146 lines
4.0 KiB
C++
146 lines
4.0 KiB
C++
/*
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* \brief Functor for painting shaded polygons
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* \author Norman Feske
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* \date 2015-06-19
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*/
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/*
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* Copyright (C) 2015-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__POLYGON_GFX__SHADED_POLYGON_PAINTER_H_
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#define _INCLUDE__POLYGON_GFX__SHADED_POLYGON_PAINTER_H_
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#include <os/surface.h>
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#include <polygon_gfx/polygon_painter_base.h>
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#include <polygon_gfx/interpolate_rgba.h>
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namespace Polygon { class Shaded_painter; }
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class Polygon::Shaded_painter : public Polygon::Painter_base
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{
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private:
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/**
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* Edge attribute IDs
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*/
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enum Edge_attr { ATTR_X, ATTR_R, ATTR_G, ATTR_B, ATTR_A, NUM_ATTR };
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Edge_buffers<NUM_ATTR> _edges;
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public:
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/**
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* Polygon point used for RGBA-shaded polygons
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*/
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struct Point : Point_base
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{
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Color color { };
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Point() { }
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Point(int x, int y, Color color) : Point_base(x, y), color(color) { }
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enum { NUM_EDGE_ATTRIBUTES = NUM_ATTR };
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inline int edge_attr(int id) const
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{
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switch (id) {
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default:
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case ATTR_X: return Point_base::edge_attr(id);
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case ATTR_R: return color.r;
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case ATTR_G: return color.g;
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case ATTR_B: return color.b;
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case ATTR_A: return color.a;
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}
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}
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inline void edge_attr(int id, int value)
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{
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switch (id) {
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case ATTR_X: Point_base::edge_attr(id, value); return;
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case ATTR_R: color.r = value; return;
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case ATTR_G: color.g = value; return;
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case ATTR_B: color.b = value; return;
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case ATTR_A: color.a = value; return;
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}
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}
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};
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/**
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* Constructor
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*
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* \param alloc allocator used for allocating edge buffers
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* \param max_height maximum size of polygon to draw, used to dimension
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* the edge buffers
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*/
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Shaded_painter(Genode::Allocator &alloc, unsigned max_height)
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:
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_edges(alloc, max_height)
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{ }
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/**
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* Draw polygon with linearly interpolated color
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*
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* \param points Array of polygon points
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* \param num_points Number of polygon points
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*
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* The pixel surface and the alpha surface must have the same
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* dimensions.
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*/
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template <typename PT, typename AT>
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void paint(Genode::Surface<PT> &pixel_surface,
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Genode::Surface<AT> &alpha_surface,
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Point const points[], unsigned num_points)
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{
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Point clipped[2*max_points_clipped(num_points)];
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num_points = clip_polygon<Point>(points, num_points, clipped,
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pixel_surface.clip());
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Rect const bbox = bounding_box(clipped, num_points, pixel_surface.size());
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fill_edge_buffers(_edges, clipped, num_points);
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int * const x_l_edge = _edges.left (ATTR_X);
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int * const x_r_edge = _edges.right(ATTR_X);
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int * const r_l_edge = _edges.left (ATTR_R);
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int * const r_r_edge = _edges.right(ATTR_R);
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int * const g_l_edge = _edges.left (ATTR_G);
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int * const g_r_edge = _edges.right(ATTR_G);
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int * const b_l_edge = _edges.left (ATTR_B);
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int * const b_r_edge = _edges.right(ATTR_B);
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int * const a_l_edge = _edges.left (ATTR_A);
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int * const a_r_edge = _edges.right(ATTR_A);
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/* calculate begin of first destination scanline */
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unsigned const dst_w = pixel_surface.size().w();
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PT *dst_pixel = pixel_surface.addr() + dst_w*bbox.y1();
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AT *dst_alpha = alpha_surface.addr() + dst_w*bbox.y1();
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for (int y = bbox.y1(); y < bbox.y2(); y++) {
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/* read left and right color values from corresponding edge buffers */
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Color l_color = Color(r_l_edge[y], g_l_edge[y], b_l_edge[y], a_l_edge[y]);
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Color r_color = Color(r_r_edge[y], g_r_edge[y], b_r_edge[y], a_r_edge[y]);
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int const x_l = x_l_edge[y];
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int const x_r = x_r_edge[y];
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if (x_l < x_r)
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interpolate_rgba(l_color, r_color, dst_pixel + x_l,
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(unsigned char *)dst_alpha + x_l,
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x_r - x_l, x_l, y);
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dst_pixel += dst_w;
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dst_alpha += dst_w;
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}
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pixel_surface.flush_pixels(bbox);
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}
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};
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#endif /* _INCLUDE__POLYGON_GFX__SHADED_POLYGON_PAINTER_H_ */
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