PathTracer: enabled simple AO in shader (#10)

data/shaders/trace.glsl

@@ -22,6 +22,7 @@ layout(binding = 1) uniform config_ { PathTracerConfig u_config; };
 
 layout(binding = 2, rgba8) uniform image2D g_raster_image;
 
+layout(binding = 4) buffer buf04_ { uint g_indices[]; };
 layout(binding = 5) buffer buf05_ { float g_vertices[]; };
 layout(binding = 6) uniform accelerationStructureEXT g_accelStruct;
 
@@ -44,6 +45,14 @@ vec3 getVertex(uint idx) {
 	return vec3(g_vertices[idx * 3 + 0], g_vertices[idx * 3 + 1], g_vertices[idx * 3 + 2]);
 }
 
+void getTriangleVertices(uint tri_id, out vec3 tri0, out vec3 tri1, out vec3 tri2) {
+	uint idx0 = g_indices[tri_id * 3 + 0], idx1 = g_indices[tri_id * 3 + 1],
+		 idx2 = g_indices[tri_id * 3 + 2];
+	tri0 = getVertex(idx0);
+	tri1 = getVertex(idx1);
+	tri2 = getVertex(idx2);
+}
+
 void getTriangleVectors(in vec3 tri0, in vec3 tri1, in vec3 tri2, out vec3 tangent, out vec3 normal,
 						out vec3 binormal) {
 	tangent = normalize(tri1 - tri0);
@@ -72,6 +81,7 @@ TraceResult rayTraceAS(vec3 origin, vec3 dir) {
 	if(rayQueryGetIntersectionTypeEXT(rq, true) != 0) {
 		result.dist = rayQueryGetIntersectionTEXT(rq, true);
 		result.tri_id = rayQueryGetIntersectionPrimitiveIndexEXT(rq, true);
+		// rayQueryGetIntersectionBarycentricsEXT
 	} else {
 		result.dist = MAX_ISECT_DIST;
 		result.tri_id = INVALID_TRI_ID;
@@ -94,7 +104,28 @@ void getScreenRay(ivec2 pixel_pos, out vec3 origin, out vec3 dir) {
 	dir += vec3(0.0000001); // avoiding division by 0
 }
 
-//#define COMPUTE_AO
+float computeAO(uint tri_id, vec3 hit_point) {
+	vec3 tri[3];
+	getTriangleVertices(tri_id, tri[0], tri[1], tri[2]);
+	vec3 tri_vecs[3];
+	getTriangleVectors(tri[0], tri[1], tri[2], tri_vecs[0], tri_vecs[1], tri_vecs[2]);
+
+	const int dim_size = 4;
+	int hits = 0, total = (dim_size + 1) * (dim_size + 1);
+
+	for(int x = 0; x <= dim_size; x++)
+		for(int y = 0; y <= dim_size; y++) {
+			vec2 pos = vec2(x, y) * (1.0 / dim_size);
+			vec3 hemi = uniformSampleHemisphere(pos);
+			vec3 dir = tri_vecs[0] * hemi[0] + tri_vecs[1] * hemi[2] + tri_vecs[2] * hemi[1];
+			vec3 origin = hit_point + dir * 0.001;
+			TraceResult ao_hit = rayTraceAS(origin, dir);
+			if(ao_hit.dist > 0.05 && ao_hit.dist < 5.0 && ao_hit.tri_id != tri_id)
+				hits++;
+		}
+
+	return max(0.0, (total - hits) / float(total) - 0.1) * (1.0 / 0.9);
+}
 
 void traceBin() {
 	ivec2 pixel_pos = ivec2(LIX & 31, LIX >> 5) + s_bin_pos;
@@ -103,30 +134,10 @@ void traceBin() {
 
 	TraceResult result = rayTraceAS(ray_origin, ray_dir);
 	float ao_value = 1.0;
-
-#ifdef COMPUTE_AO
 	if(result.dist < MAX_ISECT_DIST) {
-		vec3 tri_vecs[3];
-		getTriangleVectors(result.tri_id, tri_vecs[0], tri_vecs[1], tri_vecs[2]);
 		vec3 hit_point = ray_origin + ray_dir * result.dist;
-
-		const int dim_size = 10;
-		int hits = 0, total = (dim_size + 1) * (dim_size + 1);
-
-		for(int x = 0; x <= dim_size; x++)
-			for(int y = 0; y <= dim_size; y++) {
-				vec2 pos = vec2(x, y) * (1.0 / dim_size);
-				vec3 hemi = uniformSampleHemisphere(pos);
-				vec3 dir = tri_vecs[0] * hemi[0] + tri_vecs[1] * hemi[2] + tri_vecs[2] * hemi[1];
-				vec3 origin = hit_point + dir * 0.00001;
-				TraceResult ao_hit = rayTraceAS(origin, dir);
-				if(ao_hit.dist > 0.0001 && ao_hit.dist < 0.5 && ao_hit.tri_id != result.tri_id)
-					hits++;
-			}
-
-		ao_value = (total - hits) / float(total);
+		ao_value = computeAO(result.tri_id, hit_point);
 	}
-#endif
 
 	vec3 vcolor = vec3(0.0);
 	if(result.dist < MAX_ISECT_DIST) {

src/lucid_app.cpp

@@ -236,6 +236,8 @@ Ex<void> LucidApp::updateRenderer() {
 			insertBack(used_shaders, m_pbr_renderer->shaderDefIds());
 		if(m_lucid_renderer)
 			insertBack(used_shaders, m_lucid_renderer->shaderDefIds());
+		if(m_path_tracer)
+			insertBack(used_shaders, m_path_tracer->shaderDefIds());
 		makeSortedUnique(used_shaders);
 		if(setIntersection(used_shaders, update_list))
 			do_update = true;

src/path_tracer.cpp

@@ -124,6 +124,7 @@ Ex<> PathTracer::updateScene(VulkanDevice &device, Scene &scene) {
 		EX_PASS(VulkanAccelStruct::buildBottom(device, scene.verts.positions, scene.tris_ib));
 	VAccelStructInstance instance{blas, Matrix4::identity()};
 	m_accel_struct = EX_PASS(VulkanAccelStruct::buildTop(device, {instance}));
+	m_indices = scene.tris_ib;
 	m_vertices = scene.verts.positions;
 	// TODO: wait until AS is built?
 
@@ -151,7 +152,7 @@ void PathTracer::render(const Context &ctx) {
 	auto raster_image = swap_chain->acquiredImage();
 	ds.setStorageImage(2, raster_image, VImageLayout::general);
 
-	ds.set(5, m_vertices);
+	ds.set(4, m_indices, m_vertices);
 	ds.set(6, m_accel_struct);
 
 	auto sampler = ctx.device.getSampler(ctx.config.sampler_setup);

src/path_tracer.h

@@ -55,6 +55,7 @@ class PathTracer {
 	VBufferSpan<shader::PathTracerConfig> m_frame_config[num_frames];
 	VBufferSpan<u32> m_debug_buffer;
 
+	VBufferSpan<u32> m_indices;
 	VBufferSpan<float3> m_vertices;
 	PVAccelStruct m_accel_struct;