Moved line and shape drawing code out of the opengl folder, since it no longer directly calls any OpenGL functions.

--HG--
branch : minor

src/modules/graphics/Polyline.h

@@ -0,0 +1,188 @@
+/**
+ * Copyright (c) 2006-2016 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#pragma once
+
+// LOVE
+#include "common/config.h"
+#include "common/Vector.h"
+#include "graphics/vertex.h"
+
+// C++
+#include <vector>
+#include <string.h>
+
+namespace love
+{
+namespace graphics
+{
+
+class Graphics;
+
+/**
+ * Abstract base class for a chain of segments.
+ * @author Matthias Richter
+ **/
+class Polyline
+{
+public:
+
+	Polyline(vertex::TriangleIndexMode mode = vertex::TriangleIndexMode::STRIP)
+		: vertices(nullptr)
+		, overdraw(nullptr)
+		, vertex_count(0)
+		, overdraw_vertex_count(0)
+		, triangle_mode(mode)
+		, overdraw_vertex_start(0)
+	{}
+
+	virtual ~Polyline();
+
+	/**
+	 * @param vertices      Vertices defining the core line segments
+	 * @param count         Number of coordinates (= size of the array vertices)
+	 * @param size_hint     Expected number of vertices of the rendering sleeve around the core line.
+	 * @param halfwidth     linewidth / 2.
+	 * @param pixel_size    Dimension of one pixel on the screen in world coordinates.
+	 * @param draw_overdraw Fake antialias the line.
+	 */
+	void render(const float *vertices, size_t count, size_t size_hint, float halfwidth, float pixel_size, bool draw_overdraw);
+
+	/** Draws the line on the screen
+	 */
+	void draw(love::graphics::Graphics *gfx);
+
+protected:
+
+	virtual void calc_overdraw_vertex_count(bool is_looping);
+	virtual void render_overdraw(const std::vector<Vector> &normals, float pixel_size, bool is_looping);
+	virtual void fill_color_array(Color constant_color, Color *colors);
+
+	/** Calculate line boundary points.
+	 *
+	 * @param[out]    anchors Anchor points defining the core line.
+	 * @param[out]    normals Normals defining the edge of the sleeve.
+	 * @param[in,out] s       Direction of segment pq (updated to the segment qr).
+	 * @param[in,out] len_s   Length of segment pq (updated to the segment qr).
+	 * @param[in,out] ns      Normal on the segment pq (updated to the segment qr).
+	 * @param[in]     q       Current point on the line.
+	 * @param[in]     r       Next point on the line.
+	 * @param[in]     hw      Half line width (see Polyline.render()).
+	 */
+	virtual void renderEdge(std::vector<Vector> &anchors, std::vector<Vector> &normals,
+	                        Vector &s, float &len_s, Vector &ns,
+	                        const Vector &q, const Vector &r, float hw) = 0;
+
+	Vector *vertices;
+	Vector *overdraw;
+	size_t vertex_count;
+	size_t overdraw_vertex_count;
+	vertex::TriangleIndexMode triangle_mode;
+	size_t overdraw_vertex_start;
+
+}; // Polyline
+
+
+/**
+ * A Polyline whose segments are not connected.
+ * @author Matthias Richter
+ */
+class NoneJoinPolyline : public Polyline
+{
+public:
+
+	NoneJoinPolyline()
+		: Polyline(vertex::TriangleIndexMode::QUADS)
+	{}
+
+	void render(const float *vertices, size_t count, float halfwidth, float pixel_size, bool draw_overdraw)
+	{
+		Polyline::render(vertices, count, 2 * count - 4, halfwidth, pixel_size, draw_overdraw);
+
+		// discard the first and last two vertices. (these are redundant)
+		for (size_t i = 0; i < vertex_count - 4; ++i)
+			this->vertices[i] = this->vertices[i+2];
+
+		// The last quad is now garbage, so zero it out to make sure it doesn't
+		// get rasterized. These vertices are in between the core line vertices
+		// and the overdraw vertices in the combined vertex array, so they still
+		// get "rendered" since we draw everything with one draw call.
+		memset(&this->vertices[vertex_count - 4], 0, sizeof(love::Vector) * 4);
+
+		vertex_count -= 4;
+	}
+
+protected:
+
+	virtual void calc_overdraw_vertex_count(bool is_looping);
+	virtual void render_overdraw(const std::vector<Vector> &normals, float pixel_size, bool is_looping);
+	virtual void fill_color_array(Color constant_color, Color *colors);
+	virtual void renderEdge(std::vector<Vector> &anchors, std::vector<Vector> &normals,
+	                        Vector &s, float &len_s, Vector &ns,
+	                        const Vector &q, const Vector &r, float hw);
+
+}; // NoneJoinPolyline
+
+
+/**
+ * A Polyline whose segments are connected by a sharp edge.
+ * @author Matthias Richter
+ */
+class MiterJoinPolyline : public Polyline
+{
+public:
+
+	void render(const float *vertices, size_t count, float halfwidth, float pixel_size, bool draw_overdraw)
+	{
+		Polyline::render(vertices, count, count, halfwidth, pixel_size, draw_overdraw);
+	}
+
+protected:
+
+	virtual void renderEdge(std::vector<Vector> &anchors, std::vector<Vector> &normals,
+	                        Vector &s, float &len_s, Vector &ns,
+	                        const Vector &q, const Vector &r, float hw);
+
+}; // MiterJoinPolyline
+
+
+/**
+ * A Polyline whose segments are connected by a flat edge.
+ * @author Matthias Richter
+ */
+class BevelJoinPolyline : public Polyline
+{
+public:
+
+	void render(const float *vertices, size_t count, float halfwidth, float pixel_size, bool draw_overdraw)
+	{
+		Polyline::render(vertices, count, 2 * count - 4, halfwidth, pixel_size, draw_overdraw);
+	}
+
+protected:
+
+	virtual void renderEdge(std::vector<Vector> &anchors, std::vector<Vector> &normals,
+	                        Vector &s, float &len_s, Vector &ns,
+	                        const Vector &q, const Vector &r, float hw);
+
+}; // BevelJoinPolyline
+
+} // graphics
+} // love