From ef73539985679bedfe35400ddbc4c74530002224 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Branimir=20Karad=C5=BEi=C4=87?= <branimirkaradzic@gmail.com>
Date: Fri, 17 Jul 2026 13:44:37 -0700
Subject: [PATCH] GL: Added support for external texture. (#3839)

---
 src/renderer_gl.cpp | 27 +++++++++++++++++++++++----
 src/renderer_gl.h   |  4 ++--
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/src/renderer_gl.cpp b/src/renderer_gl.cpp
index 4c87646fd..81099d10a 100644
--- a/src/renderer_gl.cpp
+++ b/src/renderer_gl.cpp
@@ -2951,6 +2951,8 @@ namespace bgfx { namespace gl
 					: 0
 					;
 
+				g_caps.supported |= BGFX_CAPS_TEXTURE_EXTERNAL;
+
 				g_caps.supported |= false
 					|| s_extension[Extension::EXT_texture_array].m_supported
 					|| s_extension[Extension::EXT_gpu_shader4].m_supported
@@ -3452,8 +3454,7 @@ namespace bgfx { namespace gl
 
 		void* createTexture(TextureHandle _handle, const Memory* _mem, uint64_t _flags, uint8_t _skip, uint64_t _external) override
 		{
-			BX_UNUSED(_external);
-			m_textures[_handle.idx].create(_mem, _flags, _skip);
+			m_textures[_handle.idx].create(_mem, _flags, _skip, _external);
 			return NULL;
 		}
 
@@ -5688,7 +5689,7 @@ namespace bgfx { namespace gl
 		GL_CHECK(glDeleteBuffers(1, &m_id) );
 	}
 
-	bool TextureGL::init(GLenum _target, uint32_t _width, uint32_t _height, uint32_t _depth, uint8_t _numMips, uint64_t _flags)
+	bool TextureGL::init(GLenum _target, uint32_t _width, uint32_t _height, uint32_t _depth, uint8_t _numMips, uint64_t _flags, uint64_t _external)
 	{
 		m_target  = _target;
 		m_numMips = _numMips;
@@ -5707,6 +5708,18 @@ namespace bgfx { namespace gl
 			|| _target == GL_TEXTURE_CUBE_MAP_ARRAY
 			;
 
+		if (0 != _external)
+		{
+			m_id     = (GLuint)_external;
+			m_flags |= BGFX_SAMPLER_INTERNAL_SHARED;
+
+			const TextureFormatInfo& tfi = s_textureFormat[m_textureFormat];
+			m_fmt  = srgb ? tfi.m_fmtSrgb : tfi.m_fmt;
+			m_type = tfi.m_type;
+
+			return true;
+		}
+
 		if (!writeOnly
 		|| (renderTarget && textureArray) )
 		{
@@ -5876,7 +5889,7 @@ namespace bgfx { namespace gl
 		}
 	}
 
-	void TextureGL::create(const Memory* _mem, uint64_t _flags, uint8_t _skip)
+	void TextureGL::create(const Memory* _mem, uint64_t _flags, uint8_t _skip, uint64_t _external)
 	{
 		bimg::ImageContainer imageContainer;
 
@@ -5934,6 +5947,7 @@ namespace bgfx { namespace gl
 				, textureArray ? ti.numLayers : ti.depth
 				, ti.numMips
 				, _flags
+				, _external
 				) )
 			{
 				return;
@@ -5941,6 +5955,11 @@ namespace bgfx { namespace gl
 
 			m_numLayers = ti.numLayers;
 
+			if (0 != _external)
+			{
+				return;
+			}
+
 			target = isCubeMap()
 				? GL_TEXTURE_CUBE_MAP_POSITIVE_X
 				: m_target
diff --git a/src/renderer_gl.h b/src/renderer_gl.h
index a86d0a5ab..bd5e0f9d9 100644
--- a/src/renderer_gl.h
+++ b/src/renderer_gl.h
@@ -1428,8 +1428,8 @@ namespace bgfx { namespace gl
 		{
 		}
 
-		bool init(GLenum _target, uint32_t _width, uint32_t _height, uint32_t _depth, uint8_t _numMips, uint64_t _flags);
-		void create(const Memory* _mem, uint64_t _flags, uint8_t _skip);
+		bool init(GLenum _target, uint32_t _width, uint32_t _height, uint32_t _depth, uint8_t _numMips, uint64_t _flags, uint64_t _external = 0);
+		void create(const Memory* _mem, uint64_t _flags, uint8_t _skip, uint64_t _external = 0);
 		void destroy();
 		void overrideInternal(uintptr_t _ptr);
 		void update(uint8_t _side, uint8_t _mip, const Rect& _rect, uint16_t _z, uint16_t _depth, uint16_t _pitch, const Memory* _mem);