libcamera: shaders: Use highp not mediump for float precision

mediump gives 10 bits of mantissa as the resolution. At higher resolutions
10 bits of accuracy is insufficient - for example at a width of 1928 bytes
we need log2(1928) = ~11 bit resolution.

Switching to highp gives us 23 bits of mantissa giving a sample width
precision of about 2^23 ~ 8,388,608.

Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Tested-by: Robert Mader <robert.mader@collabora.com>
Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen 6 (arm64) ov02c10 + X1c gen 12 ov08x40
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com> # Lenovo X13s
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/shaders/RGB.frag

@@ -6,7 +6,7 @@
  */
 
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 varying vec2 textureOut;

src/libcamera/shaders/YUV_2_planes.frag

@@ -6,7 +6,7 @@
  */
 
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 varying vec2 textureOut;

src/libcamera/shaders/YUV_3_planes.frag

@@ -6,7 +6,7 @@
  */
 
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 varying vec2 textureOut;

src/libcamera/shaders/YUV_packed.frag

@@ -6,7 +6,7 @@
  */
 
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 varying vec2 textureOut;

src/libcamera/shaders/bayer_1x_packed.frag

@@ -20,7 +20,7 @@
  */
 
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 /*

src/libcamera/shaders/bayer_unpacked.frag

@@ -16,7 +16,7 @@ Copyright (C) 2021, Linaro
 
 //Pixel Shader
 #ifdef GL_ES
-precision mediump float;
+precision highp float;
 #endif
 
 /** Monochrome RGBA or GL_LUMINANCE Bayer encoded texture.*/