1 files changed, 80 insertions, 39 deletions

diff --git a/game/src/Game/GameSession/TerrainMap.gdshader b/game/src/Game/GameSession/TerrainMap.gdshader
index 98f9efd..467e277 100644
--- a/game/src/Game/GameSession/TerrainMap.gdshader
+++ b/game/src/Game/GameSession/TerrainMap.gdshader
@@ -34,37 +34,87 @@ uniform sampler2D colormap_water_tex: repeat_enable, filter_linear;
 // Overlay map tint
 uniform sampler2D colormap_overlay_tex: repeat_enable, filter_linear;
 
-struct terrain_args_t {
-	vec2 uv, half_pixel_size; // Components for calculating terrain sampling UV
+struct corner_args_t {
+	vec2 uv, half_pixel_size; // Components for calculating a corner's sampling UV
 	vec2 terrain_uv; // UV coordinates scaled for terrain texture tiling
 	vec3 land_tint_colour, water_tint_colour; // Colours for tinting the terrain
+	float stripe_mask; // Weight for mixing base and stripe province colours
+};
+
+struct corner_ret_t {
+	vec3 terrain_colour;
+	vec4 province_colour;
+	float highlight_mix_val;
 };
 
 // Calculate terrain colour at the specified corner of the current pixel
-vec3 get_terrain_colour(const terrain_args_t terrain_args, const vec2 corner) {
+corner_ret_t get_corner_colour(const corner_args_t corner_args, const vec2 corner) {
+	corner_ret_t ret;
+
+	uvec3 province_data = read_uvec3(fma(corner, corner_args.half_pixel_size, corner_args.uv));
+
 	// Find the terrain index at the specified corner of the current pixel
-	uint terrain_index = read_uvec3(fma(corner, terrain_args.half_pixel_size, terrain_args.uv)).z;
+	uint terrain_index = province_data.z;
 
 	// Get the tinted land colour at the current position
-	vec3 land_colour = texture(terrain_tex, vec3(terrain_args.terrain_uv, float(terrain_index))).rgb;
-	land_colour = mix(land_colour, terrain_args.land_tint_colour, 0.3);
+	vec3 land_colour = texture(terrain_tex, vec3(corner_args.terrain_uv, float(terrain_index))).rgb;
+	land_colour = mix(land_colour, corner_args.land_tint_colour, 0.3);
 
 	// TODO - proper water texture
-	vec3 water_colour = terrain_args.water_tint_colour;
+	vec3 water_colour = corner_args.water_tint_colour;
 
 	// Select land or water colour based on the terrain index (0 is water, otherwise land)
-	vec3 terrain_colour = mix(land_colour, water_colour, float(terrain_index == 0u));
+	ret.terrain_colour = mix(land_colour, water_colour, float(terrain_index == 0u));
+
+	uint province_index = uvec2_to_uint(province_data.xy);
+
+	// Get base and stripe colours for province at the current position
+	province_data.x *= 2u; // Double "x coordinate" as colours come in (base, stripe) pairs
+	vec4 province_base_colour = texelFetch(province_colour_tex, ivec2(province_data.xy), 0);
+
+	province_data.x += 1u; // Add 1 to "x coordinate" to move from base to strip colour
+	vec4 province_stripe_colour = texelFetch(province_colour_tex, ivec2(province_data.xy), 0);
+
+	// Blend the base and stripe colours according to the current position's stripe mask value
+	ret.province_colour = mix(province_base_colour, province_stripe_colour, corner_args.stripe_mask);
+
+	ret.province_colour = mix(ret.province_colour, vec4(corner_args.water_tint_colour, 0.0), float(terrain_index == 0u));
+
+	ret.highlight_mix_val = 0.4 * (
+		float(province_index == hover_index) + float(province_index == selected_index)
+	) * float(province_index != 0u);
 
-	return terrain_colour;
+	return ret;
 }
 
 // Blend together terrain colours from the four corners of the current pixel
-vec3 mix_terrain_colour(const terrain_args_t terrain_args, const vec2 pixel_offset) {
-	return mix(
-		mix(get_terrain_colour(terrain_args, vec2(-1, -1)), get_terrain_colour(terrain_args, vec2(+1, -1)), pixel_offset.x),
-		mix(get_terrain_colour(terrain_args, vec2(-1, +1)), get_terrain_colour(terrain_args, vec2(+1, +1)), pixel_offset.x),
+corner_ret_t mix_terrain_colour(const corner_args_t corner_args, const vec2 pixel_offset) {
+	corner_ret_t mm = get_corner_colour(corner_args, vec2(-1, -1));
+	corner_ret_t pm = get_corner_colour(corner_args, vec2(+1, -1));
+	corner_ret_t mp = get_corner_colour(corner_args, vec2(-1, +1));
+	corner_ret_t pp = get_corner_colour(corner_args, vec2(+1, +1));
+
+	corner_ret_t ret;
+
+	ret.terrain_colour = mix(
+		mix(mm.terrain_colour, pm.terrain_colour, pixel_offset.x),
+		mix(mp.terrain_colour, pp.terrain_colour, pixel_offset.x),
+		pixel_offset.y
+	);
+
+	ret.province_colour = mix(
+		mix(mm.province_colour, pm.province_colour, pixel_offset.x),
+		mix(mp.province_colour, pp.province_colour, pixel_offset.x),
+		pixel_offset.y
+	);
+
+	ret.highlight_mix_val = mix(
+		mix(mm.highlight_mix_val, pm.highlight_mix_val, pixel_offset.x),
+		mix(mp.highlight_mix_val, pp.highlight_mix_val, pixel_offset.x),
 		pixel_offset.y
 	);
+
+	return ret;
 }
 
 // Mix overlay and base colours, used for the parchment map
@@ -84,41 +134,33 @@ vec3 get_map_colour(vec2 uv) {
 	// Offset of uv_map_pixels from the top left corner of the current pixel
 	vec2 pixel_offset = fract(uv_map_pixels);
 
-	terrain_args_t terrain_args;
-	terrain_args.uv = uv;
-	terrain_args.half_pixel_size = 0.49 / map_size;
+	corner_args_t corner_args;
+	corner_args.uv = uv;
+	corner_args.half_pixel_size = 0.49 / map_size;
 	// Terrain texture tiling UV
-	terrain_args.terrain_uv = 0.5 - uv_map_pixels * terrain_tile_factor;
+	corner_args.terrain_uv = 0.5 - uv_map_pixels * terrain_tile_factor;
+
+	vec2 stripe_uv = uv_map_pixels * stripe_tile_factor;
+	// Stripe mask value - between 0 (base) and 1 (stripe)
+	corner_args.stripe_mask = texture(stripe_tex, stripe_uv).b;
 
 	vec2 colormap_uv = vec2(uv.x, 1.0 - uv.y);
 	// Terrain tinting colours
-	terrain_args.land_tint_colour = texture(colormap_land_tex, colormap_uv).rgb;
-	terrain_args.water_tint_colour = texture(colormap_water_tex, colormap_uv).rgb;
+	corner_args.land_tint_colour = texture(colormap_land_tex, colormap_uv).rgb;
+	corner_args.water_tint_colour = texture(colormap_water_tex, colormap_uv).rgb;
 	// Parchment tint colour
 	vec3 overlay_tint_colour = texture(colormap_overlay_tex, colormap_uv).rgb;
 
-	// Blended terrain colour (average of four corners of current pixel)
-	vec3 terrain_colour = mix_terrain_colour(terrain_args, pixel_offset);
+	corner_ret_t colours = mix_terrain_colour(corner_args, pixel_offset);
 
-	vec2 stripe_uv = uv_map_pixels * stripe_tile_factor;
-	// Stripe mask value - between 0 (base) and 1 (stripe)
-	float stripe_mask = texture(stripe_tex, stripe_uv).b;
+	// Blended terrain colour (average of four corners of current pixel)
+	vec3 terrain_colour = colours.terrain_colour;
 
 	vec2 overlay_uv = vec2(uv_map_pixels.x, map_size.y - uv_map_pixels.y) * overlay_tile_factor;
 	// Parchment overlay colour
 	vec3 overlay_colour = texture(overlay_tex, overlay_uv).rgb;
 
-	// Current province index as a pair of byte coordinates and as a combined 16 bit value
-	uvec2 province_data = read_uvec3(uv).xy;
-	uint province_index = uvec2_to_uint(province_data);
-
-	// Get base and stripe colours for province at the current position
-	province_data.x *= 2u; // Double "x coordinate" as colours come in (base, stripe) pairs
-	vec4 province_base_colour = texelFetch(province_colour_tex, ivec2(province_data), 0);
-	province_data.x += 1u; // Add 1 to "x coordinate" to move from base to strip colour
-	vec4 province_stripe_colour = texelFetch(province_colour_tex, ivec2(province_data), 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, stripe_mask);
+	vec4 province_colour = colours.province_colour;
 	// Darken the province colour
 	province_colour.rgb -= 0.7;
 
@@ -129,22 +171,21 @@ vec3 get_map_colour(vec2 uv) {
 	// Near colour is either the terrain's luma component tinted with the province colour and brightened,
 	// or the normal terrain colour
 	vec3 near_province_colour = mix(vec3(terrain_luma), province_colour.rgb, 0.3) * 1.5;
-	vec3 near_colour = mix(near_province_colour, terrain_colour, float(province_colour.a == 0.0));
+	vec3 near_colour = mix(terrain_colour, near_province_colour, province_colour.a);
 
 	// Far colour is either the province colour mixed with the overlay texture, tinted with the overlay colormap and brightened,
 	// or the normal terrain colour mixed with the overlay texture (primarily for water)
 	vec3 far_province_colour = mix_overlay(overlay_colour, province_colour.rgb);
 	far_province_colour = mix(overlay_tint_colour, far_province_colour, 0.3) * 1.5;
 	vec3 far_terrain_colour = mix_overlay(overlay_colour, terrain_colour);
-	vec3 far_colour = mix(far_province_colour, far_terrain_colour, float(province_colour.a == 0.0));
+	vec3 far_colour = mix(far_terrain_colour, far_province_colour, province_colour.a);
 
 	// Blend the near (detailed terrain) and far (parchment) colours according to the parchment mix factor (0 for near, 1 for far)
 	vec3 final_colour = mix(near_colour, far_colour, parchment_mix);
 
 	// Significantly brighted the colour if it is hovered over and/or selected, but not if it has province index 0 (all invalid pixels)
 	const vec3 highlight_colour = vec3(1.0);
-	float highlight_mix_val = 0.4 * (float(province_index == hover_index) + float(province_index == selected_index)) * float(province_index != 0u);
-	vec3 highlighted_colour = mix(final_colour, highlight_colour, highlight_mix_val);
+	vec3 highlighted_colour = mix(final_colour, highlight_colour, colours.highlight_mix_val);
 
 	return highlighted_colour;
 }