From c0d76c69cc6f3abbc2be44c79f387bab114a0875 Mon Sep 17 00:00:00 2001
From: Nathan Gass <gass@search.ch>
Date: Thu, 19 Aug 2021 20:57:56 +0200
Subject: [PATCH] Egl option (#135)

* minimal changes to get platform linux to compile again

* adapt mbgl-glfw api for keyss to mbgl-offline and mbgl-render, use maptiler configuration for all three binaries

* add an option to compile with the egl backend on linux
---
 CMakeLists.txt               |  1 +
 platform/glfw/CMakeLists.txt |  7 +++++++
 platform/linux/linux.cmake   | 29 ++++++++++++++++++++++++++---
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d2708d82..b60baf530 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,7 @@ option(MBGL_WITH_QT "Build Mapbox GL Qt bindings" OFF)
 option(MBGL_WITH_SANITIZER "Use [address|thread|undefined] here" OFF)
 option(MBGL_WITH_RTTI "Compile with runtime type information" OFF)
 option(MBGL_WITH_OPENGL "Build with OpenGL renderer" ON)
+option(MBGL_WITH_EGL "Build with EGL renderer" OFF)
 option(MBGL_WITH_WERROR "Make all compilation warnings errors" ON)
 
 add_library(
diff --git a/platform/glfw/CMakeLists.txt b/platform/glfw/CMakeLists.txt
index 986d3b013..d2eeac925 100644
--- a/platform/glfw/CMakeLists.txt
+++ b/platform/glfw/CMakeLists.txt
@@ -29,6 +29,13 @@ if(MBGL_WITH_OPENGL)
     )
 endif()
 
+if(MBGL_WITH_EGL)
+    target_compile_definitions(
+        mbgl-glfw
+        PRIVATE MBGL_WITH_EGL=1
+    )
+endif()
+
 target_include_directories(
     mbgl-glfw
     PRIVATE
diff --git a/platform/linux/linux.cmake b/platform/linux/linux.cmake
index e78274270..ca34943ba 100644
--- a/platform/linux/linux.cmake
+++ b/platform/linux/linux.cmake
@@ -2,7 +2,6 @@ find_package(CURL REQUIRED)
 find_package(ICU OPTIONAL_COMPONENTS i18n)
 find_package(ICU OPTIONAL_COMPONENTS uc)
 find_package(JPEG REQUIRED)
-find_package(OpenGL REQUIRED GLX)
 find_package(PNG REQUIRED)
 find_package(PkgConfig REQUIRED)
 find_package(X11 REQUIRED)
@@ -50,9 +49,34 @@ target_sources(
         ${PROJECT_SOURCE_DIR}/platform/default/src/mbgl/util/timer.cpp
         ${PROJECT_SOURCE_DIR}/platform/default/src/mbgl/util/utf.cpp
         ${PROJECT_SOURCE_DIR}/platform/linux/src/gl_functions.cpp
-        ${PROJECT_SOURCE_DIR}/platform/linux/src/headless_backend_glx.cpp
 )
 
+if(MBGL_WITH_EGL)
+    find_package(OpenGL REQUIRED EGL)
+    target_sources(
+        mbgl-core
+        PRIVATE
+            ${PROJECT_SOURCE_DIR}/platform/linux/src/headless_backend_egl.cpp
+    )
+    target_link_libraries(
+        mbgl-core
+        PRIVATE
+            OpenGL::EGL
+    )
+else()
+    find_package(OpenGL REQUIRED GLX)
+    target_sources(
+        mbgl-core
+        PRIVATE
+            ${PROJECT_SOURCE_DIR}/platform/linux/src/headless_backend_glx.cpp
+    )
+    target_link_libraries(
+        mbgl-core
+        PRIVATE
+            OpenGL::GLX
+    )
+endif()
+
 # FIXME: Should not be needed, but now needed by node because of the headless frontend.
 target_include_directories(
     mbgl-core
@@ -91,7 +115,6 @@ target_link_libraries(
         $<$<NOT:$<BOOL:${MBGL_USE_BUILTIN_ICU}>>:ICU::i18n>
         $<$<NOT:$<BOOL:${MBGL_USE_BUILTIN_ICU}>>:ICU::uc>
         $<$<BOOL:${MBGL_USE_BUILTIN_ICU}>:mbgl-vendor-icu>
-        OpenGL::GLX
         PNG::PNG
         mbgl-vendor-nunicode
         mbgl-vendor-sqlite