Next part of the tutorial where we have a couple compute shaders controlled by ImGUI.

vk_engine.cpp

@@ -19,7 +19,7 @@
 #define VMA_IMPLEMENTATION
 #include "vk_mem_alloc.h"
 
-constexpr bool bUseValidationLayers = false;
+constexpr bool bUseValidationLayers = true;
 
 VulkanEngine* loadedEngine = nullptr;
 
@@ -202,17 +202,35 @@ void VulkanEngine::run()
       continue;
     }
 
-    ImGui_ImplVulkan_NewFrame();
-    ImGui_ImplSDL2_NewFrame();
-    ImGui::NewFrame();
-
-    ImGui::ShowDemoWindow();
-    ImGui::Render();
-
+    render_imgui();
     draw();
   }
 }
 
+void VulkanEngine::render_imgui() {
+  ImGui_ImplVulkan_NewFrame();
+  ImGui_ImplSDL2_NewFrame();
+
+  ImGui::NewFrame();
+
+  if (ImGui::Begin("background")) {
+
+    ComputeEffect& selected = backgroundEffects[currentBackgroundEffect];
+
+    ImGui::Text("Selected effect: %s", selected.name);
+
+    ImGui::SliderInt("Effect Index", &currentBackgroundEffect,0, backgroundEffects.size() - 1);
+
+    ImGui::InputFloat4("data1",(float*)& selected.data.data1);
+    ImGui::InputFloat4("data2",(float*)& selected.data.data2);
+    ImGui::InputFloat4("data3",(float*)& selected.data.data3);
+    ImGui::InputFloat4("data4",(float*)& selected.data.data4);
+  }
+  ImGui::End();
+
+  ImGui::Render();
+}
+
 void VulkanEngine::init_vulkan() {
   vkb::InstanceBuilder builder;
 
@@ -394,13 +412,14 @@ void VulkanEngine::init_sync_structures() {
 
 void VulkanEngine::draw_background(VkCommandBuffer cmd)
 {
-// bind the gradient drawing compute pipeline
-  vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_COMPUTE, _gradientPipeline);
+  ComputeEffect &effect = backgroundEffects[currentBackgroundEffect];
+
+  vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_COMPUTE, effect.pipeline);
 
-  // bind the descriptor set containing the draw image for the compute pipeline
   vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_COMPUTE, _gradientPipelineLayout, 0, 1, &_drawImageDescriptors, 0, nullptr);
 
-  // execute the compute pipeline dispatch. We are using 16x16 workgroup size so we need to divide by it
+  vkCmdPushConstants(cmd, _gradientPipelineLayout, VK_SHADER_STAGE_COMPUTE_BIT, 0, sizeof(ComputePushConstants), &effect.data);
+
   vkCmdDispatch(cmd, std::ceil(_drawExtent.width / 16.0), std::ceil(_drawExtent.height / 16.0), 1);
 }
 
@@ -461,19 +480,28 @@ void VulkanEngine::init_background_pipelines()
   computeLayout.pSetLayouts = &_drawImageDescriptorLayout;
   computeLayout.setLayoutCount = 1;
 
+  VkPushConstantRange pushConstant{};
+  pushConstant.offset = 0;
+  pushConstant.size = sizeof(ComputePushConstants) ;
+  pushConstant.stageFlags = VK_SHADER_STAGE_COMPUTE_BIT;
+
+  computeLayout.pPushConstantRanges = &pushConstant;
+  computeLayout.pushConstantRangeCount = 1;
+
   VK_CHECK(vkCreatePipelineLayout(_device, &computeLayout, nullptr, &_gradientPipelineLayout));
 
-  VkShaderModule computeDrawShader;
+  VkShaderModule gradientShader;
+  bool good = vkutil::load_shader_module("gradient_color.comp.spv", _device, &gradientShader);
+  assert(good && "failed to load gradient_color.comp.spv");
 
-  if(!vkutil::load_shader_module("gradient.comp.spv", _device, &computeDrawShader)) {
-    std::println("Error when building compute shader");
-  }
+  VkShaderModule skyShader;
+  good = vkutil::load_shader_module("sky.comp.spv", _device, &skyShader);
 
   VkPipelineShaderStageCreateInfo stageinfo{};
   stageinfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO;
   stageinfo.pNext = nullptr;
   stageinfo.stage = VK_SHADER_STAGE_COMPUTE_BIT;
-  stageinfo.module = computeDrawShader;
+  stageinfo.module = gradientShader;
   stageinfo.pName = "main";
 
   VkComputePipelineCreateInfo computePipelineCreateInfo{};
@@ -482,13 +510,37 @@ void VulkanEngine::init_background_pipelines()
   computePipelineCreateInfo.layout = _gradientPipelineLayout;
   computePipelineCreateInfo.stage = stageinfo;
 
-  VK_CHECK(vkCreateComputePipelines(_device,VK_NULL_HANDLE,1, &computePipelineCreateInfo, nullptr, &_gradientPipeline));
+  ComputeEffect gradient;
+  gradient.layout = _gradientPipelineLayout;
+  gradient.name = "gradient";
+  gradient.data = {};
+  gradient.data.data1 = glm::vec4(1, 0, 0, 1);
+  gradient.data.data2 = glm::vec4(0, 0, 1, 1);
 
-  vkDestroyShaderModule(_device, computeDrawShader, nullptr);
+  VK_CHECK(vkCreateComputePipelines(_device, VK_NULL_HANDLE, 1, &computePipelineCreateInfo, nullptr, &gradient.pipeline));
 
-  _mainDeletionQueue.push_function([&]() {
+  // change the shader module only to create the sky
+  computePipelineCreateInfo.stage.module = skyShader;
+  ComputeEffect sky;
+  sky.layout = _gradientPipelineLayout;
+  sky.name = "sky";
+  sky.data = {};
+  // default sky
+  sky.data.data1 = glm::vec4(0.1, 0.2, 0.4, 0.97);
+
+  VK_CHECK(vkCreateComputePipelines(_device, VK_NULL_HANDLE, 1, &computePipelineCreateInfo, nullptr, &sky.pipeline));
+
+
+  backgroundEffects.push_back(gradient);
+  backgroundEffects.push_back(sky);
+  
+  vkDestroyShaderModule(_device, gradientShader, nullptr);
+  vkDestroyShaderModule(_device, skyShader, nullptr);
+
+  _mainDeletionQueue.push_function([=,this]() {
       vkDestroyPipelineLayout(_device, _gradientPipelineLayout, nullptr);
-      vkDestroyPipeline(_device, _gradientPipeline, nullptr);
+      vkDestroyPipeline(_device, sky.pipeline, nullptr);
+      vkDestroyPipeline(_device, sky.pipeline, nullptr);
   });
 }