107 lines
3.4 KiB
Text
107 lines
3.4 KiB
Text
shader_type spatial;
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render_mode cull_disabled;
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#include "include/heightmap_rgb8_encoding.gdshaderinc"
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uniform sampler2D u_terrain_heightmap;
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uniform sampler2D u_terrain_detailmap;
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uniform sampler2D u_terrain_normalmap;
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uniform sampler2D u_terrain_globalmap : source_color;
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uniform mat4 u_terrain_inverse_transform;
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uniform mat3 u_terrain_normal_basis;
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uniform sampler2D u_albedo_alpha : source_color;
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uniform float u_view_distance = 100.0;
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uniform float u_globalmap_tint_bottom : hint_range(0.0, 1.0);
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uniform float u_globalmap_tint_top : hint_range(0.0, 1.0);
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uniform float u_bottom_ao : hint_range(0.0, 1.0);
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uniform vec2 u_ambient_wind; // x: amplitude, y: time
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uniform vec3 u_instance_scale = vec3(1.0, 1.0, 1.0);
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uniform float u_roughness = 0.9;
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varying vec3 v_normal;
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varying vec2 v_map_uv;
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float get_hash(vec2 c) {
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return fract(sin(dot(c.xy, vec2(12.9898,78.233))) * 43758.5453);
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}
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vec3 unpack_normal(vec4 rgba) {
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vec3 n = rgba.xzy * 2.0 - vec3(1.0);
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n.z *= -1.0;
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return n;
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}
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vec3 get_ambient_wind_displacement(vec2 uv, float hash) {
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// TODO This is an initial basic implementation. It may be improved in the future, especially for strong wind.
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float t = u_ambient_wind.y;
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float amp = u_ambient_wind.x * (1.0 - uv.y);
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// Main displacement
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vec3 disp = amp * vec3(cos(t), 0, sin(t * 1.2));
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// Fine displacement
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float fine_disp_frequency = 2.0;
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disp += 0.2 * amp * vec3(cos(t * (fine_disp_frequency + hash)), 0, sin(t * (fine_disp_frequency + hash) * 1.2));
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return disp;
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}
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float get_height(sampler2D heightmap, vec2 uv) {
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return decode_height_from_rgb8_unorm(texture(heightmap, uv).rgb);
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}
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void vertex() {
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vec4 obj_pos = MODEL_MATRIX * vec4(0, 1, 0, 1);
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vec3 cell_coords = (u_terrain_inverse_transform * obj_pos).xyz;
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// Must add a half-offset so that we sample the center of pixels,
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// otherwise bilinear filtering of the textures will give us mixed results (#183)
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cell_coords.xz += vec2(0.5);
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vec2 map_uv = cell_coords.xz / vec2(textureSize(u_terrain_heightmap, 0));
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v_map_uv = map_uv;
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//float density = 0.5 + 0.5 * sin(4.0*TIME); // test
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float density = texture(u_terrain_detailmap, map_uv).r;
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float hash = get_hash(obj_pos.xz);
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if (density > hash) {
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vec3 normal = normalize(
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u_terrain_normal_basis * unpack_normal(texture(u_terrain_normalmap, map_uv)));
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// Snap model to the terrain
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float height = get_height(u_terrain_heightmap, map_uv) / cell_coords.y;
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VERTEX *= u_instance_scale;
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VERTEX.y += height;
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VERTEX += get_ambient_wind_displacement(UV, hash);
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// Fade alpha with distance
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vec3 wpos = (MODEL_MATRIX * vec4(VERTEX, 1)).xyz;
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float dr = distance(wpos, CAMERA_POSITION_WORLD) / u_view_distance;
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COLOR.a = clamp(1.0 - dr * dr * dr, 0.0, 1.0);
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// When using billboards,
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// the normal is the same as the terrain regardless of face orientation
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v_normal = normal;
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} else {
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// Discard, output degenerate triangles
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VERTEX = vec3(0, 0, 0);
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}
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}
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void fragment() {
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NORMAL = (VIEW_MATRIX * (MODEL_MATRIX * vec4(v_normal, 0.0))).xyz;
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ALPHA_SCISSOR_THRESHOLD = 0.5;
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ROUGHNESS = u_roughness;
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vec4 col = texture(u_albedo_alpha, UV);
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ALPHA = col.a * COLOR.a;// - clamp(1.4 - UV.y, 0.0, 1.0);//* 0.5 + 0.5*cos(2.0*TIME);
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ALBEDO = COLOR.rgb * col.rgb;
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// Blend with ground color
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float nh = sqrt(max(1.0 - UV.y, 0.0));
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ALBEDO = mix(ALBEDO, texture(u_terrain_globalmap, v_map_uv).rgb, mix(u_globalmap_tint_bottom, u_globalmap_tint_top, nh));
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// Fake bottom AO
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ALBEDO = ALBEDO * mix(1.0, 1.0 - u_bottom_ao, UV.y * UV.y);
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}
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