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+shader_type spatial;
+
+// This is the reference shader of the plugin, and has the most features.
+// it should be preferred for high-end graphics cards.
+// For less features but lower-end targets, see the lite version.
+
+#include "include/heightmap.gdshaderinc"
+
+uniform sampler2D u_terrain_heightmap;
+uniform sampler2D u_terrain_normalmap;
+// I had to remove `hint_albedo` from colormap in Godot 3 because it makes sRGB conversion kick in,
+// which snowballs to black when doing GPU painting on that texture...
+uniform sampler2D u_terrain_colormap;
+uniform sampler2D u_terrain_splatmap;
+uniform sampler2D u_terrain_globalmap : source_color;
+uniform mat4 u_terrain_inverse_transform;
+uniform mat3 u_terrain_normal_basis;
+
+// the reason bump is preferred with albedo is, roughness looks better with normal maps.
+// If we want no normal mapping, roughness would only give flat mirror surfaces,
+// while bump still allows to do depth-blending for free.
+uniform sampler2D u_ground_albedo_bump_0 : source_color;
+uniform sampler2D u_ground_albedo_bump_1 : source_color;
+uniform sampler2D u_ground_albedo_bump_2 : source_color;
+uniform sampler2D u_ground_albedo_bump_3 : source_color;
+
+uniform sampler2D u_ground_normal_roughness_0;
+uniform sampler2D u_ground_normal_roughness_1;
+uniform sampler2D u_ground_normal_roughness_2;
+uniform sampler2D u_ground_normal_roughness_3;
+
+// Had to give this uniform a suffix, because it's declared as a simple float
+// in other shaders, and its type cannot be inferred by the plugin.
+// See https://github.com/godotengine/godot/issues/24488
+uniform vec4 u_ground_uv_scale_per_texture = vec4(20.0, 20.0, 20.0, 20.0);
+
+uniform bool u_depth_blending = true;
+uniform bool u_triplanar = false;
+// Each component corresponds to a ground texture. Set greater than zero to enable.
+uniform vec4 u_tile_reduction = vec4(0.0, 0.0, 0.0, 0.0);
+
+uniform float u_globalmap_blend_start;
+uniform float u_globalmap_blend_distance;
+
+uniform vec4 u_colormap_opacity_per_texture = vec4(1.0, 1.0, 1.0, 1.0);
+
+varying float v_hole;
+varying vec3 v_tint0;
+varying vec3 v_tint1;
+varying vec3 v_tint2;
+varying vec3 v_tint3;
+varying vec4 v_splat;
+varying vec2 v_ground_uv0;
+varying vec2 v_ground_uv1;
+varying vec2 v_ground_uv2;
+varying vec3 v_ground_uv3;
+varying float v_distance_to_camera;
+
+
+vec3 unpack_normal(vec4 rgba) {
+ vec3 n = rgba.xzy * 2.0 - vec3(1.0);
+ // Had to negate Z because it comes from Y in the normal map,
+ // and OpenGL-style normal maps are Y-up.
+ n.z *= -1.0;
+ return n;
+}
+
+vec4 pack_normal(vec3 n, float a) {
+ n.z *= -1.0;
+ return vec4((n.xzy + vec3(1.0)) * 0.5, a);
+}
+
+// Blends weights according to the bump of detail textures,
+// so for example it allows to have sand fill the gaps between pebbles
+vec4 get_depth_blended_weights(vec4 splat, vec4 bumps) {
+ float dh = 0.2;
+
+ vec4 h = bumps + splat;
+
+ // TODO Keep improving multilayer blending, there are still some edge cases...
+ // Mitigation: nullify layers with near-zero splat
+ h *= smoothstep(0, 0.05, splat);
+
+ vec4 d = h + dh;
+ d.r -= max(h.g, max(h.b, h.a));
+ d.g -= max(h.r, max(h.b, h.a));
+ d.b -= max(h.g, max(h.r, h.a));
+ d.a -= max(h.g, max(h.b, h.r));
+
+ return clamp(d, 0, 1);
+}
+
+vec3 get_triplanar_blend(vec3 world_normal) {
+ vec3 blending = abs(world_normal);
+ blending = normalize(max(blending, vec3(0.00001))); // Force weights to sum to 1.0
+ float b = blending.x + blending.y + blending.z;
+ return blending / vec3(b, b, b);
+}
+
+vec4 texture_triplanar(sampler2D tex, vec3 world_pos, vec3 blend) {
+ vec4 xaxis = texture(tex, world_pos.yz);
+ vec4 yaxis = texture(tex, world_pos.xz);
+ vec4 zaxis = texture(tex, world_pos.xy);
+ // blend the results of the 3 planar projections.
+ return xaxis * blend.x + yaxis * blend.y + zaxis * blend.z;
+}
+
+vec4 depth_blend2(vec4 a_value, float a_bump, vec4 b_value, float b_bump, float t) {
+ // https://www.gamasutra.com
+ // /blogs/AndreyMishkinis/20130716/196339/Advanced_Terrain_Texture_Splatting.php
+ float d = 0.1;
+ float ma = max(a_bump + (1.0 - t), b_bump + t) - d;
+ float ba = max(a_bump + (1.0 - t) - ma, 0.0);
+ float bb = max(b_bump + t - ma, 0.0);
+ return (a_value * ba + b_value * bb) / (ba + bb);
+}
+
+vec2 rotate(vec2 v, float cosa, float sina) {
+ return vec2(cosa * v.x - sina * v.y, sina * v.x + cosa * v.y);
+}
+
+vec4 texture_antitile(sampler2D albedo_tex, sampler2D normal_tex, vec2 uv, out vec4 out_normal) {
+ float frequency = 2.0;
+ float scale = 1.3;
+ float sharpness = 0.7;
+
+ // Rotate and scale UV
+ float rot = 3.14 * 0.6;
+ float cosa = cos(rot);
+ float sina = sin(rot);
+ vec2 uv2 = rotate(uv, cosa, sina) * scale;
+
+ vec4 col0 = texture(albedo_tex, uv);
+ vec4 col1 = texture(albedo_tex, uv2);
+ vec4 nrm0 = texture(normal_tex, uv);
+ vec4 nrm1 = texture(normal_tex, uv2);
+ //col0 = vec4(0.0, 0.5, 0.5, 1.0); // Highlights variations
+
+ // Normals have to be rotated too since we are rotating the texture...
+ // TODO Probably not the most efficient but understandable for now
+ vec3 n = unpack_normal(nrm1);
+ // Had to negate the Y axis for some reason. I never remember the myriad of conventions around
+ n.xz = rotate(n.xz, cosa, -sina);
+ nrm1 = pack_normal(n, nrm1.a);
+
+ // Periodically alternate between the two versions using a warped checker pattern
+ float t = 1.2 +
+ sin(uv2.x * frequency + sin(uv.x) * 2.0)
+ * cos(uv2.y * frequency + sin(uv.y) * 2.0); // Result in [0..2]
+ t = smoothstep(sharpness, 2.0 - sharpness, t);
+
+ // Using depth blend because classic alpha blending smoothes out details.
+ out_normal = depth_blend2(nrm0, col0.a, nrm1, col1.a, t);
+ return depth_blend2(col0, col0.a, col1, col1.a, t);
+}
+
+void vertex() {
+ vec4 wpos = MODEL_MATRIX * vec4(VERTEX, 1);
+ vec2 cell_coords = (u_terrain_inverse_transform * wpos).xz;
+ // Must add a half-offset so that we sample the center of pixels,
+ // otherwise bilinear filtering of the textures will give us mixed results (#183)
+ cell_coords += vec2(0.5);
+
+ // Normalized UV
+ UV = cell_coords / vec2(textureSize(u_terrain_heightmap, 0));
+
+ // Height displacement
+ float h = sample_heightmap(u_terrain_heightmap, UV);
+ VERTEX.y = h;
+ wpos.y = h;
+
+ vec3 base_ground_uv = vec3(cell_coords.x, h * MODEL_MATRIX[1][1], cell_coords.y);
+ v_ground_uv0 = base_ground_uv.xz / u_ground_uv_scale_per_texture.x;
+ v_ground_uv1 = base_ground_uv.xz / u_ground_uv_scale_per_texture.y;
+ v_ground_uv2 = base_ground_uv.xz / u_ground_uv_scale_per_texture.z;
+ v_ground_uv3 = base_ground_uv / u_ground_uv_scale_per_texture.w;
+
+ // Putting this in vertex saves 2 fetches from the fragment shader,
+ // which is good for performance at a negligible quality cost,
+ // provided that geometry is a regular grid that decimates with LOD.
+ // (downside is LOD will also decimate tint and splat, but it's not bad overall)
+ vec4 tint = texture(u_terrain_colormap, UV);
+ v_hole = tint.a;
+ v_tint0 = mix(vec3(1.0), tint.rgb, u_colormap_opacity_per_texture.x);
+ v_tint1 = mix(vec3(1.0), tint.rgb, u_colormap_opacity_per_texture.y);
+ v_tint2 = mix(vec3(1.0), tint.rgb, u_colormap_opacity_per_texture.z);
+ v_tint3 = mix(vec3(1.0), tint.rgb, u_colormap_opacity_per_texture.w);
+ v_splat = texture(u_terrain_splatmap, UV);
+
+ // Need to use u_terrain_normal_basis to handle scaling.
+ NORMAL = u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, UV));
+
+ v_distance_to_camera = distance(wpos.xyz, CAMERA_POSITION_WORLD);
+}
+
+void fragment() {
+ if (v_hole < 0.5) {
+ // TODO Add option to use vertex discarding instead, using NaNs
+ discard;
+ }
+
+ vec3 terrain_normal_world =
+ u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, UV));
+ terrain_normal_world = normalize(terrain_normal_world);
+ vec3 normal = terrain_normal_world;
+
+ float globalmap_factor = clamp((v_distance_to_camera - u_globalmap_blend_start)
+ * u_globalmap_blend_distance, 0.0, 1.0);
+ globalmap_factor *= globalmap_factor; // slower start, faster transition but far away
+ vec3 global_albedo = texture(u_terrain_globalmap, UV).rgb;
+ ALBEDO = global_albedo;
+
+ // Doing this branch allows to spare a bunch of texture fetches for distant pixels.
+ // Eventually, there could be a split between near and far shaders in the future,
+ // if relevant on high-end GPUs
+ if (globalmap_factor < 1.0) {
+ vec4 ab0, ab1, ab2, ab3;
+ vec4 nr0, nr1, nr2, nr3;
+
+ if (u_triplanar) {
+ // Only do triplanar on one texture slot,
+ // because otherwise it would be very expensive and cost many more ifs.
+ // I chose the last slot because first slot is the default on new splatmaps,
+ // and that's a feature used for cliffs, which are usually designed later.
+
+ vec3 blending = get_triplanar_blend(terrain_normal_world);
+
+ ab3 = texture_triplanar(u_ground_albedo_bump_3, v_ground_uv3, blending);
+ nr3 = texture_triplanar(u_ground_normal_roughness_3, v_ground_uv3, blending);
+
+ } else {
+ if (u_tile_reduction[3] > 0.0) {
+ ab3 = texture_antitile(
+ u_ground_albedo_bump_3, u_ground_normal_roughness_3, v_ground_uv3.xz, nr3);
+ } else {
+ ab3 = texture(u_ground_albedo_bump_3, v_ground_uv3.xz);
+ nr3 = texture(u_ground_normal_roughness_3, v_ground_uv3.xz);
+ }
+ }
+
+ if (u_tile_reduction[0] > 0.0) {
+ ab0 = texture_antitile(
+ u_ground_albedo_bump_0, u_ground_normal_roughness_0, v_ground_uv0, nr0);
+ } else {
+ ab0 = texture(u_ground_albedo_bump_0, v_ground_uv0);
+ nr0 = texture(u_ground_normal_roughness_0, v_ground_uv0);
+ }
+ if (u_tile_reduction[1] > 0.0) {
+ ab1 = texture_antitile(
+ u_ground_albedo_bump_1, u_ground_normal_roughness_1, v_ground_uv1, nr1);
+ } else {
+ ab1 = texture(u_ground_albedo_bump_1, v_ground_uv1);
+ nr1 = texture(u_ground_normal_roughness_1, v_ground_uv1);
+ }
+ if (u_tile_reduction[2] > 0.0) {
+ ab2 = texture_antitile(
+ u_ground_albedo_bump_2, u_ground_normal_roughness_2, v_ground_uv2, nr2);
+ } else {
+ ab2 = texture(u_ground_albedo_bump_2, v_ground_uv2);
+ nr2 = texture(u_ground_normal_roughness_2, v_ground_uv2);
+ }
+
+ vec3 col0 = ab0.rgb * v_tint0;
+ vec3 col1 = ab1.rgb * v_tint1;
+ vec3 col2 = ab2.rgb * v_tint2;
+ vec3 col3 = ab3.rgb * v_tint3;
+
+ vec4 rough = vec4(nr0.a, nr1.a, nr2.a, nr3.a);
+
+ vec3 normal0 = unpack_normal(nr0);
+ vec3 normal1 = unpack_normal(nr1);
+ vec3 normal2 = unpack_normal(nr2);
+ vec3 normal3 = unpack_normal(nr3);
+
+ vec4 w;
+ // TODO An #ifdef macro would be nice! Or copy/paste everything in a different shader...
+ if (u_depth_blending) {
+ w = get_depth_blended_weights(v_splat, vec4(ab0.a, ab1.a, ab2.a, ab3.a));
+ } else {
+ w = v_splat.rgba;
+ }
+
+ float w_sum = (w.r + w.g + w.b + w.a);
+
+ ALBEDO = (
+ w.r * col0.rgb +
+ w.g * col1.rgb +
+ w.b * col2.rgb +
+ w.a * col3.rgb) / w_sum;
+
+ ROUGHNESS = (
+ w.r * rough.r +
+ w.g * rough.g +
+ w.b * rough.b +
+ w.a * rough.a) / w_sum;
+
+ vec3 ground_normal = /*u_terrain_normal_basis **/ (
+ w.r * normal0 +
+ w.g * normal1 +
+ w.b * normal2 +
+ w.a * normal3) / w_sum;
+ // If no splat textures are defined, normal vectors will default to (1,1,1),
+ // which is incorrect, and causes the terrain to be shaded wrongly in some directions.
+ // However, this should not be a problem to fix in the shader,
+ // because there MUST be at least one splat texture set.
+ //ground_normal = normalize(ground_normal);
+ // TODO Make the plugin insert a default normalmap if it's empty
+
+ // Combine terrain normals with detail normals (not sure if correct but looks ok)
+ normal = normalize(vec3(
+ terrain_normal_world.x + ground_normal.x,
+ terrain_normal_world.y,
+ terrain_normal_world.z + ground_normal.z));
+
+ normal = mix(normal, terrain_normal_world, globalmap_factor);
+
+ ALBEDO = mix(ALBEDO, global_albedo, globalmap_factor);
+ ROUGHNESS = mix(ROUGHNESS, 1.0, globalmap_factor);
+
+ // Show splatmap weights
+ //ALBEDO = w.rgb;
+ }
+ // Highlight all pixels undergoing no splatmap at all
+// else {
+// ALBEDO = vec3(1.0, 0.0, 0.0);
+// }
+
+ NORMAL = (VIEW_MATRIX * (vec4(normal, 0.0))).xyz;
+}