Add OpenGL ES Compatibility Layer

CMakeLists.txt

@@ -125,10 +125,25 @@ OPTION(FSO_BUILD_WITH_DISCORD "Build with Discord support" ON)
 
 OPTION(FSO_BUILD_WITH_OPENGL "Enable compilation of the OpenGL renderer" ON)
 OPTION(FSO_BUILD_WITH_OPENGL_DEBUG "Enables debug option for OpenGL" OFF)
+OPTION(FSO_BUILD_WITH_OPENGL_ES "When building OpenGL, use OpenGL ES compatibility layer (External shaders only!)" OFF)
 
 OPTION(FSO_BUILD_WITH_VULKAN "Enable compilation of the Vulkan renderer" OFF)
 
-IF(NOT APPLE)
+if(NOT FSO_BUILD_WITH_OPENGL AND FSO_BUILD_WITH_OPENGL_ES)
+	# Disable GLES if not building with OpenGL
+	set(FSO_BUILD_WITH_OPENGL_ES OFF FORCE)
+endif()
+
+
+if(FSO_BUILD_WITH_OPENGL_ES)
+	add_definitions(-DUSE_OPENGL_ES)
+	IF(FSO_BUILD_WITH_OPENXR)
+		MESSAGE(WARNING "FSO_BUILD_WITH_OPENXR is ON. But not supported on OpenGL ES for now - setting to OFF.")
+		SET(FSO_BUILD_WITH_OPENXR OFF CACHE BOOL "" FORCE)
+	endif()
+endif()
+
+IF(NOT APPLE AND NOT FSO_BUILD_WITH_OPENGL_ES)
 	SET(OPENXR_BUILD_DEFAULT ON)
 ELSE()
 	SET(OPENXR_BUILD_DEFAULT OFF)
@@ -156,6 +171,7 @@ mark_as_advanced(FORCE FSO_BUILD_WITH_FFMPEG)
 mark_as_advanced(FORCE FSO_BUILD_WITH_DISCORD)
 mark_as_advanced(FORCE FSO_BUILD_WITH_OPENGL)
 mark_as_advanced(FORCE FSO_BUILD_WITH_OPENGL_DEBUG)
+mark_as_advanced(FORCE FSO_BUILD_WITH_OPENGL_ES)
 mark_as_advanced(FORCE FSO_BUILD_WITH_VULKAN)
 mark_as_advanced(FORCE FSO_BUILD_WITH_OPENXR)
 mark_as_advanced(FORCE FSO_BUILD_WITH_OPENXR_DEBUG)
@@ -242,5 +258,6 @@ message(STATUS "Release logging: ${FSO_RELEASE_LOGGING}")
 message(STATUS "With FFmpeg: ${FSO_BUILD_WITH_FFMPEG}")
 message(STATUS "With Discord: ${FSO_BUILD_WITH_DISCORD}")
 message(STATUS "With OpenGL: ${FSO_BUILD_WITH_OPENGL}")
+message(STATUS "With OpenGL ES: ${FSO_BUILD_WITH_OPENGL_ES}")
 message(STATUS "With Vulkan: ${FSO_BUILD_WITH_VULKAN}")
 message(STATUS "With OpenXR: ${FSO_BUILD_WITH_OPENXR}")

code/cfile/cfile.cpp

@@ -68,7 +68,7 @@ cf_pathtype Pathtypes[CF_MAX_PATH_TYPES]  = {
 	{ CF_TYPE_MOVIES,				"data" DIR_SEPARATOR_STR "movies",											".mve .msb .ogg .mp4 .srt .webm .png",CF_TYPE_DATA	},
 	{ CF_TYPE_INTERFACE,			"data" DIR_SEPARATOR_STR "interface",										".pcx .ani .dds .tga .eff .png .jpg .rml .rcss",	CF_TYPE_DATA	},
 	{ CF_TYPE_FONT,					"data" DIR_SEPARATOR_STR "fonts",											".vf .ttf .otf",						CF_TYPE_DATA	},
-	{ CF_TYPE_EFFECTS,				"data" DIR_SEPARATOR_STR "effects",											".ani .eff .pcx .neb .tga .jpg .png .dds .sdr",	CF_TYPE_DATA	},
+	{ CF_TYPE_EFFECTS,				"data" DIR_SEPARATOR_STR "effects",											".ani .eff .pcx .neb .tga .jpg .png .dds .sdr .vert .frag .glsl",	CF_TYPE_DATA	},
 	{ CF_TYPE_HUD,					"data" DIR_SEPARATOR_STR "hud",												".pcx .ani .eff .tga .jpg .png .dds",	CF_TYPE_DATA	},
 	{ CF_TYPE_PLAYERS,				"data" DIR_SEPARATOR_STR "players",											".hcf", /* DON'T add pilot files here!! */	CF_TYPE_DATA	},
 	{ CF_TYPE_PLAYER_IMAGES,		"data" DIR_SEPARATOR_STR "players" DIR_SEPARATOR_STR "images",				".pcx .png .dds",						CF_TYPE_PLAYERS	},
@@ -186,6 +186,7 @@ int cfile_init(const char *exe_dir, const char *cdrom_dir)
 	char buf[CFILE_ROOT_DIRECTORY_LEN];
 
 	strncpy(buf, exe_dir, CFILE_ROOT_DIRECTORY_LEN - 1);
+
 	buf[CFILE_ROOT_DIRECTORY_LEN - 1] = '\0';
 
 	// are we in a root directory?		

code/ddsutils/ddsutils.cpp

@@ -2,6 +2,9 @@
 #include "ddsutils/ddsutils.h"
 #include "cfile/cfile.h"
 #include "osapi/osregistry.h"
+#ifdef USE_OPENGL_ES
+#include "graphics/opengl/es_compatibility.h"
+#endif
 
 #ifdef WITH_OPENGL
 #include <glad/glad.h>

code/globalincs/version.cpp

@@ -203,6 +203,9 @@ SCP_string get_version_string()
 	switch (gr_screen.mode) {
 	case GR_OPENGL:
 		str += " OpenGL";
+		#ifdef USE_OPENGL_ES
+		str += " ES";
+		#endif
 		break;
 	case GR_VULKAN:
 		str += " Vulkan";

code/graphics/2d.cpp

@@ -526,7 +526,11 @@ void removeResolutionVROption()
 	options::OptionsManager::instance()->removeOption(ResolutionVROption);
 }
 
+#ifndef USE_OPENGL_ES
 bool Gr_enable_soft_particles = true;
+#else
+bool Gr_enable_soft_particles = false;
+#endif
 
 static void parse_soft_particle_func() {
 	bool value;
@@ -697,7 +701,11 @@ static void parse_post_processing_func()
 	Gr_post_processing_enabled = value;
 }
 
+#ifndef USE_OPENGL_ES
 bool Gr_post_processing_enabled = true;
+#else
+bool Gr_post_processing_enabled = false;
+#endif
 
 static auto PostProcessOption __UNUSED = options::OptionBuilder<bool>("Graphics.PostProcessing",
                      std::pair<const char*, int>{"Post processing", 1726},