#include "Display.h"

#include <QTimer>

using namespace QGBA;

static const GLint _glVertices[] = {
	0, 0,
	256, 0,
	256, 256,
	0, 256
};

static const GLint _glTexCoords[] = {
	0, 0,
	1, 0,
	1, 1,
	0, 1
};

Display::Display(QWidget* parent) : QGLWidget(QGLFormat(QGL::Rgba | QGL::DoubleBuffer), parent) {
	setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	QTimer* timer = new QTimer(this);
	connect(timer, SIGNAL(timeout()), this, SLOT(updateGL()));
	timer->setInterval(0);
	timer->start();
}

void Display::initializeGL() {
	glEnable(GL_TEXTURE_2D);
	glGenTextures(1, &m_tex);
	glBindTexture(GL_TEXTURE_2D, m_tex);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}

void Display::draw(const QImage& image) {
	makeCurrent();
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, m_tex);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.constBits());
}

void Display::paintGL() {
	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
	glEnableClientState(GL_VERTEX_ARRAY);
	glVertexPointer(2, GL_INT, 0, _glVertices);
	glTexCoordPointer(2, GL_INT, 0, _glTexCoords);
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0, 240, 160, 0, 0, 1);
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, m_tex);
	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
}