From 723fded82de0b0d78b3a7bcfae2a8ac56af8fd7a Mon Sep 17 00:00:00 2001
From: Germain AUBERT <germain.aubert@gmail.com>
Date: Mon, 21 Nov 2022 18:11:45 +0100
Subject: [PATCH] fix bone weights default values

---
 .../graphics/g3d/shaders/DefaultShader.java   | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/gdx/src/com/badlogic/gdx/graphics/g3d/shaders/DefaultShader.java b/gdx/src/com/badlogic/gdx/graphics/g3d/shaders/DefaultShader.java
index 8aa136b9b0c..25d20c3a1ab 100644
--- a/gdx/src/com/badlogic/gdx/graphics/g3d/shaders/DefaultShader.java
+++ b/gdx/src/com/badlogic/gdx/graphics/g3d/shaders/DefaultShader.java
@@ -504,6 +504,7 @@ public static String getDefaultFragmentShader () {
 	protected final long attributesMask;
 	private final long vertexMask;
 	private final int textureCoordinates;
+	private int[] boneWeightsLocations;
 	protected final Config config;
 	/** Attributes which are not required but always supported. */
 	private final static long optionalAttributes = IntAttribute.CullFace | DepthTestAttribute.Type;
@@ -561,6 +562,9 @@ public DefaultShader (final Renderable renderable, final Config config, final Sh
 		if (boneWeights > config.numBoneWeights) {
 			throw new GdxRuntimeException("too many bone weights: " + boneWeights + ", max configured: " + config.numBoneWeights);
 		}
+		if (renderable.bones != null) {
+			boneWeightsLocations = new int[config.numBoneWeights];
+		}
 
 		// Global uniforms
 		u_projTrans = register(Inputs.projTrans, Setters.projTrans);
@@ -634,6 +638,12 @@ public void init () {
 		spotLightsExponentOffset = loc(u_spotLights0exponent) - spotLightsLoc;
 		spotLightsSize = loc(u_spotLights1color) - spotLightsLoc;
 		if (spotLightsSize < 0) spotLightsSize = 0;
+
+		if (boneWeightsLocations != null) {
+			for (int i = 0; i < boneWeightsLocations.length; i++) {
+				boneWeightsLocations[i] = program.getAttributeLocation(ShaderProgram.BONEWEIGHT_ATTRIBUTE + i);
+			}
+		}
 	}
 
 	private static final boolean and (final long mask, final long flag) {
@@ -783,6 +793,15 @@ public void begin (final Camera camera, final RenderContext context) {
 		lightsSet = false;
 
 		if (has(u_time)) set(u_time, time += Gdx.graphics.getDeltaTime());
+
+		// set generic vertex attribute value for all bone weights in case a mesh has missing attributes.
+		if (boneWeightsLocations != null) {
+			for (int location : boneWeightsLocations) {
+				if (location >= 0) {
+					Gdx.gl.glVertexAttrib2f(location, 0, 0);
+				}
+			}
+		}
 	}
 
 	@Override