Add placeholder PBR textures fixing many issues with many shaderpacks (…

…#130)

src/main/java/net/coderbot/iris/pipeline/DeferredWorldRenderingPipeline.java

@@ -12,6 +12,7 @@
 import net.coderbot.iris.layer.GbufferProgram;
 import net.coderbot.iris.postprocess.CompositeRenderer;
 import net.coderbot.iris.rendertarget.BuiltinNoiseTexture;
+import net.coderbot.iris.rendertarget.SingleColorTexture;
 import net.coderbot.iris.rendertarget.RenderTargets;
 import net.coderbot.iris.shaderpack.ProgramSet;
 import net.coderbot.iris.shaderpack.ProgramSource;
@@ -73,6 +74,8 @@ public class DeferredWorldRenderingPipeline implements WorldRenderingPipeline {
 
 	private final EmptyShadowMapRenderer shadowMapRenderer;
 	private final CompositeRenderer compositeRenderer;
+	private final SingleColorTexture normals;
+	private final SingleColorTexture specular;
 
 	private final int waterId;
 
@@ -108,6 +111,25 @@ public DeferredWorldRenderingPipeline(ProgramSet programs) {
 		this.clearMainBuffers = renderTargets.createFramebufferWritingToMain(buffersToBeCleared);
 		this.baseline = renderTargets.createFramebufferWritingToMain(new int[] {0});
 
+		// Don't clobber anything in texture unit 0. It probably won't cause issues, but we're just being cautious here.
+		GlStateManager.activeTexture(GL20C.GL_TEXTURE2);
+
+		// Ensure that the pixel storage mode is in a sane state, otherwise the uploaded texture data will be quite
+		// incorrect.
+		//
+		// It is likely that this also avoids the crashes on AMD that I previously experienced with texture creation.
+		//
+		// This code is from Canvas: https://github.com/grondag/canvas/commit/f0ab652d7a8b7cc9febf0209bee15cffce9eac83
+		GlStateManager.pixelStore(GL20C.GL_UNPACK_ROW_LENGTH, 0);
+		GlStateManager.pixelStore(GL20C.GL_UNPACK_SKIP_ROWS, 0);
+		GlStateManager.pixelStore(GL20C.GL_UNPACK_SKIP_PIXELS, 0);
+		GlStateManager.pixelStore(GL20C.GL_UNPACK_ALIGNMENT, 4);
+
+		// Create some placeholder PBR textures for now
+		normals = new SingleColorTexture(0xFF7F7FFF);
+		specular = new SingleColorTexture(0);
+		GlStateManager.activeTexture(GL20C.GL_TEXTURE0);
+
 		this.shadowMapRenderer = new EmptyShadowMapRenderer(2048);
 		this.compositeRenderer = new CompositeRenderer(programs, renderTargets, shadowMapRenderer);
 	}
@@ -337,6 +359,10 @@ public void use() {
 			// a given program and bind the required textures instead.
 			GlStateManager.activeTexture(GL15C.GL_TEXTURE15);
 			BuiltinNoiseTexture.bind();
+			GlStateManager.activeTexture(GL15C.GL_TEXTURE2);
+			GlStateManager.bindTexture(normals.getTextureId());
+			GlStateManager.activeTexture(GL15C.GL_TEXTURE3);
+			GlStateManager.bindTexture(specular.getTextureId());
 			GlStateManager.activeTexture(GL15C.GL_TEXTURE4);
 			GlStateManager.bindTexture(shadowMapRenderer.getDepthTextureId());
 			GlStateManager.activeTexture(GL15C.GL_TEXTURE5);

src/main/java/net/coderbot/iris/rendertarget/SingleColorTexture.java

@@ -0,0 +1,43 @@
+package net.coderbot.iris.rendertarget;
+
+import com.mojang.blaze3d.platform.GlStateManager;
+import net.coderbot.iris.gl.GlResource;
+import org.lwjgl.BufferUtils;
+import org.lwjgl.opengl.GL11C;
+import org.lwjgl.opengl.GL13C;
+
+import java.nio.IntBuffer;
+
+public class SingleColorTexture extends GlResource {
+	public SingleColorTexture(int color) {
+		super(GL11C.glGenTextures());
+		GlStateManager.bindTexture(getGlId());
+
+		IntBuffer pixel = createBuffer(color);
+
+		GL11C.glTexParameteri(GL11C.GL_TEXTURE_2D, GL11C.GL_TEXTURE_MIN_FILTER, GL11C.GL_LINEAR);
+		GL11C.glTexParameteri(GL11C.GL_TEXTURE_2D, GL11C.GL_TEXTURE_MAG_FILTER, GL11C.GL_LINEAR);
+		GL11C.glTexParameteri(GL11C.GL_TEXTURE_2D, GL11C.GL_TEXTURE_WRAP_S, GL13C.GL_REPEAT);
+		GL11C.glTexParameteri(GL11C.GL_TEXTURE_2D, GL11C.GL_TEXTURE_WRAP_T, GL13C.GL_REPEAT);
+		GL11C.glTexImage2D(GL11C.GL_TEXTURE_2D, 0, GL11C.GL_RGBA, 1, 1, 0, GL11C.GL_RGBA, GL11C.GL_UNSIGNED_BYTE, pixel);
+
+		GlStateManager.bindTexture(0);
+	}
+
+	private IntBuffer createBuffer(int color) {
+		IntBuffer pixel = BufferUtils.createIntBuffer(1);
+		pixel.put(color);
+		pixel.position(0);
+
+		return pixel;
+	}
+
+	public int getTextureId() {
+		return getGlId();
+	}
+
+	@Override
+	protected void destroyInternal() {
+		GL11C.glDeleteTextures(getGlId());
+	}
+}

src/main/java/net/coderbot/iris/texunits/TextureUnit.java

@@ -5,8 +5,8 @@
 public enum TextureUnit {
 	TERRAIN(0),
 	LIGHTMAP(1),
-	// TODO: Relocate this to a different texture unit, this is used by the normal map for normal shaders
-	OVERLAY(2);
+	// TODO: Relocate this to a different texture unit, this is used by depthtex0...
+	OVERLAY(6);
 
 	private final int samplerId;
 	private final int unitId;

src/main/java/net/coderbot/iris/uniforms/CommonUniforms.java

@@ -52,6 +52,8 @@ public static void addCommonUniforms(UniformHolder uniforms, IdMap idMap) {
 			.uniform1i(ONCE, "lightmap", TextureUnit.LIGHTMAP::getSamplerId)
 			.uniform1b(PER_FRAME, "hideGUI", () -> client.options.hudHidden)
 			.uniform1i(ONCE, "noisetex", () -> 15)
+			.uniform1i(ONCE, "normals", () -> 2)
+			.uniform1i(ONCE, "specular", () -> 3)
 			.uniform1i(ONCE, "shadowtex0", () -> 4)
 			.uniform1i(ONCE, "shadowtex1", () -> 5)
 			.uniform1f(PER_FRAME, "eyeAltitude", () -> Objects.requireNonNull(client.getCameraEntity()).getEyeY())