skunkworks/com/danitheskunk/skunkworks/backends/gl/Window.java

package com.danitheskunk.skunkworks.backends.gl;

import com.danitheskunk.skunkworks.*;
import com.danitheskunk.skunkworks.gfx.IRenderContext;
import com.danitheskunk.skunkworks.gfx.ITexture;
import com.danitheskunk.skunkworks.gfx.Image;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.opengl.GL;
import org.lwjgl.opengl.GL11;

import java.util.ArrayList;
import java.util.List;

import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL46.*;
import static org.lwjgl.system.MemoryUtil.NULL;

public class Window extends BaseWindow {
	private boolean debug;
	private final Program program;
	private final RenderContext renderContext;
	private boolean shouldClose;
	private final Vec2i size;
	private final TextureAtlas textureAtlas;
	private final long window;

	public Window(Vec2i size, String title, Engine engine) {
		super(engine);
		GLFWErrorCallback.createPrint(System.err).set();
		if(!glfwInit()) throw new IllegalStateException("Unable to initialize GLFW");

		glfwDefaultWindowHints();
		this.debug = false;
		this.size = size;

		window = glfwCreateWindow(size.getX(), size.getY(), title, NULL, NULL);
		if(window == NULL) throw new RuntimeException("Failed to create GLFW window");


		glfwShowWindow(window);
		glfwMakeContextCurrent(window);
		glfwSwapInterval(1); //vsync
		GL.createCapabilities();
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glOrtho(0.0f, size.getX(), size.getY(), 0.0f, 0.0f, 1.0f);
		glEnable(GL_COLOR);
		glEnable(GL_TEXTURE_2D);
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		glEnable(GL_BLEND);

		textureAtlas = new TextureAtlas();
		program = new Program(vertexSource, fragmentSource);
		program.use();
		renderContext = new RenderContext(textureAtlas, program.getAttribLocation("texCoord"));
		glProgramUniform2f(program.program, program.getUniformLocation("windowSize"), size.getX(), size.getY());

		shouldClose = false;

		System.out.println("Skunkworks window initialised");
		System.out.print("Maximum Texture Size: ");
		System.out.println(GL11.glGetInteger(GL_MAX_TEXTURE_SIZE));
	}

	@Override
	public ITexture loadTexture(Image image) {
		return textureAtlas.addTexture(image);
	}

	@Override
	public ITexture loadTexture(String path) {
		var img = engine.loadImage(path);
		return textureAtlas.addTexture(img);
	}

	@Override
	public List<ITexture> loadTextureArray(Image image, Vec2i tileSize) {
		var tileCount = Vec2i.div(image.getSize(), tileSize);
		var tiles = new ArrayList<ITexture>();

		for(int y = 0; y < tileCount.getY(); ++y) {
			for(int x = 0; x < tileCount.getX(); ++x) {
				var rect = new Recti(Vec2i.mul(new Vec2i(x, y), tileSize), tileSize);
				var img = image.getSubImage(rect);
				tiles.add(loadTexture(img));
			}
		}

		return tiles;
	}

	@Override
	public List<ITexture> loadTextureArray(String path, Vec2i tileSize) {
		var img = engine.loadImage(path);
		return loadTextureArray(img, tileSize);
	}

	@Override
	public void renderFinish(IRenderContext context) {
		if(debug) {
			context.drawTextureRectangle(new Recti(Vec2i.ZERO, size), textureAtlas.getAtlasTexture());
		}
		glEnd();
		glfwSwapBuffers(window);
	}

	@Override
	public IRenderContext renderStart() {
		textureAtlas.update();
		glClearColor(0.1f, 0.2f, 0.3f, 1.0f);
		glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		program.use();
		glBegin(GL_TRIANGLES);
		return renderContext;
	}

	@Override
	public void setDebug(boolean on) {
		this.debug = on;
	}

	@Override
	public boolean shouldClose() {
		return shouldClose;
	}

	@Override
	public void tick() {
		glfwMakeContextCurrent(window);
		if(glfwWindowShouldClose(window)) {
			shouldClose = true;
			return;
		}

		glfwPollEvents();
	}

	private static String vertexSource = """
		#version 450
		layout(location = 0) in vec2 pos;
		layout(location = 1) in vec2 texCoord;
		layout(location = 2) uniform vec2 windowSize;
		layout(location = 1) out vec2 out_texCoord;
		void main() {
			gl_Position = vec4(pos / windowSize * vec2(2.0f, -2.0f) + vec2(-1.0f, 1.0f), 0.0f, 1.0f);
			out_texCoord = texCoord;
		}
		""";

	private static String fragmentSource = """
  		#version 450
  		layout(location = 1) in vec2 texCoord;
  		layout(binding = 0) uniform sampler2D tex;
  		out vec4 color;
  		void main() {
  			//color = vec4(texCoord.x, texCoord.y, 0.7f, 1.0f);
  			color = texture(tex, texCoord);
  		}
		""";
}