Add scratch buffer for position.

Fixes lods "disappearing" when you zoom in

src/main/java/me/cortex/voxy/client/core/rendering/section/MDICSectionRenderer.java

@@ -57,6 +57,7 @@ public class MDICSectionRenderer extends AbstractSectionRenderer<MDICViewport, B
     //TODO: needs to be in the viewport, since it contains the compute indirect call/values
     private final GlBuffer drawCountCallBuffer = new GlBuffer(1024).zero();
     private final GlBuffer drawCallBuffer  = new GlBuffer(5*4*400000).zero();//400k draw calls
+    private final GlBuffer positionScratchBuffer  = new GlBuffer(8*400000).zero();//400k positions
 
     public MDICSectionRenderer(ModelStore modelStore, int maxSectionCount, long geometryCapacity) {
         super(modelStore, new BasicSectionGeometryManager(maxSectionCount, geometryCapacity));
@@ -89,6 +90,7 @@ public class MDICSectionRenderer extends AbstractSectionRenderer<MDICViewport, B
         glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, this.geometryManager.getGeometryBufferId());
         glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 2, this.geometryManager.getMetadataBufferId());
         this.modelStore.bind(3, 4, 0);
+        glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 5, this.positionScratchBuffer.id);
         LightMapHelper.bind(1);
 
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, SharedIndexBuffer.INSTANCE.id());
@@ -139,6 +141,7 @@ public class MDICSectionRenderer extends AbstractSectionRenderer<MDICViewport, B
             glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 3, this.geometryManager.getMetadataBufferId());
             glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 4, viewport.visibilityBuffer.id);
             glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 5, viewport.indirectLookupBuffer.id);
+            glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 6, this.positionScratchBuffer.id);
             glBindBuffer(GL_DISPATCH_INDIRECT_BUFFER, this.drawCountCallBuffer.id);
             glDispatchComputeIndirect(0);
             glMemoryBarrier(GL_COMMAND_BARRIER_BIT);
@@ -204,7 +207,7 @@ public class MDICSectionRenderer extends AbstractSectionRenderer<MDICViewport, B
     public MDICViewport createViewport() {
         return new MDICViewport();
     }
-
+//
     @Override
     public void free() {
         super.free();
@@ -215,5 +218,6 @@ public class MDICSectionRenderer extends AbstractSectionRenderer<MDICViewport, B
         this.prepShader.free();
         this.drawCallBuffer.free();
         this.drawCountCallBuffer.free();
+        this.positionScratchBuffer.free();
     }
 }

src/main/resources/assets/voxy/shaders/lod/gl46/bindings.glsl

@@ -103,6 +103,15 @@ layout(binding = MODEL_COLOUR_BUFFER_BINDING, std430) readonly restrict buffer M
 };
 #endif
 
+#ifdef POSITION_SCRATCH_BINDING
+#ifndef POSITION_SCRATCH_ACCESS
+#define POSITION_SCRATCH_ACCESS readonly
+#endif
+layout(binding = POSITION_SCRATCH_BINDING, std430) POSITION_SCRATCH_ACCESS restrict buffer PositionScratchBuffer {
+    uvec2 positionBuffer[];
+};
+#endif
+
 #ifdef LIGHTING_SAMPLER_BINDING
 
 layout(binding = LIGHTING_SAMPLER_BINDING) uniform sampler2D lightSampler;

src/main/resources/assets/voxy/shaders/lod/gl46/cmdgen.comp

@@ -8,6 +8,8 @@ layout(local_size_x = 128) in;
 #define SECTION_METADATA_BUFFER_BINDING 3
 #define VISIBILITY_BUFFER_BINDING 4
 #define INDIRECT_SECTION_LOOKUP_BINDING 5
+#define POSITION_SCRATCH_BINDING 6
+#define POSITION_SCRATCH_ACCESS writeonly
 
 #import <voxy:lod/quad_format.glsl>
 #import <voxy:lod/gl46/bindings.glsl>
@@ -34,13 +36,13 @@ uint encodeLocalLodPos(uint detail, ivec3 pos) {
 
 
 //Note: if i want reverse indexing i need to use the index buffer offset to offset
-void writeCmd(uint idx, uint encodedPos, uint offset, uint quadCount) {
+void writeCmd(uint idx, uint instance, uint offset, uint quadCount) {
     DrawCommand cmd;
     cmd.count = quadCount * 6;
     cmd.instanceCount = 1;
     cmd.firstIndex = 0;
     cmd.baseVertex = int(offset)<<2;
-    cmd.baseInstance = encodedPos;
+    cmd.baseInstance = instance;
     cmdBuffer[idx] = cmd;
 }
 
@@ -69,14 +71,15 @@ void main() {
 
     //This prevents overflow of the relative position encoder
     if (shouldRender) {
-        shouldRender = !any(lessThan(ivec3(254), abs(ipos-(baseSectionPos>>detail))));
+
     }
 
     if (shouldRender) {
-        uint encodedPos = encodeLocalLodPos(detail, ipos);
         uint ptr = extractQuadStart(meta);
         ivec3 relative = ipos-(baseSectionPos>>detail);
+        uint drawId = gl_GlobalInvocationID.x;
 
+        positionBuffer[drawId] = uvec2(meta.posA, meta.posB);
 
 
         uint msk = 0;
@@ -98,56 +101,56 @@ void main() {
         count = meta.cntA&0xFFFF;
         if (count != 0) {
             //uint translucentCommandPtr = atomicAdd(translucentDrawCount, 1) + 400000;//FIXME: dont hardcode this offset
-            //writeCmd(translucentCommandPtr, encodedPos, ptr, count);
+            //writeCmd(translucentCommandPtr, drawId, ptr, count);
         }
         ptr += count;
 
         //Double sided quads
         count = (meta.cntA>>16)&0xFFFF;
         if (count != 0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //Down
         count = (meta.cntB)&0xFFFF;
         if (((msk&(1u<<0))!=0)) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //Up
         count = (meta.cntB>>16)&0xFFFF;
         if ((msk&(1u<<1))!=0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //North
         count = (meta.cntC)&0xFFFF;
         if ((msk&(1u<<2))!=0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //South
         count = (meta.cntC>>16)&0xFFFF;
         if ((msk&(1u<<3))!=0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //West
         count = (meta.cntD)&0xFFFF;
         if ((msk&(1u<<4))!=0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
 
         //East
         count = (meta.cntD>>16)&0xFFFF;
         if ((msk&(1u<<5))!=0) {
-            writeCmd(cmdPtr++, encodedPos, ptr, count);
+            writeCmd(cmdPtr++, drawId, ptr, count);
         }
         ptr += count;
     }

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

@@ -5,6 +5,7 @@
 #define SECTION_METADATA_BUFFER_BINDING 2
 #define MODEL_BUFFER_BINDING 3
 #define MODEL_COLOUR_BUFFER_BINDING 4
+#define POSITION_SCRATCH_BINDING 5
 #define LIGHTING_SAMPLER_BINDING 1
 
 
@@ -25,6 +26,7 @@ layout(location = 5) out flat vec4 conditionalTinting;
 layout(location = 6) out flat uint quadDebug;
 #endif
 
+/*
 uint extractLodLevel() {
     return uint(gl_BaseInstance)>>27;
 }
@@ -33,7 +35,7 @@ uint extractLodLevel() {
 //Gives a relative position of +-255 relative to the player center in its respective lod
 ivec3 extractRelativeLodPos() {
     return (ivec3(gl_BaseInstance)<<ivec3(5,14,23))>>ivec3(23);
-}
+}*/
 
 vec4 uint2vec4RGBA(uint colour) {
     return vec4((uvec4(colour)>>uvec4(24,16,8,0))&uvec4(0xFF))/255.0;
@@ -69,6 +71,21 @@ vec3 swizzelDataAxis(uint axis, vec3 data) {
     return data;
 }
 
+uint extractDetail(uvec2 encPos) {
+    return encPos.x>>28;
+}
+
+ivec3 extractLoDPosition(uvec2 encPos) {
+    int y = ((int(encPos.x)<<4)>>24);
+    int x = (int(encPos.y)<<4)>>8;
+    int z = int((encPos.x&((1u<<20)-1))<<4);
+    z |= int(encPos.y>>28);
+    z <<= 8;
+    z >>= 8;
+    return ivec3(x,y,z);
+}
+
+
 //TODO: add a mechanism so that some quads can ignore backface culling
 // this would help alot with stuff like crops as they would look kinda weird i think,
 // same with flowers etc
@@ -83,7 +100,9 @@ void main() {
     bool hasAO = modelHasMipmaps(model);//TODO: replace with per face AO flag
     bool isShaded = hasAO;//TODO: make this a per face flag
 
-    uint lodLevel = extractLodLevel();
+
+    uvec2 encPos = positionBuffer[gl_BaseInstance];
+    uint lodLevel = extractDetail(encPos);
 
 
     vec2 modelUV = vec2(modelId&0xFFu, (modelId>>8)&0xFFu)*(1.0/(256.0));
@@ -153,7 +172,7 @@ void main() {
     cornerPos += swizzelDataAxis(face>>1, vec3(faceSize.xz, mix(depthOffset, 1-depthOffset, float(face&1u))));
 
 
-    vec3 origin = vec3(((extractRelativeLodPos()<<lodLevel) - (baseSectionPos&(ivec3((1<<lodLevel)-1))))<<5);
+    vec3 origin = vec3(((extractLoDPosition(encPos)<<lodLevel) - baseSectionPos)<<5);
     gl_Position = MVP*vec4((cornerPos+swizzelDataAxis(face>>1,vec3(cQuadSize,0)))*(1<<lodLevel)+origin, 1.0);
 
     #ifdef DEBUG_RENDER