2 files changed, 222 insertions, 0 deletions
diff --git a/extension/src/openvic-extension/utility/Utilities.cpp b/extension/src/openvic-extension/utility/Utilities.cpp
new file mode 100644
index 0000000..5940373
--- /dev/null
+++ b/extension/src/openvic-extension/utility/Utilities.cpp
@@ -0,0 +1,167 @@
+#include "Utilities.hpp"
+
+#include <numbers>
+
+#include <godot_cpp/classes/file_access.hpp>
+#include <godot_cpp/classes/resource_loader.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+
+#include <gli/convert.hpp>
+#include <gli/load_dds.hpp>
+
+using namespace godot;
+using namespace OpenVic;
+
+static Ref<Image> load_dds_image(String const& path) {
+	gli::texture2d texture { gli::load_dds(Utilities::godot_to_std_string(path)) };
+	if (texture.empty()) {
+		UtilityFunctions::push_error("Failed to load DDS file: ", path);
+		return nullptr;
+	}
+
+	static constexpr gli::format expected_format = gli::FORMAT_BGRA8_UNORM_PACK8;
+	const bool needs_bgr_to_rgb = texture.format() == expected_format;
+	if (!needs_bgr_to_rgb) {
+		texture = gli::convert(texture, expected_format);
+		if (texture.empty()) {
+			UtilityFunctions::push_error("Failed to convert DDS file: ", path);
+			return nullptr;
+		}
+	}
+
+	const gli::texture2d::extent_type extent { texture.extent() };
+	const int width = extent.x, height = extent.y, size = width * height * 4;
+
+	/* Only fail if there aren't enough bytes, everything seems to work fine if there are extra bytes and we ignore them */
+	if (size > texture.size()) {
+		UtilityFunctions::push_error(
+			"Texture size ", static_cast<int64_t>(texture.size()), " mismatched with dims-based size ", size, " for ", path
+		);
+		return nullptr;
+	}
+
+	PackedByteArray pixels;
+	pixels.resize(size);
+	/* Index offset used to control whether we are reading  */
+	const size_t rb_idx = 2 * needs_bgr_to_rgb;
+	uint8_t const* ptr = static_cast<uint8_t const*>(texture.data());
+	for (size_t i = 0; i < size; i += 4) {
+		pixels[i + 0] = ptr[i + rb_idx];
+		pixels[i + 1] = ptr[i + 1];
+		pixels[i + 2] = ptr[i + 2 - rb_idx];
+		pixels[i + 3] = ptr[i + 3];
+	}
+
+	return Image::create_from_data(width, height, false, Image::FORMAT_RGBA8, pixels);
+}
+
+Ref<Image> Utilities::load_godot_image(String const& path) {
+	if (path.ends_with(".dds")) {
+		return load_dds_image(path);
+	}
+	return Image::load_from_file(path);
+}
+
+Ref<FontFile> Utilities::load_godot_font(String const& fnt_path, Ref<Image> const& image) {
+	Ref<FontFile> font;
+	font.instantiate();
+	const Error err = font->load_bitmap_font(fnt_path);
+	font->set_texture_image(0, { font->get_fixed_size(), 0 }, 0, image);
+	if (err != OK) {
+		UtilityFunctions::push_error("Failed to load font (error ", err, "): ", fnt_path);
+	}
+	return font;
+}
+
+// Get the polar coordinates of a pixel relative to the center
+static Vector2 getPolar(Vector2 UVin, Vector2 center) {
+	Vector2 relcoord = (UVin - center);
+	float dist = relcoord.length();
+	float theta = std::numbers::pi / 2 + atan2(relcoord.y, relcoord.x);
+	if (theta < 0.0f) {
+		theta += std::numbers::pi * 2;
+	}
+	return { dist, theta };
+}
+
+// From thebookofshaders, returns a gradient falloff
+static inline float parabola(float base, float x, float k) {
+	return powf(base * x * (1.0 - x), k);
+}
+
+static inline float parabola_shadow(float base, float x) {
+	return base * x * x;
+}
+
+static Color pie_chart_fragment(
+	Vector2 UV, float radius, Array const& stopAngles, Array const& colours, Vector2 shadow_displacement,
+	float shadow_tightness, float shadow_radius, float shadow_thickness, Color trim_colour, float trim_size,
+	float gradient_falloff, float gradient_base, bool donut, bool donut_inner_trim, float donut_inner_radius
+) {
+
+	Vector2 coords = getPolar(UV, { 0.5, 0.5 });
+	float dist = coords.x;
+	float theta = coords.y;
+
+	Vector2 shadow_polar = getPolar(UV, shadow_displacement);
+	float shadow_peak = radius + (radius - donut_inner_radius) / 2.0;
+	float shadow_gradient =
+		shadow_thickness + parabola_shadow(shadow_tightness * -10.0, shadow_polar.x + shadow_peak - shadow_radius);
+
+	// Inner hole of the donut => make it transparent
+	if (donut && dist <= donut_inner_radius) {
+		return { 0.1, 0.1, 0.1, shadow_gradient };
+	}
+	// Inner trim
+	else if (donut && donut_inner_trim && dist <= donut_inner_radius + trim_size) {
+		return { trim_colour, 1.0 };
+	}
+	// Interior
+	else if (dist <= radius - trim_size) {
+		Color col { 1.0f, 0.0f, 0.0f };
+		for (int i = 0; i < stopAngles.size(); i++) {
+			if (theta <= float(stopAngles[i])) {
+				col = colours[i];
+				break;
+			}
+		}
+		float gradient = parabola(gradient_base, dist, gradient_falloff);
+		return { col * (1.0 - gradient), 1.0 };
+	}
+	// Outer trim
+	else if (dist <= radius) {
+		return { trim_colour, 1.0 };
+	}
+	// Outside the circle
+	else {
+		return { 0.1, 0.1, 0.1, shadow_gradient };
+	}
+}
+
+void Utilities::draw_pie_chart(
+	Ref<Image> image, Array const& stopAngles, Array const& colours, float radius, Vector2 shadow_displacement,
+	float shadow_tightness, float shadow_radius, float shadow_thickness, Color trim_colour, float trim_size,
+	float gradient_falloff, float gradient_base, bool donut, bool donut_inner_trim, float donut_inner_radius
+) {
+
+	ERR_FAIL_NULL_EDMSG(image, "Cannot draw pie chart to null image.");
+	const int32_t width = image->get_width();
+	const int32_t height = image->get_height();
+	ERR_FAIL_COND_EDMSG(width <= 0 || height <= 0, "Cannot draw pie chart to empty image.");
+	if (width != height) {
+		UtilityFunctions::push_warning("Drawing pie chart to non-square image: ", width, "x", height);
+	}
+	const int32_t size = std::min(width, height);
+	for (int32_t y = 0; y < size; ++y) {
+		for (int32_t x = 0; x < size; ++x) {
+			image->set_pixel(
+				x, y,
+				pie_chart_fragment(
+					Vector2 { static_cast<float>(x), static_cast<float>(y) } / size, radius, stopAngles, colours,
+					shadow_displacement, shadow_tightness, shadow_radius, shadow_thickness, trim_colour, trim_size,
+					gradient_falloff, gradient_base, donut, donut_inner_trim, donut_inner_radius
+				)
+			);
+		}
+	}
+}
diff --git a/extension/src/openvic-extension/utility/Utilities.hpp b/extension/src/openvic-extension/utility/Utilities.hpp
new file mode 100644
index 0000000..fc106db
--- /dev/null
+++ b/extension/src/openvic-extension/utility/Utilities.hpp
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <godot_cpp/classes/font_file.hpp>
+#include <godot_cpp/classes/image.hpp>
+
+#include <openvic-simulation/types/Colour.hpp>
+#include <openvic-simulation/types/Vector.hpp>
+
+#define ERR(x) ((x) ? OK : FAILED)
+
+namespace OpenVic::Utilities {
+
+	inline std::string godot_to_std_string(godot::String const& str) {
+		return str.ascii().get_data();
+	}
+
+	inline godot::String std_to_godot_string(std::string const& str) {
+		return str.c_str();
+	}
+
+	inline godot::String std_view_to_godot_string(std::string_view str) {
+		return std_to_godot_string(static_cast<std::string>(str));
+	}
+
+	inline godot::StringName std_to_godot_string_name(std::string const& str) {
+		return str.c_str();
+	}
+
+	inline godot::StringName std_view_to_godot_string_name(std::string_view str) {
+		return std_to_godot_string_name(static_cast<std::string>(str));
+	}
+
+	inline godot::Color to_godot_color(colour_t colour) {
+		return {
+			colour_byte_to_float((colour >> 16) & 0xFF),
+			colour_byte_to_float((colour >> 8) & 0xFF),
+			colour_byte_to_float(colour & 0xFF)
+		};
+	}
+
+	inline godot::Vector2i to_godot_ivec2(ivec2_t vec) {
+		return { vec.x, vec.y };
+	}
+
+	godot::Ref<godot::Image> load_godot_image(godot::String const& path);
+
+	godot::Ref<godot::FontFile> load_godot_font(godot::String const& fnt_path, godot::Ref<godot::Image> const& image);
+
+	void draw_pie_chart(
+		godot::Ref<godot::Image> image, godot::Array const& stopAngles, godot::Array const& colours, float radius,
+		godot::Vector2 shadow_displacement, float shadow_tightness, float shadow_radius, float shadow_thickness,
+		godot::Color trim_colour, float trim_size, float gradient_falloff, float gradient_base, bool donut,
+		bool donut_inner_trim, float donut_inner_radius
+	);
+}