J2D DottedLine & DashedLine

include/JGL/JGL.h

@@ -79,7 +79,7 @@ namespace JGL::J2D {
     /// @param color A 3-or-4 channel color value. @see class Color3, class Color4
     /// @param points A set of x,y points to render.
     /// @param radius The size of the point to plot. By default, a single pixel.
-    void DrawPoints(const Color4& color, const Vector2* points, int num_points, float radius = 1.f);
+    void DrawPoints(const Color4& color, const Vector2* points, int point_count, float radius = 1.f);
 
     /// Plots a line (segment) on the screen.
     /// @param color A 3-or-4 channel color value. @see classes Color3, Color4.
@@ -89,6 +89,27 @@ namespace JGL::J2D {
     void DrawLine(const Color4& color, const Vector2& A, const Vector2& B, float thickness = 1);
     void DrawLine(const Color4& color, float x1, float y1, float x2, float y2, float thickness = 1);
 
+    /// Plots a line segment using a series of points separated by a given distance.
+    /// @param color A 3-or-4 channel color value. @see classes Color3, Color4.
+    /// @param A The starting point of the line segment.
+    /// @param B The end point of the line segment.
+    /// @param spacing The distance between each point (px)
+    /// @param thickness The width at which to render the line.
+    /// @note With diagonal lines, the distance between points can differ by one px.
+    void DrawDottedLine(const Color4& color, const Vector2& A, const Vector2& B, float spacing = 1.f, float thickness = 1.f);
+    void DrawDottedLine(const Color4& color, float x1, float y1, float x2, float y2, float spacing = 1.f, float thickness = 1.f);
+
+    /// Plots a line segment using a series of points separated by a given distance.
+    /// @param color A 3-or-4 channel color value. @see classes Color3, Color4.
+    /// @param A The starting point of the line segment.
+    /// @param B The end point of the line segment.
+    /// @param spacing The distance between each point (px)
+    /// @param dash_length The length of each dash making up the line.
+    /// @param thickness The width at which to render the line.
+    /// @note With diagonal lines, the distance between dashes can differ by one px.
+    void DrawDashedLine(const Color4& color, const Vector2& A, const Vector2& B, float spacing = 4.f, float dash_length = 6.f, float thickness = 1.f);
+    void DrawDashedLine(const Color4& color, float x1, float y1, float x2, float y2, float spacing = 4.f, float dash_length = 6.f, float thickness = 1.f);
+
     /// Draws a line with a color gradient that transitions across it.
     /// @param color_a A 3-or-4 channel color value. @see class Color3, class Color4
     /// @param color_b A 3-or-4 channel color value. @see class Color3, class Color4
@@ -96,7 +117,7 @@ namespace JGL::J2D {
     /// @param B The end point of the line segment.
     /// @param thickness The width at which to render the line.
     void DrawGradientLine(const Color4& color_a, const Color4& color_b, const Vector2& A, const Vector2& B, float thickness = 1);
-    void DrawGradientLine(const Color4& color_a, const Color4& color_b, float x, float y, float w, float h, float thickness = 1);
+    void DrawGradientLine(const Color4& color_a, const Color4& color_b, float x1, float y1, float x2, float y2, float thickness = 1);
 
     /// Draws an outline of a rectangle on the screen.
     /// @param color A 3-or-4 channel color value. @see class Color3, class Color4

src/JGL.cpp

@@ -228,6 +228,55 @@ namespace JGL {
         J2D::DrawLine(color, {x, y}, {w, h}, thickness);
     }
 
+    void J2D::DrawDottedLine(const Color4& color, const Vector2& A, const Vector2& B, float spacing, float thickness) {
+        float distance = Vector2::Distance(A, B);
+        Vector2 direction = (B - A).Normalized();
+
+        unsigned int point_count = distance / spacing;
+        std::vector<Vector2> points(point_count);
+
+        if (spacing > distance)
+            Logger::Error("Drawing a dotted line that would have no dots?");
+
+        for (unsigned int i = 0; i < point_count; ++i)
+            points[i] = A + direction * (i * spacing);
+
+        return J2D::DrawPoints(color, points.data(), points.size(), thickness);
+    }
+
+    void J2D::DrawDottedLine(const Color4& color, float x1, float y1, float x2, float y2, float spacing, float thickness) {
+        return J2D::DrawDottedLine(color, {x1, y1}, {x2, y2}, spacing, thickness);
+    }
+
+    void J2D::DrawDashedLine(const Color4& color, const Vector2& A, const Vector2& B, float spacing, float dash_length, float thickness) {
+        float distance = Vector2::Distance(A, B);
+        Vector2 direction = (B - A).Normalized();
+        float length_of_dash_and_gap = dash_length + spacing;
+        unsigned int dash_count = distance / length_of_dash_and_gap;
+
+        if (spacing > distance)
+            Logger::Error("Drawing a dashed line that would have no dashes?");
+
+        Vector2 A_current, B_current;
+        for (unsigned int i = 0; i < dash_count; i++) {
+            A_current = A + direction * (i * length_of_dash_and_gap);
+            B_current = A_current + (direction * dash_length);
+            J2D::DrawLine(color, A_current, B_current, thickness);
+        }
+
+        // For the little piece at the end.
+        float distance_left = distance - (dash_count * length_of_dash_and_gap);
+        if (distance_left > 0) {
+             A_current = A + direction * (dash_count * length_of_dash_and_gap);
+             B_current = A_current + direction * std::min(dash_length, distance_left);
+             J2D::DrawLine(color, A_current, B_current, thickness);
+        }
+    }
+
+    void J2D::DrawDashedLine(const Color4& color, float x1, float y1, float x2, float y2, float spacing, float dash_length, float thickness) {
+        return J2D::DrawDashedLine(color, {x1, y1}, {x2, y2}, spacing, dash_length, thickness);
+    }
+
     void J2D::DrawGradientLine(const Color4& color1, const Color4& color2, const Vector2& A, const Vector2& B, float thickness) {
         if (!inJ2D)
             Logger::Error("Drawing J2D element before J2D begin.");