#include <world.h>

#define getWidth() (lineCount*HLINE)

#define GEN_INC 10
#define GRASS_HEIGHT 4

World::World(unsigned int width){
	unsigned int i;
	float inc;
	lineCount=width+GEN_INC;
	line=(struct line_t *)calloc(lineCount,sizeof(struct line_t));	// allocate space for the array of lines
	line[0].y=80;
	for(i=GEN_INC;i<lineCount;i+=GEN_INC){
		line[i].y=rand()%8-4+line[i-GEN_INC].y;
		if(line[i].y<60)line[i].y=60;
		if(line[i].y>110)line[i].y=110;
	}
	for(i=0;i<lineCount-GEN_INC;i++){
		if(!i||!(i%GEN_INC)){
			inc=(line[i+GEN_INC].y-line[i].y)/(float)GEN_INC;
		}else{
			line[i].y=line[i-1].y+inc;
		}
		line[i].color=rand()%20+130;
	}
	/*line[0].y=50;
	for(i=1;i<lineCount-20;i++){
		line[i].y=rand()%5-2+line[i-1].y;
		if(line[i].y<30)line[i].y=30;
	}*/
}

World::~World(void){
	free(line);
}

void World::draw(vec2 *vec){
	int i,ie,v_offset;
	x_start=0-getWidth()/2+GEN_INC/2*HLINE;
	v_offset=(vec->x-x_start)/HLINE;
	i=v_offset-SCREEN_WIDTH/2;
	if(i<0)i=0;
	ie=v_offset+SCREEN_WIDTH/2;
	if(ie>lineCount)ie=lineCount;
	glBegin(GL_QUADS);
		for(i=i;i<ie;i++){
			glColor3ub(0,200,0);
			glVertex2i(x_start+i*HLINE      ,line[i].y);
			glVertex2i(x_start+i*HLINE+HLINE,line[i].y);
			glVertex2i(x_start+i*HLINE+HLINE,line[i].y-GRASS_HEIGHT);
			glVertex2i(x_start+i*HLINE		,line[i].y-GRASS_HEIGHT);
			glColor3ub(line[i].color,line[i].color-50,line[i].color-100);
			glVertex2i(x_start+i*HLINE      ,line[i].y-GRASS_HEIGHT);
			glVertex2i(x_start+i*HLINE+HLINE,line[i].y-GRASS_HEIGHT);
			glVertex2i(x_start+i*HLINE+HLINE,0);
			glVertex2i(x_start+i*HLINE		,0);
		}
	glEnd();
}

void World::detect(vec2 *v,vec2 *vel,const float width){
	unsigned int i;
	i=(v->x+width/2-x_start)/HLINE;
	if(v->y<=line[i].y){
		vel->y=0;
		v->y=line[i].y+HLINE/2;
		return;
	}else{
		vel->y-=.05;
		return;
	}
}