From 5a079a2d114f96d4847d1ee305d5b7c16eeec50e Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sat, 27 Dec 2025 12:03:39 -0800
Subject: Initial commit

---
 include/model.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 include/model.h

(limited to 'include')

diff --git a/include/model.h b/include/model.h
new file mode 100644
index 0000000..9e93993
--- /dev/null
+++ b/include/model.h
@@ -0,0 +1,68 @@
+#pragma once
+
+#include <stdint.h>
+
+typedef uint16_t mdIdx;
+typedef struct mdVert { mdIdx position, normal, texcoord; } mdVert;
+typedef struct mdTri  { mdVert v0, v1, v2; } mdTri;
+typedef struct mdVec2 { float x, y;        } mdVec2;
+typedef struct mdVec3 { float x, y, z;     } mdVec3;
+
+// Every three indices form a triangle, and each index indexes all attribute
+// arrays simultaneously. This is best for a fast, linear-scan rendering.
+// This is what you would render with glDrawElements().
+typedef struct FlatModel {
+  // Counts.
+  uint32_t numIdxs;
+  uint32_t numVerts;
+  // Offsets.
+  uint32_t offsetIdxs;
+  uint32_t offsetPositions;
+  uint32_t offsetNormals;
+  uint32_t offsetTexcoords;
+  /*
+  [indices]   -- numIdxs  mdIdx
+  [positions] -- numVerts mdVec3
+  [normals]   -- numVerts mdVec3
+  [texcoords] -- numVerts mdVec2
+  */
+  uint8_t data[];
+} FlatModel;
+
+// Every triangle is made up of three vertices, and each vertex holds one index
+// for each of the attribute arrays. This allows for a smaller representation of
+// some models by virtue of being able to re-use attributes across vertices.
+// This is the sort of format that OBJ follows, where the indices to each array
+// given by a face may be non-uniform.
+typedef struct IndexedModel {
+  // Counts.
+  uint32_t numTris;
+  uint32_t numPositions;
+  uint32_t numNormals;
+  uint32_t numTexcoords;
+  // Offsets.
+  uint32_t offsetTris;
+  uint32_t offsetPositions;
+  uint32_t offsetNormals;
+  uint32_t offsetTexcoords;
+  /*
+  [triangles] -- numTris      mdTri
+  [positions] -- numPositions mdVec3
+  [normals]   -- numNormals   mdVec3
+  [texcoords] -- numTexcoords mdVec2
+  */
+  uint8_t data[];
+} IndexedModel;
+
+typedef enum ModelType {
+  ModelTypeFlat,
+  ModelTypeIndexed
+} ModelType;
+
+typedef struct Model {
+  uint32_t type;
+  union {
+    FlatModel    flat;
+    IndexedModel indexed;
+  };
+} Model;
-- 
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