attempted to improve mipping by computing dx,dy accross entire uv instead of local uv

src/main/resources/assets/voxy/shaders/lod/gl46/quads.frag

@@ -1,4 +1,8 @@
 #version 460 core
+//Use quad shuffling to compute fragment mip
+//#extension GL_KHR_shader_subgroup_quad: enable
+
+
 layout(binding = 0) uniform sampler2D blockModelAtlas;
 layout(binding = 2) uniform sampler2D depthTex;
 
@@ -13,22 +17,50 @@ layout(location = 2) in flat vec4 tinting;
 layout(location = 3) in flat vec4 addin;
 layout(location = 4) in flat uint flags;
 layout(location = 5) in flat vec4 conditionalTinting;
-
+layout(location = 6) in flat vec2 quadSize;
 
 #ifdef DEBUG_RENDER
-layout(location = 6) in flat uint quadDebug;
+layout(location = 7) in flat uint quadDebug;
 #endif
 layout(location = 0) out vec4 outColour;
+
+vec4 computeColour(vec4 colour) {
+    //Conditional tinting, TODO: FIXME: REPLACE WITH MASK OR SOMETHING, like encode data into the top bit of alpha
+    if ((flags&(1u<<2)) != 0 && abs(colour.r-colour.g) < 0.02f && abs(colour.g-colour.b) < 0.02f) {
+        colour *= conditionalTinting;
+    }
+    return (colour * tinting) + addin;
+}
+
+bool useMipmaps() {
+    return ((flags>>1)&1u)==0u;
+}
+
 void main() {
+    //Tile is the tile we are in
+    vec2 tile;
+    vec2 uv2 = modf(uv, tile)*(1.0/(vec2(3.0,2.0)*256.0));
+    vec4 colour = vec4(1);
+    vec2 texPos = uv2 + baseUV;
+    if (useMipmaps()) {
+        vec2 uvSmol = uv*(1.0/(vec2(3.0,2.0)*256.0));
+        vec2 dx = dFdx(uvSmol);//vec2(lDx, dDx);
+        vec2 dy = dFdy(uvSmol);//vec2(lDy, dDy);
+        colour = textureGrad(blockModelAtlas, texPos, dx, dy);
+    } else {
+        colour = texture(blockModelAtlas, texPos, -5.0);
+    }
+
+    if (any(notEqual(clamp(tile, vec2(0), quadSize), tile))) {
+        discard;
+    }
+
     //Check the minimum bounding texture and ensure we are greater than it
     if (gl_FragCoord.z < texelFetch(depthTex, ivec2(gl_FragCoord.xy), 0).r) {
         discard;
     }
-    vec2 uv = mod(uv, vec2(1.0))*(1.0/(vec2(3.0,2.0)*256.0));
+
-    vec2 texPos = uv + baseUV;
+
-    //vec4 colour = solidColour;
-    //TODO: FIXME, need to manually compute the mip colour
-    vec4 colour = texture(blockModelAtlas, texPos, ((flags>>1)&1u)*-5.0);//TODO: FIXME mipping needs to be fixed so that it doesnt go cross model bounds
     //Also, small quad is really fking over the mipping level somehow
     if ((flags&1u) == 1 && (texture(blockModelAtlas, texPos, -16.0).a <= 0.1f)) {
         //This is stupidly stupidly bad for divergence
@@ -38,14 +70,7 @@ void main() {
         #endif
     }
 
-    //Conditional tinting, TODO: FIXME: REPLACE WITH MASK OR SOMETHING, like encode data into the top bit of alpha
+    outColour = computeColour(colour);
-    if ((flags&(1u<<2)) != 0 && abs(colour.r-colour.g) < 0.02f && abs(colour.g-colour.b) < 0.02f) {
-        colour *= conditionalTinting;
-    }
-
-    outColour = (colour * tinting) + addin;
-
-    //outColour = vec4(uv + baseUV, 0, 1);
 
 
     #ifdef DEBUG_RENDER
@@ -56,4 +81,30 @@ void main() {
     hash = hash * 1827364925 + 123325621;
     outColour = vec4(float(hash&15u)/15, float((hash>>4)&15u)/15, float((hash>>8)&15u)/15, 1);
     #endif
-}
+}
+
+
+
+//#ifdef GL_KHR_shader_subgroup_quad
+/*
+uint hash = (uint(tile.x)*(1<<16))^uint(tile.y);
+uint horiz = subgroupQuadSwapHorizontal(hash);
+bool sameTile = horiz==hash;
+uint sv = mix(uint(-1), hash, sameTile);
+uint vert = subgroupQuadSwapVertical(sv);
+sameTile = sameTile&&vert==hash;
+mipBias = sameTile?0:-5.0;
+*/
+/*
+vec2 uvSmol = uv*(1.0/(vec2(3.0,2.0)*256.0));
+float lDx = subgroupQuadSwapHorizontal(uvSmol.x)-uvSmol.x;
+float lDy = subgroupQuadSwapVertical(uvSmol.y)-uvSmol.y;
+float dDx = subgroupQuadSwapDiagonal(lDx);
+float dDy = subgroupQuadSwapDiagonal(lDy);
+vec2 dx = vec2(lDx, dDx);
+vec2 dy = vec2(lDy, dDy);
+colour = textureGrad(blockModelAtlas, texPos, dx, dy);
+*/
+//#else
+//colour = texture(blockModelAtlas, texPos);
+//#endif

src/main/resources/assets/voxy/shaders/lod/gl46/quads2.vert

@@ -20,9 +20,10 @@ layout(location = 2) out flat vec4 tinting;
 layout(location = 3) out flat vec4 addin;
 layout(location = 4) out flat uint flags;
 layout(location = 5) out flat vec4 conditionalTinting;
+layout(location = 6) out flat vec2 size;
 
 #ifdef DEBUG_RENDER
-layout(location = 6) out flat uint quadDebug;
+layout(location = 7) out flat uint quadDebug;
 #endif
 
 /*
@@ -41,17 +42,17 @@ vec4 uint2vec4RGBA(uint colour) {
 }
 
 vec4 getFaceSize(uint faceData) {
-    float EPSILON = 0.0005f;
+    float EPSILON = 0.00005f;
 
     vec4 faceOffsetsSizes = extractFaceSizes(faceData);
 
+    //Make the end relative to the start
+    faceOffsetsSizes.yw -= faceOffsetsSizes.xz;
+
     //Expand the quads by a very small amount
     faceOffsetsSizes.xz -= vec2(EPSILON);
     faceOffsetsSizes.yw += vec2(EPSILON);
 
-    //Make the end relative to the start
-    faceOffsetsSizes.yw -= faceOffsetsSizes.xz;
-
     return faceOffsetsSizes;
 }
 
@@ -105,10 +106,10 @@ void main() {
 
     ivec2 quadSize = extractSize(quad);
 
-
-
     if (cornerIdx == 1) //Only if we are the provoking vertex
     {
+        size = vec2(quadSize-1);
+
         vec2 modelUV = vec2(modelId&0xFFu, (modelId>>8)&0xFFu)*(1.0/(256.0));
         baseUV = modelUV + (vec2(face>>1, face&1u) * (1.0/(vec2(3.0, 2.0)*256.0)));