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shader_type spatial;
render_mode unshaded;
// Cosmetic farmlands terrain texture
uniform sampler2D farmlands_tex: source_color, repeat_enable, filter_linear;
// Province index texture
uniform sampler2D province_index_tex : source_color, repeat_enable, filter_nearest;
// Province colour texture
uniform sampler2D province_colour_tex: source_color, repeat_enable, filter_nearest;
// Index of the mouse over the map mesh
uniform uint hover_index;
// Index of the currently selected province
uniform uint selected_index;
// The number of times the terrain textures should tile vertically
uniform float terrain_tile_factor;
uvec2 vec2_to_uvec2(vec2 v) {
return uvec2(v * 255.0);
}
uint uvec2_to_uint(uvec2 v) {
return (v.y << 8u) | v.x;
}
uvec2 read_uvec2(sampler2D tex, vec2 uv) {
return vec2_to_uvec2(texture(tex, uv).rg);
}
uint read_uint16(sampler2D tex, vec2 uv) {
return uvec2_to_uint(read_uvec2(tex, uv));
}
const vec3 water_colour = vec3(0, 0, 1);
vec3 get_terrain_colour(vec2 uv, vec2 corner, vec2 half_pixel_size, vec2 terrain_uv) {
uvec2 index_split = read_uvec2(province_index_tex, fma(corner, half_pixel_size, uv));
uint index = uvec2_to_uint(index_split);
vec4 province_data = texelFetch(province_colour_tex, ivec2(index_split), 0);
vec3 province_colour = province_data.rgb;
float is_land = province_data.a;
vec3 farmlands_colour = texture(farmlands_tex, terrain_uv).rgb;
vec3 terrain_colour = mix(water_colour, farmlands_colour, is_land);
float mix_val = 0.4 + float(index == hover_index) * 0.2 + float(index == selected_index) * 0.2;
vec3 mixed_colour = mix(terrain_colour, province_colour, mix_val);
return mixed_colour;
}
vec3 mix_terrain_colour(vec2 uv) {
vec2 map_size = vec2(textureSize(province_index_tex, 0));
vec2 pixel_offset = mod(fma(uv, map_size, vec2(0.5)), 1.0);
vec2 half_pixel_size = 0.49 / map_size;
vec2 terrain_uv = uv;
terrain_uv.x *= map_size.x / map_size.y;
terrain_uv *= terrain_tile_factor;
return mix(
mix(get_terrain_colour(uv, vec2(-1, -1), half_pixel_size, terrain_uv),
get_terrain_colour(uv, vec2(+1, -1), half_pixel_size, terrain_uv), pixel_offset.x),
mix(get_terrain_colour(uv, vec2(-1, +1), half_pixel_size, terrain_uv),
get_terrain_colour(uv, vec2(+1, +1), half_pixel_size, terrain_uv), pixel_offset.x),
pixel_offset.y);
}
void fragment() {
vec3 terrain_colour = mix_terrain_colour(UV);
ALBEDO = terrain_colour;
}
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