[libcamera-devel] [PATCH v5 4/9] qcam: viewfinder_gl: Copy the shaders for RAW8 Bayer format from motmot
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Jun 30 03:01:46 CEST 2021
Hi Andrey,
On Tue, Jun 22, 2021 at 04:46:47PM +0300, Andrey Konovalov wrote:
> From: Morgan McGuire <morgan3d at gmail.com>
While Morgan is the author of the code (which is correctly attributed in
the files below), listing him as the author of the commit would required
his SoB line. I'll thus reset authorship of the commit to you.
> This commit copies the shaders from:
>
> https://github.com/motmot/libcamiface/commit/e36d51580510c211afc0430141085eb7a77d811b
>
> Signed-off-by: Andrey Konovalov <andrey.konovalov at linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
> src/qcam/assets/shader/bayer_8.frag | 124 ++++++++++++++++++++++++++++
> src/qcam/assets/shader/bayer_8.vert | 70 ++++++++++++++++
> 2 files changed, 194 insertions(+)
> create mode 100644 src/qcam/assets/shader/bayer_8.frag
> create mode 100644 src/qcam/assets/shader/bayer_8.vert
>
> diff --git a/src/qcam/assets/shader/bayer_8.frag b/src/qcam/assets/shader/bayer_8.frag
> new file mode 100644
> index 00000000..707e76ed
> --- /dev/null
> +++ b/src/qcam/assets/shader/bayer_8.frag
> @@ -0,0 +1,124 @@
> +/*
> +From http://jgt.akpeters.com/papers/McGuire08/
> +
> +Efficient, High-Quality Bayer Demosaic Filtering on GPUs
> +
> +Morgan McGuire
> +
> +This paper appears in issue Volume 13, Number 4.
> +---------------------------------------------------------
> +Copyright (c) 2008, Morgan McGuire. All rights reserved.
> +
> +Redistribution and use in source and binary forms, with or without
> +modification, are permitted provided that the following conditions are
> +met:
> +
> + * Redistributions of source code must retain the above copyright
> + notice, this list of conditions and the following disclaimer.
> +
> + * Redistributions in binary form must reproduce the above
> + copyright notice, this list of conditions and the following
> + disclaimer in the documentation and/or other materials provided
> + with the distribution.
> +
> +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> +*/
> +
> +//Pixel Shader
> +
> +/** Monochrome RGBA or GL_LUMINANCE Bayer encoded texture.*/
> +uniform sampler2D source;
> +varying vec4 center;
> +varying vec4 yCoord;
> +varying vec4 xCoord;
> +
> +void main(void) {
> + #define fetch(x, y) texture2D(source, vec2(x, y)).r
> +
> + float C = texture2D(source, center.xy).r; // ( 0, 0)
> + const vec4 kC = vec4( 4.0, 6.0, 5.0, 5.0) / 8.0;
> +
> + // Determine which of four types of pixels we are on.
> + vec2 alternate = mod(floor(center.zw), 2.0);
> +
> + vec4 Dvec = vec4(
> + fetch(xCoord[1], yCoord[1]), // (-1,-1)
> + fetch(xCoord[1], yCoord[2]), // (-1, 1)
> + fetch(xCoord[2], yCoord[1]), // ( 1,-1)
> + fetch(xCoord[2], yCoord[2])); // ( 1, 1)
> +
> + vec4 PATTERN = (kC.xyz * C).xyzz;
> +
> + // Can also be a dot product with (1,1,1,1) on hardware where that is
> + // specially optimized.
> + // Equivalent to: D = Dvec[0] + Dvec[1] + Dvec[2] + Dvec[3];
> + Dvec.xy += Dvec.zw;
> + Dvec.x += Dvec.y;
> +
> + vec4 value = vec4(
> + fetch(center.x, yCoord[0]), // ( 0,-2)
> + fetch(center.x, yCoord[1]), // ( 0,-1)
> + fetch(xCoord[0], center.y), // (-1, 0)
> + fetch(xCoord[1], center.y)); // (-2, 0)
> +
> + vec4 temp = vec4(
> + fetch(center.x, yCoord[3]), // ( 0, 2)
> + fetch(center.x, yCoord[2]), // ( 0, 1)
> + fetch(xCoord[3], center.y), // ( 2, 0)
> + fetch(xCoord[2], center.y)); // ( 1, 0)
> +
> + // Even the simplest compilers should be able to constant-fold these to
> + // avoid the division.
> + // Note that on scalar processors these constants force computation of some
> + // identical products twice.
> + const vec4 kA = vec4(-1.0, -1.5, 0.5, -1.0) / 8.0;
> + const vec4 kB = vec4( 2.0, 0.0, 0.0, 4.0) / 8.0;
> + const vec4 kD = vec4( 0.0, 2.0, -1.0, -1.0) / 8.0;
> +
> + // Conserve constant registers and take advantage of free swizzle on load
> + #define kE (kA.xywz)
> + #define kF (kB.xywz)
> +
> + value += temp;
> +
> + // There are five filter patterns (identity, cross, checker,
> + // theta, phi). Precompute the terms from all of them and then
> + // use swizzles to assign to color channels.
> + //
> + // Channel Matches
> + // x cross (e.g., EE G)
> + // y checker (e.g., EE B)
> + // z theta (e.g., EO R)
> + // w phi (e.g., EO R)
> + #define A (value[0])
> + #define B (value[1])
> + #define D (Dvec.x)
> + #define E (value[2])
> + #define F (value[3])
> +
> + // Avoid zero elements. On a scalar processor this saves two MADDs
> + // and it has no effect on a vector processor.
> + PATTERN.yzw += (kD.yz * D).xyy;
> +
> + PATTERN += (kA.xyz * A).xyzx + (kE.xyw * E).xyxz;
> + PATTERN.xw += kB.xw * B;
> + PATTERN.xz += kF.xz * F;
> +
> + gl_FragColor.rgb = (alternate.y == 0.0) ?
> + ((alternate.x == 0.0) ?
> + vec3(C, PATTERN.xy) :
> + vec3(PATTERN.z, C, PATTERN.w)) :
> + ((alternate.x == 0.0) ?
> + vec3(PATTERN.w, C, PATTERN.z) :
> + vec3(PATTERN.yx, C));
> +}
> diff --git a/src/qcam/assets/shader/bayer_8.vert b/src/qcam/assets/shader/bayer_8.vert
> new file mode 100644
> index 00000000..3354860f
> --- /dev/null
> +++ b/src/qcam/assets/shader/bayer_8.vert
> @@ -0,0 +1,70 @@
> +/*
> +From http://jgt.akpeters.com/papers/McGuire08/
> +
> +Efficient, High-Quality Bayer Demosaic Filtering on GPUs
> +
> +Morgan McGuire
> +
> +This paper appears in issue Volume 13, Number 4.
> +---------------------------------------------------------
> +Copyright (c) 2008, Morgan McGuire. All rights reserved.
> +
> +Redistribution and use in source and binary forms, with or without
> +modification, are permitted provided that the following conditions are
> +met:
> +
> + * Redistributions of source code must retain the above copyright
> + notice, this list of conditions and the following disclaimer.
> +
> + * Redistributions in binary form must reproduce the above
> + copyright notice, this list of conditions and the following
> + disclaimer in the documentation and/or other materials provided
> + with the distribution.
> +
> +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> +*/
> +
> +//Vertex Shader
> +
> +
> +/** (w,h,1/w,1/h) */
> +uniform vec4 sourceSize;
> +
> +/** Pixel position of the first red pixel in the */
> +/** Bayer pattern. [{0,1}, {0, 1}]*/
> +uniform vec2 firstRed;
> +
> +/** .xy = Pixel being sampled in the fragment shader on the range [0, 1]
> + .zw = ...on the range [0, sourceSize], offset by firstRed */
> +varying vec4 center;
> +
> +/** center.x + (-2/w, -1/w, 1/w, 2/w); These are the x-positions */
> +/** of the adjacent pixels.*/
> +varying vec4 xCoord;
> +
> +/** center.y + (-2/h, -1/h, 1/h, 2/h); These are the y-positions */
> +/** of the adjacent pixels.*/
> +varying vec4 yCoord;
> +
> +void main(void) {
> + center.xy = gl_MultiTexCoord0.xy;
> + center.zw = gl_MultiTexCoord0.xy * sourceSize.xy + firstRed;
> +
> + vec2 invSize = sourceSize.zw;
> + xCoord = center.x + vec4(-2.0 * invSize.x,
> + -invSize.x, invSize.x, 2.0 * invSize.x);
> + yCoord = center.y + vec4(-2.0 * invSize.y,
> + -invSize.y, invSize.y, 2.0 * invSize.y);
> +
> + gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
> +}
--
Regards,
Laurent Pinchart
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