Added sample for VK_KHR_ray_tracing_position_fetch

shaders/glsl/raytracingpositionfetch/raygen.rgen

@@ -0,0 +1,39 @@
+/* Copyright (c) 2024, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+#version 460
+#extension GL_EXT_ray_tracing : enable
+
+layout(binding = 0, set = 0) uniform accelerationStructureEXT topLevelAS;
+layout(binding = 1, set = 0, rgba8) uniform image2D image;
+layout(binding = 2, set = 0) uniform CameraProperties 
+{
+	mat4 viewInverse;
+	mat4 projInverse;
+	vec4 lightPos;
+} ubo;
+
+layout(location = 0) rayPayloadEXT vec3 hitValue;
+
+void main() 
+{
+	const vec2 pixelCenter = vec2(gl_LaunchIDEXT.xy) + vec2(0.5);
+	const vec2 inUV = pixelCenter/vec2(gl_LaunchSizeEXT.xy);
+	vec2 d = inUV * 2.0 - 1.0;
+
+	vec4 origin = ubo.viewInverse * vec4(0,0,0,1);
+	vec4 target = ubo.projInverse * vec4(d.x, d.y, 1, 1) ;
+	vec4 direction = ubo.viewInverse*vec4(normalize(target.xyz), 0) ;
+
+	float tmin = 0.001;
+	float tmax = 10000.0;
+
+	hitValue = vec3(0.0);
+
+    traceRayEXT(topLevelAS, gl_RayFlagsOpaqueEXT, 0xff, 0, 0, 0, origin.xyz, tmin, direction.xyz, tmax, 0);
+
+	imageStore(image, ivec2(gl_LaunchIDEXT.xy), vec4(hitValue, 0.0));
+}