genode/repos/gems/include/polygon_gfx/textured_polygon_painter.h
Norman Feske 259b127f96 Polygon drawing and rudimentary 3D routines
This patch adds two new painters located at gems/include/polygon_gfx.
Both painters draw convex polygons with an arbirary number of points.
The shaded-polygon painter interpolates the color and alpha values
whereas the textured-polygon painter applies a texture to the polygon.
The painters are accompanied by simplistic 3D routines located at
gems/include/nano3d/ and a corresponding example (gems/run/nano3d.run).
2015-07-07 19:48:04 +02:00

147 lines
3.9 KiB
C++

/*
* \brief Functor for painting textured polygons
* \author Norman Feske
* \date 2015-06-29
*/
/*
* Copyright (C) 2015 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__POLYGON_GFX__TEXTURED_POLYGON_PAINTER_H_
#define _INCLUDE__POLYGON_GFX__TEXTURED_POLYGON_PAINTER_H_
#include <os/surface.h>
#include <os/texture.h>
#include <polygon_gfx/polygon_painter_base.h>
#include <polygon_gfx/texturize_rgba.h>
namespace Polygon { class Textured_painter; }
class Polygon::Textured_painter : public Polygon::Painter_base
{
private:
/**
* Edge attribute IDs
*/
enum Edge_attr { ATTR_X, ATTR_U, ATTR_V, NUM_ATTR };
Edge_buffers<NUM_ATTR> _edges;
public:
/**
* Polygon point used for textured polygons
*/
struct Point : Point_base
{
int u = 0, v = 0;
Point() { }
Point(int x, int y, int u, int v) : Point_base(x, y), u(u), v(v) { }
enum { NUM_EDGE_ATTRIBUTES = NUM_ATTR };
inline int edge_attr(int id) const
{
switch (id) {
default:
case ATTR_X: return Point_base::edge_attr(id);
case ATTR_U: return u;
case ATTR_V: return v;
}
}
inline void edge_attr(int id, int value)
{
switch (id) {
case ATTR_X: Point_base::edge_attr(id, value); return;
case ATTR_U: u = value; return;
case ATTR_V: v = value; return;
}
}
};
/**
* Constructor
*
* \param alloc allocator used for allocating edge buffers
* \param max_height maximum size of polygon to draw, used to dimension
* the edge buffers
*/
Textured_painter(Genode::Allocator &alloc, unsigned max_height)
:
_edges(alloc, max_height)
{ }
/**
* Draw textured polygon
*
* \param points Array of polygon points
* \param num_points Number of polygon points
*
* The pixel surface and the alpha surface must have the same
* dimensions.
*/
template <typename PT, typename AT>
void paint(Genode::Surface<PT> &pixel_surface,
Genode::Surface<AT> &alpha_surface,
Point const points[], unsigned num_points,
Genode::Texture<PT> const &texture)
{
Point clipped[2*max_points_clipped(num_points)];
num_points = clip_polygon<Point>(points, num_points, clipped,
pixel_surface.clip());
Rect const bbox = bounding_box(clipped, num_points, pixel_surface.size());
fill_edge_buffers(_edges, clipped, num_points);
int * const x_l_edge = _edges.left (ATTR_X);
int * const x_r_edge = _edges.right(ATTR_X);
int * const u_l_edge = _edges.left (ATTR_U);
int * const u_r_edge = _edges.right(ATTR_U);
int * const v_l_edge = _edges.left (ATTR_V);
int * const v_r_edge = _edges.right(ATTR_V);
unsigned const src_w = texture.size().w();
PT const *src_pixel = texture.pixel();
unsigned char const *src_alpha = texture.alpha();
/* calculate begin of destination scanline */
unsigned const dst_w = pixel_surface.size().w();
PT *dst_pixel = pixel_surface.addr() + dst_w*bbox.y1();
AT *dst_alpha = alpha_surface.addr() + dst_w*bbox.y1();
for (int y = bbox.y1(); y < bbox.y2(); y++) {
/*
* Read left and right texture coordinates (u,v) from
* corresponding edge buffers.
*/
Genode::Point<> const l_texpos(u_l_edge[y], v_l_edge[y]);
Genode::Point<> const r_texpos(u_r_edge[y], v_r_edge[y]);
int const x_l = x_l_edge[y];
int const x_r = x_r_edge[y];
if (x_l < x_r)
texturize_rgba(l_texpos, r_texpos,
dst_pixel + x_l, (unsigned char *)dst_alpha + x_l,
x_r - x_l, src_pixel, src_alpha, src_w);
dst_pixel += dst_w;
dst_alpha += dst_w;
}
pixel_surface.flush_pixels(bbox);
}
};
#endif /* _INCLUDE__POLYGON_GFX__TEXTURED_POLYGON_PAINTER_H_ */