Set up code examples for Vulkan and libpng

.gitignore

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+triangle
+triangle.png

Makefile

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+ifeq ($(target), cheza)
+	CXX = /usr/bin/armv7a-cros-linux-gnueabihf-clang++
+	CC = /usr/bin/armv7a-cros-linux-gnueabihf-clang
+	SYSROOT = /build/cheza
+	SSH_DUT = cheza
+else ifeq ($(target), atlas)
+	CXX = /usr/bin/x86_64-cros-linux-gnu-clang++
+	CC = /usr/bin/x86_64-cros-linux-gnu-clang
+	SYSROOT = /build/atlas
+	SSH_DUT = atlas
+else ifeq ($(target), local)
+	CXX = clang++
+	CC = clang
+else
+	CXX = INVALID
+	CC = INVALID
+endif
+
+NAME = triangle
+CFLAGS = -std=c++17 --sysroot="$(SYSROOT)" -Wall
+LDFLAGS = -lvulkan -lpng
+
+all: build deploy run
+
+build: check
+	@echo Building...
+	@$(CXX) $(CFLAGS) -o ${NAME} ${NAME}.cc $(LDFLAGS)
+
+deploy: check
+ifneq ($(target), local)
+	@echo Deploying to $(SSH_DUT)...
+	@scp ${NAME} $(SSH_DUT):~/
+endif
+
+run: check
+ifneq ($(target), local)
+	@echo Running on $(SSH_DUT)...
+	@ssh $(SSH_DUT) '~/${NAME}'
+	@scp $(SSH_DUT):~/${NAME}.png .
+else
+	@echo Running locally...
+	@./$(NAME)
+endif
+
+clean: check
+	@rm -f ${NAME}
+	@rm -f ${NAME}.png
+ifneq ($(target), local)
+	@ssh $(SSH_DUT) 'rm -f ~/${NAME} ~/${NAME}.png'
+endif
+
+check:
+ifeq ($(CXX), INVALID)
+	$(error $$target must be one of [atlas, cheza, local] )
+endif

triangle.cc

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+#include <png.h>
+#include <vulkan/vulkan.h>
+
+#include <iostream>
+#include <vector>
+
+const uint32_t kWidth = 16;
+const uint32_t kHeight = 16;
+
+int main() {
+  // Example code for creating a VkInstance.
+  VkApplicationInfo app_info = {};
+  app_info.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
+  app_info.apiVersion = VK_API_VERSION_1_1;
+
+  VkInstanceCreateInfo create_info = {};
+  create_info.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
+  create_info.pApplicationInfo = &app_info;
+  create_info.enabledExtensionCount = 0;
+  create_info.ppEnabledExtensionNames = nullptr;
+  create_info.enabledLayerCount = 0;
+  create_info.ppEnabledLayerNames = nullptr;
+
+  VkInstance instance;
+  VkResult res = vkCreateInstance(&create_info, nullptr, &instance);
+  if (res != VK_SUCCESS) {
+    std::cerr << "Error creating VkInstance: " << res;
+  }
+
+  // Example code for exporting a PNG.
+  FILE *f = fopen("triangle.png", "wb");
+
+  std::vector<uint8_t> pixels(kWidth * kHeight * 4);
+  for (size_t i = 0; i < kHeight; i++) {
+    for (size_t j = 0; j < kWidth; j++) {
+      uint32_t base_index = (i * kWidth * 4) + (j * 4);
+      pixels[base_index] = 255;
+      pixels[base_index + 1] = 255;
+      pixels[base_index + 2] = 0;
+      pixels[base_index + 3] = 255;
+    }
+  }
+
+  png_image image_info = {};
+  image_info.version = PNG_IMAGE_VERSION;
+  image_info.width = kWidth;
+  image_info.height = kHeight;
+  image_info.format = PNG_FORMAT_RGBA;
+  if (png_image_write_to_stdio(&image_info, f, 0, pixels.data(), kWidth * 4, nullptr) == 0) {
+    std::cout << "Error writing PNG: " << image_info.message << std::endl;
+  }
+
+  fclose(f);
+
+  return 0;
+}