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#if(XBMC_texture_rectangle)
# extension GL_ARB_texture_rectangle : enable
# define texture2D texture2DRect
# define sampler2D sampler2DRect
#endif
uniform sampler2D m_sampY;
uniform sampler2D m_sampU;
uniform sampler2D m_sampV;
varying vec2 m_cordY;
varying vec2 m_cordU;
varying vec2 m_cordV;
uniform vec2 m_step;
uniform mat4 m_yuvmat;
uniform float m_stretch;
vec2 stretch(vec2 pos)
{
#if (XBMC_STRETCH)
// our transform should map [0..1] to itself, with f(0) = 0, f(1) = 1, f(0.5) = 0.5, and f'(0.5) = b.
// a simple curve to do this is g(x) = b(x-0.5) + (1-b)2^(n-1)(x-0.5)^n + 0.5
// where the power preserves sign. n = 2 is the simplest non-linear case (required when b != 1)
float x = pos.x - 0.5;
return vec2(mix(2.0 * x * abs(x), x, m_stretch) + 0.5, pos.y);
#else
return pos;
#endif
}
void main()
{
#ifndef XBMC_YUY2
vec4 yuv, rgb;
yuv.rgba = vec4( texture2D(m_sampY, stretch(m_cordY)).r
, texture2D(m_sampU, stretch(m_cordU)).g
, texture2D(m_sampV, stretch(m_cordV)).a
, 1.0 );
rgb = m_yuvmat * yuv;
rgb.a = gl_Color.a;
gl_FragColor = rgb;
#else
#if(XBMC_texture_rectangle)
vec2 stepxy = vec2(1.0, 1.0);
vec2 pos = stretch(m_cordY);
pos = vec2(pos.x - 0.25, pos.y);
vec2 f = fract(pos);
#else
vec2 stepxy = m_step;
vec2 pos = stretch(m_cordY);
pos = vec2(pos.x - stepxy.x * 0.25, pos.y);
vec2 f = fract(pos / stepxy);
#endif
//y axis will be correctly interpolated by opengl
//x axis will not, so we grab two pixels at the center of two columns and interpolate ourselves
vec4 c1 = texture2D(m_sampY, vec2(pos.x + (0.5 - f.x) * stepxy.x, pos.y));
vec4 c2 = texture2D(m_sampY, vec2(pos.x + (1.5 - f.x) * stepxy.x, pos.y));
/* each pixel has two Y subpixels and one UV subpixel
YUV Y YUV
check if we're left or right of the middle Y subpixel and interpolate accordingly*/
float leftY = mix(c1.b, c1.r, f.x * 2.0);
float rightY = mix(c1.r, c2.b, f.x * 2.0 - 1.0);
float outY = mix(leftY, rightY, step(0.5, f.x));
//interpolate UV
vec2 outUV = mix(c1.ga, c2.ga, f.x);
vec4 yuv = vec4(outY, outUV, 1.0);
vec4 rgb = m_yuvmat * yuv;
gl_FragColor = rgb;
gl_FragColor.a = gl_Color.a;
#endif
}
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