Cosmetic terrain map colour tinting

1 files changed, 56 insertions, 16 deletions

diff --git a/game/src/Game/GameSession/TerrainMap.gdshader b/game/src/Game/GameSession/TerrainMap.gdshader
index ff8708a..35a108b 100644
--- a/game/src/Game/GameSession/TerrainMap.gdshader
+++ b/game/src/Game/GameSession/TerrainMap.gdshader
@@ -15,13 +15,23 @@ uniform sampler2DArray terrain_tex: source_color, 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: source_color, repeat_enable, filter_nearest;
+uniform sampler2D stripe_tex: source_color, 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: source_color, repeat_enable, filter_linear;
+// Water map tint
+uniform sampler2D colormap_water_tex: source_color, repeat_enable, filter_linear;
 
 const vec3 highlight_colour = vec3(1.0);
 
-vec3 get_terrain_colour(vec2 uv, vec2 corner, vec2 half_pixel_size, vec2 terrain_uv, vec2 stripe_uv) {
+vec3 get_terrain_colour(
+	vec2 uv, vec2 corner, vec2 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, vec3 water_tint_colour // Colours for tinting terrain
+) {
+
 	uvec3 province_data = read_uvec3(fma(corner, half_pixel_size, uv));
 	uint province_index = uvec2_to_uint(province_data.rg);
 	uint terrain_index = province_data.b;
@@ -30,33 +40,63 @@ vec3 get_terrain_colour(vec2 uv, vec2 corner, vec2 half_pixel_size, vec2 terrain
 	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);
-	float stripe = texture(stripe_tex, stripe_uv).b; // Stripe mask value - 0 for base, 1 for stripe
-	vec4 province_colour = mix(province_base_colour, province_stripe_colour, stripe);
+	vec4 province_colour = mix(province_base_colour, province_stripe_colour, stripe_mask);
 
 	vec3 terrain_colour = texture(terrain_tex, vec3(terrain_uv, float(terrain_index))).rgb;
-	vec3 mixed_colour = mix(terrain_colour, province_colour.rgb, province_colour.a);
+	vec3 tint_colour = mix(land_tint_colour, water_tint_colour, float(terrain_index == 0u));
+	vec3 tinted_terrain_colour = mix(terrain_colour, tint_colour, 0.3);
+	vec3 mixed_colour = mix(tinted_terrain_colour, province_colour.rgb, province_colour.a);
+
+	float highlight_mix_val = 0.1 * (float(province_index == hover_index) + float(province_index == selected_index));
+	return mix(mixed_colour, highlight_colour, highlight_mix_val);
+}
 
-	float mix_val = 0.1 * (float(province_index == hover_index) + float(province_index == selected_index));
-	return mix(mixed_colour, highlight_colour, mix_val);
+// Rescale UV coordinates to remove squashing caused by normalisation
+vec2 denormalise(vec2 uv, vec2 dims) {
+	return vec2(uv.x * dims.x / dims.y, uv.y);
 }
 
 vec3 mix_terrain_colour(vec2 uv) {
 	vec2 map_size = vec2(textureSize(province_shape_tex, 0).xy) * province_shape_subdivisions;
-	vec2 pixel_offset = fract(fma(uv, map_size, vec2(0.5)));
+	vec2 uv_centred = fma(uv, map_size, vec2(0.5));
+	vec2 pixel_offset = fract(uv_centred);
 	vec2 half_pixel_size = 0.49 / map_size;
 
-	// UV coords adjusted to remove squashing caused by normalisation relative to map dimensions.
-	vec2 unscaled_uv = vec2(uv.x * map_size.x / map_size.y, uv.y);
+	// UV coords adjusted to remove squashing caused by normalisation relative to map dimensions
+	vec2 unscaled_uv = denormalise(uv, map_size);
 
-	vec2 terrain_uv = unscaled_uv * terrain_tile_factor;
 	vec2 stripe_uv = unscaled_uv * stripe_tile_factor;
+	// Stripe mask value - between 0 (base) and 1 (stripe)
+	float stripe_mask = texture(stripe_tex, stripe_uv).b;
+
+	vec2 terrain_uv = unscaled_uv * terrain_tile_factor;
+	vec2 colormap_uv = vec2(uv.x, 1.0 - uv.y);
+	vec3 colormap_land_colour = texture(colormap_land_tex, colormap_uv).rgb;
+	vec3 colormap_water_colour = texture(colormap_water_tex, colormap_uv).rgb;
 
 	return mix(
-		mix(get_terrain_colour(uv, vec2(-1, -1), half_pixel_size, terrain_uv, stripe_uv),
-			get_terrain_colour(uv, vec2(+1, -1), half_pixel_size, terrain_uv, stripe_uv), pixel_offset.x),
-		mix(get_terrain_colour(uv, vec2(-1, +1), half_pixel_size, terrain_uv, stripe_uv),
-			get_terrain_colour(uv, vec2(+1, +1), half_pixel_size, terrain_uv, stripe_uv), pixel_offset.x),
-			pixel_offset.y);
+		mix(
+			get_terrain_colour(
+				uv, vec2(-1, -1), half_pixel_size, stripe_mask,
+				terrain_uv, colormap_land_colour, colormap_water_colour
+			),
+			get_terrain_colour(
+				uv, vec2(+1, -1), half_pixel_size, stripe_mask,
+				terrain_uv, colormap_land_colour, colormap_water_colour
+			), pixel_offset.x
+		),
+		mix(
+			get_terrain_colour(
+				uv, vec2(-1, +1), half_pixel_size, stripe_mask,
+				terrain_uv, colormap_land_colour, colormap_water_colour
+			),
+			get_terrain_colour(
+				uv, vec2(+1, +1), half_pixel_size, stripe_mask,
+				terrain_uv, colormap_land_colour, colormap_water_colour
+			), pixel_offset.x
+		),
+		pixel_offset.y
+	);
 }
 
 void fragment() {