// RenderArea2D.cxx - a class to manage 2D polygon-based drawing
//                    for a complex instrument (eg. GPS).
//
// Written by David Luff, started 2005.
//
// Copyright (C) 2005 - David C Luff - david.luff@nottingham.ac.uk
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
// $Id$


#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "render_area_2d.hxx"

RA2DPrimitive::RA2DPrimitive() {
	invert = false;
	debug = false;
}
										 
RenderArea2D::RenderArea2D(int logx, int logy, int sizex, int sizey, int posx, int posy) {
	_logx = logx;
	_logy = logy;
	_sizex = sizex;
	_sizey = sizey;
	_posx = posx;
	_posy = posy;
	_clipx1 = 0;
	_clipx2 = _logx - 1;
	_clipy1 = 0;
	_clipy2 = _logy - 1;
	
	_backgroundColor[0] = 0.0;
	_backgroundColor[1] = 0.0;
	_backgroundColor[2] = 0.0;
	_backgroundColor[3] = 1.0;
	_pixelColor[0] = 1.0;
	_pixelColor[1] = 0.0;
	_pixelColor[2] = 0.0;
	_pixelColor[3] = 1.0;
	
	_ra2d_debug = false;
}

void RenderArea2D::draw(osg::State& state) {
	
	static osg::ref_ptr<osg::StateSet> renderArea2DStateSet;
	if(!renderArea2DStateSet.valid()) {
		renderArea2DStateSet = new osg::StateSet;
		renderArea2DStateSet->setTextureMode(0, GL_TEXTURE_2D, osg::StateAttribute::OFF);
		renderArea2DStateSet->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
	}
	
	state.pushStateSet(renderArea2DStateSet.get());
	state.apply();
	state.setActiveTextureUnit(0);
	state.setClientActiveTextureUnit(0);
	
	// DCL - the 2 lines below are copied verbatim from the hotspot drawing code.
	// I am not sure if they are needed here or not.
	glPushAttrib(GL_ENABLE_BIT);
	glDisable(GL_COLOR_MATERIAL);
	
	// FIXME - disabling all clip planes causes bleed-through through the splash screen.
	glDisable(GL_CLIP_PLANE0);
	glDisable(GL_CLIP_PLANE1);
	glDisable(GL_CLIP_PLANE2);
	glDisable(GL_CLIP_PLANE3);

	oldDrawBackground();
	
	for(unsigned int i = 0; i < drawing_list.size(); ++i) {
		RA2DPrimitive prim = drawing_list[i];
		switch(prim.type) {
		case RA2D_LINE:
			oldDrawLine(prim.x1, prim.y1, prim.x2, prim.y2);
			break;
		case RA2D_QUAD:
			if(prim.debug) {
				//cout << "Clipping = " << _clipx1 << ", " << _clipy1 << " to " << _clipx2 << ", " << _clipy2 << '\n';
				//cout << "Drawing quad " << prim.x1 << ", " << prim.y1 << " to " << prim.x2 << ", " << prim.y2 << '\n';
			}
			oldDrawQuad(prim.x1, prim.y1, prim.x2, prim.y2, prim.invert);
			break;
		case RA2D_PIXEL:
			oldDrawPixel(prim.x1, prim.y1, prim.invert);
			break;
		}
	}
	
	glPopAttrib();
	
	state.popStateSet();
	state.apply();
	state.setActiveTextureUnit(0);
	state.setClientActiveTextureUnit(0);
}

// Set clipping region in logical units
void RenderArea2D::SetClipRegion(int x1, int y1, int x2, int y2) {
	_clipx1 = x1;
	_clipx2 = x2;
	_clipy1 = y1;
	_clipy2 = y2;
	//cout << "Set clip region, clip region = "  << _clipx1 << ", " << _clipy1 << " to " << _clipx2 << ", " << _clipy2 << '\n';
}

// Set clip region to be the same as the rendered area (default)
void RenderArea2D::ResetClipRegion() {
	_clipx1 = 0;
	_clipx2 = _logx - 1;
	_clipy1 = 0;
	_clipy2 = _logy - 1;
	//cout << "Reset clip region, clip region = "  << _clipx1 << ", " << _clipy1 << " to " << _clipx2 << ", " << _clipy2 << '\n';
}

void RenderArea2D::SetPosition(int posx, int posy) {
	_posx = posx;
	_posy = posy;
}

void RenderArea2D::SetLogicalSize(int logx, int logy) {
	_logx = logx;
	_logy = logy;
}

void RenderArea2D::SetActualSize(int sizex, int sizey) {
	_sizex = sizex;
	_sizey = sizey;
}

void RenderArea2D::DrawPixel(int x, int y, bool invert) {
	// Clipping is currently performed in oldDrawPixel - could clip here instead though.

	RA2DPrimitive prim;
	prim.x1 = x;
	prim.y1 = y;
	prim.x2 = 0;
	prim.y2 = 0;
	prim.type = RA2D_PIXEL;
	prim.invert = invert;
	drawing_list.push_back(prim);
}

void RenderArea2D::oldDrawPixel(int x, int y, bool invert) {
	// Clip
	if(x < _clipx1 || x > _clipx2 || y < _clipy1 || y > _clipy2) return;
	
	// Scale to position within background
	float fx1 = (float)x, fy1 = (float)y;
	float rx = (float)_sizex / (float)_logx;
	float ry = (float)_sizey / (float)_logy;
	fx1 *= rx;
	fy1 *= ry;
	float fx2 = fx1 + rx;
	float fy2 = fy1 + ry;
	
	// Translate to final position
	fx1 += (float)_posx;
	fx2 += (float)_posx;
	fy1 += (float)_posy;
	fy2 += (float)_posy;
	
	//cout << "DP: " << fx1 << ", " << fy1 << " ... " << fx2 << ", " << fy2 << '\n';
	
	doSetColor(invert ? _backgroundColor : _pixelColor);
	SGVec2f corners[4] = {
    SGVec2f(fx1, fy1),
    SGVec2f(fx2, fy1),
    SGVec2f(fx2, fy2),
    SGVec2f(fx1, fy2)
  };
	doDrawQuad(corners);
}

void RenderArea2D::DrawLine(int x1, int y1, int x2, int y2) {
	RA2DPrimitive prim;
	prim.x1 = x1;
	prim.y1 = y1;
	prim.x2 = x2;
	prim.y2 = y2;
	prim.type = RA2D_LINE;
	prim.invert = false;
	drawing_list.push_back(prim);
}

void RenderArea2D::oldDrawLine(int x1, int y1, int x2, int y2) {
	// Crude implementation of Bresenham line drawing algorithm.
	
	// Our lines are non directional, so first order the points x-direction-wise to leave only 4 octants to consider.
	if(x2 < x1) {
		int tmp_x = x1;
		int tmp_y = y1;
		x1 = x2;
		y1 = y2;
		x2 = tmp_x;
		y2 = tmp_y;
	}
	
	bool flip_y = (y1 > y2 ? true : false);
	int dx = x2 - x1;
	int dy = (flip_y ? y1 - y2 : y2 - y1); 
	if(dx > dy) {
		// push the x dir
		int y = y1;
		int yn = dx/2;
		for(int x=x1; x<=x2; ++x) {
			DrawPixel(x, y);
			yn += dy;
			if(yn >= dx) {
				yn -= dx;
				y = (flip_y ? y - 1 : y + 1);
			}
		}
	} else {
		// push the y dir
		int x = x1;
		int xn = dy/2;
		// Must be a more elegant way to roll the next two cases into one!
		if(flip_y) {
			for(int y=y1; y>=y2; --y) {
				DrawPixel(x, y);
				xn += dx;
				if(xn >= dy) {
					xn -= dy;
					x++;
				}
			}
		} else {
			for(int y=y1; y<=y2; ++y) {
				DrawPixel(x, y);
				xn += dx;
				if(xn >= dy) {
					xn -= dy;
					x++;
				}
			}
		}
	}
}

void RenderArea2D::DrawQuad(int x1, int y1, int x2, int y2, bool invert) {
	// Clip and sanity-check.
	if(x1 > x2) {
		int x = x2;
		x2 = x1;
		x1 = x;
	}
	if(y1 > y2) {
		int y = y2;
		y2 = y1;
		y1 = y;
	}
	x1 = x1 < _clipx1 ? _clipx1 : x1;
	if(x1 > _clipx2) { return; }
	x2 = x2 > _clipx2 ? _clipx2 : x2;
	if(x2 < _clipx1) { return; }
	y1 = y1 < _clipy1 ? _clipy1 : y1;
	if(y1 > _clipy2) { return; }
	y2 = y2 > _clipy2 ? _clipy2 : y2;
	if(y2 < _clipy1) { return; }
	
	RA2DPrimitive prim;
	prim.x1 = x1;
	prim.y1 = y1;
	prim.x2 = x2;
	prim.y2 = y2;
	prim.type = RA2D_QUAD;
	prim.invert = invert;
	if(_ra2d_debug) prim.debug = true;
	drawing_list.push_back(prim);
}

void RenderArea2D::oldDrawQuad(int x1, int y1, int x2, int y2, bool invert) {
	// Scale to position within background
	float fx1 = (float)x1, fy1 = (float)y1;
	float fx2 = (float)x2, fy2 = (float)y2;
	float rx = (float)_sizex / (float)_logx;
	float ry = (float)_sizey / (float)_logy;
	fx1 *= rx;
	fy1 *= ry;
	fx2 *= rx;
	fy2 *= ry;
	
	fx2 += rx;
	fy2 += ry;
	
	// Translate to final position
	fx1 += (float)_posx;
	fx2 += (float)_posx;
	fy1 += (float)_posy;
	fy2 += (float)_posy;
	
	//cout << "DP: " << fx1 << ", " << fy1 << " ... " << fx2 << ", " << fy2 << '\n';
	
	doSetColor(invert ? _backgroundColor : _pixelColor);
	SGVec2f corners[4] = {
    SGVec2f(fx1, fy1),
    SGVec2f(fx2, fy1),
    SGVec2f(fx2, fy2),
    SGVec2f(fx1, fy2)
  };
	doDrawQuad(corners);
}

void RenderArea2D::DrawBackground() {
	// TODO
}

void RenderArea2D::oldDrawBackground() {
	doSetColor(_backgroundColor);
	SGVec2f corners[4] = {
    SGVec2f(_posx, _posy),
    SGVec2f(_posx + _sizex, _posy),
    SGVec2f(_posx + _sizex, _posy + _sizey),
    SGVec2f(_posx, _posy + _sizey)
  };
  
	doDrawQuad(corners);
}

void RenderArea2D::Flush() {
	drawing_list.clear();
}

// -----------------------------------------
//
// Actual drawing routines copied from Atlas
//
// -----------------------------------------

void RenderArea2D::doSetColor( const float *rgba ) {
  glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, rgba);
  glColor4fv( rgba );
}

void RenderArea2D::doDrawQuad( const SGVec2f *p) {
  glBegin(GL_QUADS);
    glNormal3f(0.0f, 0.0f, 0.0f);
    glVertex2fv( p[0].data() );
    glVertex2fv( p[1].data() );
    glVertex2fv( p[2].data() );
    glVertex2fv( p[3].data() );
  glEnd();
}

void RenderArea2D::doDrawQuad( const SGVec2f *p, const SGVec4f *color ) {
  
  glBegin(GL_QUADS);
    glNormal3f(0.0f, 0.0f, 0.0f);
    glColor4fv( color[0].data() ); glVertex2fv( p[0].data() );
    glColor4fv( color[1].data() ); glVertex2fv( p[1].data() );
    glColor4fv( color[2].data() ); glVertex2fv( p[2].data() );
    glColor4fv( color[3].data() ); glVertex2fv( p[3].data() );
  glEnd();
}