uniform sampler2D u_Texture0;
uniform sampler2D u_Texture1;
uniform sampler2D u_Texture2;
// TOP DOWN 360 MODEL
// https://github.com/tokoik/fisheye ...
// https://stackoverflow.com/questions/39352533/android-opengl-es-textured-half-sphere ???
varying vec2 v_TexCoords0;
varying vec2 v_TexCoords1;
varying vec2 v_TexCoords2;

#define v_TexCoords1 v_TexCoords0
#define v_TexCoords2 v_TexCoords0
#define v_TexCoords3 v_TexCoords0

uniform float u_opacity;
uniform mat4 u_colorMatrix;

uniform int u_mode;
uniform float u_angle;
uniform int u_flip;
uniform float u_effectiveWidth;
uniform float u_clipBound;
uniform float u_whratio;
void main(void)
{
    vec2 fc = v_TexCoords0.st;
    float PI = 3.141592;

    // FLIP 반전
//    if(u_mode != 2 && u_flip == 1) {
//        fc.y = 1.0 - fc.y;
//    }

    // VR + PANORAMA
    // #if (REMOVE_360_WIDE_SINGLE)
    //if(u_mode == 3 || u_mode == 1)
    if(u_mode == 2 || u_mode == 3)
    {
        float R = u_effectiveWidth / 2.0 * 0.99;//0.5;
        float Cfx = u_effectiveWidth / 2.0;
        float Cfy = 0.5;

        float He = 1.0;
        float We = u_effectiveWidth;

        float Xe = 1.0-fc.x;    // flip h
        float Ye = 1.0-fc.y;    // upside down

//        if(u_mode == 3){
//            if(Ye > 0.62) {
//                gl_FragColor = vec4(0.0,0.0,0.0,1.0);
//                return;
//            }
//            Ye = (Ye / 0.62);
//        }

        float r = Ye/He*R;
        float theta = Xe/We*2.0*PI - (u_angle * 3.0); // TOP_DOWN_2D_360

        theta = theta * 0.2 * u_whratio;

        float Xf = Cfx+r*sin(theta);
        float Yf = Cfy+r*cos(theta);

        fc = vec2(Xf,Yf);
    }
    else if(u_mode == 1) // PANORAMA 2CH
    {
        fc.y = 1.0 - fc.y;

        float Hf = 1.0;
        float R = u_effectiveWidth / 2.0 * 0.99;
        float Cfx = u_effectiveWidth / 2.0;
        float Cfy = 0.5;

        float He = 1.0;
        float We = u_effectiveWidth;

        float Xe = 1.0-fc.x;    // flip h
        float Ye = 1.0-fc.y;    // upside down

        if(fc.y < 0.5) // top (0~180 -> bottom
        {
            Ye = 1.0-Ye;

            float scale = (Ye + 0.5) * 2.0;   // 0.0~0.5 = 1.0~2.0
            float r = ((Ye/He*R)+0.25) / scale;
            float theta = Xe/We*PI+(PI/2.0); // 1/2
            theta += PI;
            float Xf = Cfx+r*sin(theta) * scale * 1.0;
            float Yf = Cfy+r*cos(theta) * scale;

            fc = vec2(Xf,Yf);
        }
        else // bottom 180 ~ 360
        {
            Ye = 1.0-Ye-0.5;
            float scale = (Ye + 0.5) * 2.0;   // 0.0~0.5 = 1.0~2.0
            float r = ((Ye/He*R)+0.25) / scale;
            float theta = Xe/We*PI+(PI/2.0); // 1/2
            float Xf = Cfx+r*sin(theta) * scale;
            float Yf = Cfy+r*cos(theta) * scale;

            fc = vec2(Xf,Yf);
        }

        if(u_clipBound > 0.0) {
            //if(v_TexCoords0.st.x < u_clipBound || v_TexCoords0.st.x > (1.0 - u_clipBound))
            if(v_TexCoords0.st.x < 0.0 || v_TexCoords0.st.x > 1.0)
            {
                gl_FragColor = clamp(u_colorMatrix
                                         * vec4(texture2D(u_Texture0, fc).r,
                                                texture2D(u_Texture1, fc).r,
                                                texture2D(u_Texture2, fc).r,
                                                1.0) * 0.9, 0.0, 1.0);
                return;
            }
        }

    }
    else // CLIP ZOOM
    {
        // ZOOM CLIP
        if (fc.x < 0.0 || fc.x > 1.0) {
            gl_FragColor = vec4(0.0,0.0,0.0,1.0);
            return;
        }
        fc.x *= u_effectiveWidth;
    }



    gl_FragColor = clamp(u_colorMatrix
                             * vec4(texture2D(u_Texture0, fc).r,
                                    texture2D(u_Texture1, fc).r,
                                    texture2D(u_Texture2, fc).r,
                                    1.0), 0.0, 1.0);

}