fix(shaders): parallax mapping of the opengl33 materials is shared by the four parallax shaders in parallax.glsl and samples its depth with the gradients of the surface instead of letting a loop of varying length pick the mip level, picks the number of layers by the angle of view alone and refines the hit with a binary search instead of one linear step, so stones near the camera no longer show combs of layer slices; it fades out between 60 and 100 m instead of stopping at a hard line and fades out at grazing angles, and the simple offset without extra effects no longer divides by an unbounded cosine of the view

shaders/mat_detail_parallax.frag

@@ -38,13 +38,13 @@ uniform sampler2D detailnormalmap;
 #include <apply_fog.glsl>
 #include <tonemapping.glsl>
 
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir);
+#include <parallax.glsl>
 
 void main()
 {
 	//parallax mapping
 	vec3 viewDir = normalize(-TangentFragPos); //tangent view pos - tangent frag pos
-	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir);
+	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir, param[2].z, param[2].w);
 	vec4 normal_map = texture(normalmap, f_coord_p);
 	vec4 detailnormal_map = texture(detailnormalmap, f_coord_p * param[2].x);
 	vec4 tex_color = texture(diffuse, f_coord_p);
@@ -87,48 +87,3 @@ void main()
 	}
 #endif
 }
-
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir)
-{
-	float pos_len = length(f_pos.xyz);
-
-	if (pos_len > 100.0) {
-		return f_coord;
-	}
-
-#if EXTRAEFFECTS_ENABLED
-	const float minLayers = 8.0;
-	const float maxLayers = 32.0;
-	float LayersWeight = pos_len / 20.0;
-	vec2  currentTexCoords = f_coord;
-	float currentDepthMapValue = texture(normalmap, currentTexCoords).b;
-	LayersWeight = min(abs(dot(vec3(0.0, 0.0, 1.0), viewDir)),LayersWeight);
-	float numLayers = mix(maxLayers, minLayers, clamp(LayersWeight, 0.0, 1.0)); // number of depth layers
-	float layerDepth = 1.0 / numLayers; // calculate the size of each layer
-	float currentLayerDepth = 0.0; // depth of current layer
-	vec2 P = viewDir.xy * param[2].z; // the amount to shift the texture coordinates per layer (from vector P)
-	vec2 deltaTexCoords = P / numLayers;
-
-	  
-	while(currentLayerDepth < currentDepthMapValue)
-	{
-		currentTexCoords -= deltaTexCoords;		// shift texture coordinates along direction of P
-		currentDepthMapValue = texture(normalmap, currentTexCoords).b;		// get depthmap value at current texture coordinates
-		currentLayerDepth += layerDepth;  		// get depth of next layer
-	}
-	
-	vec2 prevTexCoords = currentTexCoords + deltaTexCoords; // get texture coordinates before collision (reverse operations)
-
-	float afterDepth  = currentDepthMapValue - currentLayerDepth; // get depth after and before collision for linear interpolation
-	float beforeDepth = texture(normalmap, prevTexCoords).b - currentLayerDepth + layerDepth;
-	 
-	float weight = afterDepth / (afterDepth - beforeDepth); // interpolation of texture coordinates
-	vec2 finalTexCoords = prevTexCoords * weight + currentTexCoords * (1.0 - weight);
-
-	return finalTexCoords;
-#else
-	float height = texture(normalmap, f_coord).b;
-	vec2 p = viewDir.xy / viewDir.z * (height * (param[2].z - param[2].w) * 0.2);
-	return f_coord - p;
-#endif
-} 

shaders/mat_detail_parallax_specgloss.frag

@@ -42,13 +42,13 @@ uniform sampler2D detailnormalmap;
 #include <apply_fog.glsl>
 #include <tonemapping.glsl>
 
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir);
+#include <parallax.glsl>
 
 void main()
 {
 	//parallax mapping
 	vec3 viewDir = normalize(vec3(0.0f, 0.0f, 0.0f) - TangentFragPos); //tangent view pos - tangent frag pos
-	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir);
+	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir, param[2].z, param[2].w);
 	
 	vec4 normal_map = texture(normalmap, f_coord_p);
 	vec4 detailnormal_map = texture(detailnormalmap,  f_coord_p * param[2].x);
@@ -93,49 +93,3 @@ void main()
 	}
 #endif
 }
-
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir)
-{	
-
-	float pos_len = length(f_pos.xyz);
-
-	if (pos_len > 100.0) {
-		return f_coord;
-	}
-
-#if EXTRAEFFECTS_ENABLED
-	const float minLayers = 8.0;
-	const float maxLayers = 32.0;
-	float LayersWeight = pos_len / 20.0;
-	vec2  currentTexCoords = f_coord;
-	float currentDepthMapValue = texture(normalmap, currentTexCoords).b;
-	LayersWeight = min(abs(dot(vec3(0.0, 0.0, 1.0), viewDir)),LayersWeight);
-	float numLayers = mix(maxLayers, minLayers, clamp(LayersWeight, 0.0, 1.0)); // number of depth layers
-	float layerDepth = 1.0 / numLayers; // calculate the size of each layer
-	float currentLayerDepth = 0.0; // depth of current layer
-	vec2 P = viewDir.xy * param[2].z; // the amount to shift the texture coordinates per layer (from vector P)
-	vec2 deltaTexCoords = P / numLayers;
-
-	  
-	while(currentLayerDepth < currentDepthMapValue)
-	{
-		currentTexCoords -= deltaTexCoords;		// shift texture coordinates along direction of P
-		currentDepthMapValue = texture(normalmap, currentTexCoords).b;		// get depthmap value at current texture coordinates
-		currentLayerDepth += layerDepth;  		// get depth of next layer
-	}
-	
-	vec2 prevTexCoords = currentTexCoords + deltaTexCoords; // get texture coordinates before collision (reverse operations)
-
-	float afterDepth  = currentDepthMapValue - currentLayerDepth; // get depth after and before collision for linear interpolation
-	float beforeDepth = texture(normalmap, prevTexCoords).b - currentLayerDepth + layerDepth;
-	 
-	float weight = afterDepth / (afterDepth - beforeDepth); // interpolation of texture coordinates
-	vec2 finalTexCoords = prevTexCoords * weight + currentTexCoords * (1.0 - weight);
-
-	return finalTexCoords;
-#else
-	float height = texture(normalmap, f_coord).b;
-	vec2 p = viewDir.xy / viewDir.z * (height * (param[2].z - param[2].w) * 0.2);
-	return f_coord - p;
-#endif
-} 

shaders/mat_parallax.frag

@@ -32,13 +32,13 @@ uniform sampler2D normalmap;
 #include <apply_fog.glsl>
 #include <tonemapping.glsl>
 
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir);
+#include <parallax.glsl>
 
 void main()
 {
 	//parallax mapping
 	vec3 viewDir = normalize(vec3(0.0f, 0.0f, 0.0f) - TangentFragPos); //tangent view pos - tangent frag pos
-	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir);
+	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir, param[2].y, param[2].z);
 
 	vec4 tex_color = texture(diffuse, f_coord_p);
 
@@ -74,48 +74,3 @@ void main()
 	}
 #endif
 }
-
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir)
-{
-	float pos_len = length(f_pos.xyz);
-
-	if (pos_len > 100.0) {
-		return f_coord;
-	}
-
-#if EXTRAEFFECTS_ENABLED
-	const float minLayers = 8.0;
-	const float maxLayers = 32.0;
-	float LayersWeight = pos_len / 20.0;
-	vec2  currentTexCoords = f_coord;
-	float currentDepthMapValue = texture(normalmap, currentTexCoords).b;
-	LayersWeight = min(abs(dot(vec3(0.0, 0.0, 1.0), viewDir)),LayersWeight);
-	float numLayers = mix(maxLayers, minLayers, clamp(LayersWeight, 0.0, 1.0)); // number of depth layers
-	float layerDepth = 1.0 / numLayers; // calculate the size of each layer
-	float currentLayerDepth = 0.0; // depth of current layer
-	vec2 P = viewDir.xy * param[2].y; // the amount to shift the texture coordinates per layer (from vector P)
-	vec2 deltaTexCoords = P / numLayers;
-
-	  
-	while(currentLayerDepth < currentDepthMapValue)
-	{
-		currentTexCoords -= deltaTexCoords;		// shift texture coordinates along direction of P
-		currentDepthMapValue = texture(normalmap, currentTexCoords).b;		// get depthmap value at current texture coordinates
-		currentLayerDepth += layerDepth;  		// get depth of next layer
-	}
-	
-	vec2 prevTexCoords = currentTexCoords + deltaTexCoords; // get texture coordinates before collision (reverse operations)
-
-	float afterDepth  = currentDepthMapValue - currentLayerDepth; // get depth after and before collision for linear interpolation
-	float beforeDepth = texture(normalmap, prevTexCoords).b - currentLayerDepth + layerDepth;
-	 
-	float weight = afterDepth / (afterDepth - beforeDepth); // interpolation of texture coordinates
-	vec2 finalTexCoords = prevTexCoords * weight + currentTexCoords * (1.0 - weight);
-
-	return finalTexCoords;
-#else
-	float height = texture(normalmap, f_coord).b;
-	vec2 p = viewDir.xy / viewDir.z * (height * (param[2].y - param[2].z) * 0.2);
-	return f_coord - p;
-#endif
-} 

shaders/mat_parallax_specgloss.frag

@@ -36,13 +36,13 @@ uniform sampler2D specgloss;
 #include <apply_fog.glsl>
 #include <tonemapping.glsl>
 
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir);
+#include <parallax.glsl>
 
 void main()
 {
 	//parallax mapping
 	vec3 viewDir = normalize(vec3(0.0f, 0.0f, 0.0f) - TangentFragPos); //tangent view pos - tangent frag pos
-	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir);
+	vec2 f_coord_p = ParallaxMapping(f_coord, viewDir, param[2].y, param[2].z);
 
 	vec4 tex_color = texture(diffuse, f_coord_p);
 
@@ -80,48 +80,3 @@ void main()
 	}
 #endif
 }
-
-vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir)
-{
-	float pos_len = length(f_pos.xyz);
-
-	if (pos_len > 100.0) {
-		return f_coord;
-	}
-
-#if EXTRAEFFECTS_ENABLED
-	const float minLayers = 8.0;
-	const float maxLayers = 32.0;
-	float LayersWeight = pos_len / 20.0;
-	vec2  currentTexCoords = f_coord;
-	float currentDepthMapValue = texture(normalmap, currentTexCoords).b;
-	LayersWeight = min(abs(dot(vec3(0.0, 0.0, 1.0), viewDir)),LayersWeight);
-	float numLayers = mix(maxLayers, minLayers, clamp(LayersWeight, 0.0, 1.0)); // number of depth layers
-	float layerDepth = 1.0 / numLayers; // calculate the size of each layer
-	float currentLayerDepth = 0.0; // depth of current layer
-	vec2 P = viewDir.xy * param[2].y; // the amount to shift the texture coordinates per layer (from vector P)
-	vec2 deltaTexCoords = P / numLayers;
-
-	  
-	while(currentLayerDepth < currentDepthMapValue)
-	{
-		currentTexCoords -= deltaTexCoords;		// shift texture coordinates along direction of P
-		currentDepthMapValue = texture(normalmap, currentTexCoords).b;		// get depthmap value at current texture coordinates
-		currentLayerDepth += layerDepth;  		// get depth of next layer
-	}
-	
-	vec2 prevTexCoords = currentTexCoords + deltaTexCoords; // get texture coordinates before collision (reverse operations)
-
-	float afterDepth  = currentDepthMapValue - currentLayerDepth; // get depth after and before collision for linear interpolation
-	float beforeDepth = texture(normalmap, prevTexCoords).b - currentLayerDepth + layerDepth;
-	 
-	float weight = afterDepth / (afterDepth - beforeDepth); // interpolation of texture coordinates
-	vec2 finalTexCoords = prevTexCoords * weight + currentTexCoords * (1.0 - weight);
-
-	return finalTexCoords;
-#else
-	float height = texture(normalmap, f_coord).b;
-	vec2 p = viewDir.xy / viewDir.z * (height * (param[2].y - param[2].z) * 0.2);
-	return f_coord - p;
-#endif
-} 

shaders/parallax.glsl

@@ -0,0 +1,45 @@
+vec2 ParallaxMapping(vec2 f_coord, vec3 viewDir, float scale, float offset)
+{
+	vec2 dx = dFdx(f_coord);
+	vec2 dy = dFdy(f_coord);
+	float fade = (1.0 - smoothstep(60.0, 100.0, length(f_pos.xyz))) * smoothstep(0.0, 0.1, viewDir.z);
+	if (fade <= 0.0) {
+		return f_coord;
+	}
+
+#if EXTRAEFFECTS_ENABLED
+	const float minLayers = 8.0;
+	const float maxLayers = 32.0;
+	float numLayers = mix(maxLayers, minLayers, clamp(viewDir.z, 0.0, 1.0));
+	float layerDepth = 1.0 / numLayers;
+	vec2 deltaTexCoords = viewDir.xy * scale * fade / numLayers;
+	vec2 currentTexCoords = f_coord;
+	float currentLayerDepth = 0.0;
+	float currentDepthMapValue = textureGrad(normalmap, currentTexCoords, dx, dy).b;
+	for (int i = 0; i < 40 && currentLayerDepth < currentDepthMapValue; ++i)
+	{
+		currentTexCoords -= deltaTexCoords;
+		currentLayerDepth += layerDepth;
+		currentDepthMapValue = textureGrad(normalmap, currentTexCoords, dx, dy).b;
+	}
+	for (int i = 0; i < 5; ++i)
+	{
+		deltaTexCoords *= 0.5;
+		layerDepth *= 0.5;
+		if (currentLayerDepth < currentDepthMapValue) {
+			currentTexCoords -= deltaTexCoords;
+			currentLayerDepth += layerDepth;
+		}
+		else {
+			currentTexCoords += deltaTexCoords;
+			currentLayerDepth -= layerDepth;
+		}
+		currentDepthMapValue = textureGrad(normalmap, currentTexCoords, dx, dy).b;
+	}
+	return currentTexCoords;
+#else
+	float height = textureGrad(normalmap, f_coord, dx, dy).b;
+	vec2 p = viewDir.xy / max(viewDir.z, 0.2) * (height * (scale - offset) * 0.2 * fade);
+	return f_coord - p;
+#endif
+}