From b3cb830df191768fe13fc5b21fb0a8e690ae86b2 Mon Sep 17 00:00:00 2001
From: Sergey Kosarevsky <sk@linderdaum.com>
Date: Sun, 18 Aug 2024 12:36:16 -0700
Subject: [PATCH] Added new sample `005_MeshShaders`

---
 samples/005_MeshShaders.cpp | 177 ++++++++++++++++++++++++++++++++++++
 samples/CMakeLists.txt      |   5 +-
 2 files changed, 180 insertions(+), 2 deletions(-)
 create mode 100644 samples/005_MeshShaders.cpp

diff --git a/samples/005_MeshShaders.cpp b/samples/005_MeshShaders.cpp
new file mode 100644
index 0000000000..d1da34c818
--- /dev/null
+++ b/samples/005_MeshShaders.cpp
@@ -0,0 +1,177 @@
+/*
+* LightweightVK
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+#include <shared/UtilsFPS.h>
+
+#include <lvk/LVK.h>
+#if defined(ANDROID)
+#include <android_native_app_glue.h>
+#include <jni.h>
+#include <time.h>
+#else
+#include <GLFW/glfw3.h>
+#endif
+
+// we are going to use raw Vulkan here to initialize VK_EXT_mesh_shader
+#include <lvk/vulkan/VulkanUtils.h>
+
+const char* codeTask = R"(
+layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
+
+void main() {
+  EmitMeshTasksEXT(1, 1, 1);
+}
+)";
+
+const char* codeMesh = R"(
+layout(triangles, max_vertices = 3, max_primitives = 1) out;
+
+layout (location=0) out vec3 color[3];
+
+const vec2 pos[3] = vec2[3](
+  vec2(-0.6, -0.4),
+  vec2( 0.6, -0.4),
+  vec2( 0.0,  0.6)
+);
+const vec3 col[3] = vec3[3](
+  vec3(1.0, 0.0, 0.0),
+  vec3(0.0, 1.0, 0.0),
+  vec3(0.0, 0.0, 1.0)
+);
+void main() {
+  SetMeshOutputsEXT(3, 1);
+
+  for (uint i = 0; i != 3; i++) {
+    gl_MeshVerticesEXT[i].gl_Position = vec4(pos[i], 0.0, 1.0);
+    color[i] = col[i];
+  }
+
+  gl_MeshPrimitivesEXT[0].gl_CullPrimitiveEXT = false;
+  gl_PrimitiveTriangleIndicesEXT[0] = uvec3(0, 1, 2);
+}
+)";
+
+const char* codeFrag = R"(
+#version 460
+layout (location=0) in vec3 color;
+layout (location=0) out vec4 out_FragColor;
+
+void main() {
+  out_FragColor = vec4(color, 1.0);
+};
+)";
+
+int width_ = 800;
+int height_ = 600;
+FramesPerSecondCounter fps_;
+
+std::unique_ptr<lvk::IContext> ctx_;
+
+struct {
+  lvk::Holder<lvk::RenderPipelineHandle> renderPipelineState_Triangle_;
+  lvk::Holder<lvk::ShaderModuleHandle> task_;
+  lvk::Holder<lvk::ShaderModuleHandle> mesh_;
+  lvk::Holder<lvk::ShaderModuleHandle> frag_;
+} res;
+
+void init() {
+  res.task_ = ctx_->createShaderModule({codeTask, lvk::Stage_Task, "Shader Module: main (task)"});
+  res.mesh_ = ctx_->createShaderModule({codeMesh, lvk::Stage_Mesh, "Shader Module: main (mesh)"});
+  res.frag_ = ctx_->createShaderModule({codeFrag, lvk::Stage_Frag, "Shader Module: main (frag)"});
+
+  res.renderPipelineState_Triangle_ = ctx_->createRenderPipeline(
+      {
+          .smTask = res.task_,
+          .smMesh = res.mesh_,
+          .smFrag = res.frag_,
+          .color = {{.format = ctx_->getSwapchainFormat()}},
+      },
+      nullptr);
+
+  LVK_ASSERT(res.renderPipelineState_Triangle_.valid());
+}
+
+void destroy() {
+  res = {};
+  ctx_ = nullptr;
+}
+
+void resize() {
+  if (!width_ || !height_) {
+    return;
+  }
+  ctx_->recreateSwapchain(width_, height_);
+}
+
+void render() {
+  if (!width_ || !height_) {
+    return;
+  }
+
+  lvk::ICommandBuffer& buffer = ctx_->acquireCommandBuffer();
+
+  // This will clear the framebuffer
+  buffer.cmdBeginRendering(
+      {.color = {{.loadOp = lvk::LoadOp_Clear, .clearColor = {1.0f, 1.0f, 1.0f, 1.0f}}}},
+      {.color = {{.texture = ctx_->getCurrentSwapchainTexture()}}});
+  buffer.cmdBindRenderPipeline(res.renderPipelineState_Triangle_);
+  buffer.cmdPushDebugGroupLabel("Render Triangle", 0xff0000ff);
+  buffer.cmdDrawMeshTasks({1, 1, 1});
+
+  buffer.cmdPopDebugGroupLabel();
+  buffer.cmdEndRendering();
+  ctx_->submit(buffer, ctx_->getCurrentSwapchainTexture());
+}
+
+int main(int argc, char* argv[]) {
+  minilog::initialize(nullptr, {.threadNames = false});
+
+  GLFWwindow* window = lvk::initWindow("Vulkan Hello Mesh Shaders", width_, height_, true);
+
+  VkPhysicalDeviceMeshShaderFeaturesEXT meshShaderFeatures = {
+      .sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_FEATURES_EXT,
+      .taskShader = VK_TRUE,
+      .meshShader = VK_TRUE,
+  };
+
+  ctx_ = lvk::createVulkanContextWithSwapchain(window,
+                                               width_,
+                                               height_,
+                                               {
+                                                   .extensionsDevice = {"VK_EXT_mesh_shader"},
+                                                   .extensionsDeviceFeatures = &meshShaderFeatures,
+                                               });
+  if (!ctx_) {
+    return 255;
+  }
+  init();
+
+  glfwSetFramebufferSizeCallback(window, [](GLFWwindow*, int width, int height) {
+    width_ = width;
+    height_ = height;
+    resize();
+  });
+
+  double prevTime = glfwGetTime();
+
+  // main loop
+  while (!glfwWindowShouldClose(window)) {
+    const double newTime = glfwGetTime();
+    fps_.tick(newTime - prevTime);
+    prevTime = newTime;
+    render();
+    glfwPollEvents();
+  }
+
+  // destroy all the Vulkan stuff before closing the window
+  destroy();
+
+  glfwDestroyWindow(window);
+  glfwTerminate();
+
+  return 0;
+}
diff --git a/samples/CMakeLists.txt b/samples/CMakeLists.txt
index e749090587..a32d424bc1 100644
--- a/samples/CMakeLists.txt
+++ b/samples/CMakeLists.txt
@@ -125,11 +125,12 @@ ADD_DEMO("001_HelloTriangle")
 ADD_DEMO("002_RenderToCubeMap")
 ADD_DEMO("003_RenderToCubeMapSinglePass")
 ADD_DEMO("004_YUV")
+if(WIN32 AND NOT (ANDROID OR APPLE))
+  ADD_DEMO("005_MeshShaders")
+endif()
 
 ADD_DEMO("Tiny")
-
 ADD_DEMO("Tiny_Mesh")
-
 ADD_DEMO("Tiny_MeshLarge")
 ADD_DEMO_SOURCES("Tiny_MeshLarge"
   "${LVK_ROOT_DIR}/third-party/deps/src/3D-Graphics-Rendering-Cookbook/shared/UtilsCubemap.cpp")