libcamera/vivid.git - libcamera pipeline handler for VIVID

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Diffstat (limited to 'src/v4l2/v4l2_camera.h')

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/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2020, Laurent Pinchart <laurent.pinchart@ideasonboard.com> * * YUV_packed.frag - Fragment shader code for YUYV packed formats */ #ifdef GL_ES precision mediump float; #endif varying vec2 textureOut; uniform sampler2D tex_y; uniform float tex_stepx; void main(void) { mat3 yuv2rgb_bt601_mat = mat3( vec3(1.164, 1.164, 1.164), vec3(0.000, -0.392, 2.017), vec3(1.596, -0.813, 0.000) ); vec3 yuv2rgb_bt601_offset = vec3(0.063, 0.500, 0.500); /* * The sampler won't interpolate the texture correctly along the X axis, * as each RGBA pixel effectively stores two pixels. We thus need to * interpolate manually. * * In integer texture coordinates, the Y values are layed out in the * texture memory as follows: * * ...| Y U Y V | Y U Y V | Y U Y V |... * ...| R G B A | R G B A | R G B A |... * ^ ^ ^ ^ ^ ^ * | | | | | | * n-1 n-0.5 n n+0.5 n+1 n+1.5 * * For a texture location x in the interval [n, n+1[, sample the left * and right pixels at n and n+1, and interpolate them with * * left.r * (1 - a) + left.b * a if fract(x) < 0.5 * left.b * (1 - a) + right.r * a if fract(x) >= 0.5 * * with a = fract(x * 2) which can also be written * * a = fract(x) * 2 if fract(x) < 0.5 * a = fract(x) * 2 - 1 if fract(x) >= 0.5 */ vec2 pos = textureOut; float f_x = fract(pos.x / tex_stepx); vec4 left = texture2D(tex_y, vec2(pos.x - f_x * tex_stepx, pos.y)); vec4 right = texture2D(tex_y, vec2(pos.x + (1.0 - f_x) * tex_stepx , pos.y)); #if defined(YUV_PATTERN_UYVY) float y_left = mix(left.g, left.a, f_x * 2.0); float y_right = mix(left.a, right.g, f_x * 2.0 - 1.0); vec2 uv = mix(left.rb, right.rb, f_x); #elif defined(YUV_PATTERN_VYUY) float y_left = mix(left.g, left.a, f_x * 2.0); float y_right = mix(left.a, right.g, f_x * 2.0 - 1.0); vec2 uv = mix(left.br, right.br, f_x); #elif defined(YUV_PATTERN_YUYV) float y_left = mix(left.r, left.b, f_x * 2.0); float y_right = mix(left.b, right.r, f_x * 2.0 - 1.0); vec2 uv = mix(left.ga, right.ga, f_x); #elif defined(YUV_PATTERN_YVYU) float y_left = mix(left.r, left.b, f_x * 2.0); float y_right = mix(left.b, right.r, f_x * 2.0 - 1.0); vec2 uv = mix(left.ag, right.ag, f_x); #else #error Invalid pattern #endif float y = mix(y_left, y_right, step(0.5, f_x)); vec3 rgb = yuv2rgb_bt601_mat * (vec3(y, uv) - yuv2rgb_bt601_offset); gl_FragColor = vec4(rgb, 1.0); }


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