| |
| /* |
| ** 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; |
| vec3 x = 2.0 * (gtf_Color.ggg - 0.5); |
| vec3 y = 2.0 * (gtf_Color.bbb - 0.5); |
| const float epsilon = 1.0e-4; |
| color = vec4(0.0, 0.0, 0.0, 1.0); |
| |
| // Avoid evaluating atan(0, x) for x < epsilon because it's implementation-dependent |
| if(x[0] > epsilon || abs(y[0]) > epsilon) |
| { |
| color[0] = atan(y[0], x[0]) / (2.0 * M_PI) + 0.5; |
| } |
| |
| if(x[1] > epsilon || abs(y[1]) > epsilon) |
| { |
| color[1] = atan(y[1], x[1]) / (2.0 * M_PI) + 0.5; |
| } |
| |
| if(x[2] > epsilon || abs(y[2]) > epsilon) |
| { |
| color[2] = atan(y[2], x[2]) / (2.0 * M_PI) + 0.5; |
| } |
| |
| gl_Position = gtf_ModelViewProjectionMatrix * gtf_Vertex; |
| } |