From 18827109c7f60163cfa60a0473d44c7505cbc5d4 Mon Sep 17 00:00:00 2001
From: XProger <xproger@list.ru>
Date: Sun, 26 Mar 2017 14:32:17 +0300
Subject: [PATCH] #23 shadow volume shader

---
 src/volume.glsl | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 src/volume.glsl

diff --git a/src/volume.glsl b/src/volume.glsl
new file mode 100644
index 0000000..0a7b841
--- /dev/null
+++ b/src/volume.glsl
@@ -0,0 +1,45 @@
+R"====(
+#ifdef GL_ES
+    precision lowp  int;
+    precision highp float;
+#endif
+
+
+varying vec3 color;
+
+#ifdef VERTEX
+    attribute vec4 aCoord;
+    attribute vec4 aNormal;
+    attribute vec4 aColor;
+
+    uniform mat4 uViewProj;
+    uniform vec4 uBasis[2]; // quat rot, pos
+    uniform vec3 uPosScale; // xyz - scale
+    uniform vec4 uLightPos; // xyz - pos, w - radius
+
+    vec3 mulQuat(vec4 q, vec3 v) {
+        return v + 2.0 * cross(q.xyz, cross(q.xyz, v) + v * q.w);
+    }
+
+    vec3 mulBasis(vec4 rot, vec4 pos, vec3 v) {
+        return mulQuat(rot, v) + pos.xyz;
+    }
+
+    void main() {
+        vec4 c  = vec4(mulBasis(uBasis[0], uBasis[1], aCoord.xyz * uPosScale), 1.0);
+        vec3 n  = mulQuat(uBasis[0], normalize(aNormal.xyz));
+        vec3 lv = uLightPos.xyz - c.xyz;
+
+        if (dot(lv, n) < 0.0)
+            c.xyz -= normalize(lv) * 3000.0;//uLightPos.w;
+
+        color = aColor.xyz;
+
+        gl_Position = uViewProj * c;
+    }
+#else
+    void main() {
+        gl_FragColor = vec4(color, 1.0);
+    }
+#endif
+)===="
\ No newline at end of file