#include "viewerwindow.h"

ViewerWindow::ViewerWindow(QOpenGLContext *share) :
	QOpenGLWindow(share),
	texture(0)
{}

void ViewerWindow::set_texture(GLuint t, double iar) {
	texture = t;
	ar = iar;
	update();
}

void ViewerWindow::paintGL() {
	if (texture > 0) {
		glClearColor(0.0, 0.0, 0.0, 1.0);
		glClear(GL_COLOR_BUFFER_BIT);

		glEnable(GL_TEXTURE_2D);

		glBindTexture(GL_TEXTURE_2D, texture);

		glLoadIdentity();
		glOrtho(0, 1, 0, 1, -1, 1);

		glBegin(GL_QUADS);

		double top = 0;
		double left = 0;
		double right = 1;
		double bottom = 1;

		double widget_ar = double(width()) / double(height());

		if (widget_ar > ar) {
			double width = 1.0 * ar / widget_ar;
			left = (1.0 - width)*0.5;
			right = left + width;
		} else {
			double height = 1.0 / ar * widget_ar;
			top = (1.0 - height)*0.5;
			bottom = top + height;
		}

		glVertex2d(left, top);
		glTexCoord2d(0, 0);
		glVertex2d(left, bottom);
		glTexCoord2d(1, 0);
		glVertex2d(right, bottom);
		glTexCoord2d(1, 1);
		glVertex2d(right, top);
		glTexCoord2d(0, 1);

		glEnd();

		glBindTexture(GL_TEXTURE_2D, 0);

		glDisable(GL_TEXTURE_2D);
	}
}