From 251f0534b74bcb46c777aa0df34b1b4142b664f5 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 28 Aug 2022 03:40:25 +0300 Subject: qcam: viewfinder_gl: Take color space into account for YUV rendering Update the YUV shaders and the viewfinder_gl to correctly take the Y'CbCr encoding and the quantization range into account when rendering YUV formats to RGB. Support for the primaries and transfer function will be added in a subsequent step. Signed-off-by: Laurent Pinchart Reviewed-by: Umang Jain Reviewed-by: Kunal Agarwal --- src/qcam/assets/shader/YUV_2_planes.frag | 29 ++++++++++++++++------------- src/qcam/assets/shader/YUV_3_planes.frag | 27 +++++++++++++++------------ src/qcam/assets/shader/YUV_packed.frag | 17 +++++++++-------- 3 files changed, 40 insertions(+), 33 deletions(-) (limited to 'src/qcam/assets/shader') diff --git a/src/qcam/assets/shader/YUV_2_planes.frag b/src/qcam/assets/shader/YUV_2_planes.frag index 254463c0..da8dbcc5 100644 --- a/src/qcam/assets/shader/YUV_2_planes.frag +++ b/src/qcam/assets/shader/YUV_2_planes.frag @@ -13,27 +13,30 @@ varying vec2 textureOut; uniform sampler2D tex_y; uniform sampler2D tex_u; +const mat3 yuv2rgb_matrix = mat3( + YUV2RGB_MATRIX +); + +const vec3 yuv2rgb_offset = vec3( + YUV2RGB_Y_OFFSET / 255.0, 128.0 / 255.0, 128.0 / 255.0 +); + void main(void) { vec3 yuv; - vec3 rgb; - 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) - ); - - yuv.x = texture2D(tex_y, textureOut).r - 0.063; + + yuv.x = texture2D(tex_y, textureOut).r; #if defined(YUV_PATTERN_UV) - yuv.y = texture2D(tex_u, textureOut).r - 0.500; - yuv.z = texture2D(tex_u, textureOut).a - 0.500; + yuv.y = texture2D(tex_u, textureOut).r; + yuv.z = texture2D(tex_u, textureOut).a; #elif defined(YUV_PATTERN_VU) - yuv.y = texture2D(tex_u, textureOut).a - 0.500; - yuv.z = texture2D(tex_u, textureOut).r - 0.500; + yuv.y = texture2D(tex_u, textureOut).a; + yuv.z = texture2D(tex_u, textureOut).r; #else #error Invalid pattern #endif - rgb = yuv2rgb_bt601_mat * yuv; + vec3 rgb = yuv2rgb_matrix * (vec3(y, uv) - yuv2rgb_offset); + gl_FragColor = vec4(rgb, 1.0); } diff --git a/src/qcam/assets/shader/YUV_3_planes.frag b/src/qcam/assets/shader/YUV_3_planes.frag index 2be74b5d..e754129d 100644 --- a/src/qcam/assets/shader/YUV_3_planes.frag +++ b/src/qcam/assets/shader/YUV_3_planes.frag @@ -14,20 +14,23 @@ uniform sampler2D tex_y; uniform sampler2D tex_u; uniform sampler2D tex_v; +const mat3 yuv2rgb_matrix = mat3( + YUV2RGB_MATRIX +); + +const vec3 yuv2rgb_offset = vec3( + YUV2RGB_Y_OFFSET / 255.0, 128.0 / 255.0, 128.0 / 255.0 +); + void main(void) { vec3 yuv; - vec3 rgb; - 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) - ); - - yuv.x = texture2D(tex_y, textureOut).r - 0.063; - yuv.y = texture2D(tex_u, textureOut).r - 0.500; - yuv.z = texture2D(tex_v, textureOut).r - 0.500; - - rgb = yuv2rgb_bt601_mat * yuv; + + yuv.x = texture2D(tex_y, textureOut).r; + yuv.y = texture2D(tex_u, textureOut).r; + yuv.z = texture2D(tex_v, textureOut).r; + + vec3 rgb = yuv2rgb_matrix * (vec3(y, uv) - yuv2rgb_offset); + gl_FragColor = vec4(rgb, 1.0); } diff --git a/src/qcam/assets/shader/YUV_packed.frag b/src/qcam/assets/shader/YUV_packed.frag index d6efd4ce..b9ef9d41 100644 --- a/src/qcam/assets/shader/YUV_packed.frag +++ b/src/qcam/assets/shader/YUV_packed.frag @@ -14,15 +14,16 @@ varying vec2 textureOut; uniform sampler2D tex_y; uniform vec2 tex_step; +const mat3 yuv2rgb_matrix = mat3( + YUV2RGB_MATRIX +); + +const vec3 yuv2rgb_offset = vec3( + YUV2RGB_Y_OFFSET / 255.0, 128.0 / 255.0, 128.0 / 255.0 +); + 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 @@ -76,7 +77,7 @@ void main(void) float y = mix(y_left, y_right, step(0.5, f_x)); - vec3 rgb = yuv2rgb_bt601_mat * (vec3(y, uv) - yuv2rgb_bt601_offset); + vec3 rgb = yuv2rgb_matrix * (vec3(y, uv) - yuv2rgb_offset); gl_FragColor = vec4(rgb, 1.0); } -- cgit v1.2.1