Add anisotropic filtering to GLES2 backend

Move definition of rendering/quality/filters/anisotropic_filter_level to
servers/visual_server.cpp, since both GLES2 and GLES3 now use it

rasterizer_storage_gles3.cpp: Remove a spurious variable write (the
value gets overwritten soon after)

drivers/gles2/rasterizer_storage_gles2.cpp

@@ -79,6 +79,9 @@ GLuint RasterizerStorageGLES2::system_fbo = 0;
 
 #define _EXT_TEXTURE_CUBE_MAP_SEAMLESS 0x884F
 
+#define _GL_TEXTURE_MAX_ANISOTROPY_EXT 0x84FE
+#define _GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT 0x84FF
+
 #define _RED_OES 0x1903
 
 #define _DEPTH_COMPONENT24_OES 0x81A6
@@ -749,6 +752,16 @@ void RasterizerStorageGLES2::texture_set_data(RID p_texture, const Ref<Image> &p
 		glTexParameterf(texture->target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 	}
 
+	if (config.use_anisotropic_filter) {
+
+		if (texture->flags & VS::TEXTURE_FLAG_ANISOTROPIC_FILTER) {
+
+			glTexParameterf(texture->target, _GL_TEXTURE_MAX_ANISOTROPY_EXT, config.anisotropic_level);
+		} else {
+			glTexParameterf(texture->target, _GL_TEXTURE_MAX_ANISOTROPY_EXT, 1);
+		}
+	}
+
 	int mipmaps = ((texture->flags & VS::TEXTURE_FLAG_MIPMAPS) && img->has_mipmaps()) ? img->get_mipmap_count() + 1 : 1;
 
 	int w = img->get_width();
@@ -957,6 +970,16 @@ void RasterizerStorageGLES2::texture_set_flags(RID p_texture, uint32_t p_flags)
 		glTexParameterf(texture->target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 	}
 
+	if (config.use_anisotropic_filter) {
+
+		if (texture->flags & VS::TEXTURE_FLAG_ANISOTROPIC_FILTER) {
+
+			glTexParameterf(texture->target, _GL_TEXTURE_MAX_ANISOTROPY_EXT, config.anisotropic_level);
+		} else {
+			glTexParameterf(texture->target, _GL_TEXTURE_MAX_ANISOTROPY_EXT, 1);
+		}
+	}
+
 	if ((texture->flags & VS::TEXTURE_FLAG_MIPMAPS) && !texture->ignore_mipmaps) {
 		if (!had_mipmaps && texture->mipmaps == 1) {
 			glGenerateMipmap(texture->target);
@@ -6069,6 +6092,13 @@ void RasterizerStorageGLES2::initialize() {
 	config.rgtc_supported = config.extensions.has("GL_EXT_texture_compression_rgtc") || config.extensions.has("GL_ARB_texture_compression_rgtc") || config.extensions.has("EXT_texture_compression_rgtc");
 	config.bptc_supported = config.extensions.has("GL_ARB_texture_compression_bptc") || config.extensions.has("EXT_texture_compression_bptc");
 
+	config.anisotropic_level = 1.0;
+	config.use_anisotropic_filter = config.extensions.has("GL_EXT_texture_filter_anisotropic");
+	if (config.use_anisotropic_filter) {
+		glGetFloatv(_GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &config.anisotropic_level);
+		config.anisotropic_level = MIN(int(ProjectSettings::get_singleton()->get("rendering/quality/filters/anisotropic_filter_level")), config.anisotropic_level);
+	}
+
 	//determine formats for depth textures (or renderbuffers)
 	if (config.support_depth_texture) {
 		// Will use texture for depth

drivers/gles2/rasterizer_storage_gles2.h

@@ -56,6 +56,7 @@ public:
 
 		bool shrink_textures_x2;
 		bool use_fast_texture_filter;
+		bool use_anisotropic_filter;
 		bool use_skeleton_software;
 		bool use_lightmap_filter_bicubic;
 
@@ -82,6 +83,8 @@ public:
 		bool use_rgba_2d_shadows;
 		bool use_rgba_3d_shadows;
 
+		float anisotropic_level;
+
 		bool support_32_bits_indices;
 		bool support_write_depth;
 		bool support_half_float_vertices;

drivers/gles3/rasterizer_gles3.cpp

@@ -408,9 +408,6 @@ void RasterizerGLES3::make_current() {
 }
 
 void RasterizerGLES3::register_config() {
-
-	GLOBAL_DEF("rendering/quality/filters/anisotropic_filter_level", 4);
-	ProjectSettings::get_singleton()->set_custom_property_info("rendering/quality/filters/anisotropic_filter_level", PropertyInfo(Variant::INT, "rendering/quality/filters/anisotropic_filter_level", PROPERTY_HINT_RANGE, "1,16,1"));
 }
 
 // returns NULL if no error, or an error string

drivers/gles3/rasterizer_storage_gles3.cpp

@@ -8355,7 +8355,6 @@ void RasterizerStorageGLES3::initialize() {
 
 	config.shrink_textures_x2 = false;
 	config.use_fast_texture_filter = int(ProjectSettings::get_singleton()->get("rendering/quality/filters/use_nearest_mipmap_filter"));
-	config.use_anisotropic_filter = config.extensions.has("rendering/quality/filters/anisotropic_filter_level");
 
 	config.etc_supported = config.extensions.has("GL_OES_compressed_ETC1_RGB8_texture");
 	config.latc_supported = config.extensions.has("GL_EXT_texture_compression_latc");

servers/visual_server.cpp

@@ -2437,6 +2437,8 @@ VisualServer::VisualServer() {
 	GLOBAL_DEF("rendering/quality/depth_prepass/enable", true);
 	GLOBAL_DEF("rendering/quality/depth_prepass/disable_for_vendors", "PowerVR,Mali,Adreno,Apple");
 
+	GLOBAL_DEF("rendering/quality/filters/anisotropic_filter_level", 4);
+	ProjectSettings::get_singleton()->set_custom_property_info("rendering/quality/filters/anisotropic_filter_level", PropertyInfo(Variant::INT, "rendering/quality/filters/anisotropic_filter_level", PROPERTY_HINT_RANGE, "1,16,1"));
 	GLOBAL_DEF("rendering/quality/filters/use_nearest_mipmap_filter", false);
 
 	GLOBAL_DEF("rendering/quality/skinning/software_skinning_fallback", true);