Added shaders

Shaders/ursc/spatial/flat_sky.gdshader

@@ -0,0 +1,75 @@
+shader_type spatial;
+render_mode unshaded;
+
+global uniform bool texture_filtering;
+
+uniform sampler2D albedo_texture : source_color, filter_nearest, repeat_enable;
+uniform vec2 uv_offset = vec2(0.0);
+uniform vec2 uv_scale = vec2(1.0);
+uniform vec2 uv_scroll_speed = vec2(0.0);
+
+vec4 albedoTextureFiltered(vec2 uv)
+{
+	vec2 albedo_texture_size = vec2(textureSize(albedo_texture, 0));
+
+	vec2 tex_pix_a = vec2(1.0 / albedo_texture_size.x, 0.0);
+	vec2 tex_pix_b = vec2(0.0, 1.0 / albedo_texture_size.y);
+	vec2 tex_pix_c = vec2(tex_pix_a.x,tex_pix_b.y);
+	vec2 half_tex = vec2(tex_pix_a.x * 0.5, tex_pix_b.y * 0.5);
+	vec2 uv_centered = uv - half_tex;
+
+	vec4 diffuse_color = texture(albedo_texture, uv_centered);
+	vec4 sample_a = texture(albedo_texture, uv_centered + tex_pix_a);
+	vec4 sample_b = texture(albedo_texture, uv_centered + tex_pix_b);
+	vec4 sample_c = texture(albedo_texture, uv_centered + tex_pix_c);
+
+	float interp_x = modf(uv_centered.x * albedo_texture_size.x, albedo_texture_size.x);
+	float interp_y = modf(uv_centered.y * albedo_texture_size.y, albedo_texture_size.y);
+
+	if (uv_centered.x < 0.0)
+	{
+		interp_x = 1.0 - interp_x * -1.0;
+	}
+	if (uv_centered.y < 0.0)
+	{
+		interp_y = 1.0 - interp_y * -1.0;
+	}
+
+	diffuse_color = (
+		diffuse_color +
+		interp_x * (sample_a - diffuse_color) +
+		interp_y * (sample_b - diffuse_color)) *
+		(1.0 - step(1.0, interp_x + interp_y));
+
+	diffuse_color += (
+		(sample_c + (1.0 - interp_x) * (sample_b - sample_c) +
+		(1.0 - interp_y) * (sample_a - sample_c)) *
+		step(1.0, interp_x + interp_y));
+
+    return diffuse_color;
+}
+
+void fragment()
+{
+	float y = atan(VIEW_MATRIX[0][2], VIEW_MATRIX[2][2]);
+	float x = asin(VIEW_MATRIX[1][2]);
+
+	vec2 bg_coordinates = (vec2(y * 0.5, -x) * -(1.0 / PI)) + 0.5;
+	bg_coordinates.y *= 0.5;
+
+	vec2 bg_scale;
+
+	bg_scale.y = 0.5;
+
+	vec2 albedo_texture_size = vec2(textureSize(albedo_texture, 0));
+	float aspect_ratio = albedo_texture_size.x / albedo_texture_size.y;
+	bg_scale.x = VIEWPORT_SIZE.x / (VIEWPORT_SIZE.y * aspect_ratio) * bg_scale.y;
+
+	vec2 uv = (
+		SCREEN_UV * uv_scale + uv_offset + (uv_scroll_speed * TIME)) * bg_scale + bg_coordinates;
+
+	if (texture_filtering)
+		ALBEDO = albedoTextureFiltered(uv).rgb;
+	else
+		ALBEDO = texture(albedo_texture, uv).rgb;
+}