Index: conformance/ogles/GL/acos/acos_float_vert_xvary_ref.vert |
=================================================================== |
--- conformance/ogles/GL/acos/acos_float_vert_xvary_ref.vert (revision 0) |
+++ conformance/ogles/GL/acos/acos_float_vert_xvary_ref.vert (working copy) |
@@ -0,0 +1,58 @@ |
+ |
+/* |
+** 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; |
+ float c = 2.0 * (gtf_Color.r - 0.5); |
+ |
+ float acos_c = 0.0; |
+ float scale = 1.0; |
+ float sign = 1.0; |
+ |
+ // pow can't handle negative numbers so take advantage of symmetry |
+ if(c < 0.0) |
+ { |
+ sign = -1.0; |
+ c *= -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 += scale * pow(c, float(i)) / float(i); |
+ scale *= float(i) / float(i + 1); |
+ } |
+ acos_c = M_PI / 2.0 - sign * acos_c; |
+ |
+ color = vec4(acos_c / M_PI, 0.0, 0.0, 1.0); |
+ gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex; |
+} |