diff --git a/src/engine/renderer/gl_shader.cpp b/src/engine/renderer/gl_shader.cpp
index 91de1bfee2..f43d773dd7 100644
--- a/src/engine/renderer/gl_shader.cpp
+++ b/src/engine/renderer/gl_shader.cpp
@@ -529,8 +529,19 @@ static std::string GenCompatHeader() {
 		str += "float smoothstep(float edge0, float edge1, float x) { float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0); return t * t * (3.0 - 2.0 * t); }\n";
 	}
 
-	if ( !glConfig2.gpuShader5Available ) {
-		str += "#define unpackUnorm4x8( value ) ( ( vec4( value, value >> 8, value >> 16, value >> 24 ) & 0xFF ) / 255.0f )\n";
+	if ( !glConfig2.gpuShader5Available && glConfig2.gpuShader4Available )
+	{
+		str +=
+R"(vec4 unpackUnorm4x8( uint value )
+{
+	uint x = value & 0xFFu;
+	uint y = ( value >> 8u ) & 0xFFu;
+	uint z = ( value >> 16u ) & 0xFFu;
+	uint w = ( value >> 24u ) & 0xFFu;
+
+	return vec4( x, y, z, w ) / 255.0f;
+}
+)";
 	}
 
 	/* Driver bug: Adrenaline/OGLP drivers fail to recognise the ARB function versions when they return a 4.6 context
diff --git a/src/engine/renderer/glsl_source/computeLight_fp.glsl b/src/engine/renderer/glsl_source/computeLight_fp.glsl
index 64d405ecb6..514fe4b27a 100644
--- a/src/engine/renderer/glsl_source/computeLight_fp.glsl
+++ b/src/engine/renderer/glsl_source/computeLight_fp.glsl
@@ -199,7 +199,7 @@ void computeDynamicLight( uint idx, vec3 P, vec3 normal, vec3 viewDir, vec4 diff
 		diffuse, material, color );
 }
 
-const int lightsPerLayer = 16;
+const uint lightsPerLayer = 16u;
 
 #define idxs_t uvec4
 
@@ -213,7 +213,7 @@ idxs_t fetchIdxs( in vec3 coords, in usampler3D u_LightTiles ) {
 
 // 8 bits per light ID
 uint nextIdx( in uint count, in idxs_t idxs ) {
-	return ( idxs[count / 4] >> ( 8 * ( count % 4 ) ) ) & 0xFFu;
+	return ( idxs[count / 4u] >> ( 8u * ( count % 4u ) ) ) & 0xFFu;
 }
 
 void computeDynamicLights( vec3 P, vec3 normal, vec3 viewDir, vec4 diffuse, vec4 material,
@@ -225,20 +225,20 @@ void computeDynamicLights( vec3 P, vec3 normal, vec3 viewDir, vec4 diffuse, vec4
 
 	vec2 tile = floor( gl_FragCoord.xy * ( 1.0 / float( TILE_SIZE ) ) ) + 0.5;
 
-	for( uint layer = 0; layer < NUM_LIGHT_LAYERS; layer++ ) {
-		uint lightCount = 0;
+	for( uint layer = 0u; layer < uint( NUM_LIGHT_LAYERS ); layer++ ) {
+		uint lightCount = 0u;
 		idxs_t idxs = fetchIdxs( tileScale * vec3( tile, float( layer ) + 0.5 ), u_LightTiles );
 
-		for( uint i = 0; i < lightsPerLayer; i++ ) {
+		for( uint i = 0u; i < lightsPerLayer; i++ ) {
 			uint idx = nextIdx( lightCount, idxs );
 
-			if( idx == 0 ) {
+			if( idx == 0u ) {
 				break;
 			}
 
 			/* Light IDs are stored relative to the layer
 			Subtract 1 because 0 means there's no light */
-			idx = ( idx - 1 ) * NUM_LIGHT_LAYERS + layer;
+			idx = ( idx - 1u ) * uint( NUM_LIGHT_LAYERS ) + layer;
 
 			computeDynamicLight( idx, P, normal, viewDir, diffuse, material, color );
 			lightCount++;
diff --git a/src/engine/renderer/glsl_source/lighttile_fp.glsl b/src/engine/renderer/glsl_source/lighttile_fp.glsl
index a737ccebbd..331d46ca4a 100644
--- a/src/engine/renderer/glsl_source/lighttile_fp.glsl
+++ b/src/engine/renderer/glsl_source/lighttile_fp.glsl
@@ -59,7 +59,7 @@ uniform sampler2D u_DepthMap;
 uniform int u_lightLayer;
 uniform vec3 u_zFar;
 
-const int lightsPerLayer = 16;
+const uint lightsPerLayer = 16u;
 
 #define idxs_t uvec4
 
@@ -67,8 +67,8 @@ DECLARE_OUTPUT(uvec4)
 
 // 8 bits per light ID
 void pushIdxs( in uint idx, in uint count, inout uvec4 idxs ) {
-	idxs[count / 4] <<= 8;
-	idxs[count / 4] |= idx & 0xFFu;
+	idxs[count / 4u] <<= 8u;
+	idxs[count / 4u] |= idx & 0xFFu;
 }
 
 #define exportIdxs( x ) outputColor = ( x )
@@ -114,13 +114,13 @@ void main() {
 
 	idxs_t idxs = uvec4( 0, 0, 0, 0 );
 
-	uint lightCount = 0;
+	uint lightCount = 0u;
 
 	/* Dynamic lights are put into 4 layers of a 3D texture. Since checking if we already added some light is infeasible,
 	only process 1 / 4 of different lights for each layer, extra lights going into the last layer. This can fail to add some lights
 	if 1 / 4 of all lights is more than the amount of lights that each layer can hold (16). To fix this, we'd need to either do this on CPU
 	or use compute shaders with atomics so we can have a variable amount of lights for each tile. */
-	for( uint i = u_lightLayer; i < u_numLights; i += NUM_LIGHT_LAYERS ) {
+	for( uint i = uint( u_lightLayer ); i < uint( u_numLights ); i += uint( NUM_LIGHT_LAYERS ) ) {
 		Light l = GetLight( i );
 		vec3 center = ( u_ModelMatrix * vec4( l.center, 1.0 ) ).xyz;
 		float radius = max( 2.0 * l.radius, 2.0 * 32.0 ); // Avoid artifacts with weak light sources
@@ -136,7 +136,7 @@ void main() {
 		if( radius > 0.0 ) {
 			/* Light IDs are stored relative to the layer
 			Add 1 because 0 means there's no light */
-			pushIdxs( ( i / NUM_LIGHT_LAYERS ) + 1, lightCount, idxs );
+			pushIdxs( ( i / uint( NUM_LIGHT_LAYERS ) ) + 1u, lightCount, idxs );
 			lightCount++;
 
 			if( lightCount == lightsPerLayer ) {