Oculus DK2 shader fixes

// Oculus DK2 lens distortion shader for single eye

// shader is adapted from Oculus DK1 distortion shader by

// Lubosz Sarnecki(lubosz.wordpress.com/)a

uniform sampler2D bgl_RenderedTexture;

uniform float bgl_RenderedTextureWidth;

uniform float bgl_RenderedTextureHeight;

uniform float bgl_RenderedStereoEye;

const vec4 kappa = vec4(1.0,0.7,1.0,1.0);

const vec4 kappa = vec4(1.0,0.9,1.0,2.0);

float screen_width = bgl_RenderedTextureWidth;

float screen_height = bgl_RenderedTextureHeight;

const float scaleFactor = 0.85;

const vec2 leftCenter = vec2(0.25, 0.5);

const vec2 rightCenter = vec2(0.75, 0.5);

const float scaleFactor = 0.83;

const float separation = -0.00;

const vec2 lensCenter = vec2(0.5, 0.5);

// Scales input texture coordinates for distortion.

vec2 hmdWarp(vec2 LensCenter, vec2 texCoord, vec2 Scale, vec2 ScaleIn, float eta) {

    vec2 theta = (texCoord - LensCenter) * ScaleIn;

vec2 hmdWarp(vec2 texCoord, vec2 Scale, vec2 ScaleIn, float eta) {

    vec2 theta = (texCoord - lensCenter) * ScaleIn;

    float rSq = theta.x * theta.x + theta.y * theta.y;

    vec2 rvector = theta * (kappa.x + kappa.y * rSq + kappa.z * rSq * rSq + kappa.w * rSq * rSq * rSq);

    vec2 tc = LensCenter + Scale * eta * rvector;

    vec2 tc = lensCenter + Scale * eta * rvector;

    return tc;

}

bool validate(vec2 tc, int left_eye)

float edges(vec2 tc)

{

    //keep within bounds of texture

    if ((left_eye == 1 && (tc.x < 0.0 || tc.x > 0.5)) ||

        (left_eye == 0 && (tc.x < 0.5 || tc.x > 1.0)) ||

        tc.y < 0.0 || tc.y > 1.0) {

        return false;

    }

    return true;

    float vertL = smoothstep(0.0,0.05,tc.x);

    float vertR = smoothstep(1.0,0.95,tc.x);

    float horizL = smoothstep(0.0,0.05,tc.y);

    float horizR = smoothstep(1.0,0.95,tc.y);

    return vertL*vertR*horizL*horizR;

}

void main()

{

    vec2 screen = vec2(screen_width, screen_height);

    vec3 eta = vec3(1.00,1.018,1.042); //refraction indices

    float as = float(screen.x / 2.0) / float(screen.y);

    vec2 Scale = vec2(0.47, as);

    vec2 ScaleIn = vec2(2.0 * scaleFactor, 1.0 / as * scaleFactor);

    vec2 texCoord = (gl_TexCoord[0].st);

    texCoord.x *= 0.5;

    float as = float(screen.x) / float(screen.y);

    vec2 Scale = vec2(1.0, 1.0);

    vec2 ScaleIn = vec2(scaleFactor, scaleFactor);

    if (bgl_RenderedStereoEye > 0.1)

        texCoord.x += 0.5;

    vec2 texCoordSeparated = texCoord;

    vec2 texCoord = gl_TexCoord[0].st;

    vec2 tcR = vec2(0.0);

    vec2 tcG = vec2(0.0);

    vec4 color = vec4(0.0);

    if (texCoord.x < 0.5) {

        texCoordSeparated.x += separation;

        tcR = hmdWarp(leftCenter, texCoordSeparated, Scale, ScaleIn, eta.r );

        tcG = hmdWarp(leftCenter, texCoordSeparated, Scale, ScaleIn, eta.g );

        tcB = hmdWarp(leftCenter, texCoordSeparated, Scale, ScaleIn, eta.b );

    tcR = hmdWarp(texCoord, Scale, ScaleIn, eta.r );

    tcG = hmdWarp(texCoord, Scale, ScaleIn, eta.g );

    tcB = hmdWarp(texCoord, Scale, ScaleIn, eta.b );

    color.r = texture2D(bgl_RenderedTexture, tcR).r;

    color.g = texture2D(bgl_RenderedTexture, tcG).g;

    color.b = texture2D(bgl_RenderedTexture, tcB).b;

    color = color * edges(tcR);

        if (!validate(tcR, 1))

            color = vec4(0.0);

    } else {

        texCoordSeparated.x -= separation;

        tcR = hmdWarp(rightCenter, texCoordSeparated, Scale, ScaleIn, eta.r );

        tcG = hmdWarp(rightCenter, texCoordSeparated, Scale, ScaleIn, eta.g );

        tcB = hmdWarp(rightCenter, texCoordSeparated, Scale, ScaleIn, eta.b );

        color.r = texture2D(bgl_RenderedTexture, tcR).r;

        color.g = texture2D(bgl_RenderedTexture, tcG).g;

        color.b = texture2D(bgl_RenderedTexture, tcB).b;

        if (!validate(tcR, 0))

            color = vec4(0.0);

    }

    gl_FragColor = color;

}