qcam: viewfinder_gl: Add support for RAW8 Bayer formats

This integrates the vertex and the fragment shaders by Morgan McGuire
into qcam.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/qcam/assets/shader/bayer_8.frag

@@ -9,20 +9,23 @@ Morgan McGuire
 This paper appears in issue Volume 13, Number 4.
 ---------------------------------------------------------
 Copyright (c) 2008, Morgan McGuire. All rights reserved.
+
+Modified by Linaro Ltd to integrate it into libcamera.
+Copyright (C) 2021, Linaro
 */
 
 //Pixel Shader
 
 /** Monochrome RGBA or GL_LUMINANCE Bayer encoded texture.*/
-uniform sampler2D       source;
+uniform sampler2D       tex_y;
 varying vec4            center;
 varying vec4            yCoord;
 varying vec4            xCoord;
 
 void main(void) {
-    #define fetch(x, y) texture2D(source, vec2(x, y)).r
+    #define fetch(x, y) texture2D(tex_y, vec2(x, y)).r
 
-    float C = texture2D(source, center.xy).r; // ( 0, 0)
+    float C = texture2D(tex_y, 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.

src/qcam/assets/shader/bayer_8.vert

@@ -9,17 +9,22 @@ Morgan McGuire
 This paper appears in issue Volume 13, Number 4.
 ---------------------------------------------------------
 Copyright (c) 2008, Morgan McGuire. All rights reserved.
+
+Modified by Linaro Ltd to integrate it into libcamera.
+Copyright (C) 2021, Linaro
 */
 
 //Vertex Shader
 
+attribute vec4 vertexIn;
+attribute vec2 textureIn;
 
-/** (w,h,1/w,1/h) */
+uniform vec2 tex_size;	/* The texture size in pixels */
-uniform vec4            sourceSize;
+uniform vec2 tex_step;
 
 /** Pixel position of the first red pixel in the */
 /**  Bayer pattern.  [{0,1}, {0, 1}]*/
-uniform vec2            firstRed;
+uniform vec2            tex_bayer_first_red;
 
 /** .xy = Pixel being sampled in the fragment shader on the range [0, 1]
     .zw = ...on the range [0, sourceSize], offset by firstRed */
@@ -34,14 +39,13 @@ varying vec4            xCoord;
 varying vec4            yCoord;
 
 void main(void) {
-    center.xy = gl_MultiTexCoord0.xy;
+    center.xy = textureIn;
-    center.zw = gl_MultiTexCoord0.xy * sourceSize.xy + firstRed;
+    center.zw = textureIn * tex_size + tex_bayer_first_red;
 
-    vec2 invSize = sourceSize.zw;
+    xCoord = center.x + vec4(-2.0 * tex_step.x,
-    xCoord = center.x + vec4(-2.0 * invSize.x,
+                             -tex_step.x, tex_step.x, 2.0 * tex_step.x);
-                             -invSize.x, invSize.x, 2.0 * invSize.x);
+    yCoord = center.y + vec4(-2.0 * tex_step.y,
-    yCoord = center.y + vec4(-2.0 * invSize.y,
+                              -tex_step.y, tex_step.y, 2.0 * tex_step.y);
-                              -invSize.y, invSize.y, 2.0 * invSize.y);
 
-    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
+    gl_Position = vertexIn;
 }

src/qcam/assets/shader/shaders.qrc

@@ -6,6 +6,8 @@
 	<file>YUV_3_planes.frag</file>
 	<file>YUV_packed.frag</file>
 	<file>bayer_1x_packed.frag</file>
+	<file>bayer_8.frag</file>
+	<file>bayer_8.vert</file>
 	<file>identity.vert</file>
 </qresource>
 </RCC>

src/qcam/viewfinder_gl.cpp

@@ -36,6 +36,11 @@ static const QList<libcamera::PixelFormat> supportedFormats{
 	libcamera::formats::RGBA8888,
 	libcamera::formats::BGR888,
 	libcamera::formats::RGB888,
+	/* Raw Bayer 8-bit */
+	libcamera::formats::SBGGR8,
+	libcamera::formats::SGBRG8,
+	libcamera::formats::SGRBG8,
+	libcamera::formats::SRGGB8,
 	/* Raw Bayer 10-bit packed */
 	libcamera::formats::SBGGR10_CSI2P,
 	libcamera::formats::SGBRG10_CSI2P,
@@ -223,6 +228,34 @@ bool ViewFinderGL::selectFormat(const libcamera::PixelFormat &format)
 		fragmentShaderDefines_.append("#define RGB_PATTERN bgr");
 		fragmentShaderFile_ = ":RGB.frag";
 		break;
+	case libcamera::formats::SBGGR8:
+		firstRed_.setX(1.0);
+		firstRed_.setY(1.0);
+		vertexShaderFile_ = ":bayer_8.vert";
+		fragmentShaderFile_ = ":bayer_8.frag";
+		textureMinMagFilters_ = GL_NEAREST;
+		break;
+	case libcamera::formats::SGBRG8:
+		firstRed_.setX(0.0);
+		firstRed_.setY(1.0);
+		vertexShaderFile_ = ":bayer_8.vert";
+		fragmentShaderFile_ = ":bayer_8.frag";
+		textureMinMagFilters_ = GL_NEAREST;
+		break;
+	case libcamera::formats::SGRBG8:
+		firstRed_.setX(1.0);
+		firstRed_.setY(0.0);
+		vertexShaderFile_ = ":bayer_8.vert";
+		fragmentShaderFile_ = ":bayer_8.frag";
+		textureMinMagFilters_ = GL_NEAREST;
+		break;
+	case libcamera::formats::SRGGB8:
+		firstRed_.setX(0.0);
+		firstRed_.setY(0.0);
+		vertexShaderFile_ = ":bayer_8.vert";
+		fragmentShaderFile_ = ":bayer_8.frag";
+		textureMinMagFilters_ = GL_NEAREST;
+		break;
 	case libcamera::formats::SBGGR10_CSI2P:
 		firstRed_.setX(1.0);
 		firstRed_.setY(1.0);
@@ -627,6 +660,10 @@ void ViewFinderGL::doRender()
 		shaderProgram_.setUniformValue(textureUniformY_, 0);
 		break;
 
+	case libcamera::formats::SBGGR8:
+	case libcamera::formats::SGBRG8:
+	case libcamera::formats::SGRBG8:
+	case libcamera::formats::SRGGB8:
 	case libcamera::formats::SBGGR10_CSI2P:
 	case libcamera::formats::SGBRG10_CSI2P:
 	case libcamera::formats::SGRBG10_CSI2P:
@@ -636,8 +673,8 @@ void ViewFinderGL::doRender()
 	case libcamera::formats::SGRBG12_CSI2P:
 	case libcamera::formats::SRGGB12_CSI2P:
 		/*
-		 * Packed raw Bayer 10-bit and 12-bit formats are stored in
+		 * Raw Bayer 8-bit, and packed raw Bayer 10-bit/12-bit formats
-		 * GL_RED texture.
+		 * are stored in GL_RED texture.
 		 * The texture width is equal to the stride.
 		 */
 		glActiveTexture(GL_TEXTURE0);