#version 120 ////  oculus.vert//  vertex shader////  Created by Ben Arnold on 6/24/14.//  Copyright 2014 High Fidelity, Inc.////  this shader is an adaptation (HLSL -> GLSL) of the one in the//  Oculus_SDK_Overview.pdf for the 3.2 SDK.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// uniform vec2 EyeToSourceUVScale;uniform vec2 EyeToSourceUVOffset;uniform mat4 EyeRotationStart;uniform mat4 EyeRotationEnd; attribute vec2 position;attribute vec4 color;attribute vec2 texCoord0;attribute vec2 texCoord1;attribute vec2 texCoord2; varying float vFade;varying vec2 oTexCoord0;varying vec2 oTexCoord1;varying vec2 oTexCoord2; vec2 TimewarpTexCoord(vec2 texCoord, mat4 rotMat){    // Vertex inputs are in TanEyeAngle space for the R,G,B channels (i.e. after chromatic    // aberration and distortion). These are now "real world" vectors in direction (x,y,1)    // relative to the eye of the HMD. Apply the 3x3 timewarp rotation to these vectors.    vec3 transformed = vec3( rotMat * vec4(texCoord.xy, 1, 1) );        // Project them back onto the Z=1 plane of the rendered images.    vec2 flattened = (transformed.xy / transformed.z);        // Scale them into ([0,0.5],[0,1]) or ([0.5,0],[0,1]) UV lookup space (depending on eye)    return (EyeToSourceUVScale * flattened + EyeToSourceUVOffset);} void main(){    float timewarpMixFactor = color.a;    mat4 mixedEyeRot = EyeRotationStart * (1.0 - timewarpMixFactor) + EyeRotationEnd * (timewarpMixFactor);        oTexCoord0 = TimewarpTexCoord(texCoord0, mixedEyeRot);    oTexCoord1 = TimewarpTexCoord(texCoord1, mixedEyeRot);    oTexCoord2 = TimewarpTexCoord(texCoord2, mixedEyeRot);        //Flip y texture coordinates    oTexCoord0.y = 1.0 - oTexCoord0.y;    oTexCoord1.y = 1.0 - oTexCoord1.y;    oTexCoord2.y = 1.0 - oTexCoord2.y;        gl_Position = vec4(position.xy, 0.5, 1.0);    vFade = color.r; // For vignette fade}