[libcamera-devel] [PATCH v5 4/9] qcam: viewfinder_gl: Copy the shaders for RAW8 Bayer format from motmot
paul.elder at ideasonboard.com
paul.elder at ideasonboard.com
Mon Jun 28 12:23:38 CEST 2021
Hi Andrey,
On Tue, Jun 22, 2021 at 04:46:47PM +0300, Andrey Konovalov wrote:
> From: Morgan McGuire <morgan3d at gmail.com>
>
> 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: Paul Elder <paul.elder 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;
> +}
> --
> 2.25.1
>
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