Merge branch '26-asset-loading' into 'develop'

Resolve "Asset Loading"

Closes #26

See merge request !19

projects/first_mesh/src/main.cpp

+#include <iostream>
+#include <stdio.h>
+#include <vkcv/asset/asset_loader.hpp>
+
+
+int main(int argc, const char** argv) {
+	vkcv::asset::Mesh mesh;
+	
+	const char *path = argc > 1 ? argv[1] : "resources/cube/cube.gltf";
+	int result = vkcv::asset::loadMesh(path, mesh);
+	
+	if (result == 1) {
+		std::cout << "Mesh loading successful!" << std::endl;
+	} else {
+		std::cout << "Mesh loading failed: " << result << std::endl;
+		return 1;
+	}
+
+	/* Demonstration of how to use the vkcv::asset::Mesh struct. */
+	const char *primitive_modes[] = {
+		"points", "lines", "line loop", "line strip", "triangles",
+		"triangle strip", "triangle fan"
+	};
+	const char *primitive_types[] = {
+		"unknown", "position", "normal", "texcoord0"
+	};
+	printf("Mesh %s (%s) has %lu vertex group(s) and %lu material(s):\n",
+			mesh.name.c_str(), path, mesh.vertexGroups.size(),
+			mesh.materials.size());
+	for (size_t i = 0; i < mesh.vertexGroups.size(); i++) {
+		printf("--- vertex group %lu ---\n", i);
+		const auto &vg = mesh.vertexGroups[i];
+		printf("primitive mode: %d (%s)\n", vg.mode,
+				primitive_modes[vg.mode]);
+		printf("index buffer: %lu bytes for %lu indices ",
+				vg.indexBuffer.data.size(), vg.numIndices);
+		const auto itype = vg.indexBuffer.type;
+		printf("(%s @ %p)\n",
+				itype == vkcv::asset::UINT32 ? "UINT32" :
+				itype == vkcv::asset::UINT16 ? "UINT16" :
+				"UINT8", vg.indexBuffer.data.data());
+		printf("\tindices: ");
+		const size_t n = vg.numIndices;
+		if (vg.indexBuffer.type == vkcv::asset::UINT32) {
+			uint32_t *idx = (uint32_t*)vg.indexBuffer.data.data();
+			for (size_t j = 0; j < n; j++) printf("%u ", idx[j]);
+		} else
+		if (vg.indexBuffer.type == vkcv::asset::UINT16) {
+			uint16_t *idx = (uint16_t*)vg.indexBuffer.data.data();
+			for (size_t j = 0; j < n; j++) printf("%u ", idx[j]);
+		} else
+		if (vg.indexBuffer.type == vkcv::asset::UINT8) {
+			uint8_t *idx = (uint8_t*)vg.indexBuffer.data.data();
+			for (size_t j = 0; j < n; j++) printf("%u ", idx[j]);
+		} else {
+			fprintf(stderr, "ERROR Invalid IndexType: %d\n",
+					vg.indexBuffer.type);
+			return 0;
+		}
+		printf("\n");
+		printf("vertex buffer: %lu bytes for %lu vertices with %lu "
+				"attributes (starting at %p)\n",
+				vg.vertexBuffer.data.size(), vg.numVertices,
+				vg.vertexBuffer.attributes.size(),
+				vg.vertexBuffer.data.data());
+		printf("attributes:\toffset\tlength\tstride\tcomponents\n");
+		for (const auto att : vg.vertexBuffer.attributes) {
+			printf("%11s\t%u\t%u\t%u\t%hhux%hu\n",
+					primitive_types[att.type],
+					att.offset, att.length, att.stride,
+					att.componentCount, att.componentType);
+		}
+	}
+	
+	return 0;
+}