アクションゲームでの色判定で坂道の移動をさせて
いるのですが、どうも動きが思い通りにいきません。例えば、右上の坂があるとして、
右に移動する→上に上がる→右に移動する→少し上に上がるを繰りかえてしまいます。
どうすれば、坂道移動を自然な形で出来るでしょうか。よろしくおねがいします。

#include"Main.h"

Jiki Player;
/*
Teki Enemy[MAX_ENEMY];
Tama Bullet[MAX_BULLET];
System Sys;
*/

int MouseX,MouseY;
int map;
int g=10;
int GetCol(int x,int y)
{
	int r,g,b,a;
	GetPixelSoftImage(map, x, y, &r, &g, &b, &a ) ;
	return GetColor(r,g,b);
}

void DivideColor(int src,int *r,int *g,int *b)
{
	*r = ((src>>16)&0xFF);
	*g = ((src>>8)&0xFF);
	*b = (src&0xFF);
}

void HitCheckColor()
{
	int i,j;
	int white=GetColor(255,255,255);
	float speed=0.15f;
	float jump_speed=-4.0f;
	float jump_accel=0.5f;
	static int Jump=1;
	static float VX=0;
	static float VY=0;
	static int ground_y;

	if(!Jump)
	{
		
		

		if(CheckHitKey(KEY_INPUT_X))
		{
			Jump=1;
			VY=jump_speed;
		}
	}
	else
	{
		VY+=jump_accel;
		Player.y+=VY;

		
		
	}
	if(CheckHitKey(KEY_INPUT_LEFT)){ Jump=1;Player.x--;}
	if(CheckHitKey(KEY_INPUT_RIGHT)){ Jump=1;Player.x++;}

			//if(GetPixel(i+1,j)==white) Player.x++;
			//if(GetPixel(i-1,j)==white) Player.x--;
			//if(GetPixel(i,j+1)==white) 
			//Player.y++;
	//Player.y++;
		DrawFormatString(0,45,GetColor(255,0,0),"GetColor=%d",GetColor(255,255,255));
		DrawFormatString(0,70,GetColor(255,0,0),"GetPixel(x,y)=%d",GetPixel(Player.x,Player.y+63));
		DrawFormatString(0,90,GetColor(255,0,0),"x,y=(%d,%d)",Player.x,Player.y);
		DrawFormatString(0,128,GetColor(255,0,0),"Jump=%d",Jump);

		
		if(GetCol(Player.x,Player.y)==white)
		{
			//MessageBox(NULL,"OK","OK",NULL);
			DrawString(0,0,"左上",GetColor(255,255,255));
			Player.x++;
			Jump=1;
		}
		if(GetCol(Player.x+31,Player.y)==white)
		{
			//MessageBox(NULL,"OK","OK",NULL);
			DrawString(0,0,"右上",GetColor(255,255,255));
			Player.x--;
			Jump=1;
		}
		if(GetCol(Player.x,Player.y+60)==white)
		{
			//MessageBox(NULL,"OK","OK",NULL);
			DrawString(0,0,"左下",GetColor(255,255,255));
			Player.y--;
			ground_y=Player.y+64;
			Jump=0;
		}
		if(GetCol(Player.x+31,Player.y+60)==white)
		{
			//MessageBox(NULL,"OK","OK",NULL);
			DrawString(0,0,"右下",GetColor(255,255,255));
			Player.y--;
			Jump=0;
		}
}

void Init()
{
	Player.x=(640-32)/2;
	Player.y=0;
	map = LoadSoftImage( "./DATA/Map.png" ) ;
}

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hP,LPSTR lpC,int nC)
{
	ChangeWindowMode(TRUE);			//ウィンドウモードで起動
	SetGraphMode(640,480,32);
	SetMainWindowText("METAL TANK ver0.01"); //ウィンドウのタイトル
	if(DxLib_Init() == -1) return (-1);	//DXライブラリ初期化
	
	Init();

	//データ読み込み中と表示する
	DrawString( 0 , 0 , "データ読み込み中" , GetColor(255,255,255) );

	
	//乱数の初期化
	srand((unsigned)GetTickCount());
	
	SetDrawScreen(DX_SCREEN_BACK);
	
	//メインループ
	while( ProcessMessage()==0 && CheckHitKey(KEY_INPUT_ESCAPE)==0){
		ProcessMessage();
		ClsDrawScreen();			//画面を初期化
		

		Player.Move();

		HitCheckColor();

		DrawSoftImage(0,0, map ) ;

		Player.Draw();
				GetMousePoint( &MouseX, &MouseY );
		
		if(GetPixel(MouseX,MouseY)==GetColor(255,255,255))
		{
			DrawFormatString( 0 , 25 , GetColor(255,255,255) ,
				"(%d,%d)=%d" , MouseX,MouseY,GetPixel(MouseX,MouseY) ) ;
			//Player.y--;
			//MessageBox(NULL,"OK","OK",NULL);
		}
		
		

		ScreenFlip();				//フリップする
	}
	
	DxLib_End();	//DXライブラリ終了処理
	return (0);		//終了
}