io.github.mwttg.pixelartillery2d.graphic.PlaneFactory Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of pixel-artillery-2d Show documentation
A library for 2D OpenGL and OpenAL support based on LWJGL 3
The newest version!
package io.github.mwttg.pixelartillery2d.graphic;

// @formatter:off
/**
 * Wavefront OBJ file example # Blender v2.92.0 OBJ File: '' # www.blender.org o Plane v 0.000000
 * 0.000000 0.000000 v 1.000000 0.000000 0.000000 v 0.000000 1.000000 0.000000 v 1.000000 1.000000
 * 0.000000 vt 1.000000 0.000000 vt 0.000000 1.000000 vt 0.000000 0.000000 vt 1.000000 1.000000 s
 * off f 2/1 3/2 1/3 f 2/1 4/4 3/2
 *
 * OpenGL coordinates example The coordinates for the example plane from above would look like: v
 * = 3 = (0.0, 1.0, 0.0) v = 4 = (1.0, 1.0, 0.0) vt = 2 = (0.0, 1.0) vt = 4 = (1.0, 1.0)
 * ------------------------ | \ | | \ | | \ | | \ | | \ | | \ | | \ | ------------------------ v = 1
 * = (0.0, 0.0, 0.0) v = 2 = (1.0, 0.0, 0.0) vt = 3 = (0.0, 0.0) vt = 1 = (1.0, 0.0)
 */
// @formatter:on
final class PlaneFactory {

  private static final int FLOATS_PER_PLANE = 18;
  private static final int FLOAT_PER_UV = 12;

  private PlaneFactory() {}

  static Plane create(final float width, final float height) {
    final var geometry = geometry(width, height);
    final var uvCoordinates = uvCoordinates(0, 1);
    final var uvCoordinatesHorizontalFlipped = uvCoordinatesFlippedHorizontal(0, 1);
    return new Plane(geometry, uvCoordinates, uvCoordinatesHorizontalFlipped);
  }

  static Plane createPlaneStrip(final float width, final float height, final int maxFrames) {
    var geometry = new float[maxFrames * FLOATS_PER_PLANE];
    var uvCoordinates = new float[maxFrames * FLOAT_PER_UV];
    var uvCoordinatesFlippedHorizontal = new float[maxFrames * FLOAT_PER_UV];

    for (int frame = 0; frame < maxFrames; frame++) {
      final var plane = geometry(width, height);
      var geometryIndex = frame * FLOATS_PER_PLANE;
      for (float f : plane) {
        geometry[geometryIndex] = f;
        geometryIndex++;
      }

      final var uv = uvCoordinates(frame, maxFrames);
      var uvIndex = frame * FLOAT_PER_UV;
      for (float f : uv) {
        uvCoordinates[uvIndex] = f;
        uvIndex++;
      }

      final var uvFlippedHorizontal = uvCoordinatesFlippedHorizontal(frame, maxFrames);
      var uvIndexFlippedHorizontal = frame * FLOAT_PER_UV;
      for (float f : uvFlippedHorizontal) {
        uvCoordinatesFlippedHorizontal[uvIndexFlippedHorizontal] = f;
        uvIndexFlippedHorizontal++;
      }
    }
    return new Plane(geometry, uvCoordinates, uvCoordinatesFlippedHorizontal);
  }

  private static float[] geometry(final float width, final float height) {
    // @formatter:off
    return new float[] {
      width, 0.0f, 0.0f, 0.0f, height, 0.0f, 0.0f, 0.0f, 0.0f, width, 0.0f, 0.0f, width, height,
      0.0f, 0.0f, height, 0.0f
    };
    // @formatter:on
  }

  private static float[] uvCoordinates(final int currentFrame, final int maxFrames) {
    final var width = 1.0f / (float) maxFrames;
    final var left = width * currentFrame;
    final var right = left + width;
    // @formatter:off
    return new float[] {
      right, 0.0f,
      left, 1.0f,
      left, 0.0f,
      right, 0.0f,
      right, 1.0f,
      left, 1.0f
    };
    // @formatter:on
  }

  private static float[] uvCoordinatesFlippedHorizontal(
      final int currentFrame, final int maxFrames) {
    final var width = 1.0f / (float) maxFrames;
    final var left = width * currentFrame;
    final var right = left + width;
    // @formatter:off
    return new float[] {
      left, 0.0f,
      right, 1.0f,
      right, 0.0f,
      left, 0.0f,
      left, 1.0f,
      right, 1.0f
    };
    // @formatter:on
  }
}