Fix #4574 (#5080)

* Improve normal accuracy & Fix wrong SSR

* One less sample count

data/shaders/IBL.frag

@@ -15,26 +15,19 @@ out vec4 Spec;
 #stk_include "utils/DiffuseIBL.frag"
 #stk_include "utils/SpecularIBL.frag"
 
-
-float makeLinear(float f, float n, float z)
-{
-    return (2.0f * n) / (f + n - z * (f - n));
-}
-
-vec3 CalcViewPositionFromDepth(in vec2 TexCoord)
+vec3 CalcViewPositionFromDepth(in vec2 uv)
 {
     // Combine UV & depth into XY & Z (NDC)
-    float z = makeLinear(1000.0, 1.0, textureLod(dtex, TexCoord, 0.).x);
-    vec3 rawPosition                = vec3(TexCoord, z);
+    float z = texture(dtex, uv).x;
+    return getPosFromUVDepth(vec3(uv, z), u_inverse_projection_matrix).xyz;
+}
 
-    // Convert from (0, 1) range to (-1, 1)
-    vec4 ScreenSpacePosition        = vec4( rawPosition * 2.0 - 1.0, 1.0);
-
-    // Undo Perspective transformation to bring into view space
-    vec4 ViewPosition               = u_inverse_projection_matrix * ScreenSpacePosition;
-
-    // Perform perspective divide and return
-    return                          ViewPosition.xyz / ViewPosition.w;
+vec2 CalcCoordFromPosition(in vec3 pos)
+{
+    vec4 projectedCoord     = u_projection_matrix * vec4(pos, 1.0);
+    projectedCoord.xy      /= projectedCoord.w;
+    projectedCoord.xy       = projectedCoord.xy * 0.5 + 0.5;
+    return projectedCoord.xy;
 }
 
 // Fade out edges of screen buffer tex
@@ -48,35 +41,33 @@ float GetEdgeFade(vec2 coords)
     return min(min(gradL, gradR), min(gradT, gradB));
 }
 
-vec2 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth)
+vec2 RayCast(vec3 dir, vec3 hitCoord)
 {
-    dir *= 0.25f;
+    vec2 projectedCoord;
+    vec3 dirstep = dir * 0.5f;
+    float depth;
+    hitCoord += dirstep;
 
-    for(int i = 0; i < 8; ++i) {
-        hitCoord               += dir;
+    for (int i = 1; i <= 32; i++)
+    {
+        projectedCoord          = CalcCoordFromPosition(hitCoord);
 
-        vec4 projectedCoord     = u_projection_matrix * vec4(hitCoord, 1.0);
-        projectedCoord.xy      /= projectedCoord.w;
-        projectedCoord.xy       = projectedCoord.xy * 0.5 + 0.5;
+        float depth             = CalcViewPositionFromDepth(projectedCoord).z;
 
-        float depth             = CalcViewPositionFromDepth(projectedCoord.xy).z;
-        dDepth                  = hitCoord.z - depth;
-
-        if (dDepth < 0.0)
-        {
-            if (projectedCoord.x > 0.0 && projectedCoord.x < 1.0 &&
-                projectedCoord.y > 0.0 && projectedCoord.y < 1.0)
-            {
-                return projectedCoord.xy;
-            }
-            else
-            {
-                return vec2(0.f);
-            }
-        }
+        float directionSign = sign(abs(hitCoord.z) - depth);
+        dirstep = dirstep * (1.0 - 0.5 * max(directionSign, 0.0));
+        hitCoord += dirstep * (-directionSign);
     }
 
-    return vec2(0.f);
+    if (projectedCoord.x > 0.0 && projectedCoord.x < 1.0 &&
+        projectedCoord.y > 0.0 && projectedCoord.y < 1.0)
+    {
+        return projectedCoord.xy;
+    }
+    else
+    {
+        return vec2(0.f);
+    }
 }
 
 // Main ===================================================================
@@ -84,7 +75,7 @@ vec2 RayCast(vec3 dir, inout vec3 hitCoord, out float dDepth)
 void main(void)
 {
     vec2 uv = gl_FragCoord.xy / u_screen;
-    vec3 normal = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
+    vec3 normal = DecodeNormal(texture(ntex, uv).xy);
 
     Diff = vec4(0.25 * DiffuseIBL(normal), 1.);
 
@@ -110,18 +101,10 @@ void main(void)
     // otherwise just use specular IBL
     if (specval > 0.5)
     {
-        vec3 View_Pos               = CalcViewPositionFromDepth(uv);
-
         // Reflection vector
-        vec3 reflected              = normalize(reflect(eyedir, normal));
+        vec3 reflected              = reflect(-eyedir, normal);
 
-        // Ray cast
-        vec3 hitPos                 = View_Pos.xyz;
-        float dDepth;
-        float minRayStep            = 50.0f;
-
-        vec2 coords = RayCast(reflected * max(minRayStep, -View_Pos.z),
-                                hitPos, dDepth);
+        vec2 coords = RayCast(reflected, xpos.xyz);
 
         if (coords.x == 0.0 && coords.y == 0.0) {
             outColor = fallback;

data/shaders/degraded_ibl.frag

@@ -16,7 +16,7 @@ out vec4 Spec;
 void main(void)
 {
     vec2 uv = gl_FragCoord.xy / u_screen;
-    vec3 normal = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
+    vec3 normal = DecodeNormal(texture(ntex, uv).xy);
 
     Diff = vec4(0.25 * DiffuseIBL(normal), 1.);
     Spec = vec4(0.031, 0.106, 0.173, 1.);

data/shaders/pointlight.frag

@@ -27,7 +27,7 @@ void main()
 {
     vec2 texc = gl_FragCoord.xy / u_screen;
     float z = texture(dtex, texc).x;
-    vec3 norm = normalize(DecodeNormal(2. * texture(ntex, texc).xy - 1.));
+    vec3 norm = DecodeNormal(texture(ntex, texc).xy);
     float roughness = texture(ntex, texc).z;
 
     vec4 xpos = getPosFromUVDepth(vec3(texc, z), u_inverse_projection_matrix);

data/shaders/sp_alpha_test.frag

@@ -32,7 +32,7 @@ void main(void)
     vec4 layer_2 = sampleTextureLayer2(uv);
     o_diffuse_color = vec4(col.xyz, layer_2.z);
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(col.xyz, 1.0);

data/shaders/sp_decal.frag

@@ -20,7 +20,7 @@ void main(void)
     vec4 layer_2 = sampleTextureLayer2(uv);
     o_diffuse_color = vec4(final_color, layer_2.z);
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_dynamic_night_bloom.frag

@@ -48,7 +48,7 @@ void main()
 
     vec3 world_normal = t_b_n * tangent_space_normal;
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(world_normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(world_normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_grass.frag

@@ -31,7 +31,7 @@ void main(void)
     vec4 layer_2 = sampleTextureLayer2(uv);
     o_diffuse_color = vec4(col.xyz, layer_2.z);
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(col.xyz, 1.0);

data/shaders/sp_normal_map.frag

@@ -47,7 +47,7 @@ void main()
 
     vec3 world_normal = t_b_n * tangent_space_normal;
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(world_normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(world_normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_road_blending.frag

@@ -85,7 +85,7 @@ void main()
 
     vec3 world_normal = t_b_n * tangent_space_normal;
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(world_normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(world_normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_solid.frag

@@ -37,7 +37,7 @@ void main(void)
     vec4 layer_2 = sampleTextureLayer2(uv);
     o_diffuse_color = vec4(final_color, layer_2.z);
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_tilling_mitigation.frag

@@ -49,7 +49,7 @@ void main()
 
     vec3 world_normal = t_b_n * tangent_space_normal;
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(world_normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(world_normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_unlit.frag

@@ -22,7 +22,7 @@ void main(void)
 #if defined(Advanced_Lighting_Enabled)
     o_diffuse_color = vec4(final_color, 0.4);
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(normal));
     o_normal_color.zw = vec2(0.0);
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sp_vertical_mapping.frag

@@ -55,7 +55,7 @@ void main()
 
     vec3 world_normal = t_b_n * tangent_space_normal;
 
-    o_normal_color.xy = 0.5 * EncodeNormal(normalize(world_normal)) + 0.5;
+    o_normal_color.xy = EncodeNormal(normalize(world_normal));
     o_normal_color.zw = layer_2.xy;
 #else
     o_diffuse_color = vec4(final_color, 1.0);

data/shaders/sunlight.frag

@@ -23,7 +23,7 @@ void main() {
     float z = texture(dtex, uv).x;
     vec4 xpos = getPosFromUVDepth(vec3(uv, z), u_inverse_projection_matrix);
 
-    vec3 norm = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
+    vec3 norm = DecodeNormal(texture(ntex, uv).xy);
     float roughness = texture(ntex, uv).z;
     vec3 eyedir = -normalize(xpos.xyz);
 

data/shaders/sunlightshadow.frag

@@ -88,7 +88,7 @@ void main() {
     float z = texture(dtex, uv).x;
     vec4 xpos = getPosFromUVDepth(vec3(uv, z), u_inverse_projection_matrix);
 
-    vec3 norm = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
+    vec3 norm = DecodeNormal(texture(ntex, uv).xy);
     float roughness =texture(ntex, uv).z;
     vec3 eyedir = -normalize(xpos.xyz);