Divide map texture to fit in 16384 GPU dim limit

2 files changed, 17 insertions, 18 deletions

diff --git a/game/src/GameSession/MapView.gd b/game/src/GameSession/MapView.gd
index 510d70a..e74ea59 100644
--- a/game/src/GameSession/MapView.gd
+++ b/game/src/GameSession/MapView.gd
@@ -41,7 +41,6 @@ var _mouse_over_viewport : bool = true
 var _map_mesh : MapMesh
 var _map_shader_material : ShaderMaterial
 var _map_image_size : Vector2
-var _map_province_index_image : Image
 var _map_province_colour_image : Image
 var _map_province_colour_texture : ImageTexture
 var _map_mesh_corner : Vector2
@@ -77,12 +76,15 @@ func _ready():
 		return
 	_map_shader_material = map_material
 
-	# Province index texture
-	_map_province_index_image = GameSingleton.get_province_index_image()
-	if _map_province_index_image == null:
+	# Province index textures
+	var map_province_index_images := GameSingleton.get_province_index_images()
+	if map_province_index_images == null or map_province_index_images.is_empty():
 		push_error("Failed to get province index image!")
 		return
-	var province_index_texture := ImageTexture.create_from_image(_map_province_index_image)
+	var province_index_texture := Texture2DArray.new()
+	if province_index_texture.create_from_images(map_province_index_images) != OK:
+		push_error("Failed to generate province index texture array!")
+		return
 	_map_shader_material.set_shader_parameter(_shader_param_province_index, province_index_texture)
 
 	# Province colour texture
diff --git a/game/src/GameSession/TerrainMap.gdshader b/game/src/GameSession/TerrainMap.gdshader
index 9ce1a24..305a34b 100644
--- a/game/src/GameSession/TerrainMap.gdshader
+++ b/game/src/GameSession/TerrainMap.gdshader
@@ -5,7 +5,7 @@ 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;
+uniform sampler2DArray 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
@@ -18,23 +18,20 @@ uniform float terrain_tile_factor;
 uvec2 vec2_to_uvec2(vec2 v) {
 	return uvec2(v * 255.0);
 }
-
+uvec2 read_uvec2(vec2 uv) {
+	float width_divisions = float(textureSize(province_index_tex, 0).z);
+	uv.x *= width_divisions;
+	float idx = mod(floor(uv.x),  width_divisions);
+	return vec2_to_uvec2(texture(province_index_tex, vec3(uv, idx)).rg);
+}
 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));
+	uvec2 index_split = read_uvec2(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;
@@ -47,8 +44,8 @@ vec3 get_terrain_colour(vec2 uv, vec2 corner, vec2 half_pixel_size, vec2 terrain
 }
 
 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 map_size = vec2(textureSize(province_index_tex, 0).xy);
+	vec2 pixel_offset = fract(fma(uv, map_size, vec2(0.5)));
 	vec2 half_pixel_size = 0.49 / map_size;
 
 	vec2 terrain_uv = uv;