// Copyright (c) 2007, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:zeratul@cellosoft.com
//


///////////
// Headers
#include <GL/gl.h>
#include "gl_wrap.h"


/////////////
// Draw line
void OpenGLWrapper::DrawLine(float x1,float y1,float x2,float y2) {
	SetModeLine();
	glBegin(GL_LINES);
		glVertex2f(x1,y1);
		glVertex2f(x2,y2);
	glEnd();
}


///////////////
// Draw circle
void OpenGLWrapper::DrawEllipse(float x,float y,float radiusX,float radiusY) {
	DrawRing(x,y,radiusY,radiusY,radiusX/radiusY);
}


//////////////////
// Draw rectangle
void OpenGLWrapper::DrawRectangle(float x1,float y1,float x2,float y2) {
	// Fill
	if (a2 != 0.0) {
		SetModeFill();
		glBegin(GL_QUADS);
			glVertex2f(x1,y1);
			glVertex2f(x2,y1);
			glVertex2f(x2,y2);
			glVertex2f(x1,y2);
		glEnd();
	}

	// Outline
	if (a1 != 0.0) {
		SetModeLine();
		glBegin(GL_LINE_LOOP);
			glVertex2f(x1,y1);
			glVertex2f(x2,y1);
			glVertex2f(x2,y2);
			glVertex2f(x1,y2);
		glEnd();
	}
}


///////////////////////
// Draw ring (annulus)
void OpenGLWrapper::DrawRing(float x,float y,float r1,float r2,float ar,float arcStart,float arcEnd) {
	// Make r1 bigger
	if (r2 > r1) {
		float temp = r1;
		r1 = r2;
		r2 = temp;
	}

	// Arc range
	bool hasEnds = arcStart != arcEnd;
	float pi = 3.1415926535897932384626433832795f;
	arcEnd *= pi / 180.f;
	arcStart *= pi / 180.f;
	if (arcEnd <= arcStart) arcEnd += 2.0f*pi;
	float range = arcEnd - arcStart;

	// Math
	int steps = int((r1 + r1*ar) * range / (2.0f*pi))*4;
	if (steps < 12) steps = 12;
	//float end = arcEnd;
	float step = range/steps;
	float curAngle = arcStart;

	// Fill
	if (a2 != 0.0) {
		SetModeFill();

		// Annulus
		if (r1 != r2) {
			glBegin(GL_QUADS);
			for (int i=0;i<steps;i++) {
				glVertex2f(x+sin(curAngle)*r1*ar,y+cos(curAngle)*r1);
				glVertex2f(x+sin(curAngle)*r2*ar,y+cos(curAngle)*r2);
				curAngle += step;
				glVertex2f(x+sin(curAngle)*r2*ar,y+cos(curAngle)*r2);
				glVertex2f(x+sin(curAngle)*r1*ar,y+cos(curAngle)*r1);
			}
			glEnd();
		}

		// Circle
		else {
			glBegin(GL_POLYGON);
			for (int i=0;i<steps;i++) {
				glVertex2f(x+sin(curAngle)*r1,y+cos(curAngle)*r1);
				curAngle += step;
			}
			glEnd();
		}

		// Reset angle
		curAngle = arcStart;
	}

	// Outlines
	if (a1 != 0.0) {
		// Outer
		steps++;
		SetModeLine();
		glBegin(GL_LINE_STRIP);
		for (int i=0;i<steps;i++) {
			glVertex2f(x+sin(curAngle)*r1,y+cos(curAngle)*r1);
			curAngle += step;
		}
		glEnd();

		// Inner
		if (r1 != r2) {
			curAngle = arcStart;
			glBegin(GL_LINE_STRIP);
			for (int i=0;i<steps;i++) {
				glVertex2f(x+sin(curAngle)*r2,y+cos(curAngle)*r2);
				curAngle += step;
			}
			glEnd();

			// End caps
			if (hasEnds) {
				glBegin(GL_LINES);
					glVertex2f(x+sin(arcStart)*r1,y+cos(arcStart)*r1);
					glVertex2f(x+sin(arcStart)*r2,y+cos(arcStart)*r2);
					glVertex2f(x+sin(arcEnd)*r1,y+cos(arcEnd)*r1);
					glVertex2f(x+sin(arcEnd)*r2,y+cos(arcEnd)*r2);
				glEnd();
			}
		}
	}
}


///////////////////
// Set line colour
void OpenGLWrapper::SetLineColour(wxColour col,float alpha,int width) {
	r1 = col.Red()/255.0f;
	g1 = col.Green()/255.0f;
	b1 = col.Blue()/255.0f;
	a1 = alpha;
	lw = width;
}


///////////////////
// Set fill colour
void OpenGLWrapper::SetFillColour(wxColour col,float alpha) {
	r2 = col.Red()/255.0f;
	g2 = col.Green()/255.0f;
	b2 = col.Blue()/255.0f;
	a2 = alpha;
}


////////
// Line
void OpenGLWrapper::SetModeLine() {
	glColor4f(r1,g1,b1,a1);
	if (a1 == 1.0f) glDisable(GL_BLEND);
	else {
		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
	}
	glLineWidth(lw);
	//glEnable(GL_LINE_SMOOTH);
}


////////
// Fill
void OpenGLWrapper::SetModeFill() {
	glColor4f(r2,g2,b2,a2);
	if (a2 == 1.0f) glDisable(GL_BLEND);
	else {
		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
	}
}