1 files changed, 97 insertions, 0 deletions

diff --git a/assets/shaders/TwistVert.vert.glsl b/assets/shaders/TwistVert.vert.glsl
new file mode 100644
index 00000000..29cb30ea
--- /dev/null
+++ b/assets/shaders/TwistVert.vert.glsl
@@ -0,0 +1,97 @@
+/* <copyright>
+This file contains proprietary software owned by Motorola Mobility, Inc.<br/>
+No rights, expressed or implied, whatsoever to this software are provided by Motorola Mobility, Inc. hereunder.<br/>
+(c) Copyright 2011 Motorola Mobility, Inc.  All Rights Reserved.
+</copyright> */
+
+
+#ifdef GL_ES
+precision highp float;
+#endif
+
+
+// attributes
+attribute vec3 vert;
+attribute vec3 normal;
+attribute vec2 texcoord;
+
+// scalar uniforms
+uniform float u_limit1;
+uniform float u_limit2;
+uniform float u_twistAmount;
+uniform float u_center;
+
+// texture sampler uniforms
+uniform sampler2D u_tex0;
+uniform sampler2D u_tex1;
+
+uniform vec4 color;
+
+
+// matrix uniforms
+uniform mat4 u_mvMatrix;
+uniform mat4 u_projMatrix;
+uniform mat4 u_worldMatrix;
+
+//varying vec4 v_color;
+varying float v_zNormal;
+varying vec2 v_texcoord;
+
+
+float GetAngle( float t )
+{
+        float angle= 0.0;
+        if (t < u_limit2)
+        {
+                if (t < u_limit1)
+                {
+                        angle = u_twistAmount;
+                }
+                else
+                {
+                        angle = (t - u_limit2)/(u_limit1 - u_limit2)*u_twistAmount;
+                }
+        }
+
+        return angle;
+}
+
+
+void main(void)
+{
+        vec3 pos = vert;
+        vec2 uv = texcoord;
+        v_texcoord = texcoord;
+
+        //v_color = vec4(texcoord.x, texcoord.y, 0, 1);
+
+        v_zNormal = 1.0;
+        if (uv.x < u_limit2)
+        {
+                float angle = GetAngle( uv.x );
+                float cs = cos(angle),  sn = sin(angle);
+
+                pos.y -= u_center;
+                vec3 ctrPt = pos;
+                float y = pos.y*cs - pos.z*sn + u_center;
+                pos.z   = pos.y*sn + pos.z*cs;
+                pos.y = y;
+
+                // rotate the normal
+                mat3 rotMat = mat3( vec3( 1.0,  0.0,  0.0 ),  vec3( 0.0,   cs,   sn ),  vec3( 0.0,  -sn,   cs ) );
+                vec3 pt0 = ctrPt, pt1 = vec3(ctrPt.x, ctrPt.y+1.0, ctrPt.z),  pt2 = vec3( ctrPt.x+1.0, ctrPt.y, ctrPt.z);
+                pt0 = rotMat * pt0;  pt1 = rotMat * pt1;
+                angle = GetAngle(1.0);
+                cs = cos(angle); sn = sin(angle);
+                rotMat = mat3( vec3( 1.0,  0.0,  0.0 ),  vec3( 0.0,   cs,   sn ),  vec3( 0.0,  -sn,   cs ) );
+                pt2 = rotMat * pt2;
+                pt0.y += u_center;  pt1.y += u_center;  pt2.y += u_center;
+                //vec4 nrm = u_projMatrix * u_mvMatrix * vec4( cross(pt1-pt0, pt2-pt0), 1.0 );
+                vec4 nrm = vec4( cross(pt1-pt0, pt2-pt0), 1.0 );
+                
+                //v_zNormal   = normal.y*sn + normal.z*cs;
+                v_zNormal   = -nrm.z;
+        }
+
+        gl_Position = u_projMatrix * u_mvMatrix * vec4(pos,1.0) ;
+}
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