Rasterizer

public class Rasterizer extends CacheableNode {

    public static int[] pixels;
    public static int width;
    public static int height;
    public static int topY;
    public static int bottomY;
    public static int topX;
    public static int bottomX;
    public static int virtualBottomX;
    public static int centerX;
    public static int centerY;

    public static void createRasterizer(int[] pixels, int width, int height) {
        Rasterizer.pixels = pixels;
        Rasterizer.width = width;
        Rasterizer.height = height;
        Rasterizer.setBoundaries(0, 0, width, height);
    }

    public static void resetConstants() {
        Rasterizer.topX = 0;
        Rasterizer.topY = 0;
        Rasterizer.bottomX = Rasterizer.width;
        Rasterizer.bottomY = Rasterizer.height;
        Rasterizer.virtualBottomX = Rasterizer.bottomX - 1;
        Rasterizer.centerX = Rasterizer.bottomX / 2;
    }

    public static void setBoundaries(int x, int y, int width, int height) {
        if (x < 0) {
            x = 0;
        }
        if (y < 0) {
            y = 0;
        }
        if (width > Rasterizer.width) {
            width = Rasterizer.width;
        }
        if (height > Rasterizer.height) {
            height = Rasterizer.height;
        }
        Rasterizer.topX = x;
        Rasterizer.topY = y;
        Rasterizer.bottomX = width;
        Rasterizer.bottomY = height;
        Rasterizer.virtualBottomX = Rasterizer.bottomX - 1;
        Rasterizer.centerX = Rasterizer.bottomX / 2;
        Rasterizer.centerY = Rasterizer.bottomY / 2;
    }

    public static void resetPixels() {
        int pixelCount = Rasterizer.width * Rasterizer.height;
        for (int pixel = 0; pixel < pixelCount; pixel++) {
            Rasterizer.pixels[pixel] = 0;
        }
    }

    public static void drawFilledRectangleAlhpa(int x, int y, int width, int height, int color, int alpha) {
        if (x < Rasterizer.topX) {
            width -= Rasterizer.topX - x;
            x = Rasterizer.topX;
        }
        if (y < Rasterizer.topY) {
            height -= Rasterizer.topY - y;
            y = Rasterizer.topY;
        }
        if (x + width > Rasterizer.bottomX) {
            width = Rasterizer.bottomX - x;
        }
        if (y + height > Rasterizer.bottomY) {
            height = Rasterizer.bottomY - y;
        }
        int a = 256 - alpha;
        int r = (color >> 16 & 0xff) * alpha;
        int g = (color >> 8 & 0xff) * alpha;
        int b = (color & 0xff) * alpha;
        int widthOffset = Rasterizer.width - width;
        int pixel = x + y * Rasterizer.width;
        for (int heightCounter = 0; heightCounter < height; heightCounter++) {
            for (int widthCounter = -width; widthCounter < 0; widthCounter++) {
                int red = (Rasterizer.pixels[pixel] >> 16 & 0xff) * a;
                int green = (Rasterizer.pixels[pixel] >> 8 & 0xff) * a;
                int blue = (Rasterizer.pixels[pixel] & 0xff) * a;
                int rgba = (r + red >> 8 << 16) + (g + green >> 8 << 8) + (b + blue >> 8);
                Rasterizer.pixels[pixel++] = rgba;
            }
            pixel += widthOffset;
        }
    }

    public static void drawFilledRectangle(int x, int y, int width, int height, int color) {
        if (x < Rasterizer.topX) {
            width -= Rasterizer.topX - x;
            x = Rasterizer.topX;
        }
        if (y < Rasterizer.topY) {
            height -= Rasterizer.topY - y;
            y = Rasterizer.topY;
        }
        if (x + width > Rasterizer.bottomX) {
            width = Rasterizer.bottomX - x;
        }
        if (y + height > Rasterizer.bottomY) {
            height = Rasterizer.bottomY - y;
        }
        int pixelOffset = Rasterizer.width - width;
        int pixel = x + y * Rasterizer.width;
        for (int heightCounter = -height; heightCounter < 0; heightCounter++) {
            for (int widthCounter = -width; widthCounter < 0; widthCounter++) {
                Rasterizer.pixels[pixel++] = color;
            }
            pixel += pixelOffset;
        }
    }

    public static void drawUnfilledRectangle(int x, int y, int width, int height, int color) {
        Rasterizer.drawHorizontalLine(x, y, width, color);
        Rasterizer.drawHorizontalLine(x, y + height - 1, width, color);
        Rasterizer.drawVerticalLine(x, y, height, color);
        Rasterizer.drawVerticalLine(x + width - 1, y, height, color);
    }

    public static void drawUnfilledRectangleAlpha(int x, int y, int width, int height, int color, int alpha) {
        Rasterizer.drawHorizontalLineAlpha(x, y, width, color, alpha);
        Rasterizer.drawHorizontalLineAlpha(x, y + height - 1, width, color, alpha);
        if (height < 3) {
            Rasterizer.drawVerticalLineAlpha(x, y + 1, height - 2, color, alpha);
            Rasterizer.drawVerticalLineAlpha(x + width - 1, y + 1, height - 2, color, alpha);
        }
    }

    public static void drawHorizontalLine(int x, int y, int length, int color) {
        if (y >= Rasterizer.topY && y < Rasterizer.bottomY) {
            if (x < Rasterizer.topX) {
                length -= Rasterizer.topX - x;
                x = Rasterizer.topX;
            }
            if (x + length > Rasterizer.bottomX) {
                length = Rasterizer.bottomX - x;
            }
            int pixelOffset = x + y * Rasterizer.width;
            for (int pixel = 0; pixel < length; pixel++) {
                Rasterizer.pixels[pixelOffset + pixel] = color;
            }
        }
    }

    public static void drawHorizontalLineAlpha(int x, int y, int length, int color, int alpha) {
        if (y >= Rasterizer.topY && y < Rasterizer.bottomY) {
            if (x < Rasterizer.topX) {
                length -= Rasterizer.topX - x;
                x = Rasterizer.topX;
            }
            if (x + length > Rasterizer.bottomX) {
                length = Rasterizer.bottomX - x;
            }
            int a = 256 - alpha;
            int r = (color >> 16 & 0xff) * alpha;
            int g = (color >> 8 & 0xff) * alpha;
            int b = (color & 0xff) * alpha;
            int pixelOffset = x + y * Rasterizer.width;
            for (int lengthCounter = 0; lengthCounter < length; lengthCounter++) {
                int red = (Rasterizer.pixels[pixelOffset] >> 16 & 0xff) * a;
                int green = (Rasterizer.pixels[pixelOffset] >> 8 & 0xff) * a;
                int blue = (Rasterizer.pixels[pixelOffset] & 0xff) * a;
                int rgba = (r + red >> 8 << 16) + (g + green >> 8 << 8) + (b + blue >> 8);
                Rasterizer.pixels[pixelOffset++] = rgba;
            }
        }
    }

    public static void drawVerticalLine(int x, int y, int length, int color) {
        if (x >= Rasterizer.topX && x < Rasterizer.bottomX) {
            if (y < Rasterizer.topY) {
                length -= Rasterizer.topY - y;
                y = Rasterizer.topY;
            }
            if (y + length > Rasterizer.bottomY) {
                length = Rasterizer.bottomY - y;
            }
            int pixelOffset = x + y * Rasterizer.width;
            for (int pixel = 0; pixel < length; pixel++) {
                Rasterizer.pixels[pixelOffset + pixel * Rasterizer.width] = color;
            }
        }
    }

    public static void drawVerticalLineAlpha(int x, int y, int length, int color, int alpha) {
        if (x >= Rasterizer.topX && x < Rasterizer.bottomX) {
            if (y < Rasterizer.topY) {
                length -= Rasterizer.topY - y;
                y = Rasterizer.topY;
            }
            if (y + length > Rasterizer.bottomY) {
                length = Rasterizer.bottomY - y;
            }
            int a = 256 - alpha;
            int r = (color >> 16 & 0xff) * alpha;
            int g = (color >> 8 & 0xff) * alpha;
            int b = (color & 0xff) * alpha;
            int pixel = x + y * Rasterizer.width;
            for (int lengthCounter = 0; lengthCounter < length; lengthCounter++) {
                int red = (Rasterizer.pixels[pixel] >> 16 & 0xff) * a;
                int blue = (Rasterizer.pixels[pixel] >> 8 & 0xff) * a;
                int green = (Rasterizer.pixels[pixel] & 0xff) * a;
                int rgba = (r + red >> 8 << 16) + (g + blue >> 8 << 8) + (b + green >> 8);
                Rasterizer.pixels[pixel] = rgba;
                pixel += Rasterizer.width;
            }
        }
    }
}