From 4ccf3731bce7c80c07d7826e3e0b09c8f8b7a6de Mon Sep 17 00:00:00 2001
From: Trevor Hollmann <thollmann@uni-koblenz.de>
Date: Fri, 21 May 2021 11:48:25 +0200
Subject: [PATCH] [#26] Add indexBuffer struct and improve documentation.
---
include/asset_loader/asset_loader.hpp | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/include/asset_loader/asset_loader.hpp b/include/asset_loader/asset_loader.hpp
index d48c5cdd..61c1ee76 100644
--- a/include/asset_loader/asset_loader.hpp
+++ b/include/asset_loader/asset_loader.hpp
@@ -52,6 +52,7 @@ typedef struct {
// TODO not yet needed for the first (unlit) triangle
} Material;
+/* This struct describes one vertex attribute of a vertex buffer. */
typedef struct {
PrimitiveType type; // POSITION, NORMAL, ...
uint32_t offset; // offset in bytes
@@ -61,10 +62,25 @@ typedef struct {
uint8_t componentCount; // eg. 3 for vec3
} VertexAttribute;
+/* This struct represents one (possibly the only) part of a mesh. There is
+ * always one vertexBuffer and zero or one indexBuffer (indexed rendering is
+ * common but not always used). If there is no indexBuffer, this is indicated
+ * by indexBuffer.data being NULL.
+ * Each vertex buffer can have one or more vertex attributes.
+ * Note that the indexBuffer and vertexBuffer might be pointing to the same
+ * block of memory.
+ *
+ * TODO For now, the caller of loadMesh() has to free this memory when they are
+ * done, but since this is not generally good practice in C++, this behaviour
+ * will likely be changed later. */
typedef struct {
enum PrimitiveMode mode; // draw as points, lines or triangle?
size_t numIndices, numVertices;
- uint32_t *indexBuffer; // array of indices for indexed rendering
+ struct {
+ void *data; // binary data of the index buffer
+ size_t byteLength; // length of the index buffer
+ uint32_t byteOffset; // offset into the buffer in bytes
+ } indexBuffer;
struct {
void *data; // the binary data of the buffer
size_t byteLength; // the length of the entire buffer in bytes
@@ -75,7 +91,8 @@ typedef struct {
uint8_t materialIndex; // index to one of the meshes materials
} VertexGroup;
-/* This struct represents a single mesh loaded from a glTF file. */
+/* This struct represents a single mesh loaded from a glTF file. It consists of
+ * at least one VertexVroup and any number of Materials. */
typedef struct {
std::string name;
std::vector<VertexGroup> vertexGroups;
--
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