Work on the funny

src/main/resources/assets/voxy/shaders/lod/gl46mesh/bindings.glsl

@@ -0,0 +1,76 @@
+struct BlockModel {
+    uint faceData[6];
+    uint flagsA;
+    uint colourTint;
+    uint _pad[8];
+};
+
+struct SectionMeta {
+    uint posA;
+    uint posB;
+    uint AABB;
+    uint ptr;
+    uint cntA;
+    uint cntB;
+    uint cntC;
+    uint cntD;
+};
+
+//TODO: see if making the stride 2*4*4 bytes or something cause you get that 16 byte write
+struct DrawCommand {
+    uint  count;
+    uint  instanceCount;
+    uint  firstIndex;
+    int  baseVertex;
+    uint  baseInstance;
+};
+
+layout(binding = 0) uniform sampler2D blockModelAtlas;
+
+#ifndef Quad
+#define Quad ivec2
+#endif
+layout(binding = 1, std430) readonly restrict buffer QuadBuffer {
+Quad quadData[];
+};
+
+layout(binding = 2, std430) restrict buffer DrawBuffer {
+    DrawCommand drawCmd;
+};
+
+#ifndef Quad
+#define MESHLET_ACCESS readonly writeonly
+#endif
+layout(binding = 3, std430) MESHLET_ACCESS restrict buffer MeshletListData {
+    uint meshlets[];
+};
+
+layout(binding = 4, std430) readonly restrict buffer SectionBuffer {
+    SectionMeta sectionData[];
+};
+
+#ifndef VISIBILITY_ACCESS
+#define VISIBILITY_ACCESS readonly
+#endif
+layout(binding = 5, std430) VISIBILITY_ACCESS restrict buffer VisibilityBuffer {
+    uint visibilityData[];
+};
+
+layout(binding = 6, std430) readonly restrict buffer ModelBuffer {
+    BlockModel modelData[];
+};
+
+layout(binding = 7, std430) readonly restrict buffer ModelColourBuffer {
+    uint colourData[];
+};
+
+layout(binding = 8, std430) readonly restrict buffer LightingBuffer {
+    uint lightData[];
+};
+
+vec4 getLighting(uint index) {
+    uvec4 arr = uvec4(lightData[index]);
+    arr = arr>>uvec4(16,8,0,24);
+    arr = arr & uvec4(0xFF);
+    return vec4(arr)*vec4(1.0f/255.0f);
+}

src/main/resources/assets/voxy/shaders/lod/gl46mesh/cmdgen.comp

@@ -0,0 +1,60 @@
+#version 450
+#define MESHLET_ACCESS writeonly
+#import <voxy:lod/quad_format.glsl>
+#import <voxy:lod/gl46mesh/bindings.glsl>
+#import <voxy:lod/section.glsl>
+#define extractMeshletStart extractQuadStart
+layout(local_size_x = 64) in;
+#define QUADS_PER_MESHLET 126
+
+void emitMeshlets(inout uint mli, inout uint meshletPtr, uint mskedCnt, uint cnt) {
+    for (;mskedCnt != 0; mskedCnt--,mli++) {
+        meshlets[mli] = meshletPtr + (mskedCnt-1);
+    }
+    meshletPtr += cnt;
+}
+
+void main() {
+    if (gl_GlobalInvocationID.x == 0) {
+        //Setup the remaining state of the drawElementsIndirect command
+        drawCmd.count = QUADS_PER_MESHLET*6;
+        drawCmd.firstIndex = 0;
+        drawCmd.baseVertex = 0;
+        drawCmd.baseInstance = 0;
+    }
+    if (gl_GlobalInvocationID.x >= sectionCount) {
+        return;
+    }
+
+    //Check the occlusion data from last frame
+    bool shouldRender = visibilityData[gl_GlobalInvocationID.x] == frameId - 1;
+    if (shouldRender) {
+        SectionMeta meta = sectionData[gl_GlobalInvocationID.x];
+        uint detail = extractDetail(meta);
+        ivec3 ipos = extractPosition(meta);
+
+        ivec3 relative = ipos-(baseSectionPos>>detail);
+
+        uint a = ((meta.cntA>>16)&0xFFFF);
+        uint u = (meta.cntB      &0xFFFF) * uint(relative.y>-1);
+        uint d = ((meta.cntB>>16)&0xFFFF) * uint(relative.y<1 );
+        uint s = (meta.cntC      &0xFFFF) * uint(relative.z>-1);
+        uint n = ((meta.cntC>>16)&0xFFFF) * uint(relative.z<1 );
+        uint w = (meta.cntD      &0xFFFF) * uint(relative.x>-1);
+        uint e = ((meta.cntD>>16)&0xFFFF) * uint(relative.x<1 );
+        uint total = a + u + d + s + n + w + e;
+
+        uint mli = atomicAdd(drawCmd.instanceCount, total);//meshletListIndex
+
+        uint meshletPtr = extractMeshletStart(meta);
+
+        emitMeshlets(mli, meshletPtr, a, a);
+        emitMeshlets(mli, meshletPtr, u, (meta.cntB      &0xFFFF));
+        emitMeshlets(mli, meshletPtr, d, ((meta.cntB>>16)&0xFFFF));
+        emitMeshlets(mli, meshletPtr, s, (meta.cntC      &0xFFFF));
+        emitMeshlets(mli, meshletPtr, n, ((meta.cntC>>16)&0xFFFF));
+        emitMeshlets(mli, meshletPtr, w, (meta.cntD      &0xFFFF));
+        emitMeshlets(mli, meshletPtr, e, ((meta.cntD>>16)&0xFFFF));
+        //TODO: also increment a secondary atomic buffer that can be used to do a compute pass over all meshlets (need to basicly divide the meshletCounter by the computes workGroup size)
+    }
+}

src/main/resources/assets/voxy/shaders/lod/gl46mesh/cull.frag

@@ -0,0 +1,3 @@
+#version 450
+void main() {
+}

src/main/resources/assets/voxy/shaders/lod/gl46mesh/cull.vert

@@ -0,0 +1,3 @@
+#version 450
+void main() {
+}

src/main/resources/assets/voxy/shaders/lod/gl46mesh/quads.frag

@@ -0,0 +1,5 @@
+#version 460 core
+layout(location = 0) out vec4 outColour;
+void main() {
+    outColour = vec4(1,0,0,1);
+}

src/main/resources/assets/voxy/shaders/lod/gl46mesh/quads.vert

@@ -0,0 +1,38 @@
+#version 450
+#define MESHLET_ACCESS readonly
+#define QUADS_PER_MESHLET 126
+//There are 16 bytes of metadata at the start of the meshlet
+#define MESHLET_SIZE (QUADS_PER_MESHLET+2)
+#import <voxy:lod/quad_format.glsl>
+#import <voxy:lod/gl46mesh/bindings.glsl>
+#import <voxy:lod/section.glsl>
+
+uvec2 meshletPosition;
+Quad quad;
+bool setupMeshlet() {
+    gl_CullDistance[0] = 1;
+    //TODO: replace with vertexAttribute that has a divisor of 1
+    uint data = meshlets[gl_InstanceID];
+    if (data == uint(-1)) {//Came across a culled meshlet
+        gl_CullDistance[0] = -1;
+        //Since the primative is culled, dont need to do any more work or set any values as the primative is discarded
+        // we dont need to care about undefined values
+        return true;
+    }
+
+    uint baseId = (data*QUADS_PER_MESHLET);
+    uint quadIndex = baseId + (gl_VertexID>>2) + 2;
+    meshletPosition = geometryPool[baseId];
+    quad = geometryPool[quadIndex];
+    if (isQuadEmpty(quad)) {
+        gl_CullDistance[0] = -1;
+        return true;
+    }
+    return false;
+}
+
+void main() {
+    if (setupMeshlet()) {
+        return;
+    }
+}

src/main/resources/assets/voxy/shaders/lod/quad_format.glsl

@@ -29,6 +29,10 @@ uint extractLightId(uint64_t quad) {
     return Eu32(quad, 8, 55);
 }
 
+bool isQuadEmpty(uint64_t quad) {
+    return quad == uint64_t(0);
+}
+
 #else
 //TODO: FIXME, ivec2 swaps around the data of the x and y cause its written in little endian
 
@@ -69,4 +73,8 @@ uint extractBiomeId(ivec2 quad) {
 uint extractLightId(ivec2 quad) {
     return Eu32v(quad, 8, 55);
 }
+
+bool isQuadEmpty(ivec2 quad) {
+    return all(equal(quad, ivec2(0)));
+}
 #endif