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

package com.danitheskunk.skunkworks.backends.gl;

import com.danitheskunk.skunkworks.*;
import com.danitheskunk.skunkworks.gfx.*;

import static org.lwjgl.opengl.GL46.*;

class RenderContext extends BaseRenderContext implements IRenderContext {
	private final TextureAtlas atlas;
	private final int texCoordIndex;
	private final int texOffsetIndex;
	private final int texSizeIndex;

	public RenderContext(TextureAtlas atlas, int texCoordIndex, int texOffsetIndex, int texSizeIndex) {
		this.atlas = atlas;
		this.texCoordIndex = texCoordIndex;
		this.texOffsetIndex = texOffsetIndex;
		this.texSizeIndex = texSizeIndex;
	}

	@Override
	public void drawNineSlice(NineSlice slice, Recti rect) {
		var centerWidth = Math.min(0, rect.getWidth() - slice.getLeft().getSize().getX() - slice.getRight().getSize().getX());
		var centerHeight = Math.min(0, rect.getHeight() - slice.getTop().getSize().getY() - slice.getBottom().getSize().getY());
		var pos = rect.getPos();
		var size = rect.getSize();

		drawTexture(pos, slice.getTopLeft());
	}

	@Override
	public void drawRectangle(Recti rect, Color color) {
		var tl = rect.getTopLeft();
		var tr = rect.getTopRight();
		var bl = rect.getBottomLeft();
		var br = rect.getBottomRight();

		//todo: make work with enabled textures

		glColor4f(
			color.getR() / 255.0f,
			color.getG() / 255.0f,
			color.getB() / 255.0f,
			color.getA() / 255.0f
		);

		//counterclockwise triangles
		glVertex2i(bl.getX(), bl.getY());
		glVertex2i(tr.getX(), tr.getY());
		glVertex2i(tl.getX(), tl.getY());

		glVertex2i(tr.getX(), tr.getY());
		glVertex2i(bl.getX(), bl.getY());
		glVertex2i(br.getX(), bl.getY());
	}

	@Override
	public void drawTexture(Vec2i pos, ITexture texture) {
		drawTextureRectangle(new Recti(pos, texture.getSize()), texture, true);
	}

	@Override
	public void drawTexture(Vec2i pos, ITexture texture, Color color) {
		drawTextureRectangle(new Recti(pos, texture.getSize()), texture, color, true);
	}

	@Override
	public void drawTextureRectangle(Recti rect, ITexture texture, boolean repeat) {
		drawTextureRectangle(rect, texture, Color.WHITE, repeat);
	}

	@Override
	public void drawTextureRectangle(Recti rect, ITexture texture, Color color, boolean repeat) {
		var tex = (Texture)texture;

		var tl = rect.getTopLeft();
		var tr = rect.getTopRight();
		var bl = rect.getBottomLeft();
		var br = rect.getBottomRight();

		/*
		var ttl = Vec2i.divf(tex.getTexArea().getTopLeft(),     atlas.getSize());
		var ttr = Vec2i.divf(tex.getTexArea().getTopRight(),    atlas.getSize());
		var tbl = Vec2i.divf(tex.getTexArea().getBottomLeft(),  atlas.getSize());
		var tbr = Vec2i.divf(tex.getTexArea().getBottomRight(), atlas.getSize());
		*/

		var topleft = tex.getTexArea().getTopLeft();
		var size = repeat ? tex.getSize() : rect.getSize();
		/*var ttl = Vec2i.ZERO;
		var ttr = Vec2i.sub(tex.getTexArea().getTopRight(), topleft);
		var tbl = Vec2i.sub(tex.getTexArea().getBottomLeft(), topleft);
		var tbr = Vec2i.sub(tex.getTexArea().getBottomRight(), topleft);
		*/
		var ttl = Vec2i.ZERO;
		var ttr = new Vec2i(rect.getWidth(), 0);
		var tbl = new Vec2i(0, rect.getHeight());
		var tbr = new Vec2i(rect.getWidth(), rect.getHeight());

		if(!repeat) {
			ttr = Vec2i.sub(tex.getTexArea().getTopRight(), topleft);
			tbl = Vec2i.sub(tex.getTexArea().getBottomLeft(), topleft);
			tbr = Vec2i.sub(tex.getTexArea().getBottomRight(), topleft);
		}

		glColor4f(
			color.getR() / 255.0f,
			color.getG() / 255.0f,
			color.getB() / 255.0f,
			color.getA() / 255.0f
		);

		glUniform2i(texOffsetIndex, topleft.getX(), topleft.getY());
		glUniform2i(texSizeIndex, size.getX(), size.getY());
		glBegin(GL_TRIANGLES);
		//counterclockwise triangles
		glVertexAttribI2i(texCoordIndex, tbl.getX(), tbl.getY());
		glVertex2i(bl.getX(), bl.getY());
		glVertexAttribI2i(texCoordIndex, ttr.getX(), ttr.getY());
		glVertex2i(tr.getX(), tr.getY());
		glVertexAttribI2i(texCoordIndex, ttl.getX(), ttl.getY());
		glVertex2i(tl.getX(), tl.getY());

		glVertexAttribI2i(texCoordIndex, ttr.getX(), ttr.getY());
		glVertex2i(tr.getX(), tr.getY());
		glVertexAttribI2i(texCoordIndex, tbl.getX(), tbl.getY());
		glVertex2i(bl.getX(), bl.getY());
		glVertexAttribI2i(texCoordIndex, tbr.getX(), tbr.getY());
		glVertex2i(br.getX(), bl.getY());
		glEnd();
	}
}