From 3ad6037fe222c8c96725ba34625b7f39f48293f2 Mon Sep 17 00:00:00 2001
From: Georg Hagen <git.georg.hagen@madvoxel.com>
Date: Fri, 18 Apr 2025 17:55:11 +0200
Subject: [PATCH] Add Origin Indicator drawable

---
 .../Scene/Prefabs/OriginIndicatorDrawable.hpp | 46 +++++++++++++++++++
 openVulkanoCpp/Shader/originIndicator.vert    | 23 ++++++++++
 .../OriginIndicatorDrawableVulkanEncoder.cpp  | 29 ++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 openVulkanoCpp/Scene/Prefabs/OriginIndicatorDrawable.hpp
 create mode 100644 openVulkanoCpp/Shader/originIndicator.vert
 create mode 100644 openVulkanoCpp/Vulkan/Scene/OriginIndicatorDrawableVulkanEncoder.cpp

diff --git a/openVulkanoCpp/Scene/Prefabs/OriginIndicatorDrawable.hpp b/openVulkanoCpp/Scene/Prefabs/OriginIndicatorDrawable.hpp
new file mode 100644
index 0000000..95c33a4
--- /dev/null
+++ b/openVulkanoCpp/Scene/Prefabs/OriginIndicatorDrawable.hpp
@@ -0,0 +1,46 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include "Scene/Drawable.hpp"
+#include "Scene/Shader/Shader.hpp"
+#include "Scene/Node.hpp"
+
+namespace OpenVulkano::Scene
+{
+	class OriginIndicatorDrawable final : public Drawable
+	{
+		Shader m_shader;
+
+	public:
+		OriginIndicatorDrawable()
+			: Drawable(DrawEncoder::GetDrawEncoder<OriginIndicatorDrawable>(), DrawPhase::MAIN)
+		{
+			m_shader.cullMode = CullMode::NONE;
+			m_shader.topology = Topology::LINE_LIST;
+			m_shader.AddShaderProgram(ShaderProgramType::VERTEX, "Shader/originIndicator");
+			m_shader.AddShaderProgram(ShaderProgramType::FRAGMENT, "Shader/basic");
+			SetShader(&m_shader);
+		}
+	};
+	
+	class OriginIndicatorNode final : public Node
+	{
+		OriginIndicatorDrawable drawable;
+		
+		public:
+		OriginIndicatorNode(float size = 0.25f) : Node(Math::Utils::scale(Math::Vector3f(size, size, size)))
+		{
+			AddChild(&drawable);
+		}
+		
+		void SetSize(float size = 0.25f)
+		{
+			SetMatrix(Math::Utils::scale(Math::Vector3f(size, size, size)));
+		}
+	};
+}
diff --git a/openVulkanoCpp/Shader/originIndicator.vert b/openVulkanoCpp/Shader/originIndicator.vert
new file mode 100644
index 0000000..0c51ec5
--- /dev/null
+++ b/openVulkanoCpp/Shader/originIndicator.vert
@@ -0,0 +1,23 @@
+#version 450
+#extension GL_ARB_separate_shader_objects : enable
+
+layout(set = 0, binding = 0) uniform NodeData
+{
+	mat4 world;
+} node;
+
+layout(set = 1, binding = 0) uniform CameraData
+{
+	mat4 viewProjection;
+} cam;
+
+layout(location = 0) out vec4 color;
+
+void main()
+{
+	int i = gl_VertexIndex & -2;
+	color = vec4(i == 0, i == 2, i == 4, 1);
+	vec4 position = color * (gl_VertexIndex & 1);
+	position.w = 1;
+	gl_Position = cam.viewProjection * node.world * position;
+}
diff --git a/openVulkanoCpp/Vulkan/Scene/OriginIndicatorDrawableVulkanEncoder.cpp b/openVulkanoCpp/Vulkan/Scene/OriginIndicatorDrawableVulkanEncoder.cpp
new file mode 100644
index 0000000..dafb540
--- /dev/null
+++ b/openVulkanoCpp/Vulkan/Scene/OriginIndicatorDrawableVulkanEncoder.cpp
@@ -0,0 +1,29 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include "Scene/Prefabs/OriginIndicatorDrawable.hpp"
+#include "VulkanGeometry.hpp"
+#include "Vulkan/VulkanDrawContext.hpp"
+
+using namespace OpenVulkano::Scene;
+
+namespace OpenVulkano::Vulkan
+{
+	void EncodeOriginIndicatorDrawable(Drawable* instance, Vulkan::VulkanDrawContext* drawContext)
+	{
+		for(Node* node : instance->GetNodes())
+		{
+			if (!node->IsEnabled()) [[unlikely]] continue;
+			drawContext->EncodeNode(node);
+			drawContext->commandBuffer.draw(6, 1, 0, 0);
+		}
+	}
+}
+
+namespace
+{
+	void* gridDrawableVulkanEncoderReg = DrawEncoder::RegisterVulkanEncodeFunction<OriginIndicatorDrawable>(&OpenVulkano::Vulkan::EncodeOriginIndicatorDrawable);
+}
\ No newline at end of file