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Greatly accelerated geometry cleaner gpu code

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mcrcortex
2025-04-08 12:35:02 +10:00
parent 3569e1d889
commit 7cd2ecfcde
2 changed files with 110 additions and 23 deletions
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4
src/main/java/me/cortex/voxy/client/core/rendering/hierachical/NodeCleaner.java
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@@ -35,6 +35,7 @@ public class NodeCleaner {
private static final int SORTING_WORKER_SIZE = 64;
private static final int WORK_PER_THREAD = 8;
private static final int OUTPUT_COUNT = 256;
@@ -43,6 +44,7 @@ public class NodeCleaner {
private final AutoBindingShader sorter = Shader.makeAuto(PrintfDebugUtil.PRINTF_processor)
.define("WORK_SIZE", SORTING_WORKER_SIZE)
.define("ELEMS_PER_THREAD", WORK_PER_THREAD)
.define("OUTPUT_SIZE", OUTPUT_COUNT)
.define("VISIBILITY_BUFFER_BINDING", 1)
.define("OUTPUT_BUFFER_BINDING", 2)
@@ -134,7 +136,7 @@ public class NodeCleaner {
//TODO: choose whether this is in nodeSpace or section/geometryId space
//
glDispatchCompute((this.nodeManager.getCurrentMaxNodeId() + SORTING_WORKER_SIZE - 1) / SORTING_WORKER_SIZE, 1, 1);
glDispatchCompute((this.nodeManager.getCurrentMaxNodeId() + (SORTING_WORKER_SIZE+WORK_PER_THREAD) - 1) / (SORTING_WORKER_SIZE+WORK_PER_THREAD), 1, 1);
glMemoryBarrier(GL_SHADER_STORAGE_BARRIER_BIT);
this.resultTransformer.bind();

129
src/main/resources/assets/voxy/shaders/lod/hierarchical/cleaner/sort_visibility.comp
View File

@@ -5,12 +5,12 @@
//#define OUTPUT_SIZE 128
layout(local_size_x=WORK_SIZE, local_size_y=1) in;
//256 workgroup
#define OPS_PER_THREAD (OUTPUT_SIZE/WORK_SIZE)
#import <voxy:lod/hierarchical/node.glsl>
layout(binding = VISIBILITY_BUFFER_BINDING, std430) restrict readonly buffer VisibilityDataBuffer {
uint[] visiblity;
uint[] visibility;
};
layout(binding = OUTPUT_BUFFER_BINDING, std430) restrict volatile buffer MinimumVisibilityBuffer {//TODO: might need to be volatile
@@ -18,12 +18,15 @@ layout(binding = OUTPUT_BUFFER_BINDING, std430) restrict volatile buffer Minimum
};
//Returns the id of the max value
uint atomicDerefMaxExchange(uint atId, uint id) {
const uint value = visiblity[id];
uint atomicDerefMaxExchangeGlobal(uint atId, uint id) {
const uint value = visibility[id];
while (true) {
const uint existingId = minVisIds[atId];
const uint existingId = minVisIds[atId];//TODO: check that this does what we want, and that it obtains the value of atValue, at this point
if (existingId == id) {//If we are trying to insert self, return -1
return uint(-1);
}
//Check if the value is less than the dereferenced value, if its not, return our own id
if (visiblity[existingId] <= value) {
if (visibility[existingId&((1u<<31)-1)] <= value) {//Remove the flag bit
return id;
}
//Attempt to swap, since we know we are less than the existingId
@@ -39,37 +42,70 @@ uint atomicDerefMaxExchange(uint atId, uint id) {
}
//TODO: optimize
void bubbleSort(uint start, uint id) {
void bubbleSortGlobal(uint start, uint id) {
for (uint i = start; i < OUTPUT_SIZE; i++) {
id = atomicDerefMaxExchange(i, id);
id = atomicDerefMaxExchangeGlobal(i, id);
if (id == uint(-1)) {
break;
}
}
}
void main() {
//if (gl_GlobalInvocationID.x <64) {
// minVisIds[gl_GlobalInvocationID.x] = visiblity[gl_GlobalInvocationID.x];
//}
//First do a min sort/set of min OUTPUT_SIZE values of the set
uint vis = visiblity[gl_GlobalInvocationID.x];
if (vis == uint(-1)) {
return;
//TODO: maybe also have a shared "cache" of the visibility data
// meaning that the shader doesnt need to access global memory as much
shared uint initalSort[OUTPUT_SIZE];
//Returns the id of the max value
uint atomicDerefMaxExchangeLocal(uint atId, uint id) {
const uint value = visibility[id];
while (true) {
const uint existingId = initalSort[atId];//TODO: check that this does what we want, and that it obtains the value of atValue, at this point
if (existingId == id) {//If we are trying to insert self, return -1
return uint(-1);
}
//Check if the value is less than the dereferenced value, if its not, return our own id
if (visibility[existingId&((1u<<31)-1)] <= value) {//Remove the flag bit
return id;
}
//Attempt to swap, since we know we are less than the existingId
const uint c = atomicCompSwap(initalSort[atId], existingId, id);
//Check if we did swap, else if we failed (or got reswapped else where) recheck
//We did swap, (since the original mem contents was the existing id)
// which means existingId is now the max of the ptr
if (c == existingId) {
return existingId;
}
}
if (visiblity[minVisIds[OUTPUT_SIZE-1]] <= vis) {
return;
}
void bubbleSortInital(uint vis, uint id) {
uint start = 0;
//Fast path cut out half the ops
if (visibility[initalSort[(OUTPUT_SIZE-1)>>1]] <= vis) {//Check if we are more than half way
start = (OUTPUT_SIZE-1)>>1;
}
for (uint i = start; i < OUTPUT_SIZE; i++) {
id = atomicDerefMaxExchangeLocal(i, id);
}
}
bool shouldSortId(uint id) {
UnpackedNode node;
if (unpackNode(node, gl_GlobalInvocationID.x)==uvec4(-1)) {
return;//Unallocated node
return false;//Unallocated node
}
if (isEmptyMesh(node) || (!hasMesh(node))) {//|| (!hasChildren(node))
return;
return false;
}
//TODO: FIXME: DONT HARDCODE TOP LEVEL LOD LEVEL
if (node.lodLevel == 4) {// (!hasChildren(node)) -> Assume leaf node
return;//Cannot remove geometry from top level node
return false;//Cannot remove geometry from top level node
}
/*THIS IS COMPLETLY WRONG, we need to check if all the children of the parent of the child are leaf nodes
// not this node
@@ -87,7 +123,56 @@ void main() {
}
*/
return true;
}
void main() {
//Cheaky trick, copy the _global buffer_ into the local buffer
// this means that insertion into the local buffer can be accelerated W.R.T global
for (uint i = 0; i < OPS_PER_THREAD; i++) {
//Copy in with warp size batch fetch
uint id = gl_LocalInvocationID.x + (i*WORK_SIZE);
initalSort[id] = minVisIds[id]|(1u<<31);//Flag the id as being external
}
barrier();
//Do insertion and sort into local shared buffer
for (uint i = 0; i < ELEMS_PER_THREAD; i++) {
uint id = gl_GlobalInvocationID.x*ELEMS_PER_THREAD+i;
uint vis = visibility[id];
if (vis == uint(-1)) {
continue;
}
//Quick exit if this element is already bigger than global output
if (visibility[minVisIds[OUTPUT_SIZE-1]] <= vis) {
continue;
}
if (!shouldSortId(id)) {
continue;
}
bubbleSortInital(vis, id);
}
barrier();
//Do insertion into global visibility array
// this is done front to back
bubbleSort(0, gl_GlobalInvocationID.x);
//Work size batching
for (uint i = 0; i < OPS_PER_THREAD; i++) {
barrier();
uint id = gl_LocalInvocationID.x+(i*WORK_SIZE);
uint sid = initalSort[id];
if ((sid&(1u<<31)) != 0) {
//The flag being external was set, meaning we should NOT insert this element
continue;
}
uint vis = visibility[sid];
//If output is already smaller than self
if (visibility[minVisIds[OUTPUT_SIZE-1]] <= vis) {
continue;
}
uint start = id;
if (visibility[minVisIds[(id+OUTPUT_SIZE)>>1]] <= vis) {//Try to skip
start = (id+OUTPUT_SIZE)>>1;
}
bubbleSortGlobal(start, sid);//Insert into global
}
}