Add sampler array texel fetch

Author: gkjohnson

src/materials/PhysicalPathTracingMaterial.js

@@ -41,6 +41,11 @@ export class PhysicalPathTracingMaterial extends MaterialBase {
 				// 1 = Orthographic
 				// 2 = Equirectangular
 				CAMERA_TYPE: 0,
+
+				ATTR_NORMAL: 0,
+				ATTR_TANGENT: 1,
+				ATTR_UV: 2,
+				ATTR_COLOR: 3,
 			},
 
 			uniforms: {

src/shader/shaderUtils.js

@@ -361,4 +361,25 @@ export const shaderUtils = /* glsl */`
 
 	}
 
+	// add texel fetch functions for texture arrays
+	vec4 texelFetch1D( sampler2DArray tex, int layer, uint index ) {
+
+		uint width = uint( textureSize( tex, 0 ).x );
+		uvec2 uv;
+		uv.x = index % width;
+		uv.y = index / width;
+
+		return texelFetch( tex, ivec3( uv, layer ), 0 );
+
+	}
+
+	vec4 textureSampleBarycoord( sampler2DArray tex, int layer, vec3 barycoord, vec3 faceIndices ) {
+
+		return
+			barycoord.x * texelFetch1D( tex, layer, faceIndices.x ) +
+			barycoord.y * texelFetch1D( tex, layer, faceIndices.y ) +
+			barycoord.z * texelFetch1D( tex, layer, faceIndices.z );
+
+	}
+
 `;