Clean up texture filtering settings (#13683)

builtin/settingtypes.txt

@@ -371,35 +371,21 @@ enable_3d_clouds (3D clouds) bool true
 
 [**Filtering and Antialiasing]
 
-#    Use mipmapping to scale textures. May slightly increase performance,
+#    Use mipmaps when scaling textures down. May slightly increase performance,
 #    especially when using a high resolution texture pack.
-#    Gamma correct downscaling is not supported.
+#    Gamma-correct downscaling is not supported.
 mip_map (Mipmapping) bool false
 
-#    Use anisotropic filtering when viewing at textures from an angle.
-anisotropic_filter (Anisotropic filtering) bool false
-
-#    Use bilinear filtering when scaling textures.
+#    Use bilinear filtering when scaling textures down.
 bilinear_filter (Bilinear filtering) bool false
 
-#    Use trilinear filtering when scaling textures.
+#    Use trilinear filtering when scaling textures down.
+#    If both bilinear and trilinear filtering are enabled, trilinear filtering
+#    is applied.
 trilinear_filter (Trilinear filtering) bool false
 
-#    Filtered textures can blend RGB values with fully-transparent neighbors,
-#    which PNG optimizers usually discard, often resulting in dark or
-#    light edges to transparent textures. Apply a filter to clean that up
-#    at texture load time. This is automatically enabled if mipmapping is enabled.
-texture_clean_transparent (Clean transparent textures) bool false
-
-#    When using bilinear/trilinear/anisotropic filters, low-resolution textures
-#    can be blurred, so automatically upscale them with nearest-neighbor
-#    interpolation to preserve crisp pixels. This sets the minimum texture size
-#    for the upscaled textures; higher values look sharper, but require more
-#    memory. Powers of 2 are recommended. This setting is ONLY applied if
-#    bilinear/trilinear/anisotropic filtering is enabled.
-#    This is also used as the base node texture size for world-aligned
-#    texture autoscaling.
-texture_min_size (Minimum texture size) int 64 1 32768
+#    Use anisotropic filtering when looking at textures from an angle.
+anisotropic_filter (Anisotropic filtering) bool false
 
 #    Select the antialiasing method to apply.
 #
@@ -1831,6 +1817,9 @@ world_aligned_mode (World-aligned textures mode) enum enable disable,enable,forc
 #    Warning: This option is EXPERIMENTAL!
 autoscale_mode (Autoscaling mode) enum disable disable,enable,force
 
+#    The base node texture size used for world-aligned texture autoscaling.
+texture_min_size (Base texture size) int 64 1 32768
+
 #    Side length of a cube of map blocks that the client will consider together
 #    when generating meshes.
 #    Larger values increase the utilization of the GPU by reducing the number of

src/client/clientmap.cpp

@@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "clientmap.h"
 #include "client.h"
+#include "client/mesh.h"
 #include "mapblock_mesh.h"
 #include <IMaterialRenderer.h>
 #include <matrix4.h>
@@ -843,7 +844,7 @@ void ClientMap::renderMap(video::IVideoDriver* driver, s32 pass)
 
 			// Apply filter settings
 			material.forEachTexture([this] (auto &tex) {
-				tex.setFiltersMinetest(m_cache_bilinear_filter, m_cache_trilinear_filter,
+				setMaterialFilters(tex, m_cache_bilinear_filter, m_cache_trilinear_filter,
 						m_cache_anistropic_filter);
 			});
 			material.Wireframe = m_control.show_wireframe;

src/client/content_cao.cpp

@@ -1355,7 +1355,7 @@ void GenericCAO::updateTextures(std::string mod)
 			}
 
 			material.forEachTexture([=] (auto &tex) {
-				tex.setFiltersMinetest(use_bilinear_filter, use_trilinear_filter,
+				setMaterialFilters(tex, use_bilinear_filter, use_trilinear_filter,
 						use_anisotropic_filter);
 			});
 		}
@@ -1383,15 +1383,8 @@ void GenericCAO::updateTextures(std::string mod)
 				material.Lighting = true;
 				material.BackfaceCulling = m_prop.backface_culling;
 
-				// don't filter low-res textures, makes them look blurry
-				// player models have a res of 64
-				const core::dimension2d<u32> &size = texture->getOriginalSize();
-				const u32 res = std::min(size.Height, size.Width);
-				use_trilinear_filter &= res > 64;
-				use_bilinear_filter &= res > 64;
-
 				material.forEachTexture([=] (auto &tex) {
-					tex.setFiltersMinetest(use_bilinear_filter, use_trilinear_filter,
+					setMaterialFilters(tex, use_bilinear_filter, use_trilinear_filter,
 							use_anisotropic_filter);
 				});
 			}
@@ -1438,7 +1431,7 @@ void GenericCAO::updateTextures(std::string mod)
 				}
 
 				material.forEachTexture([=] (auto &tex) {
-					tex.setFiltersMinetest(use_bilinear_filter, use_trilinear_filter,
+					setMaterialFilters(tex, use_bilinear_filter, use_trilinear_filter,
 							use_anisotropic_filter);
 				});
 			}
@@ -1463,7 +1456,7 @@ void GenericCAO::updateTextures(std::string mod)
 				}
 
 				material.forEachTexture([=] (auto &tex) {
-					tex.setFiltersMinetest(use_bilinear_filter, use_trilinear_filter,
+					setMaterialFilters(tex, use_bilinear_filter, use_trilinear_filter,
 							use_anisotropic_filter);
 				});
 			}
@@ -1492,7 +1485,7 @@ void GenericCAO::updateTextures(std::string mod)
 				}
 
 				material.forEachTexture([=] (auto &tex) {
-					tex.setFiltersMinetest(use_bilinear_filter, use_trilinear_filter,
+					setMaterialFilters(tex, use_bilinear_filter, use_trilinear_filter,
 							use_anisotropic_filter);
 				});
 			}

src/client/mesh.cpp

@@ -503,3 +503,18 @@ scene::IMesh* convertNodeboxesToMesh(const std::vector<aabb3f> &boxes,
 	}
 	return dst_mesh;
 }
+
+void setMaterialFilters(video::SMaterialLayer &tex, bool bilinear, bool trilinear, bool anisotropic) {
+	if (trilinear)
+		tex.MinFilter = video::ETMINF_LINEAR_MIPMAP_LINEAR;
+	else if (bilinear)
+		tex.MinFilter = video::ETMINF_LINEAR_MIPMAP_NEAREST;
+	else
+		tex.MinFilter = video::ETMINF_NEAREST_MIPMAP_NEAREST;
+
+	// "We don't want blurriness after all." ~ Desour, #13108
+	// (because of pixel art)
+	tex.MagFilter = video::ETMAGF_NEAREST;
+
+	tex.AnisotropicFilter = anisotropic ? 0xFF : 0;
+}

src/client/mesh.h

@@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #pragma once
 
+#include "SMaterialLayer.h"
 #include "irrlichttypes_extrabloated.h"
 #include "nodedef.h"
 
@@ -133,3 +134,10 @@ void recalculateBoundingBox(scene::IMesh *src_mesh);
 	We assume normal to be valid when it's 0 < length < Inf. and not NaN
  */
 bool checkMeshNormals(scene::IMesh *mesh);
+
+/*
+	Set the MinFilter, MagFilter and AnisotropicFilter properties of a texture
+	layer according to the three relevant boolean values found in the Minetest
+	settings.
+*/ 
+void setMaterialFilters(video::SMaterialLayer &tex, bool bilinear, bool trilinear, bool anisotropic);

src/client/tile.cpp

@@ -433,10 +433,8 @@ private:
 	// Maps image file names to loaded palettes.
 	std::unordered_map<std::string, Palette> m_palettes;
 
-	// Cached settings needed for making textures from meshes
-	bool m_setting_mipmap;
-	bool m_setting_trilinear_filter;
-	bool m_setting_bilinear_filter;
+	// Cached settings needed for making textures for meshes
+	bool m_mesh_texture_prefilter;
 };
 
 IWritableTextureSource *createTextureSource()
@@ -455,9 +453,9 @@ TextureSource::TextureSource()
 	// Cache some settings
 	// Note: Since this is only done once, the game must be restarted
 	// for these settings to take effect
-	m_setting_mipmap = g_settings->getBool("mip_map");
-	m_setting_trilinear_filter = g_settings->getBool("trilinear_filter");
-	m_setting_bilinear_filter = g_settings->getBool("bilinear_filter");
+	m_mesh_texture_prefilter =
+			g_settings->getBool("mip_map") || g_settings->getBool("bilinear_filter") ||
+			g_settings->getBool("trilinear_filter") || g_settings->getBool("anisotropic_filter");
 }
 
 TextureSource::~TextureSource()
@@ -701,12 +699,8 @@ video::ITexture* TextureSource::getTexture(const std::string &name, u32 *id)
 
 video::ITexture* TextureSource::getTextureForMesh(const std::string &name, u32 *id)
 {
-	static thread_local bool filter_needed =
-		g_settings->getBool("texture_clean_transparent") || m_setting_mipmap ||
-		((m_setting_trilinear_filter || m_setting_bilinear_filter) &&
-		g_settings->getS32("texture_min_size") > 1);
 	// Avoid duplicating texture if it won't actually change
-	if (filter_needed)
+	if (m_mesh_texture_prefilter)
 		return getTexture(name + "^[applyfiltersformesh", id);
 	return getTexture(name, id);
 }
@@ -1741,46 +1735,8 @@ bool TextureSource::generateImagePart(std::string part_of_name,
 			}
 
 			// Apply the "clean transparent" filter, if needed
-			if (m_setting_mipmap || g_settings->getBool("texture_clean_transparent"))
+			if (m_mesh_texture_prefilter)
 				imageCleanTransparent(baseimg, 127);
-
-			/* Upscale textures to user's requested minimum size.  This is a trick to make
-			 * filters look as good on low-res textures as on high-res ones, by making
-			 * low-res textures BECOME high-res ones.  This is helpful for worlds that
-			 * mix high- and low-res textures, or for mods with least-common-denominator
-			 * textures that don't have the resources to offer high-res alternatives.
-			 */
-			const bool filter = m_setting_trilinear_filter || m_setting_bilinear_filter;
-			const s32 scaleto = filter ? g_settings->getU16("texture_min_size") : 1;
-			if (scaleto > 1) {
-				const core::dimension2d<u32> dim = baseimg->getDimension();
-
-				/* Calculate scaling needed to make the shortest texture dimension
-				 * equal to the target minimum.  If e.g. this is a vertical frames
-				 * animation, the short dimension will be the real size.
-				 */
-				if ((dim.Width == 0) || (dim.Height == 0)) {
-					errorstream << "generateImagePart(): Illegal 0 dimension "
-						<< "for part_of_name=\""<< part_of_name
-						<< "\", cancelling." << std::endl;
-					return false;
-				}
-				u32 xscale = scaleto / dim.Width;
-				u32 yscale = scaleto / dim.Height;
-				u32 scale = (xscale > yscale) ? xscale : yscale;
-
-				// Never downscale; only scale up by 2x or more.
-				if (scale > 1) {
-					u32 w = scale * dim.Width;
-					u32 h = scale * dim.Height;
-					const core::dimension2d<u32> newdim = core::dimension2d<u32>(w, h);
-					video::IImage *newimg = driver->createImage(
-							baseimg->getColorFormat(), newdim);
-					baseimg->copyToScaling(newimg);
-					baseimg->drop();
-					baseimg = newimg;
-				}
-			}
 		}
 		/*
 			[resize:WxH

src/client/wieldmesh.cpp

@@ -297,11 +297,8 @@ void WieldMeshSceneNode::setExtruded(const std::string &imagename,
 		material.MaterialType = m_material_type;
 		material.MaterialTypeParam = 0.5f;
 		material.BackfaceCulling = true;
-		// Enable bi/trilinear filtering only for high resolution textures
-		bool bilinear_filter = dim.Width > 32 && m_bilinear_filter;
-		bool trilinear_filter = dim.Width > 32 && m_trilinear_filter;
 		material.forEachTexture([=] (auto &tex) {
-			tex.setFiltersMinetest(bilinear_filter, trilinear_filter,
+			setMaterialFilters(tex, m_bilinear_filter, m_trilinear_filter,
 					m_anisotropic_filter);
 		});
 		// mipmaps cause "thin black line" artifacts
@@ -465,7 +462,7 @@ void WieldMeshSceneNode::setItem(const ItemStack &item, Client *client, bool che
 			material.MaterialTypeParam = 0.5f;
 			material.BackfaceCulling = cull_backface;
 			material.forEachTexture([this] (auto &tex) {
-				tex.setFiltersMinetest(m_bilinear_filter, m_trilinear_filter,
+				setMaterialFilters(tex, m_bilinear_filter, m_trilinear_filter,
 						m_anisotropic_filter);
 			});
 		}

src/defaultsettings.cpp

@@ -176,6 +176,7 @@ void set_default_settings()
 	settings->setDefault("undersampling", "1");
 	settings->setDefault("world_aligned_mode", "enable");
 	settings->setDefault("autoscale_mode", "disable");
+	settings->setDefault("texture_min_size", "64");
 	settings->setDefault("enable_fog", "true");
 	settings->setDefault("fog_start", "0.4");
 	settings->setDefault("3d_mode", "none");
@@ -235,8 +236,6 @@ void set_default_settings()
 	settings->setDefault("hud_hotbar_max_width", "1.0");
 	settings->setDefault("enable_local_map_saving", "false");
 	settings->setDefault("show_entity_selectionbox", "false");
-	settings->setDefault("texture_clean_transparent", "false");
-	settings->setDefault("texture_min_size", "64");
 	settings->setDefault("ambient_occlusion_gamma", "1.8");
 	settings->setDefault("enable_shaders", "true");
 	settings->setDefault("enable_particles", "true");
@@ -252,9 +251,9 @@ void set_default_settings()
 	settings->setDefault("directional_colored_fog", "true");
 	settings->setDefault("inventory_items_animations", "false");
 	settings->setDefault("mip_map", "false");
-	settings->setDefault("anisotropic_filter", "false");
 	settings->setDefault("bilinear_filter", "false");
 	settings->setDefault("trilinear_filter", "false");
+	settings->setDefault("anisotropic_filter", "false");
 	settings->setDefault("tone_mapping", "false");
 	settings->setDefault("enable_waving_water", "false");
 	settings->setDefault("water_wave_height", "1.0");