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shader_type spatial;
render_mode unshaded;
#include "res://src/Game/GameSession/ProvinceIndexSampler.gdshaderinc"
// The samplers below do not have the source_color hint because we do not want them
// to be converted from sRGB to linear colour space, we do that manually at the end.
// Province colour texture
uniform sampler2D province_colour_tex: 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;
// Cosmetic terrain textures
uniform sampler2DArray terrain_tex: repeat_enable, filter_linear;
// The number of times the terrain textures should tile vertically
uniform float terrain_tile_factor;
// Map stripe mask texture
uniform sampler2D stripe_tex: repeat_enable, filter_linear;
// The number of times the stripe texture should tile vertically
uniform float stripe_tile_factor;
// Land map tint
uniform sampler2D colormap_land_tex: repeat_enable, filter_linear;
// Water map tint
uniform sampler2D colormap_water_tex: repeat_enable, filter_linear;
const vec3 highlight_colour = vec3(1.0);
// Rec.709 luma coefficients
const vec3 luma_weights = vec3(0.2126, 0.7152, 0.0722);
struct args_t {
vec2 uv, half_pixel_size; // Components for calculating province sampling UV
float stripe_mask; // Stripe mask value - between 0 (base) and 1 (stripe)
vec2 terrain_uv; // UV coordinates scaled for terrain texture tiling
vec3 land_tint_colour, water_tint_colour; // Colours for tinting terrain
};
// TODO - add parchment overlay, borders, coastlines, rivers, fog of war
// (when borders are added we can move province colour calculations out of get_terrain_colour
// and into get_map_colour, as we won't need to blend along the borders between provinces)
// This calculates the terrain and base-stripe province colours, blends them together, and then returns
// either the blended colour or just the terrain colour depending on whether the province colour's alpha
// value was set. It also highlights the result if the province is currently selected and/or hovered over.
vec3 get_terrain_colour(const args_t args, const vec2 corner) {
// Find the province and terrain indices at the specified corner of a pixel centred on uv
uvec3 province_data = read_uvec3(fma(corner, args.half_pixel_size, args.uv));
uint province_index = uvec2_to_uint(province_data.rg);
uint terrain_index = province_data.b;
// Get the tinted terrain colour at the current position
vec3 terrain_colour = texture(terrain_tex, vec3(args.terrain_uv, float(terrain_index))).rgb;
vec3 tint_colour = mix(args.land_tint_colour, args.water_tint_colour, float(terrain_index == 0u));
vec3 tinted_terrain_colour = mix(terrain_colour, tint_colour, 0.3);
float terrain_luma = dot(tinted_terrain_colour, luma_weights);
// Get base and stripe colours for province at the current position
province_data.r *= 2u; // Double "x coordinate" as colours come in (base, stripe) pairs
vec4 province_base_colour = texelFetch(province_colour_tex, ivec2(province_data.rg), 0);
province_data.r += 1u; // Add 1 to "x coordinate" to move from base to strip colour
vec4 province_stripe_colour = texelFetch(province_colour_tex, ivec2(province_data.rg), 0);
// Blend the base and stripe colours according to the current position's stripe mask value
vec4 province_colour = mix(province_base_colour, province_stripe_colour, args.stripe_mask);
// Darken the province colour, use it to tint the monochrome terrain colour, and re-lighten the result
province_colour.rgb = mix(vec3(terrain_luma), province_colour.rgb - 0.7, 0.3) * 1.5;
// Show the terrain colour if the province colour has no alpha, otherwise show the province colour
vec3 mixed_colour = mix(tinted_terrain_colour, province_colour.rgb, float(province_colour.a != 0.0));
float highlight_mix_val = 0.4 * (float(province_index == hover_index) + float(province_index == selected_index)) * float(province_index != 0u);
return mix(mixed_colour, highlight_colour, highlight_mix_val);
}
// Rescale UV coordinates to remove squashing caused by normalisation
vec2 denormalise(const vec2 uv, const vec2 dims) {
return vec2(uv.x * dims.x / dims.y, uv.y);
}
// Calculate position-specific values and then calculate and blend map colours at the four corners
// of a pixel centred at uv in order to have smooth transitions between terrain types.
vec3 get_map_colour(vec2 uv) {
args_t args;
args.uv = uv;
vec2 map_size = vec2(textureSize(province_shape_tex, 0).xy) * province_shape_subdivisions;
vec2 uv_centred = fma(uv, map_size, vec2(0.5));
vec2 pixel_offset = fract(uv_centred);
args.half_pixel_size = 0.49 / map_size;
// UV coords adjusted to remove squashing caused by normalisation relative to map dimensions
vec2 unscaled_uv = denormalise(uv, map_size);
vec2 stripe_uv = unscaled_uv * stripe_tile_factor;
// Stripe mask value - between 0 (base) and 1 (stripe)
args.stripe_mask = texture(stripe_tex, stripe_uv).b;
args.terrain_uv = 0.5 - unscaled_uv * terrain_tile_factor;
vec2 colormap_uv = vec2(uv.x, 1.0 - uv.y);
args.land_tint_colour = texture(colormap_land_tex, colormap_uv).rgb;
args.water_tint_colour = texture(colormap_water_tex, colormap_uv).rgb;
return mix(
mix(get_terrain_colour(args, vec2(-1, -1)), get_terrain_colour(args, vec2(+1, -1)), pixel_offset.x),
mix(get_terrain_colour(args, vec2(-1, +1)), get_terrain_colour(args, vec2(+1, +1)), pixel_offset.x),
pixel_offset.y
);
}
// Convert from standard RGB to linear colour space (Godot requires the output to be linear)
vec3 srgb_to_linear(vec3 srgb) {
return mix(
srgb * (1.0 / 12.92),
pow((srgb + vec3(0.055)) * (1.0 / (1.0 + 0.055)), vec3(2.4)),
greaterThan(srgb, vec3(0.04045))
);
}
void fragment() {
ALBEDO = srgb_to_linear(get_map_colour(UV));
}
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zaaarf