Add ToT WebGL conformance tests : part 9

conformance/ogles/GL/acos/acos_vec2_vert_xvary_ref.vert

+
+/*
+** Copyright (c) 2012 The Khronos Group Inc.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a
+** copy of this software and/or associated documentation files (the
+** "Materials"), to deal in the Materials without restriction, including
+** without limitation the rights to use, copy, modify, merge, publish,
+** distribute, sublicense, and/or sell copies of the Materials, and to
+** permit persons to whom the Materials are furnished to do so, subject to
+** the following conditions:
+**
+** The above copyright notice and this permission notice shall be included
+** in all copies or substantial portions of the Materials.
+**
+** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
+*/
+
+
+attribute vec4 gtf_Vertex;
+attribute vec4 gtf_Color;
+uniform mat4 gtf_ModelViewProjectionMatrix;
+varying vec4 color;
+
+void main (void)
+{
+        const float M_PI = 3.14159265358979323846;
+        vec2 c = 2.0 * (gtf_Color.rg - 0.5);
+        vec2 acos_c = vec2(0.0);
+        vec2 scale = vec2(1.0);
+        vec2 sign = vec2(1.0);
+
+        // pow can't handle negative numbers so take advantage of symmetry
+        if(c.r < 0.0)
+        {
+                sign.r = -1.0;
+                c.r *= -1.0;
+        }
+
+        // Taylors series expansion for acos
+        // 1000/2 iterations necessary to get the accuracy with this method
+        for(int i = 1; i < 1000; i += 2)
+        {
+                acos_c.r += scale.r * pow(c.r, float(i)) / float(i);
+                scale.r *= float(i) / float(i + 1);
+        }
+        acos_c.r = M_PI / 2.0 - sign.r * acos_c.r;
+
+        // pow can't handle negative numbers so take advantage of symmetry
+        if(c.g < 0.0)
+        {
+                sign.g = -1.0;
+                c.g *= -1.0;
+        }
+
+        // Taylors series expansion for acos
+        // 1000/2 iterations necessary to get the accuracy with this method
+        for(int i = 1; i < 1000; i += 2)
+        {
+                acos_c.g += scale.g * pow(c.g, float(i)) / float(i);
+                scale.g *= float(i) / float(i + 1);
+        }
+        acos_c.g = M_PI / 2.0 - sign.g * acos_c.g;
+
+        color = vec4(acos_c / M_PI, 0.0, 1.0);
+        gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex;
+}