
+    float mui = (r * mu + t) / ri;
+    float muSi = (nu * t + muS * r) / ri;
+    return texture4D(deltaJSampler, ri, mui, muSi, nu).rgb * transmittance(r, mu, t);
+}
+
+vec3 inscatter(float r, float mu, float muS, float nu) {
+    vec3 raymie = vec3(0.0);
+    float dx = limit(r, mu) / float(INSCATTER_INTEGRAL_SAMPLES);
+    float xi = 0.0;
+    vec3 raymiei = integrand(r, mu, muS, nu, 0.0);
+    for (int i = 1; i <= INSCATTER_INTEGRAL_SAMPLES; ++i) {
+        float xj = float(i) * dx;
+        vec3 raymiej = integrand(r, mu, muS, nu, xj);
+        raymie += (raymiei + raymiej) / 2.0 * dx;
+        xi = xj;
+        raymiei = raymiej;
+    }
+    return raymie;
+}
+
+void main() {
+    float mu, muS, nu;
+    getMuMuSNu(r, dhdH, mu, muS, nu);
+    gl_FragColor.rgb = inscatter(r, mu, muS, nu);
+}
+
+#endif
+