From 84f9cbfb734163c43ac1067f579998ab46210a14 Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Tue, 9 Aug 2022 11:04:28 -0700
Subject: [PATCH 1/8] Conditionally disable the const keyword in the BC3
 shaders

Increases compatibility with GLSL ES version 310.
---
 bin/Data/bc1.glsl | 8 ++++++++
 bin/Data/bc4.glsl | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index 8568800..a87639b 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -1,5 +1,13 @@
 #version 430 core
 
+#if defined(GL_ES) && GL_ES == 1
+	// Desktop GLSL allows the const keyword for either compile-time or
+	// run-time constants. GLSL ES only allows the keyword for compile-time
+	// constants. Since we use const on run-time constants, define it to
+	// nothing.
+	#define const
+#endif
+
 // #include "/media/matias/Datos/SyntaxHighlightingMisc.h"
 
 #include "CrossPlatformSettings_piece_all.glsl"
diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index 1c8cbe3..97d6474 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -1,5 +1,13 @@
 #version 430 core
 
+#if defined(GL_ES) && GL_ES == 1
+	// Desktop GLSL allows the const keyword for either compile-time or
+	// run-time constants. GLSL ES only allows the keyword for compile-time
+	// constants. Since we use const on run-time constants, define it to
+	// nothing.
+	#define const
+#endif
+
 // #include "/media/matias/Datos/SyntaxHighlightingMisc.h"
 
 #include "CrossPlatformSettings_piece_all.glsl"

From 0034afb2056bdc768207a3b152b8d4641a5a42bf Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Wed, 9 Nov 2022 10:51:39 -0800
Subject: [PATCH 2/8] Make the params uniform in the BC4 shader uint2

This is a better fit for indexing and for using as a boolean.

While we're here, avoid implicit data type conversions with the elements
in the uniform. This increases compatibility with GLSL ES version 310.
---
 bin/Data/bc4.glsl        | 6 +++---
 src/betsy/EncoderBC1.cpp | 2 +-
 src/betsy/EncoderBC4.cpp | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index 97d6474..03edfee 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -16,7 +16,7 @@
 shared float2 g_minMaxValues[4u * 4u * 4u];
 shared uint2 g_mask[4u * 4u];
 
-layout( location = 0 ) uniform float2 params;
+layout( location = 0 ) uniform uint2 params;
 
 #define p_channelIdx params.x
 #define p_useSNorm params.y
@@ -55,7 +55,7 @@ void main()
 		const uint2 pixelsToLoad = pixelsToLoadBase + uint2( i, blockThreadId );
 
 		const float4 value = OGRE_Load2D( srcTex, int2( pixelsToLoad ), 0 ).xyzw;
-		srcPixel[i] = p_channelIdx == 0 ? value.x : ( p_channelIdx == 1 ? value.y : value.w );
+		srcPixel[i] = p_channelIdx == 0u ? value.x : ( p_channelIdx == 1u ? value.y : value.w );
 		srcPixel[i] *= 255.0f;
 	}
 
@@ -144,7 +144,7 @@ void main()
 		// Save data
 		uint2 outputBytes;
 
-		if( p_useSNorm != 0.0f )
+		if( p_useSNorm != 0u )
 		{
 			outputBytes.x =
 				packSnorm4x8( float4( maxVal * ( 1.0f / 255.0f ) * 2.0f - 1.0f,
diff --git a/src/betsy/EncoderBC1.cpp b/src/betsy/EncoderBC1.cpp
index 4cdccd7..9f12562 100644
--- a/src/betsy/EncoderBC1.cpp
+++ b/src/betsy/EncoderBC1.cpp
@@ -131,7 +131,7 @@ namespace betsy
 			bindUav( 0u, m_bc4TargetRes, PFG_RG32_UINT, ResourceAccess::Write );
 
 			// p_channelIdx, p_useSNorm
-			glUniform2f( 0, 3.0f, 0.0f );
+			glUniform2ui( 0, 3u, 0u );
 
 			glDispatchCompute( 1u,  //
 							   alignToNextMultiple( m_width, 16u ) / 16u,
diff --git a/src/betsy/EncoderBC4.cpp b/src/betsy/EncoderBC4.cpp
index 37b0e1f..66a26aa 100644
--- a/src/betsy/EncoderBC4.cpp
+++ b/src/betsy/EncoderBC4.cpp
@@ -110,7 +110,7 @@ namespace betsy
 			bindUav( 0u, m_bc4TargetRes[i], PFG_RG32_UINT, ResourceAccess::Write );
 
 			// p_channelIdx, p_useSNorm
-			glUniform2f( 0, i == 0u ? 0.0f : 1.0f, m_encodeSNorm ? 1.0f : 0.0f );
+			glUniform2ui( 0, i, m_encodeSNorm ? 1u : 0u );
 
 			glDispatchCompute( 1u,  //
 							   alignToNextMultiple( m_width, 16u ) / 16u,

From ba044d87cfceebc50aaac7f10d550cf4d7b97c26 Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Tue, 9 Aug 2022 11:07:25 -0700
Subject: [PATCH 3/8] Avoid implicit data type conversions in the BC3 shaders

Increases compatibility with GLSL ES version 310.
---
 bin/Data/bc1.glsl | 28 ++++++++++++++--------------
 bin/Data/bc4.glsl |  4 ++--
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index a87639b..fa6e640 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -117,7 +117,7 @@ void OptimizeColorsBlock( const uint srcPixelsBlock[16], out float outMinEndp16,
 	// determine covariance matrix
 	float cov[6];
 	for( int i = 0; i < 6; ++i )
-		cov[i] = 0;
+		cov[i] = 0.0f;
 
 	for( int i = 0; i < 16; ++i )
 	{
@@ -243,10 +243,10 @@ uint MatchColorsBlock( const uint srcPixelsBlock[16], float3 colour[4] )
 		float3 currColour;
 		float dotValue;
 
-		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4 + 0] ).xyz * 255.0f;
+		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4u + 0u] ).xyz * 255.0f;
 		dotValue = dot( currColour, dir );
 
-		ditherDot = ( dotValue * 16.0f ) + ( 3 * ep2[1] + 5 * ep2[0] );
+		ditherDot = ( dotValue * 16.0f ) + ( 3.0f * ep2[1] + 5.0f * ep2[0] );
 		if( ditherDot < halfPoint )
 			step = ( ditherDot < c0Point ) ? 1u : 3u;
 		else
@@ -254,10 +254,10 @@ uint MatchColorsBlock( const uint srcPixelsBlock[16], float3 colour[4] )
 		ep1[0] = dotValue - stops[step];
 		lmask = step;
 
-		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4 + 1] ).xyz * 255.0f;
+		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4u + 1u] ).xyz * 255.0f;
 		dotValue = dot( currColour, dir );
 
-		ditherDot = ( dotValue * 16.0f ) + ( 7 * ep1[0] + 3 * ep2[2] + 5 * ep2[1] + ep2[0] );
+		ditherDot = ( dotValue * 16.0f ) + ( 7.0f * ep1[0] + 3.0f * ep2[2] + 5.0f * ep2[1] + ep2[0] );
 		if( ditherDot < halfPoint )
 			step = ( ditherDot < c0Point ) ? 1u : 3u;
 		else
@@ -265,10 +265,10 @@ uint MatchColorsBlock( const uint srcPixelsBlock[16], float3 colour[4] )
 		ep1[1] = dotValue - stops[step];
 		lmask |= step << 2u;
 
-		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4 + 2] ).xyz * 255.0f;
+		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4u + 2u] ).xyz * 255.0f;
 		dotValue = dot( currColour, dir );
 
-		ditherDot = ( dotValue * 16.0f ) + ( 7 * ep1[1] + 3 * ep2[3] + 5 * ep2[2] + ep2[1] );
+		ditherDot = ( dotValue * 16.0f ) + ( 7.0f * ep1[1] + 3.0f * ep2[3] + 5.0f * ep2[2] + ep2[1] );
 		if( ditherDot < halfPoint )
 			step = ( ditherDot < c0Point ) ? 1u : 3u;
 		else
@@ -276,10 +276,10 @@ uint MatchColorsBlock( const uint srcPixelsBlock[16], float3 colour[4] )
 		ep1[2] = dotValue - stops[step];
 		lmask |= step << 4u;
 
-		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4 + 2] ).xyz * 255.0f;
+		currColour = unpackUnorm4x8( srcPixelsBlock[y * 4u + 2u] ).xyz * 255.0f;
 		dotValue = dot( currColour, dir );
 
-		ditherDot = ( dotValue * 16.0f ) + ( 7 * ep1[2] + 5 * ep2[3] + ep2[2] );
+		ditherDot = ( dotValue * 16.0f ) + ( 7.0f * ep1[2] + 5.0f * ep2[3] + ep2[2] );
 		if( ditherDot < halfPoint )
 			step = ( ditherDot < c0Point ) ? 1u : 3u;
 		else
@@ -328,7 +328,7 @@ bool RefineBlock( const uint srcPixelsBlock[16], uint mask, inout float inOutMin
 	}
 	else
 	{
-		const float w1Tab[4] = { 3, 0, 2, 1 };
+		const float w1Tab[4] = { 3.0f, 0.0f, 2.0f, 1.0f };
 		const float prods[4] = { 589824.0f, 2304.0f, 262402.0f, 66562.0f };
 		// ^some magic to save a lot of multiplies in the accumulating loop...
 		// (precomputed products of weights for least squares system, accumulated inside one 32-bit
@@ -400,24 +400,24 @@ void DitherBlock( const uint srcPixBlck[16], out uint dthPixBlck[16] )
 		float3 srcPixel, dithPixel;
 
 		srcPixel = unpackUnorm4x8( srcPixBlck[y + 0u] ).xyz * 255.0f;
-		dithPixel = quant( srcPixel + trunc( ( 3 * ep2[1] + 5 * ep2[0] ) * ( 1.0f / 16.0f ) ) );
+		dithPixel = quant( srcPixel + trunc( ( 3.0f * ep2[1] + 5.0f * ep2[0] ) * ( 1.0f / 16.0f ) ) );
 		ep1[0] = srcPixel - dithPixel;
 		dthPixBlck[y + 0u] = packUnorm4x8( float4( dithPixel * ( 1.0f / 255.0f ), 1.0f ) );
 
 		srcPixel = unpackUnorm4x8( srcPixBlck[y + 1u] ).xyz * 255.0f;
 		dithPixel = quant(
-			srcPixel + trunc( ( 7 * ep1[0] + 3 * ep2[2] + 5 * ep2[1] + ep2[0] ) * ( 1.0f / 16.0f ) ) );
+			srcPixel + trunc( ( 7.0f * ep1[0] + 3.0f * ep2[2] + 5.0f * ep2[1] + ep2[0] ) * ( 1.0f / 16.0f ) ) );
 		ep1[1] = srcPixel - dithPixel;
 		dthPixBlck[y + 1u] = packUnorm4x8( float4( dithPixel * ( 1.0f / 255.0f ), 1.0f ) );
 
 		srcPixel = unpackUnorm4x8( srcPixBlck[y + 2u] ).xyz * 255.0f;
 		dithPixel = quant(
-			srcPixel + trunc( ( 7 * ep1[1] + 3 * ep2[3] + 5 * ep2[2] + ep2[1] ) * ( 1.0f / 16.0f ) ) );
+			srcPixel + trunc( ( 7.0f * ep1[1] + 3.0f * ep2[3] + 5.0f * ep2[2] + ep2[1] ) * ( 1.0f / 16.0f ) ) );
 		ep1[2] = srcPixel - dithPixel;
 		dthPixBlck[y + 2u] = packUnorm4x8( float4( dithPixel * ( 1.0f / 255.0f ), 1.0f ) );
 
 		srcPixel = unpackUnorm4x8( srcPixBlck[y + 3u] ).xyz * 255.0f;
-		dithPixel = quant( srcPixel + trunc( ( 7 * ep1[2] + 5 * ep2[3] + ep2[2] ) * ( 1.0f / 16.0f ) ) );
+		dithPixel = quant( srcPixel + trunc( ( 7.0f * ep1[2] + 5.0f * ep2[3] + ep2[2] ) * ( 1.0f / 16.0f ) ) );
 		ep1[3] = srcPixel - dithPixel;
 		dthPixBlck[y + 3u] = packUnorm4x8( float4( dithPixel * ( 1.0f / 255.0f ), 1.0f ) );
 
diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index 03edfee..da461c3 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -85,8 +85,8 @@ void main()
 	float dist = maxVal - minVal;
 	float dist4 = dist * 4.0f;
 	float dist2 = dist * 2.0f;
-	float bias = ( dist < 8 ) ? ( dist - 1 ) : ( trunc( dist * 0.5f ) + 2 );
-	bias -= minVal * 7;
+	float bias = ( dist < 8.0f ) ? ( dist - 1.0f ) : ( trunc( dist * 0.5f ) + 2.0f );
+	bias -= minVal * 7.0f;
 
 	uint mask0 = 0u, mask1 = 0u;
 

From 1f63a1d1ad95c2003c8fbaeeb25ed89c19de9a4e Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Mon, 29 Aug 2022 16:43:42 -0700
Subject: [PATCH 4/8] Use constructors for array initialization in the BC1
 shader

Increases compatibility with GLSL ES version 310.
---
 bin/Data/bc1.glsl | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index fa6e640..f7178b0 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -328,8 +328,8 @@ bool RefineBlock( const uint srcPixelsBlock[16], uint mask, inout float inOutMin
 	}
 	else
 	{
-		const float w1Tab[4] = { 3.0f, 0.0f, 2.0f, 1.0f };
-		const float prods[4] = { 589824.0f, 2304.0f, 262402.0f, 66562.0f };
+		const float w1Tab[4] = float[4]( 3.0f, 0.0f, 2.0f, 1.0f );
+		const float prods[4] = float[4]( 589824.0f, 2304.0f, 262402.0f, 66562.0f );
 		// ^some magic to save a lot of multiplies in the accumulating loop...
 		// (precomputed products of weights for least squares system, accumulated inside one 32-bit
 		// register)
@@ -392,8 +392,8 @@ float3 quant( float3 srcValue )
 
 void DitherBlock( const uint srcPixBlck[16], out uint dthPixBlck[16] )
 {
-	float3 ep1[4] = { float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ) };
-	float3 ep2[4] = { float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ) };
+	float3 ep1[4] = float3[4]( float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ) );
+	float3 ep2[4] = float3[4]( float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ), float3( 0, 0, 0 ) );
 
 	for( uint y = 0u; y < 16u; y += 4u )
 	{

From b82131766c37cde383d07eff0fb7325ffd06ad42 Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Mon, 15 Aug 2022 14:29:55 -0700
Subject: [PATCH 5/8] Add precision qualifiers to the BC3 shaders

Increases compatibility with GLSL ES version 310.
---
 bin/Data/bc1.glsl              | 2 +-
 bin/Data/bc4.glsl              | 2 +-
 bin/Data/etc2_rgba_stitch.glsl | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index f7178b0..4fe9300 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -19,7 +19,7 @@ layout( location = 0 ) uniform uint p_numRefinements;
 
 uniform sampler2D srcTex;
 
-layout( rg32ui ) uniform restrict writeonly uimage2D dstTexture;
+layout( rg32ui ) uniform restrict writeonly highp uimage2D dstTexture;
 
 layout( std430, binding = 1 ) readonly restrict buffer globalBuffer
 {
diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index da461c3..001f919 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -23,7 +23,7 @@ layout( location = 0 ) uniform uint2 params;
 
 uniform sampler2D srcTex;
 
-layout( rg32ui ) uniform restrict writeonly uimage2D dstTexture;
+layout( rg32ui ) uniform restrict writeonly highp uimage2D dstTexture;
 
 layout( local_size_x = 4,  //
 		local_size_y = 4,  //
diff --git a/bin/Data/etc2_rgba_stitch.glsl b/bin/Data/etc2_rgba_stitch.glsl
index 5a068ab..33b0923 100644
--- a/bin/Data/etc2_rgba_stitch.glsl
+++ b/bin/Data/etc2_rgba_stitch.glsl
@@ -13,9 +13,9 @@ layout( local_size_x = 8,  //
 		local_size_y = 8,  //
 		local_size_z = 1 ) in;
 
-layout( binding = 0 ) uniform usampler2D srcRGB;
-layout( binding = 1 ) uniform usampler2D srcAlpha;
-layout( rgba32ui ) uniform restrict writeonly uimage2D dstTexture;
+layout( binding = 0 ) uniform highp usampler2D srcRGB;
+layout( binding = 1 ) uniform highp usampler2D srcAlpha;
+layout( rgba32ui ) uniform restrict writeonly highp uimage2D dstTexture;
 
 void main()
 {

From d08dc5edc6dc1ee36ddecf3453adc2912b1f312f Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Mon, 29 Aug 2022 15:29:20 -0700
Subject: [PATCH 6/8] Add PFG_RGBA16_UINT to the PixelFormat enum

To be used in the following commit.
---
 include/betsy/EncoderGL.h | 1 +
 src/betsy/CpuImage.cpp    | 1 +
 src/betsy/EncoderGL.cpp   | 7 +++++++
 3 files changed, 9 insertions(+)

diff --git a/include/betsy/EncoderGL.h b/include/betsy/EncoderGL.h
index 3e8dbc2..7714681 100644
--- a/include/betsy/EncoderGL.h
+++ b/include/betsy/EncoderGL.h
@@ -11,6 +11,7 @@ namespace betsy
 	{
 		PFG_RGBA32_UINT,
 		PFG_RGBA32_FLOAT,
+		PFG_RGBA16_UINT,
 		PFG_RGBA16_FLOAT,
 		PFG_R32_FLOAT,
 		PFG_RG32_UINT,
diff --git a/src/betsy/CpuImage.cpp b/src/betsy/CpuImage.cpp
index e806b32..e5eb2c3 100644
--- a/src/betsy/CpuImage.cpp
+++ b/src/betsy/CpuImage.cpp
@@ -167,6 +167,7 @@ namespace betsy
 		case PFG_RGBA32_UINT:
 		case PFG_RGBA32_FLOAT:
 			return 4u * 4u;
+		case PFG_RGBA16_UINT:
 		case PFG_RGBA16_FLOAT:
 			return 2u * 4u;
 		case PFG_R32_FLOAT:
diff --git a/src/betsy/EncoderGL.cpp b/src/betsy/EncoderGL.cpp
index 946acd3..8e37583 100644
--- a/src/betsy/EncoderGL.cpp
+++ b/src/betsy/EncoderGL.cpp
@@ -60,6 +60,8 @@ namespace betsy
 			return GL_RGBA32UI;
 		case PFG_RGBA32_FLOAT:
 			return GL_RGBA32F;
+		case PFG_RGBA16_UINT:
+			return GL_RGBA16UI;
 		case PFG_RGBA16_FLOAT:
 			return GL_RGBA16F;
 		case PFG_R32_FLOAT:
@@ -104,6 +106,7 @@ namespace betsy
 		{
 		case PFG_RGBA32_UINT:
 		case PFG_RGBA32_FLOAT:
+		case PFG_RGBA16_UINT:
 		case PFG_RGBA16_FLOAT:
 		case PFG_RGBA8_UNORM:
 		case PFG_RGBA8_UNORM_SRGB:
@@ -134,6 +137,7 @@ namespace betsy
 		switch( pixelFormat )
 		{
 		case PFG_RGBA32_UINT:
+		case PFG_RGBA16_UINT:
 			format = GL_RGBA_INTEGER;
 			break;
 		case PFG_R32_FLOAT:
@@ -180,6 +184,9 @@ namespace betsy
 		case PFG_RG32_UINT:
 			type = GL_UNSIGNED_INT;
 			break;
+		case PFG_RGBA16_UINT:
+			type = GL_UNSIGNED_SHORT;
+			break;
 		case PFG_RGBA8_UNORM:
 		case PFG_RGBA8_UNORM_SRGB:
 			type = GL_UNSIGNED_INT_8_8_8_8_REV;

From ea4558bade47d9e0786eb18006555185f4344c37 Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Tue, 9 Aug 2022 10:35:15 -0700
Subject: [PATCH 7/8] Output to an rgba16ui image for the BC1 and BC4 shaders

Increases compatibility with GLSL ES version 310.

The ARB_shader_image_load_store extension says,

	For textures allocated by the GL, an image unit format is
	compatible with a texture internal format if they match by size.

The textures were allocated by the GL implementation, so this format
substitution is safe to do.
---
 bin/Data/bc1.glsl        | 12 +++++++-----
 bin/Data/bc4.glsl        | 11 ++++++-----
 src/betsy/EncoderBC1.cpp |  4 ++--
 src/betsy/EncoderBC4.cpp |  2 +-
 4 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index 4fe9300..51e82c9 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -19,7 +19,7 @@ layout( location = 0 ) uniform uint p_numRefinements;
 
 uniform sampler2D srcTex;
 
-layout( rg32ui ) uniform restrict writeonly highp uimage2D dstTexture;
+layout( rgba16ui ) uniform restrict writeonly mediump uimage2D dstTexture;
 
 layout( std430, binding = 1 ) readonly restrict buffer globalBuffer
 {
@@ -513,10 +513,12 @@ void main()
 		mask ^= 0x55555555u;
 	}
 
-	uint2 outputBytes;
-	outputBytes.x = uint( maxEndp16 ) | ( uint( minEndp16 ) << 16u );
-	outputBytes.y = mask;
+	uint4 outputBytes;
+	outputBytes.x = uint( maxEndp16 );
+	outputBytes.y = uint( minEndp16 );
+	outputBytes.z = mask & 0xFFFFu;
+	outputBytes.w = mask >> 16u;
 
 	uint2 dstUV = gl_GlobalInvocationID.xy;
-	imageStore( dstTexture, int2( dstUV ), uint4( outputBytes.xy, 0u, 0u ) );
+	imageStore( dstTexture, int2( dstUV ), outputBytes );
 }
diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index 001f919..004f405 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -23,7 +23,7 @@ layout( location = 0 ) uniform uint2 params;
 
 uniform sampler2D srcTex;
 
-layout( rg32ui ) uniform restrict writeonly highp uimage2D dstTexture;
+layout( rgba16ui ) uniform restrict writeonly mediump uimage2D dstTexture;
 
 layout( local_size_x = 4,  //
 		local_size_y = 4,  //
@@ -142,7 +142,7 @@ void main()
 	if( blockThreadId == 0u )
 	{
 		// Save data
-		uint2 outputBytes;
+		uint4 outputBytes;
 
 		if( p_useSNorm != 0u )
 		{
@@ -155,10 +155,11 @@ void main()
 			outputBytes.x = packUnorm4x8(
 				float4( maxVal * ( 1.0f / 255.0f ), minVal * ( 1.0f / 255.0f ), 0.0f, 0.0f ) );
 		}
-		outputBytes.x |= g_mask[maskIdxBase].x;
-		outputBytes.y = g_mask[maskIdxBase].y;
+		outputBytes.y = g_mask[maskIdxBase].x >> 16u;
+		outputBytes.z = g_mask[maskIdxBase].y & 0xFFFFu;
+		outputBytes.w = g_mask[maskIdxBase].y >> 16u;
 
 		uint2 dstUV = gl_GlobalInvocationID.yz;
-		imageStore( dstTexture, int2( dstUV ), uint4( outputBytes.xy, 0u, 0u ) );
+		imageStore( dstTexture, int2( dstUV ), outputBytes );
 	}
 }
diff --git a/src/betsy/EncoderBC1.cpp b/src/betsy/EncoderBC1.cpp
index 9f12562..b72f6e1 100644
--- a/src/betsy/EncoderBC1.cpp
+++ b/src/betsy/EncoderBC1.cpp
@@ -116,7 +116,7 @@ namespace betsy
 	{
 		bindTexture( 0u, m_srcTexture );
 		bindComputePso( m_bc1Pso );
-		bindUav( 0u, m_bc1TargetRes, PFG_RG32_UINT, ResourceAccess::Write );
+		bindUav( 0u, m_bc1TargetRes, PFG_RGBA16_UINT, ResourceAccess::Write );
 		bindUavBuffer( 1u, m_bc1TablesSsbo, 0u, sizeof( Bc1Tables ) );
 
 		glUniform1ui( 0, 2u );
@@ -128,7 +128,7 @@ namespace betsy
 		{
 			// Compress Alpha too (using BC4)
 			bindComputePso( m_bc4Pso );
-			bindUav( 0u, m_bc4TargetRes, PFG_RG32_UINT, ResourceAccess::Write );
+			bindUav( 0u, m_bc4TargetRes, PFG_RGBA16_UINT, ResourceAccess::Write );
 
 			// p_channelIdx, p_useSNorm
 			glUniform2ui( 0, 3u, 0u );
diff --git a/src/betsy/EncoderBC4.cpp b/src/betsy/EncoderBC4.cpp
index 66a26aa..7383f41 100644
--- a/src/betsy/EncoderBC4.cpp
+++ b/src/betsy/EncoderBC4.cpp
@@ -107,7 +107,7 @@ namespace betsy
 		const size_t numChannels = m_bc4TargetRes[1] ? 2u : 1u;
 		for( size_t i = 0u; i < numChannels; ++i )
 		{
-			bindUav( 0u, m_bc4TargetRes[i], PFG_RG32_UINT, ResourceAccess::Write );
+			bindUav( 0u, m_bc4TargetRes[i], PFG_RGBA16_UINT, ResourceAccess::Write );
 
 			// p_channelIdx, p_useSNorm
 			glUniform2ui( 0, i, m_encodeSNorm ? 1u : 0u );

From 38a46c2c3c9a840cafa33a3af4904e3481ba9b71 Mon Sep 17 00:00:00 2001
From: Nanley Chery <nanley.g.chery@intel.com>
Date: Tue, 9 Aug 2022 11:16:55 -0700
Subject: [PATCH 8/8] Set the version of the BC3 shaders to 310 es

The shaders are compatible with GLSL ES version 310. Require the
GL_ARB_ES3_1_compatibility extension and change the version directives
accordingly so that we get validation from the GL implementation.
---
 bin/Data/bc1.glsl              | 2 +-
 bin/Data/bc1_dither.glsl       | 2 +-
 bin/Data/bc4.glsl              | 2 +-
 bin/Data/etc2_rgba_stitch.glsl | 2 +-
 src/PlatformGL.cpp             | 8 ++++++++
 5 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/bin/Data/bc1.glsl b/bin/Data/bc1.glsl
index 51e82c9..e796602 100644
--- a/bin/Data/bc1.glsl
+++ b/bin/Data/bc1.glsl
@@ -1,4 +1,4 @@
-#version 430 core
+#version 310 es
 
 #if defined(GL_ES) && GL_ES == 1
 	// Desktop GLSL allows the const keyword for either compile-time or
diff --git a/bin/Data/bc1_dither.glsl b/bin/Data/bc1_dither.glsl
index 4ca239f..f4c011f 100644
--- a/bin/Data/bc1_dither.glsl
+++ b/bin/Data/bc1_dither.glsl
@@ -1,4 +1,4 @@
-#version 430 core
+#version 310 es
 
 #define BC1_DITHER
 #include "bc1.glsl"
diff --git a/bin/Data/bc4.glsl b/bin/Data/bc4.glsl
index 004f405..163e333 100644
--- a/bin/Data/bc4.glsl
+++ b/bin/Data/bc4.glsl
@@ -1,4 +1,4 @@
-#version 430 core
+#version 310 es
 
 #if defined(GL_ES) && GL_ES == 1
 	// Desktop GLSL allows the const keyword for either compile-time or
diff --git a/bin/Data/etc2_rgba_stitch.glsl b/bin/Data/etc2_rgba_stitch.glsl
index 33b0923..d06d0f2 100644
--- a/bin/Data/etc2_rgba_stitch.glsl
+++ b/bin/Data/etc2_rgba_stitch.glsl
@@ -2,7 +2,7 @@
 // This compute shader merely stitches them together to form the final result
 // It's also used by RG11 driver to stitch two R11 into one RG11
 
-#version 430 core
+#version 310 es
 
 // #include "/media/matias/Datos/SyntaxHighlightingMisc.h"
 
diff --git a/src/PlatformGL.cpp b/src/PlatformGL.cpp
index 96ffa00..b91b8ac 100644
--- a/src/PlatformGL.cpp
+++ b/src/PlatformGL.cpp
@@ -69,12 +69,20 @@ namespace betsy
 
 		g_glContext = SDL_GL_CreateContext( g_sdlWindow );
 
+		const SDL_bool has_required_extensions = SDL_GL_ExtensionSupported( "GL_ARB_ES3_1_compatibility" );
+
 		if( !g_glContext )
 		{
 			fprintf( stderr, "GL Context creation failed.\n" );
 			SDL_Quit();
 			abort();
 		}
+		else if ( has_required_extensions == SDL_FALSE )
+		{
+			fprintf( stderr, "GL Context lacks required extensions.\n" );
+			SDL_Quit();
+			abort();
+		}
 		else
 		{
 			printf( "GL Context creation suceeded.\n" );