Added game map drawing.

src/GameMap.cpp

@@ -0,0 +1,123 @@
+#include "GameMap.hpp"
+
+bool operator==(Field left, Field right) {
+    return left.x == right.x && left.y == right.y;
+}
+
+bool operator!=(Field left, Field right) {
+    return left == right;
+}
+
+Field operator+(Field left, Field right) {
+    return Field(left.x + right.x, left.y + right.y, left.z + right.z);
+}
+
+Field operator-(Field left, Field right) {
+    return Field(left.x - right.x, left.y - right.y, left.z - right.z);
+}
+
+Field operator*(Field left, Field right) {
+    return Field(left.x * right.x, left.y * right.y, left.z * right.z);
+}
+
+Field operator/(Field left, Field right) {
+    return cubic_round(left.x / right.x, left.y / right.y, right.z / left.z);
+}
+
+Field cubic_round(double x, double y, double z) {
+    int8_t round_x = (int8_t) std::round(x);
+    int8_t round_y = (int8_t) std::round(y);
+    int8_t round_z = (int8_t) std::round(z);
+    double x_err = std::abs(round_x - x);
+    double y_err = std::abs(round_y - y);
+    double z_err = std::abs(round_z - z);
+    if (x_err > y_err && x_err > z_err) {
+        round_x = -round_y - round_z;
+    } else if (y_err > z_err) {
+        round_y = -round_x - round_z;
+    } else {
+        round_z = -round_x - round_y;
+    }
+    return Field(round_x, round_y, round_z);
+}
+
+int cubic_distance(Field a, Field b) {
+    return (abs(a.x - b.x) + abs(a.y - b.y) + abs(a.z - b.z)) / 2;
+}
+
+Field hex_direction(int direction) {
+    assert (0 <= direction && direction <= 5);
+    return hex_directions[direction];
+}
+
+Field hex_neighbor(int8_t direction, Field f) {
+    return hex_direction(direction) + f;
+}
+
+Point field_to_point(const Field *f, const Layout *layout) {
+    const Orientation m = layout->orientation;
+    double x = (m.f0 * f->x + m.f1 * f->y) * layout->size;
+    double y = (m.f2 * f->x + m.f3 * f->y) * layout->size;
+    return Point(x + layout->origin.x, y + layout->origin.y);
+}
+
+Field point_to_field(Point point, const Layout *layout) {
+    const Orientation m = layout->orientation;
+    double rel_x = (point.x - layout->origin.x) / layout->size;
+    double rel_y = (point.y - layout->origin.y) / layout->size;
+    double x = m.b0 * rel_x + m.b1 * rel_y;
+    double y = m.b2 * rel_x + m.b3 * rel_y;
+    return cubic_round(x, y, -x - y);
+}
+
+Point field_corner_offset(uint8_t corner, const Layout *layout) {
+    double angle = 2.0 * M_PI * (corner + layout->orientation.start_angle) / 6;
+    return Point(layout->size * cos(angle), layout->size * sin(angle));
+
+    //uint8_t i = (uint8_t) ((corner + layout->orientation.start_corner) % 6);
+    //return Point(layout->size * COS_ANGLES_HEX[i], layout->size * SIN_ANGLES_HEX[i]);
+}
+
+std::vector<Point> field_to_polygon(const Field *field, const Layout *layout) {
+    std::vector<Point> corners = {};
+    Point center = field_to_point(field, layout);
+    for (uint8_t i = 0; i < 6; i++) {
+        Point offset = field_corner_offset(i, layout);
+        corners.push_back(Point(center.x + offset.x, center.y + offset.y));
+    }
+    return corners;
+}
+
+Grid::Grid() {
+    this->fields = std::unordered_set<Field>();
+}
+
+HexagonGrid::HexagonGrid(Sint16 grid_radius)
+        : Grid() {
+    // first lower half, then upper half
+    for (Sint16 x = -grid_radius; x <= grid_radius; x++) {
+        Sint16 y_l = (-grid_radius > -x - grid_radius) ? -grid_radius : -x - grid_radius;
+        Sint16 y_u = (grid_radius < -x + grid_radius) ? grid_radius : -x + grid_radius;
+        for (Sint16 y = y_l; y <= y_u; y++) {
+            Sint16 z = -x - y;
+            this->fields.insert({x, y, z});
+        }
+    }
+}
+
+bool HexagonGrid::render(SDL_Renderer *renderer, const SDL_Color color, const Layout *layout) {
+    for (const Field &elem : this->fields) {
+        std::vector<Point> polygon = field_to_polygon(&elem, layout);
+        assert(polygon.size() > 5);
+        Sint16 vx[6];
+        Sint16 vy[6];
+        for (uint8_t i = 0; i < 6; i++) {
+            vx[i] = (Sint16) polygon[i].x;
+            vy[i] = (Sint16) polygon[i].y;
+        }
+        const Sint16 x[6] = {vx[0], vx[1], vx[2], vx[3], vx[4], vx[5]};
+        const Sint16 y[6] = {vy[0], vy[1], vy[2], vy[3], vy[4], vy[5]};
+        aapolygonRGBA(renderer, x, y, 6, color.r, color.g, color.b, color.a);
+    }
+    return true;
+}