Emil_Shanaty/Cortex_Engine
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feat: directional lighting with per-face normals

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- Add Normal to Vertex struct and vertex input pipeline.
- Update vertex/fragment shaders with push-constant light data (direction, color, ambient).
- Compute per-face normals in ObjLoader and GltfLoader for flat shading.
- Add Transform.TransformNormal() using inverse-transpose of the model matrix.
- MeshRenderer builds world-space normals and pushes light constants each frame.
- Recompile SPIR-V shaders.
This commit is contained in:
emil28092005
2026-06-16 20:18:20 +03:00
parent 9312810f0c
commit 98a429710a
10 changed files with 198 additions and 48 deletions
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src/Engine.Graphics/Loaders/GltfLoader.cs
+49 -13
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@@ -10,6 +10,7 @@ namespace Engine.Graphics.Loaders;
/// <summary>
/// glTF/glTF binary loader using SharpGLTF.Core.
/// Loads the first primitive of the first mesh and converts it to a colored Mesh component.
/// Creates per-face normals for flat shading if the glTF does not provide normals.
/// </summary>
public static class GltfLoader
{
@@ -31,28 +32,63 @@ public static class GltfLoader
throw new InvalidOperationException($"glTF primitive has no POSITION accessor: {path}");
var positions = positionAccessor.AsVector3Array();
var vertices = new Vertex[positions.Count];
for (var i = 0; i < positions.Count; i++)
var indices = GetIndices(primitive, positions.Count);
var vertices = new List<Vertex>();
var newIndices = new List<uint>();
for (var i = 0; i < indices.Length; i += 3)
{
vertices[i] = new Vertex(positions[i], color);
var i0 = (int)indices[i];
var i1 = (int)indices[i + 1];
var i2 = (int)indices[i + 2];
var v0 = new Vector3(positions[i0].X, positions[i0].Y, positions[i0].Z);
var v1 = new Vector3(positions[i1].X, positions[i1].Y, positions[i1].Z);
var v2 = new Vector3(positions[i2].X, positions[i2].Y, positions[i2].Z);
var normal = ComputeFaceNormal(v0, v1, v2);
var vertexBase = (uint)vertices.Count;
newIndices.Add(vertexBase);
newIndices.Add(vertexBase + 1);
newIndices.Add(vertexBase + 2);
vertices.Add(new Vertex(v0, color, normal));
vertices.Add(new Vertex(v1, color, normal));
vertices.Add(new Vertex(v2, color, normal));
}
uint[] indices;
return new Engine.Core.Components.Mesh(vertices.ToArray(), newIndices.ToArray());
}
private static uint[] GetIndices(MeshPrimitive primitive, int positionCount)
{
if (primitive.IndexAccessor != null)
{
var idx = primitive.IndexAccessor.AsIndexArray();
indices = new uint[idx.Count];
var indices = new uint[idx.Count];
for (var i = 0; i < idx.Count; i++)
indices[i] = idx[i];
}
else
{
// Non-indexed primitive
indices = new uint[positions.Count];
for (var i = 0; i < positions.Count; i++)
indices[i] = (uint)i;
return indices;
}
return new Engine.Core.Components.Mesh(vertices, indices);
// Non-indexed primitive
var auto = new uint[positionCount];
for (var i = 0; i < positionCount; i++)
auto[i] = (uint)i;
return auto;
}
private static Vector3 ComputeFaceNormal(Vector3 a, Vector3 b, Vector3 c)
{
var ab = b - a;
var ac = c - a;
var normal = Vector3.Cross(ab, ac);
if (normal.LengthSquared() > 0.00001f)
normal = Vector3.Normalize(normal);
else
normal = Vector3.UnitY;
return normal;
}
}
src/Engine.Graphics/Loaders/ObjLoader.cs
+34 -13
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@@ -9,7 +9,7 @@ namespace Engine.Graphics.Loaders;
/// <summary>
/// Minimal .obj loader.
/// Supports vertices (v) and faces (f). Ignores normals/UVs for now.
/// Supports vertices (v) and faces (f). Creates per-face normals for flat shading.
/// Produces a colored Mesh component.
/// </summary>
public static class ObjLoader
@@ -19,6 +19,7 @@ public static class ObjLoader
var color = defaultColor ?? new Vector3(0.7f, 0.7f, 0.7f);
var positions = new List<Vector3>();
var vertices = new List<Vertex>();
var indices = new List<uint>();
foreach (var rawLine in File.ReadLines(path))
@@ -41,28 +42,36 @@ public static class ObjLoader
break;
case "f" when parts.Length >= 4:
// Triangulate the face as a fan. Only the position index is used.
// Triangulate the face as a fan.
var baseIndex = ParseFaceIndex(parts[1]);
for (var i = 2; i < parts.Length - 1; i++)
{
indices.Add(baseIndex);
indices.Add(ParseFaceIndex(parts[i]));
indices.Add(ParseFaceIndex(parts[i + 1]));
var i0 = baseIndex;
var i1 = ParseFaceIndex(parts[i]);
var i2 = ParseFaceIndex(parts[i + 1]);
var v0 = positions[(int)i0];
var v1 = positions[(int)i1];
var v2 = positions[(int)i2];
var normal = ComputeFaceNormal(v0, v1, v2);
var vertexBase = (uint)vertices.Count;
indices.Add(vertexBase);
indices.Add(vertexBase + 1);
indices.Add(vertexBase + 2);
vertices.Add(new Vertex(v0, color, normal));
vertices.Add(new Vertex(v1, color, normal));
vertices.Add(new Vertex(v2, color, normal));
}
break;
}
}
if (positions.Count == 0)
if (vertices.Count == 0)
throw new InvalidOperationException($"OBJ file has no vertices: {path}");
var vertices = new Vertex[positions.Count];
for (var i = 0; i < positions.Count; i++)
{
vertices[i] = new Vertex(positions[i], color);
}
return new Mesh(vertices, indices.ToArray());
return new Mesh(vertices.ToArray(), indices.ToArray());
}
private static uint ParseFaceIndex(string part)
@@ -73,4 +82,16 @@ public static class ObjLoader
var index = int.Parse(indexStr);
return (uint)(index - 1); // OBJ indices are 1-based
}
private static Vector3 ComputeFaceNormal(Vector3 a, Vector3 b, Vector3 c)
{
var ab = b - a;
var ac = c - a;
var normal = Vector3.Cross(ab, ac);
if (normal.LengthSquared() > 0.00001f)
normal = Vector3.Normalize(normal);
else
normal = Vector3.UnitY;
return normal;
}
}
src/Engine.Graphics/MeshRenderer.cs
+47 -16
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@@ -1,6 +1,7 @@
using System;
using System.Collections.Generic;
using System.Numerics;
using System.Runtime.InteropServices;
using Flecs.NET.Core;
using Silk.NET.Core;
using Silk.NET.Vulkan;
@@ -27,6 +28,18 @@ public sealed unsafe class MeshRenderer : IDisposable
private Silk.NET.Vulkan.Fence[] _inFlightFences = null!;
private int _currentFrame;
[StructLayout(LayoutKind.Sequential)]
private struct PushConstants
{
public Matrix4x4 Mvp;
public Vector3 LightDirection;
public float Pad1;
public Vector3 LightColor;
public float Pad2;
public Vector3 AmbientColor;
public float Pad3;
}
private sealed class MeshBuffers : IDisposable
{
public VertexBuffer VertexBuffer;
@@ -194,7 +207,17 @@ public sealed unsafe class MeshRenderer : IDisposable
var model = transform.GetMatrix();
var mvp = Matrix4x4.Multiply(Matrix4x4.Multiply(model, view), proj);
var mvpT = Matrix4x4.Transpose(mvp);
_context.Vk.CmdPushConstants(drawCmd, _pipeline.Layout, ShaderStageFlags.VertexBit, 0, 64, &mvpT);
var push = new PushConstants
{
Mvp = mvpT,
LightDirection = new Vector3(0.5f, -1.0f, -0.5f),
LightColor = new Vector3(1.0f, 0.95f, 0.8f),
AmbientColor = new Vector3(0.15f, 0.15f, 0.2f)
};
var pushSize = (uint)sizeof(PushConstants);
_context.Vk.CmdPushConstants(drawCmd, _pipeline.Layout, ShaderStageFlags.VertexBit | ShaderStageFlags.FragmentBit, 0, pushSize, &push);
var vertexBuffer = buffers.VertexBuffer.Buffer;
var offset = 0ul;
@@ -252,19 +275,22 @@ public sealed unsafe class MeshRenderer : IDisposable
private MeshBuffers CreateMeshBuffers(Mesh mesh)
{
var vertexBytes = new byte[mesh.Vertices.Length * 6 * sizeof(float)];
var vertexBytes = new byte[mesh.Vertices.Length * 9 * sizeof(float)];
fixed (byte* p = vertexBytes)
{
var dst = (float*)p;
for (var i = 0; i < mesh.Vertices.Length; i++)
{
var v = mesh.Vertices[i];
dst[i * 6 + 0] = v.Position.X;
dst[i * 6 + 1] = v.Position.Y;
dst[i * 6 + 2] = v.Position.Z;
dst[i * 6 + 3] = v.Color.X;
dst[i * 6 + 4] = v.Color.Y;
dst[i * 6 + 5] = v.Color.Z;
dst[i * 9 + 0] = v.Position.X;
dst[i * 9 + 1] = v.Position.Y;
dst[i * 9 + 2] = v.Position.Z;
dst[i * 9 + 3] = v.Color.X;
dst[i * 9 + 4] = v.Color.Y;
dst[i * 9 + 5] = v.Color.Z;
dst[i * 9 + 6] = v.Normal.X;
dst[i * 9 + 7] = v.Normal.Y;
dst[i * 9 + 8] = v.Normal.Z;
}
}
@@ -283,19 +309,24 @@ public sealed unsafe class MeshRenderer : IDisposable
private byte[] BuildMeshVertices(Mesh mesh, Transform transform)
{
var matrix = transform.GetMatrix();
var bytes = new byte[mesh.Vertices.Length * 6 * sizeof(float)];
var bytes = new byte[mesh.Vertices.Length * 9 * sizeof(float)];
fixed (byte* p = bytes)
{
var dst = (float*)p;
for (var i = 0; i < mesh.Vertices.Length; i++)
{
var transformed = Vector3.Transform(mesh.Vertices[i].Position, matrix);
dst[i * 6 + 0] = transformed.X;
dst[i * 6 + 1] = transformed.Y;
dst[i * 6 + 2] = transformed.Z;
dst[i * 6 + 3] = mesh.Vertices[i].Color.X;
dst[i * 6 + 4] = mesh.Vertices[i].Color.Y;
dst[i * 6 + 5] = mesh.Vertices[i].Color.Z;
var v = mesh.Vertices[i];
var transformed = Vector3.Transform(v.Position, matrix);
var normal = transform.TransformNormal(v.Normal);
dst[i * 9 + 0] = transformed.X;
dst[i * 9 + 1] = transformed.Y;
dst[i * 9 + 2] = transformed.Z;
dst[i * 9 + 3] = v.Color.X;
dst[i * 9 + 4] = v.Color.Y;
dst[i * 9 + 5] = v.Color.Z;
dst[i * 9 + 6] = normal.X;
dst[i * 9 + 7] = normal.Y;
dst[i * 9 + 8] = normal.Z;
}
}
return bytes;
src/Engine.Graphics/Shaders/fragment.frag
+22 -1
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@@ -1,10 +1,31 @@
#version 450
layout(location = 0) in vec3 fragColor;
layout(location = 1) in vec3 fragNormal;
layout(location = 2) in vec3 fragWorldPos;
layout(location = 0) out vec4 outColor;
layout(push_constant) uniform PushConstants
{
mat4 mvp;
vec3 lightDirection;
float pad1;
vec3 lightColor;
float pad2;
vec3 ambientColor;
float pad3;
} push;
void main()
{
outColor = vec4(fragColor, 1.0);
vec3 normal = normalize(fragNormal);
vec3 lightDir = normalize(-push.lightDirection);
float diff = max(dot(normal, lightDir), 0.0);
vec3 diffuse = push.lightColor * diff;
vec3 ambient = push.ambientColor;
vec3 result = (ambient + diffuse) * fragColor;
outColor = vec4(result, 1.0);
}
src/Engine.Graphics/Shaders/fragment.spv
BIN
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src/Engine.Graphics/Shaders/vertex.spv
BIN
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src/Engine.Graphics/Shaders/vertex.vert
+11
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@@ -2,16 +2,27 @@
layout(location = 0) in vec3 inPosition;
layout(location = 1) in vec3 inColor;
layout(location = 2) in vec3 inNormal;
layout(location = 0) out vec3 fragColor;
layout(location = 1) out vec3 fragNormal;
layout(location = 2) out vec3 fragWorldPos;
layout(push_constant) uniform PushConstants
{
mat4 mvp;
vec3 lightDirection;
float pad1;
vec3 lightColor;
float pad2;
vec3 ambientColor;
float pad3;
} push;
void main()
{
gl_Position = push.mvp * vec4(inPosition, 1.0);
fragColor = inColor;
fragNormal = inNormal;
fragWorldPos = inPosition;
}
src/Engine.Graphics/VulkanPipeline.cs
+10 -3
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@@ -57,9 +57,9 @@ public sealed unsafe class VulkanPipeline : IDisposable
{
var pushConstantRange = new PushConstantRange
{
StageFlags = ShaderStageFlags.VertexBit,
StageFlags = ShaderStageFlags.VertexBit | ShaderStageFlags.FragmentBit,
Offset = 0,
Size = (uint)(16 * sizeof(float))
Size = (uint)(28 * sizeof(float))
};
var createInfo = new PipelineLayoutCreateInfo
@@ -101,7 +101,7 @@ public sealed unsafe class VulkanPipeline : IDisposable
var bindingDescription = new VertexInputBindingDescription
{
Binding = 0,
Stride = (uint)(6 * sizeof(float)),
Stride = (uint)(9 * sizeof(float)),
InputRate = VertexInputRate.Vertex
};
@@ -120,6 +120,13 @@ public sealed unsafe class VulkanPipeline : IDisposable
Location = 1,
Format = Format.R32G32B32Sfloat,
Offset = (uint)(3 * sizeof(float))
},
new VertexInputAttributeDescription
{
Binding = 0,
Location = 2,
Format = Format.R32G32B32Sfloat,
Offset = (uint)(6 * sizeof(float))
}
};