SimpleNES/src/VirtualScreen.cpp

#include "VirtualScreen.h"

namespace sn
{
    void VirtualScreen::create(unsigned int w, unsigned int h, float pixel_size, sf::Color color)
    {
        m_vertices.resize(w * h * 6);
        m_screenSize = {w, h};
        m_vertices.setPrimitiveType(sf::Triangles);
        m_pixelSize = pixel_size;
        for (std::size_t x = 0; x < w; ++x)
        {
            for (std::size_t y = 0; y < h; ++y)
            {
                auto index = (x * m_screenSize.y + y) * 6;
                sf::Vector2f coord2d (x * m_pixelSize, y * m_pixelSize);

                //Triangle-1
                //top-left
                m_vertices[index].position = coord2d;
                m_vertices[index].color    = color;

                //top-right
                m_vertices[index + 1].position = coord2d + sf::Vector2f{m_pixelSize, 0};
                m_vertices[index + 1].color = color;

                //bottom-right
                m_vertices[index + 2].position = coord2d + sf::Vector2f{m_pixelSize, m_pixelSize};
                m_vertices[index + 2].color = color;

                //Triangle-2
                //bottom-right
                m_vertices[index + 3].position = coord2d + sf::Vector2f{m_pixelSize, m_pixelSize};
                m_vertices[index + 3].color = color;

                //bottom-left
                m_vertices[index + 4].position = coord2d + sf::Vector2f{0, m_pixelSize};
                m_vertices[index + 4].color = color;

                //top-left
                m_vertices[index + 5].position = coord2d;
                m_vertices[index + 5].color    = color;
            }
        }
    }

    void VirtualScreen::setPixel(std::size_t x, std::size_t y, sf::Color color)
    {
        auto index = (x * m_screenSize.y + y) * 6;
        if (index >= m_vertices.getVertexCount())
            return;

        sf::Vector2f coord2d (x * m_pixelSize, y * m_pixelSize);

        //Triangle-1
        //top-left
        m_vertices[index].color    = color;

        //top-right
        m_vertices[index + 1].color = color;

        //bottom-right
        m_vertices[index + 2].color = color;

        //Triangle-2
        //bottom-right
        m_vertices[index + 3].color = color;

        //bottom-left
        m_vertices[index + 4].color = color;

        //top-left
        m_vertices[index + 5].color    = color;
    }

    void VirtualScreen::draw(sf::RenderTarget& target, sf::RenderStates states) const
    {
        target.draw(m_vertices, states);
    }


}