From e4c9e10ca914aaaa032cab384f619e449bf43092 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Branimir=20Karad=C5=BEi=C4=87?= <branimirkaradzic@gmail.com>
Date: Thu, 1 Oct 2026 21:52:42 -0700
Subject: [PATCH] Replaced per-view sequence counter with render item index.
 (#4013)

---
 src/bgfx.cpp | 14 ++++++--------
 src/bgfx_p.h |  7 +------
 src/config.h |  2 +-
 3 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/src/bgfx.cpp b/src/bgfx.cpp
index 0aa581208..cb8d6b0ed 100644
--- a/src/bgfx.cpp
+++ b/src/bgfx.cpp
@@ -1591,15 +1591,15 @@ namespace bgfx
 		SortKey::Enum type;
 		switch (s_ctx->m_view[_id].m_mode)
 		{
-		case ViewMode::Sequential:      m_key.m_seq   = s_ctx->getSeqIncr(_id); type = SortKey::SortSequence; break;
-		case ViewMode::DepthAscending:  m_key.m_depth =            _depth;      type = SortKey::SortDepth;    break;
-		case ViewMode::DepthDescending: m_key.m_depth = UINT32_MAX-_depth;      type = SortKey::SortDepth;    break;
-		default:                        m_key.m_depth =            _depth;      type = SortKey::SortProgram;  break;
+		case ViewMode::Sequential:      m_key.m_seq   =     renderItemIdx; type = SortKey::SortSequence; break;
+		case ViewMode::DepthAscending:  m_key.m_depth =            _depth; type = SortKey::SortDepth;    break;
+		case ViewMode::DepthDescending: m_key.m_depth = UINT32_MAX-_depth; type = SortKey::SortDepth;    break;
+		default:                        m_key.m_depth =            _depth; type = SortKey::SortProgram;  break;
 		}
 
 		uint64_t key = m_key.encodeDraw(type);
 
-		m_frame->m_sortKeys[renderItemIdx]   = key;
+		m_frame->m_sortKeys  [renderItemIdx] = key;
 		m_frame->m_sortValues[renderItemIdx] = RenderItemCount(renderItemIdx);
 
 		m_draw.m_uniformIdx   = m_uniformIdx;
@@ -1675,7 +1675,7 @@ namespace bgfx
 		m_key.m_program = _handle;
 		m_key.m_depth   = 0;
 		m_key.m_view    = _id;
-		m_key.m_seq     = s_ctx->getSeqIncr(_id);
+		m_key.m_seq     = renderItemIdx;
 
 		uint64_t key = m_key.encodeCompute();
 		m_frame->m_sortKeys[renderItemIdx]   = key;
@@ -2948,8 +2948,6 @@ namespace bgfx
 		uint32_t nextFrameNum = m_render->m_frameNum + 1;
 		m_submit->start(nextFrameNum);
 
-		bx::memSet(m_seq, 0, sizeof(m_seq) );
-
 		if (BX_ENABLED(BGFX_CONFIG_DEBUG_TEXT) )
 		{
 			m_submit->m_textVideoMem->resize(
diff --git a/src/bgfx_p.h b/src/bgfx_p.h
index d8e2318a6..d71aeb28d 100644
--- a/src/bgfx_p.h
+++ b/src/bgfx_p.h
@@ -1391,6 +1391,7 @@ namespace bgfx
 	static constexpr uint64_t kSortKeyComputeProgramMask  = uint64_t(BGFX_CONFIG_MAX_PROGRAMS-1)<<kSortKeyComputeProgramShift;
 
 	static_assert(BGFX_CONFIG_MAX_VIEWS <= (1<<kSortKeyViewNumBits) );
+	static_assert(BGFX_CONFIG_MAX_DRAW_CALLS <= (1<<BGFX_CONFIG_SORT_KEY_NUM_BITS_SEQ), "BGFX_CONFIG_MAX_DRAW_CALLS must fit into BGFX_CONFIG_SORT_KEY_NUM_BITS_SEQ bits.");
 	static_assert( (BGFX_CONFIG_MAX_PROGRAMS & (BGFX_CONFIG_MAX_PROGRAMS-1) ) == 0); // Must be power of 2.
 	static_assert( (0 // Render key mask shouldn't overlap.
 		| kSortKeyViewMask
@@ -7801,11 +7802,6 @@ namespace bgfx
 
 		BGFX_API_FUNC(uint32_t frame(uint8_t _flags = BGFX_FRAME_NONE) );
 
-		uint32_t getSeqIncr(ViewId _id)
-		{
-			return bx::atomicFetchAndAdd<uint32_t>(&m_seq[_id], 1);
-		}
-
 		void dumpViewStats();
 		void freeDynamicBuffers();
 		void freeAllHandles(Frame* _frame);
@@ -8002,7 +7998,6 @@ namespace bgfx
 		VertexLayoutRef m_vertexLayoutRef;
 
 		ViewId m_viewRemap[BGFX_CONFIG_MAX_VIEWS];
-		uint32_t m_seq[BGFX_CONFIG_MAX_VIEWS];
 		View m_view[BGFX_CONFIG_MAX_VIEWS];
 
 		UniformCache m_uniformCache;
diff --git a/src/config.h b/src/config.h
index 796afd414..82b76313f 100644
--- a/src/config.h
+++ b/src/config.h
@@ -370,7 +370,7 @@
 #endif // BGFX_CONFIG_SORT_KEY_NUM_BITS_DEPTH
 
 /// Number of bits used for sequence number in the sort key. Default is 20.
-/// Determines maximum draw calls per view in sequential mode (2^20 = ~1M).
+/// Determines maximum BGFX_CONFIG_MAX_DRAW_CALLS (2^20 = ~1M).
 #ifndef BGFX_CONFIG_SORT_KEY_NUM_BITS_SEQ
 #	define BGFX_CONFIG_SORT_KEY_NUM_BITS_SEQ 20
 #endif // BGFX_CONFIG_SORT_KEY_NUM_BITS_SEQ