minecraft-src/com/mojang/blaze3d/pipeline/RenderTarget.java

package com.mojang.blaze3d.pipeline;

import com.mojang.blaze3d.buffers.GpuBuffer;
import com.mojang.blaze3d.systems.RenderPass;
import com.mojang.blaze3d.systems.RenderSystem;
import com.mojang.blaze3d.textures.AddressMode;
import com.mojang.blaze3d.textures.FilterMode;
import com.mojang.blaze3d.textures.GpuTexture;
import com.mojang.blaze3d.textures.TextureFormat;
import com.mojang.blaze3d.vertex.VertexFormat;
import java.util.OptionalInt;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.client.renderer.RenderPipelines;
import org.jetbrains.annotations.Nullable;

@Environment(EnvType.CLIENT)
public abstract class RenderTarget {
	private static int UNNAMED_RENDER_TARGETS = 0;
	public int width;
	public int height;
	public int viewWidth;
	public int viewHeight;
	protected final String label;
	public final boolean useDepth;
	@Nullable
	protected GpuTexture colorTexture;
	@Nullable
	protected GpuTexture depthTexture;
	public FilterMode filterMode;

	public RenderTarget(@Nullable String name, boolean useDepth) {
		this.label = name == null ? "FBO " + UNNAMED_RENDER_TARGETS++ : name;
		this.useDepth = useDepth;
	}

	public void resize(int width, int height) {
		RenderSystem.assertOnRenderThread();
		this.destroyBuffers();
		this.createBuffers(width, height);
	}

	public void destroyBuffers() {
		RenderSystem.assertOnRenderThread();
		if (this.depthTexture != null) {
			this.depthTexture.close();
			this.depthTexture = null;
		}

		if (this.colorTexture != null) {
			this.colorTexture.close();
			this.colorTexture = null;
		}
	}

	public void copyDepthFrom(RenderTarget otherTarget) {
		RenderSystem.assertOnRenderThread();
		if (this.depthTexture == null) {
			throw new IllegalStateException("Trying to copy depth texture to a RenderTarget without a depth texture");
		} else if (otherTarget.depthTexture == null) {
			throw new IllegalStateException("Trying to copy depth texture from a RenderTarget without a depth texture");
		} else {
			RenderSystem.getDevice().createCommandEncoder().copyTextureToTexture(otherTarget.depthTexture, this.depthTexture, 0, 0, 0, 0, 0, this.width, this.height);
		}
	}

	public void createBuffers(int width, int height) {
		RenderSystem.assertOnRenderThread();
		int i = RenderSystem.getDevice().getMaxTextureSize();
		if (width > 0 && width <= i && height > 0 && height <= i) {
			this.viewWidth = width;
			this.viewHeight = height;
			this.width = width;
			this.height = height;
			if (this.useDepth) {
				this.depthTexture = RenderSystem.getDevice().createTexture(() -> this.label + " / Depth", TextureFormat.DEPTH32, width, height, 1);
				this.depthTexture.setTextureFilter(FilterMode.NEAREST, false);
				this.depthTexture.setAddressMode(AddressMode.CLAMP_TO_EDGE);
			}

			this.colorTexture = RenderSystem.getDevice().createTexture(() -> this.label + " / Color", TextureFormat.RGBA8, width, height, 1);
			this.colorTexture.setAddressMode(AddressMode.CLAMP_TO_EDGE);
			this.setFilterMode(FilterMode.NEAREST, true);
		} else {
			throw new IllegalArgumentException("Window " + width + "x" + height + " size out of bounds (max. size: " + i + ")");
		}
	}

	public void setFilterMode(FilterMode filterMode) {
		this.setFilterMode(filterMode, false);
	}

	private void setFilterMode(FilterMode filterMode, boolean force) {
		if (this.colorTexture == null) {
			throw new IllegalStateException("Can't change filter mode, color texture doesn't exist yet");
		} else {
			if (force || filterMode != this.filterMode) {
				this.filterMode = filterMode;
				this.colorTexture.setTextureFilter(filterMode, false);
			}
		}
	}

	public void blitToScreen() {
		if (this.colorTexture == null) {
			throw new IllegalStateException("Can't blit to screen, color texture doesn't exist yet");
		} else {
			RenderSystem.getDevice().createCommandEncoder().presentTexture(this.colorTexture);
		}
	}

	public void blitAndBlendToTexture(GpuTexture texture) {
		RenderSystem.assertOnRenderThread();
		RenderSystem.AutoStorageIndexBuffer autoStorageIndexBuffer = RenderSystem.getSequentialBuffer(VertexFormat.Mode.QUADS);
		GpuBuffer gpuBuffer = autoStorageIndexBuffer.getBuffer(6);
		GpuBuffer gpuBuffer2 = RenderSystem.getQuadVertexBuffer();

		try (RenderPass renderPass = RenderSystem.getDevice().createCommandEncoder().createRenderPass(texture, OptionalInt.empty())) {
			renderPass.setPipeline(RenderPipelines.ENTITY_OUTLINE_BLIT);
			renderPass.setVertexBuffer(0, gpuBuffer2);
			renderPass.setIndexBuffer(gpuBuffer, autoStorageIndexBuffer.type());
			renderPass.bindSampler("InSampler", this.colorTexture);
			renderPass.drawIndexed(0, 6);
		}
	}

	@Nullable
	public GpuTexture getColorTexture() {
		return this.colorTexture;
	}

	@Nullable
	public GpuTexture getDepthTexture() {
		return this.depthTexture;
	}
}