1 files changed, 122 insertions, 0 deletions

diff --git a/assets/shaders/Taper.vert.glsl b/assets/shaders/Taper.vert.glsl
new file mode 100644
index 00000000..30b73456
--- /dev/null
+++ b/assets/shaders/Taper.vert.glsl
@@ -0,0 +1,122 @@
+/* <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_limit3;
+uniform float u_taperAmount;
+uniform float u_minVal;
+uniform float u_maxVal;
+uniform float u_center;
+
+uniform vec4 color;
+
+
+// matrix uniforms
+uniform mat4 u_mvMatrix;
+uniform mat4 u_projMatrix;
+uniform mat4 u_worldMatrix;
+
+varying vec4 v_color;
+
+
+
+float TaperAmount( float param )
+{
+        // Bezier coordinates of the X coordinate.
+        // Adjust these to get tighter or looser
+        float tightness = 0.8;
+
+        float x0, y0,  x1, y1,  x2, y2;
+        float t;
+        if (param < 0.5)
+        {
+                t = 2.0*param;
+                x0 = 0.0;  y0 = 0.0;
+                x1 = tightness;  y1 = 0.0;
+                x2 = 1.0;  y2 = 0.5;
+        }
+        else
+        {
+                t = (param - 0.5)*2.0;
+                x0 = 0.0;  y0 = 0.5;
+                x1 = 1.0 - tightness;  y1 = 1.0;
+                x2 = 1.0;  y2 = 1.0;
+        }
+
+        float a = x0 - 2.0*x1 + x2;
+        float b = 2.0*(x1 - x0);
+        float c = x0 - t;
+
+        float descr = sqrt( b*b - 4.0*a*c );
+        float denom = 2.0*a;
+        float n1 = (-b + descr)/denom;
+        float n2 = (-b - descr)/denom;
+        if      ((n1 >= 0.0) || (n1 <= 1.0))  t = n1;
+        else if ((n2 >= 0.0) || (n2 <= 1.0))  t = n2;
+        else
+                t = 0.0;
+
+        float ya = y0 + t*(y1 - y0);
+        float yb = y1 + t*(y2 - y1);
+        float yc = ya + t*(yb - ya);
+
+        return yc;
+}
+
+
+void main(void)
+{
+        vec3 pos = vert;
+        vec2 uv = texcoord;
+
+
+        float   limit1 = u_limit1,
+                        limit2 = u_limit2,
+                        limit3 = u_limit2;
+
+        v_color = vec4(texcoord.x, texcoord.y, 0, 1);
+        if ((uv.x > u_limit1) && (uv.x < u_limit3))
+        {
+                float t;
+                if (uv.x < u_limit2)
+                {
+                        t = (uv.x - u_limit1)/(u_limit2 - u_limit1);
+                }
+                else
+                {
+                        t = 1.0 - (uv.x - u_limit2)/(u_limit3 - u_limit2);
+                }
+                t = TaperAmount( t );
+
+                float maxVal;
+                if (pos.y > u_center)
+                {
+                        maxVal = u_maxVal;
+                }
+                else
+                {
+                        maxVal = u_minVal;
+                }
+
+                float yFrac = (pos.y - u_center)/(maxVal-u_center);
+                pos.y = pos.y - yFrac * (maxVal - u_center)*t*u_taperAmount;
+        }
+
+        gl_Position = u_projMatrix * u_mvMatrix * vec4(pos,1.0) ;
+}
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