/*********************************************************************************************
*
*	raylib.shapes
*
*	Basic functions to draw 2d Shapes
*	 
*	Copyright (c) 2013 Ramon Santamaria (Ray San - raysan@raysanweb.com)
*	
*	This software is provided "as-is", without any express or implied warranty. In no event 
*	will the authors be held liable for any damages arising from the use of this software.
*
*	Permission is granted to anyone to use this software for any purpose, including commercial 
*	applications, and to alter it and redistribute it freely, subject to the following restrictions:
*
*	  1. The origin of this software must not be misrepresented; you must not claim that you 
*	  wrote the original software. If you use this software in a product, an acknowledgment 
*	  in the product documentation would be appreciated but is not required.
*
*	  2. Altered source versions must be plainly marked as such, and must not be misrepresented
*	  as being the original software.
*
*	  3. This notice may not be removed or altered from any source distribution.
*
**********************************************************************************************/

#include "raylib.h"

#include <GL/gl.h>		// OpenGL functions
#include <math.h>		// Math related functions, sin() and cos() used on DrawCircle*

//----------------------------------------------------------------------------------
// Defines and Macros
//----------------------------------------------------------------------------------
// Nop...

//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------
// Not here...

//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
// It's lonely here...

//----------------------------------------------------------------------------------
// Module specific Functions Declaration
//----------------------------------------------------------------------------------
// No private (static) functions in this module (.c file)

//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------

// Draw a pixel
void DrawPixel(int posX, int posY, Color color)
{
	glBegin(GL_POINTS);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(posX, posY);
	glEnd();
	
	// NOTE: Alternative method to draw a pixel (point)
/*
	glEnable(GL_POINT_SMOOTH);
	glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);	// Deprecated on OGL 3.0
	
	glPointSize(1.0f);
	glPoint((float)posX, (float)posY, 0.0f);
*/
}

// Draw a pixel (Vector version)
void DrawPixelV(Vector2 position, Color color)
{
	glBegin(GL_POINTS);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2f(position.x, position.y);
	glEnd();
}

// Draw a line
void DrawLine(int startPosX, int startPosY, int endPosX, int endPosY, Color color)
{
	glBegin(GL_LINES);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(startPosX, startPosY);
		glVertex2i(endPosX, endPosY);
	glEnd();
}

// Draw a line  (Vector version)
void DrawLineV(Vector2 startPos, Vector2 endPos, Color color)
{
	glBegin(GL_LINES);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2f(startPos.x, startPos.y);
		glVertex2f(endPos.x, endPos.y);
	glEnd();
}

// Draw a color-filled circle
void DrawCircle(int centerX, int centerY, float radius, Color color)
{
	glEnable(GL_POLYGON_SMOOTH);
	glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
	
	glBegin(GL_TRIANGLE_FAN);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(centerX, centerY);

		for (int i=0; i <= 360; i++)		//i++ --> Step = 1.0 pixels
		{
			float degInRad = i*DEG2RAD;
			//glVertex2f(cos(degInRad)*radius,sin(degInRad)*radius);

			glVertex2f(centerX + sin(degInRad) * radius, centerY + cos(degInRad) * radius);
		}
	glEnd();
	
	glDisable(GL_POLYGON_SMOOTH);
	
	// NOTE: Alternative method to draw a circle (point)
/*
	glEnable(GL_POINT_SMOOTH);
	glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);	// Deprecated on OGL 3.0
	
	glPointSize(radius);
	glPoint((float)centerX, (float)centerY, 0.0f);
*/
}

// Draw a gradient-filled circle
// NOTE: Gradient goes from center (color1) to border (color2)
void DrawCircleGradient(int centerX, int centerY, float radius, Color color1, Color color2)
{
	glBegin(GL_TRIANGLE_FAN);
		glColor4ub(color1.r, color1.g, color1.b, color1.a);
		glVertex2i(centerX, centerY);
		glColor4ub(color2.r, color2.g, color2.b, color2.a);
		
		for (int i=0; i <= 360; i++)		//i++ --> Step = 1.0 pixels
		{
			glVertex2f(centerX + sin(DEG2RAD*i) * radius, centerY + cos(DEG2RAD*i) * radius);
		}
	glEnd();
}

// Draw a color-filled circle (Vector version)
void DrawCircleV(Vector2 center, float radius, Color color)
{
	glEnable(GL_POLYGON_SMOOTH);
	glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
	
	glBegin(GL_TRIANGLE_FAN);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2f(center.x, center.y);

		for (int i=0; i <= 360; i++)		//i++ --> Step = 1.0 pixels
		{
			glVertex2f(center.x + sin(DEG2RAD*i) * radius, center.y + cos(DEG2RAD*i) * radius);
		}
	glEnd();
	
	glDisable(GL_POLYGON_SMOOTH);
}

// Draw circle outline
void DrawCircleLines(int centerX, int centerY, float radius, Color color)
{
	glEnable(GL_LINE_SMOOTH);					// Smoothies circle outline (anti-aliasing applied)
	glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);		// Best quality for line smooth (anti-aliasing best algorithm)
	
	glBegin(GL_LINE_LOOP);
		glColor4ub(color.r, color.g, color.b, color.a);
		
		// NOTE: Circle outline is drawn pixel by pixel every degree (0 to 360)
		for (int i=0; i < 360; i++)
		{
			glVertex2f(centerX + sin(DEG2RAD*i) * radius, centerY + cos(DEG2RAD*i) * radius);
		}
   glEnd();
   
// NOTE: Alternative method to draw circle outline
/*
	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
	DrawCircle(centerX, centerY, radius, color);
	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
*/
   glDisable(GL_LINE_SMOOTH);
}

// Draw a color-filled rectangle
void DrawRectangle(int posX, int posY, int width, int height, Color color)
{
	glBegin(GL_QUADS);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(posX, posY);
		glVertex2i(posX + width, posY);
		glVertex2i(posX + width, posY + height);
		glVertex2i(posX, posY + height);
	glEnd();
}

// Draw a color-filled rectangle
void DrawRectangleRec(Rectangle rec, Color color)
{
	DrawRectangle(rec.x, rec.y, rec.width, rec.height, color);
}											

// Draw a gradient-filled rectangle
// NOTE: Gradient goes from bottom (color1) to top (color2)
void DrawRectangleGradient(int posX, int posY, int width, int height, Color color1, Color color2)
{
	glBegin(GL_QUADS);
		glColor4ub(color1.r, color1.g, color1.b, color1.a);
		glVertex2i(posX, posY);
		glVertex2i(posX + width, posY);
		glColor4ub(color2.r, color2.g, color2.b, color2.a);
		glVertex2i(posX + width, posY + height);
		glVertex2i(posX, posY + height);
	glEnd();
}

// Draw a color-filled rectangle (Vector version)
void DrawRectangleV(Vector2 position, Vector2 size, Color color)
{
	glBegin(GL_QUADS);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(position.x, position.y);
		glVertex2i(position.x + size.x, position.y);
		glVertex2i(position.x + size.x, position.y + size.y);
		glVertex2i(position.x, position.y + size.y);
	glEnd();
}

// Draw rectangle outline
void DrawRectangleLines(int posX, int posY, int width, int height, Color color)
{
	//glEnable(GL_LINE_SMOOTH);						// Smoothies circle outline (anti-aliasing applied)
	//glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);		// Best quality for line smooth (anti-aliasing best algorithm)
	
	// NOTE: Lines are rasterized using the "Diamond Exit" rule so, it's nearly impossible to obtain a pixel-perfect engine
	// NOTE: Recommended trying to avoid using lines, at least >1.0f pixel lines with anti-aliasing (glLineWidth function)

	glBegin(GL_LINE_LOOP);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2i(posX, posY);
		glVertex2i(posX + width - 1, posY);
		glVertex2i(posX + width - 1, posY + height - 1);
		glVertex2i(posX, posY + height - 1);
	glEnd();

// NOTE: Alternative method to draw rectangle outline
/*
	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
	DrawRectangle(posX, posY, width - 1, height - 1, color);
	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
*/
	//glDisable(GL_LINE_SMOOTH);
}

// Draw a triangle
void DrawTriangle(Vector2 v1, Vector2 v2, Vector2 v3, Color color)
{
	glBegin(GL_TRIANGLES);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2f(v1.x, v1.y);
		glVertex2f(v2.x, v2.y);
		glVertex2f(v3.x, v3.y);
	glEnd();
}

void DrawTriangleLines(Vector2 v1, Vector2 v2, Vector2 v3, Color color)
{
	glBegin(GL_LINE_LOOP);
		glColor4ub(color.r, color.g, color.b, color.a);
		glVertex2f(v1.x, v1.y);
		glVertex2f(v2.x, v2.y);
		glVertex2f(v3.x, v3.y);
	glEnd();
}

// Draw a closed polygon defined by points
// NOTE: Array num elements MUST be passed as parameter to function
void DrawPoly(Vector2 *points, int numPoints, Color color)
{
	if (numPoints >= 3)
	{
		glEnable(GL_POLYGON_SMOOTH);
		glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
	
		glBegin(GL_POLYGON);
			glColor4ub(color.r, color.g, color.b, color.a);
			
			for (int i = 0; i < numPoints; i++)
			{
				glVertex2f(points[i].x, points[i].y);
			}
		glEnd();
		
		glDisable(GL_POLYGON_SMOOTH);
	}
}

// Draw polygon lines
// NOTE: Array num elements MUST be passed as parameter to function												
void DrawPolyLine(Vector2 *points, int numPoints, Color color)
{
	if (numPoints >= 2)
	{
		//glEnable(GL_LINE_SMOOTH);						// Smoothies circle outline (anti-aliasing applied)
		//glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);		// Best quality for line smooth (anti-aliasing best algorithm)
	
		glBegin(GL_LINE_LOOP);
			glColor4ub(color.r, color.g, color.b, color.a);
			
			for (int i = 0; i < numPoints; i++)
			{
				glVertex2f(points[i].x, points[i].y);
			}
		glEnd();
		
		//glDisable(GL_LINE_SMOOTH);
	}
}