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// license:BSD-3-Clause
// copyright-holders:Sven Gothel
#pragma optimize (on)
#pragma debug (off)
uniform sampler2D color_texture;
uniform vec2 color_texture_pow2_sz; // pow2 tex size
uniform vec4 vid_attributes; // gamma, contrast, brightness
// #define DO_GAMMA 1 // 'pow' is very slow on old hardware, i.e. pre R600 and 'slow' in general
#define TEX2D(v) texture2D(color_texture,(v))
void main()
{
// mix(x,y,a): x*(1-a) + y*a
//
// bilinear filtering includes 2 mix:
//
// pix1 = tex[x0][y0] * ( 1 - u_ratio ) + tex[x1][y0] * u_ratio
// pix2 = tex[x0][y1] * ( 1 - u_ratio ) + tex[x1][y1] * u_ratio
// fin = pix1 * ( 1 - v_ratio ) + pix2 * v_ratio
//
// so we can use the build in mix function for these 2 computations ;-)
//
vec2 pixel = gl_TexCoord[0].st * color_texture_pow2_sz - 0.5;
vec2 uv_ratio = fract(pixel);
vec2 one = 1.0 / color_texture_pow2_sz;
vec2 xy = (floor(pixel) + 0.5) * one;
#if 1
vec4 col, col2;
col = mix( TEX2D(xy ), TEX2D(xy + vec2(one.x, 0.0)), uv_ratio.x);
col2 = mix( TEX2D(xy + vec2(0.0, one.y)), TEX2D(xy + one ), uv_ratio.x);
col = mix ( col, col2, uv_ratio.y );
#else
// doesn't work on MacOSX GLSL engine ..
//
vec4 col = mix ( mix( TEX2D(xy ), TEX2D(xy + vec2(one.x, 0.0)), uv_ratio.x),
mix( TEX2D(xy + vec2(0.0, one.y)), TEX2D(xy + one ), uv_ratio.x), uv_ratio.y );
#endif
// gamma, contrast, brightness equation from: rendutil.h / apply_brightness_contrast_gamma_fp
#ifdef DO_GAMMA
// gamma/contrast/brightness
vec4 gamma = vec4(1.0 / vid_attributes.r, 1.0 / vid_attributes.r, 1.0 / vid_attributes.r, 0.0);
gl_FragColor = ( pow ( col, gamma ) * vid_attributes.g) + vid_attributes.b - 1.0;
#else
// contrast/brightness
gl_FragColor = ( col * vid_attributes.g) + vid_attributes.b - 1.0;
#endif
}
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