From 38601dc42cd8e936cd7d3313f57fc27f687bf721 Mon Sep 17 00:00:00 2001
From: IntegratedQuantum <jahe788@gmail.com>
Date: Wed, 12 Apr 2023 20:33:58 +0200
Subject: [PATCH] Reduce raymarching pixel errors and add chunkmesh gpu memory
 usage to the debug menu.

---
 assets/cubyz/shaders/chunks/chunk_fragment.fs | 3 ++-
 src/graphics.zig                              | 9 ++++++++-
 src/gui/windows/debug.zig                     | 2 ++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/assets/cubyz/shaders/chunks/chunk_fragment.fs b/assets/cubyz/shaders/chunks/chunk_fragment.fs
index 88dcdf32..2b38483d 100644
--- a/assets/cubyz/shaders/chunks/chunk_fragment.fs
+++ b/assets/cubyz/shaders/chunks/chunk_fragment.fs
@@ -101,6 +101,7 @@ RayMarchResult rayMarching(vec3 startPosition, vec3 direction) { // TODO: Mipmap
 	vec3 tDelta = 1/direction;
 	vec3 t2 = t1 + tDelta;
 	tDelta = abs(tDelta);
+	vec3 invTDelta = intBitsToFloat(floatBitsToInt(1.0) | modelSize)/tDelta;
 	vec3 tMax = max(t1, t2) - tDelta;
 	if(direction.x == 0) tMax.x = 1.0/0.0;
 	if(direction.y == 0) tMax.y = 1.0/0.0;
@@ -120,7 +121,7 @@ RayMarchResult rayMarching(vec3 startPosition, vec3 direction) { // TODO: Mipmap
 		it++;
 		vec3 tNext = tMax + block*tDelta;
 		total_tMax = min(tNext.x, min(tNext.y, tNext.z));
-		vec3 missingSteps = floor((total_tMax - tMax)/tDelta + 0.00001);
+		vec3 missingSteps = floor((total_tMax - tMax)*invTDelta);
 		voxelIndex += int(dot(missingSteps, stepInIndex));
 		tMax += missingSteps*tDelta;
 		if((voxelIndex & overflowMask) != 0)
diff --git a/src/graphics.zig b/src/graphics.zig
index 3f06bac7..69b86921 100644
--- a/src/graphics.zig
+++ b/src/graphics.zig
@@ -1141,11 +1141,14 @@ pub const LargeBuffer = struct {
 	};
 	ssbo: SSBO,
 	freeBlocks: std.ArrayList(Allocation),
+	capacity: u32,
+	used: u32,
 
 	pub fn init(self: *LargeBuffer, allocator: Allocator, size: u31, binding: c_uint) !void {
 		self.ssbo = SSBO.init();
 		self.ssbo.createDynamicBuffer(size);
 		self.ssbo.bind(binding);
+		self.capacity = size;
 
 		self.freeBlocks = std.ArrayList(Allocation).init(allocator);
 		try self.freeBlocks.append(.{.start = 0, .len = size});
@@ -1157,6 +1160,7 @@ pub const LargeBuffer = struct {
 	}
 
 	fn alloc(self: *LargeBuffer, size: u31) !Allocation {
+		self.used += size;
 		var smallestBlock: ?*Allocation = null;
 		for(self.freeBlocks.items, 0..) |*block, i| {
 			if(size == block.len) {
@@ -1175,6 +1179,7 @@ pub const LargeBuffer = struct {
 	}
 
 	pub fn free(self: *LargeBuffer, _allocation: Allocation) !void {
+		self.used -= _allocation.len;
 		var allocation = _allocation;
 		if(allocation.len == 0) return;
 		for(self.freeBlocks.items, 0..) |*block, i| {
@@ -1198,6 +1203,7 @@ pub const LargeBuffer = struct {
 		if(newSize == allocation.len) return;
 		if(newSize < allocation.len) {
 			const diff = allocation.len - newSize;
+			self.used -= diff;
 			// Check if there is a free block directly after:
 			for(self.freeBlocks.items) |*block| {
 				if(allocation.start + allocation.len == block.start and block.len + allocation.len >= newSize) {
@@ -1211,10 +1217,11 @@ pub const LargeBuffer = struct {
 			allocation.len -= diff;
 			try self.freeBlocks.append(.{.start = allocation.start + allocation.len, .len = diff});
 		} else {
+			const diff = newSize - allocation.len;
+			self.used += diff;
 			// Check if the buffer can be extended without a problem:
 			for(self.freeBlocks.items, 0..) |*block, i| {
 				if(allocation.start + allocation.len == block.start and block.len + allocation.len >= newSize) {
-					const diff = newSize - allocation.len;
 					allocation.len += diff;
 					if(block.len != diff) {
 						block.start += diff;
diff --git a/src/gui/windows/debug.zig b/src/gui/windows/debug.zig
index f5bc4ae6..733b06b3 100644
--- a/src/gui/windows/debug.zig
+++ b/src/gui/windows/debug.zig
@@ -35,6 +35,8 @@ fn flawedRender() !void {
 		y += 8;
 		try draw.print("Queue size: {}", .{main.threadPool.loadList.size}, 0, y, 8, .left);
 		y += 8;
+		try draw.print("ChunkMesh memory: {} MiB / {} MiB (fragmentation: {})", .{main.chunk.meshing.faceBuffer.used >> 20, main.chunk.meshing.faceBuffer.capacity >> 20, main.chunk.meshing.faceBuffer.freeBlocks.items.len}, 0, y, 8, .left);
+		y += 8;
 		// TODO: biome
 		y += 8;
 		// TODO: packet loss