diff --git a/client/shaders/inventory_shader/opengl_fragment.glsl b/client/shaders/inventory_shader/opengl_fragment.glsl
index 60627ad59..43d610a06 100644
--- a/client/shaders/inventory_shader/opengl_fragment.glsl
+++ b/client/shaders/inventory_shader/opengl_fragment.glsl
@@ -4,8 +4,6 @@
 	uniform sampler2D baseTexture;
 #endif
 
-VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 CENTROID_ VARYING_ lowp vec4 varColor;
 CENTROID_ VARYING_ mediump vec2 varTexCoord;
 CENTROID_ VARYING_ float varTexLayer; // actually int
diff --git a/client/shaders/inventory_shader/opengl_vertex.glsl b/client/shaders/inventory_shader/opengl_vertex.glsl
index 8739775d9..75f076564 100644
--- a/client/shaders/inventory_shader/opengl_vertex.glsl
+++ b/client/shaders/inventory_shader/opengl_vertex.glsl
@@ -1,5 +1,3 @@
-VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 CENTROID_ VARYING_ lowp vec4 varColor;
 CENTROID_ VARYING_ mediump vec2 varTexCoord;
 CENTROID_ VARYING_ float varTexLayer; // actually int
@@ -13,8 +11,6 @@ void main(void)
 
 	vec4 pos = inVertexPosition;
 	gl_Position = mWorldViewProj * pos;
-	vPosition = gl_Position.xyz;
-	vNormal = inVertexNormal;
 
 	vec4 color = inVertexColor;
 	varColor = clamp(color, 0.0, 1.0);
diff --git a/client/shaders/nodes_shader/opengl_fragment.glsl b/client/shaders/nodes_shader/opengl_fragment.glsl
index da5ba8407..c3aa9d098 100644
--- a/client/shaders/nodes_shader/opengl_fragment.glsl
+++ b/client/shaders/nodes_shader/opengl_fragment.glsl
@@ -42,7 +42,6 @@ uniform float crackTextureScale;
 
 
 VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 // World position in the visible world (i.e. relative to the cameraOffset.)
 // This can be used for many shader effects without loss of precision.
 // If the absolute position is required it can be calculated with
@@ -63,7 +62,8 @@ vec4 perm(vec4 x)
 }
 
 // Corresponding gradient of snoise
-vec3 gnoise(vec3 p){
+vec3 gnoise(vec3 p)
+{
     vec3 a = floor(p);
     vec3 d = p - a;
     vec3 dd = 6.0 * d * (1.0 - d);
@@ -96,7 +96,10 @@ vec3 gnoise(vec3 p){
 }
 
 vec2 wave_noise(vec3 p, float off) {
-	return (gnoise(p + vec3(0.0, 0.0, off)) * 0.4 + gnoise(2.0 * p + vec3(0.0, off, off)) * 0.2 + gnoise(3.0 * p + vec3(0.0, off, off)) * 0.225 + gnoise(4.0 * p + vec3(-off, off, 0.0)) * 0.2).xz;
+	return (gnoise(p + vec3(0.0, 0.0, off)) * 0.4 +
+		gnoise(2.0 * p + vec3(0.0, off, off)) * 0.2 +
+		gnoise(3.0 * p + vec3(0.0, off, off)) * 0.225 +
+		gnoise(4.0 * p + vec3(-off, off, 0.0)) * 0.2).xz;
 }
 #endif
 
@@ -110,13 +113,16 @@ vec3 getLightSpacePosition()
 {
 	return shadow_position * 0.5 + 0.5;
 }
-// custom smoothstep implementation because it's not defined in glsl1.2
-// https://docs.gl/sl4/smoothstep
+
+#if __VERSION__ >= 130
+#define mtsmoothstep smoothstep
+#else
 float mtsmoothstep(in float edge0, in float edge1, in float x)
 {
 	float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
 	return t * t * (3.0 - 2.0 * t);
 }
+#endif
 
 float shadowCutoff(float x) {
 	#if defined(ENABLE_TRANSLUCENT_FOLIAGE) && MATERIAL_TYPE == TILE_MATERIAL_WAVING_LEAVES
diff --git a/client/shaders/nodes_shader/opengl_vertex.glsl b/client/shaders/nodes_shader/opengl_vertex.glsl
index 5ac10eaff..e53ffe47c 100644
--- a/client/shaders/nodes_shader/opengl_vertex.glsl
+++ b/client/shaders/nodes_shader/opengl_vertex.glsl
@@ -7,7 +7,6 @@ uniform highp vec3 cameraOffset;
 uniform float animationTimer;
 
 VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 // World position in the visible world (i.e. relative to the cameraOffset.)
 // This can be used for many shader effects without loss of precision.
 // If the absolute position is required it can be calculated with
@@ -43,14 +42,13 @@ CENTROID_ VARYING_ float nightRatio;
 VARYING_ highp vec3 eyeVec;
 // Color of the light emitted by the light sources.
 const vec3 artificialLight = vec3(1.04, 1.04, 1.04);
-const float e = 2.718281828459;
-const float BS = 10.0;
+
+#ifdef ENABLE_DYNAMIC_SHADOWS
+
 uniform float xyPerspectiveBias0;
 uniform float xyPerspectiveBias1;
 uniform float zPerspectiveBias;
 
-#ifdef ENABLE_DYNAMIC_SHADOWS
-
 vec4 getRelativePosition(in vec4 position)
 {
 	vec2 l = position.xy - CameraPos.xy;
@@ -77,14 +75,16 @@ vec4 applyPerspectiveDistortion(in vec4 position)
 	return position;
 }
 
-// custom smoothstep implementation because it's not defined in glsl1.2
-// https://docs.gl/sl4/smoothstep
+#if __VERSION__ >= 130
+#define mtsmoothstep smoothstep
+#else
 float mtsmoothstep(in float edge0, in float edge1, in float x)
 {
 	float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
 	return t * t * (3.0 - 2.0 * t);
 }
 #endif
+#endif
 
 
 float smoothCurve(float x)
@@ -189,7 +189,6 @@ void main(void)
 	worldPosition = (mWorld * pos).xyz;
 	gl_Position = mWorldViewProj * pos;
 
-	vPosition = gl_Position.xyz;
 	eyeVec = -(mWorldView * pos).xyz;
 #ifdef SECONDSTAGE
 	normalPass = normalize((inVertexNormal+1)/2);
diff --git a/client/shaders/object_shader/opengl_fragment.glsl b/client/shaders/object_shader/opengl_fragment.glsl
index e446b3ae2..ede9d642d 100644
--- a/client/shaders/object_shader/opengl_fragment.glsl
+++ b/client/shaders/object_shader/opengl_fragment.glsl
@@ -35,7 +35,6 @@ uniform float animationTimer;
 
 
 VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 // World position in the visible world (i.e. relative to the cameraOffset.)
 // This can be used for many shader effects without loss of precision.
 // If the absolute position is required it can be calculated with
@@ -62,13 +61,16 @@ vec3 getLightSpacePosition()
 {
 	return shadow_position * 0.5 + 0.5;
 }
-// custom smoothstep implementation because it's not defined in glsl1.2
-// https://docs.gl/sl4/smoothstep
+
+#if __VERSION__ >= 130
+#define mtsmoothstep smoothstep
+#else
 float mtsmoothstep(in float edge0, in float edge1, in float x)
 {
 	float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
 	return t * t * (3.0 - 2.0 * t);
 }
+#endif
 
 #ifdef COLORED_SHADOWS
 
@@ -363,7 +365,6 @@ float getShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
 
 void main(void)
 {
-	vec3 color;
 	vec2 uv = varTexCoord.st;
 
 #ifdef USE_ARRAY_TEXTURE
@@ -382,8 +383,7 @@ void main(void)
 		discard;
 #endif
 
-	color = base.rgb;
-	vec4 col = vec4(color.rgb * varColor.rgb, 1.0);
+	vec4 col = vec4(base.rgb * varColor.rgb, 1.0);
 	col.rgb *= vIDiff;
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
diff --git a/client/shaders/object_shader/opengl_vertex.glsl b/client/shaders/object_shader/opengl_vertex.glsl
index 31396825c..819a43449 100644
--- a/client/shaders/object_shader/opengl_vertex.glsl
+++ b/client/shaders/object_shader/opengl_vertex.glsl
@@ -4,7 +4,6 @@ uniform float animationTimer;
 uniform lowp vec4 materialColor;
 
 VARYING_ vec3 vNormal;
-VARYING_ vec3 vPosition;
 VARYING_ vec3 worldPosition;
 VARYING_ lowp vec4 varColor;
 CENTROID_ VARYING_ mediump vec2 varTexCoord;
@@ -32,14 +31,13 @@ VARYING_ float nightRatio;
 // Color of the light emitted by the light sources.
 const vec3 artificialLight = vec3(1.04, 1.04, 1.04);
 VARYING_ float vIDiff;
-const float e = 2.718281828459;
-const float BS = 10.0;
+
+#ifdef ENABLE_DYNAMIC_SHADOWS
+
 uniform float xyPerspectiveBias0;
 uniform float xyPerspectiveBias1;
 uniform float zPerspectiveBias;
 
-#ifdef ENABLE_DYNAMIC_SHADOWS
-
 vec4 getRelativePosition(in vec4 position)
 {
 	vec2 l = position.xy - CameraPos.xy;
@@ -66,8 +64,9 @@ vec4 applyPerspectiveDistortion(in vec4 position)
 	return position;
 }
 
-// custom smoothstep implementation because it's not defined in glsl1.2
-// https://docs.gl/sl4/smoothstep
+#if __VERSION__ >= 130
+#define mtsmoothstep smoothstep
+#else
 float mtsmoothstep(in float edge0, in float edge1, in float x)
 {
 	float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
@@ -75,6 +74,8 @@ float mtsmoothstep(in float edge0, in float edge1, in float x)
 }
 #endif
 
+#endif
+
 
 float directional_ambient(vec3 normal)
 {
@@ -95,7 +96,6 @@ void main(void)
 
 	gl_Position = mWorldViewProj * inVertexPosition;
 
-	vPosition = gl_Position.xyz;
 	vNormal = (mWorld * vec4(inVertexNormal, 0.0)).xyz;
 	worldPosition = (mWorld * inVertexPosition).xyz;
 	eyeVec = -(mWorldView * inVertexPosition).xyz;
diff --git a/src/client/shader.cpp b/src/client/shader.cpp
index 5715738e6..6fc5010af 100644
--- a/src/client/shader.cpp
+++ b/src/client/shader.cpp
@@ -696,6 +696,9 @@ void ShaderSource::generateShader(ShaderInfo &shaderinfo)
 				shaders_header << "#version 100\n"
 					<< "#define CENTROID_\n";
 			}
+			// Precision is only meaningful on GLES
+			shaders_header << "precision mediump float;\n"
+				"precision mediump sampler2D;\n";
 		} else {
 			assert(false);
 		}
@@ -708,8 +711,6 @@ void ShaderSource::generateShader(ShaderInfo &shaderinfo)
 
 		// cf. EVertexAttributes.h for the predefined ones
 		vertex_header = R"(
-			precision mediump float;
-
 			uniform highp mat4 mWorldView;
 			uniform highp mat4 mWorldViewProj;
 			uniform mediump mat4 mTexture;
@@ -732,9 +733,7 @@ void ShaderSource::generateShader(ShaderInfo &shaderinfo)
 		// normally expects, so we need to take that into account.
 		vertex_header += "#define inVertexColor (inVertexColor.bgra)\n";
 
-		fragment_header = R"(
-			precision mediump float;
-		)";
+		fragment_header = "";
 		if (use_glsl3) {
 			fragment_header += "#define VARYING_ in\n"
 				"#define gl_FragColor outFragColor\n"