Add optional ANGLE support for Windows destop.

Originally From https://github.com/EIRTeam/godot.git
Some precision fixes by iFire at https://github.com/V-Sekai/godot.git

Put the self-compiled angle folder in thirdparty. The release folder should be `thirdparty/angle/out/Release`.

drivers/gl_context/SCsub

@@ -2,7 +2,12 @@
 
 Import("env")
 
-if env["platform"] in ["haiku", "osx", "windows", "x11"]:
+if env["platform"] in ["windows"] and env["use_angle"]:
+    # ANGLE on windows desktop
+    thirdparty_dir = "#thirdparty/angle/include"
+    env.Prepend(CPPPATH=[thirdparty_dir])
+    env.Append(LIBPATH=["#thirdparty/angle/out/Release"])
+elif env["platform"] in ["windows", "haiku", "osx", "x11"]:
     # Thirdparty source files
     thirdparty_dir = "#thirdparty/glad/"
     thirdparty_sources = [

drivers/gles2/rasterizer_storage_gles2.cpp

@@ -88,7 +88,10 @@ GLuint RasterizerStorageGLES2::system_fbo = 0;
 
 // enable extensions manually for android and ios
 #ifndef UWP_ENABLED
+#ifndef WINDOWS_ENABLED
 #include <dlfcn.h> // needed to load extensions
+
+#endif // !WINDOWS_ENABLED
 #endif
 
 #ifdef IPHONE_ENABLED

drivers/gles3/shaders/blend_shape.glsl

@@ -103,7 +103,7 @@ out vec2 uv2_out; //tfb:ENABLE_UV2
 #endif
 
 #ifdef ENABLE_SKELETON
-out ivec4 bone_out; //tfb:ENABLE_SKELETON
+flat out ivec4 bone_out; //tfb:ENABLE_SKELETON
 out vec4 weight_out; //tfb:ENABLE_SKELETON
 #endif
 

drivers/gles3/shaders/scene.glsl

@@ -114,7 +114,7 @@ uniform highp mat4 world_transform;
 layout(std140) uniform DirectionalLightData { //ubo:3
 
 	highp vec4 light_pos_inv_radius;
-	mediump vec4 light_direction_attenuation;
+	highp vec4 light_direction_attenuation;
 	mediump vec4 light_color_energy;
 	mediump vec4 light_params; // cone attenuation, angle, specular, shadow enabled,
 	mediump vec4 light_clamp;
@@ -134,7 +134,7 @@ layout(std140) uniform DirectionalLightData { //ubo:3
 struct LightData {
 
 	highp vec4 light_pos_inv_radius;
-	mediump vec4 light_direction_attenuation;
+	highp vec4 light_direction_attenuation;
 	mediump vec4 light_color_energy;
 	mediump vec4 light_params; // cone attenuation, angle, specular, shadow enabled,
 	mediump vec4 light_clamp;
@@ -752,7 +752,7 @@ layout(std140) uniform SceneData {
 layout(std140) uniform DirectionalLightData {
 
 	highp vec4 light_pos_inv_radius;
-	mediump vec4 light_direction_attenuation;
+	highp vec4 light_direction_attenuation;
 	mediump vec4 light_color_energy;
 	mediump vec4 light_params; // cone attenuation, angle, specular, shadow enabled,
 	mediump vec4 light_clamp;
@@ -777,7 +777,7 @@ in vec4 specular_light_interp;
 struct LightData {
 
 	highp vec4 light_pos_inv_radius;
-	mediump vec4 light_direction_attenuation;
+	highp vec4 light_direction_attenuation;
 	mediump vec4 light_color_energy;
 	mediump vec4 light_params; // cone attenuation, angle, specular, shadow enabled,
 	mediump vec4 light_clamp;

gles_builders.py

@@ -158,8 +158,9 @@ def include_file_in_legacygl_header(filename, header_data, depth):
                     bind = bind.replace("attrib:", "").strip()
                     header_data.attributes += [(name, bind)]
 
-        if line.strip().find("out ") == 0 and line.find("tfb:") != -1:
+        if (line.strip().find("out ") == 0 or line.strip().find("flat out ") == 0) and line.find("tfb:") != -1:
             uline = line.replace("out ", "")
+            uline = uline.replace("flat ", "")
             uline = uline.replace("highp ", "")
             uline = uline.replace(";", "")
             uline = uline[uline.find(" ") :].strip()

platform/windows/SCsub

@@ -8,7 +8,6 @@ import platform_windows_builders
 
 common_win = [
     "godot_windows.cpp",
-    "context_gl_windows.cpp",
     "crash_handler_windows.cpp",
     "os_windows.cpp",
     "key_mapping_windows.cpp",
@@ -17,6 +16,11 @@ common_win = [
     "windows_terminal_logger.cpp",
 ]
 
+if env["use_angle"]:
+    common_win.append("context_gl_windows_angle.cpp")
+else:
+    common_win.append("context_gl_windows.cpp")
+
 res_file = "godot_res.rc"
 res_target = "godot_res" + env["OBJSUFFIX"]
 res_obj = env.RES(res_target, res_file)