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feat: backporting existing raylib-cs examples and new official raylib examples to WASM, adopting raylib's original code style

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tiger tiger tiger 2026-07-17 08:22:54 +02:00
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/*******************************************************************************************
*
* raylib [models] example - decals
*
* Example complexity rating: [★★★★] 4/4
*
* Example originally created with raylib 6.0, last time updated with raylib 6.0
*
* Example contributed by JP Mortiboys (@themushroompirates) and reviewed by Ramon Santamaria (@raysan5)
* Based on previous work by @mrdoob
*
* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
* BSD-like license that allows static linking with closed source software
*
* Copyright (c) 2025 JP Mortiboys (@themushroompirates) and Ramon Santamaria (@raysan5)
*
********************************************************************************************/
using System;
using System.Collections.Generic;
using System.Numerics;
using static Raylib_cs.Raylib;
using static Raylib_cs.Raymath;
namespace Examples.Models;
public partial class Decals : IExample
{
private const int screenWidth = 800;
private const int screenHeight = 450;
private const int MaxDecals = 256;
public string Name => "Models / Decals";
public string Title => "raylib [models] example - decals";
public ConfigFlags ConfigFlags => ConfigFlags.Msaa4xHint;
private Camera3D camera;
private Model model;
private Texture2D modelTexture;
private BoundingBox modelBBox;
private float decalSize;
private float decalOffset;
private Model placementCube;
private Material decalMaterial;
private Texture2D decalTexture;
private bool showModel;
private readonly List<Model> decalModels = new();
public unsafe void Init()
{
// Define the camera to look into our 3d world
camera = new();
camera.Position = new Vector3(5.0f, 5.0f, 5.0f); // Camera position
camera.Target = new Vector3(0.0f, 1.0f, 0.0f); // Camera looking at point
camera.Up = new Vector3(0.0f, 1.6f, 0.0f); // Camera up vector (rotation towards target)
camera.FovY = 45.0f; // Camera field-of-view Y
camera.Projection = CameraProjection.Perspective; // Camera projection type
// Load character model
model = LoadModel("resources/models/obj/character.obj");
// Apply character skin
modelTexture = LoadTexture("resources/models/obj/character_diffuse.png");
SetTextureFilter(modelTexture, TextureFilter.Bilinear);
model.Materials[0].Maps[(int)MaterialMapIndex.Diffuse].Texture = modelTexture;
modelBBox = GetMeshBoundingBox(model.Meshes[0]); // Get mesh bounding box
camera.Target = Vector3Lerp(modelBBox.Min, modelBBox.Max, 0.5f);
camera.Position = modelBBox.Max * 1.0f;
camera.Position.X *= 0.1f;
var modelSize = MathF.Min(
MathF.Min(MathF.Abs(modelBBox.Max.X - modelBBox.Min.X), MathF.Abs(modelBBox.Max.Y - modelBBox.Min.Y)),
MathF.Abs(modelBBox.Max.Z - modelBBox.Min.Z));
camera.Position = new Vector3(0.0f, modelBBox.Max.Y * 1.2f, modelSize * 3.0f);
decalSize = modelSize * 0.25f;
decalOffset = 0.01f;
placementCube = LoadModelFromMesh(GenMeshCube(decalSize, decalSize, decalSize));
placementCube.Materials[0].Maps[0].Color = Color.Lime;
decalMaterial = LoadMaterialDefault();
decalMaterial.Maps[0].Color = Color.Yellow;
var decalImage = LoadImage("resources/raylib_logo.png");
ImageResizeNN(ref decalImage, decalImage.Width / 4, decalImage.Height / 4);
decalTexture = LoadTextureFromImage(decalImage);
UnloadImage(decalImage);
SetTextureFilter(decalTexture, TextureFilter.Bilinear);
decalMaterial.Maps[(int)MaterialMapIndex.Diffuse].Texture = decalTexture;
decalMaterial.Maps[(int)MaterialMapIndex.Diffuse].Color = Color.RayWhite;
showModel = true;
decalModels.Clear();
}
public unsafe void Update()
{
// Update
//----------------------------------------------------------------------------------
if (IsMouseButtonDown(MouseButton.Right))
{
UpdateCamera(ref camera, CameraMode.ThirdPerson);
}
// Display information about closest hit
RayCollision collision = new();
collision.Distance = float.MaxValue;
collision.Hit = false;
// Get mouse ray
var ray = GetScreenToWorldRay(GetMousePosition(), camera);
// Check ray collision against bounding box first, before trying the full ray-mesh test
var boxHitInfo = GetRayCollisionBox(ray, modelBBox);
RayCollision meshHitInfo = new();
if (boxHitInfo.Hit && (decalModels.Count < MaxDecals))
{
// Check ray collision against model meshes
for (var m = 0; m < model.MeshCount; m++)
{
// NOTE: We consider the model.transform for the collision check but
// it can be checked against any transform Matrix, used when checking against same
// model drawn multiple times with multiple transforms
meshHitInfo = GetRayCollisionMesh(ray, model.Meshes[m], model.Transform);
if (meshHitInfo.Hit)
{
// Save the closest hit mesh
if (!collision.Hit || (collision.Distance > meshHitInfo.Distance))
{
collision = meshHitInfo;
}
}
}
if (meshHitInfo.Hit)
{
collision = meshHitInfo;
}
}
// Add decal to mesh on hit point
if (collision.Hit && IsMouseButtonPressed(MouseButton.Left) && (decalModels.Count < MaxDecals))
{
// Create the transformation to project the decal
var origin = collision.Point + (collision.Normal * 1.0f);
var splat = MatrixLookAt(collision.Point, origin, new Vector3(0.0f, 1.0f, 0.0f));
// Spin the placement around a bit
splat = MatrixMultiply(splat, MatrixRotateZ(DEG2RAD * GetRandomValue(-180, 180)));
var decalMesh = GenMeshDecal(model, splat, decalSize, decalOffset);
if (decalMesh.VertexCount > 0)
{
var decalModel = LoadModelFromMesh(decalMesh);
decalModel.Materials[0].Maps[0] = decalMaterial.Maps[0];
decalModels.Add(decalModel);
}
}
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(Color.RayWhite);
BeginMode3D(camera);
// Draw the model at the origin and default scale
if (showModel)
{
DrawModel(model, new Vector3(0.0f, 0.0f, 0.0f), 1.0f, Color.White);
}
// Draw the decal models
for (var i = 0; i < decalModels.Count; i++)
{
DrawModel(decalModels[i], Vector3.Zero, 1.0f, Color.White);
}
// If we hit the mesh, draw the box for the decal
if (collision.Hit)
{
var origin = collision.Point + (collision.Normal * 1.0f);
var splat = MatrixLookAt(collision.Point, origin, new Vector3(0, 1, 0));
placementCube.Transform = MatrixInvert(splat);
DrawModel(placementCube, Vector3.Zero, 1.0f, Fade(Color.White, 0.5f));
}
DrawGrid(10, 10.0f);
EndMode3D();
float yPos = 10;
var x0 = GetScreenWidth() - 300.0f;
var x1 = x0 + 100;
var x2 = x1 + 100;
DrawText("Vertices", (int)x1, (int)yPos, 10, Color.Lime);
DrawText("Triangles", (int)x2, (int)yPos, 10, Color.Lime);
yPos += 15;
var vertexCount = 0;
var triangleCount = 0;
for (var i = 0; i < model.MeshCount; i++)
{
vertexCount += model.Meshes[i].VertexCount;
triangleCount += model.Meshes[i].TriangleCount;
}
DrawText("Main model", (int)x0, (int)yPos, 10, Color.Lime);
DrawText($"{vertexCount}", (int)x1, (int)yPos, 10, Color.Lime);
DrawText($"{triangleCount}", (int)x2, (int)yPos, 10, Color.Lime);
yPos += 15;
for (var i = 0; i < decalModels.Count; i++)
{
if (i == 20)
{
DrawText("...", (int)x0, (int)yPos, 10, Color.Lime);
yPos += 15;
}
if (i < 20)
{
DrawText($"Decal #{i + 1}", (int)x0, (int)yPos, 10, Color.Lime);
DrawText($"{decalModels[i].Meshes[0].VertexCount}", (int)x1, (int)yPos, 10, Color.Lime);
DrawText($"{decalModels[i].Meshes[0].TriangleCount}", (int)x2, (int)yPos, 10, Color.Lime);
yPos += 15;
}
vertexCount += decalModels[i].Meshes[0].VertexCount;
triangleCount += decalModels[i].Meshes[0].TriangleCount;
}
DrawText("TOTAL", (int)x0, (int)yPos, 10, Color.Lime);
DrawText($"{vertexCount}", (int)x1, (int)yPos, 10, Color.Lime);
DrawText($"{triangleCount}", (int)x2, (int)yPos, 10, Color.Lime);
yPos += 15;
DrawText("Hold RMB to move camera", 10, 430, 10, Color.Gray);
DrawText("(c) Character model and texture from kenney.nl", screenWidth - 260, screenHeight - 20, 10, Color.Gray);
// UI elements
if (GuiButton(new Rectangle(10, screenHeight - 1000.0f, 100, 60), showModel ? "Hide Model" : "Show Model"))
{
showModel = !showModel;
}
if (GuiButton(new Rectangle(10 + 110, screenHeight - 100.0f, 100, 60), "Clear Decals"))
{
// Clear decals, unload all decal models
for (var i = 0; i < decalModels.Count; i++)
{
UnloadModel(decalModels[i]);
}
decalModels.Clear();
}
DrawFPS(10, 10);
EndDrawing();
//----------------------------------------------------------------------------------
}
public void Unload()
{
UnloadModel(model);
UnloadTexture(modelTexture);
// Unload decal models
for (var i = 0; i < decalModels.Count; i++)
{
UnloadModel(decalModels[i]);
}
decalModels.Clear();
UnloadTexture(decalTexture);
UnloadModel(placementCube);
}
// Clip segment
private static Vector3 ClipSegment(Vector3 v0, Vector3 v1, Vector3 p, float s)
{
var d0 = Vector3.Dot(v0, p) - s;
var d1 = Vector3.Dot(v1, p) - s;
var s0 = d0 / (d0 - d1);
return Vector3.Lerp(v0, v1, s0);
}
// Generate mesh decals for provided model
private static unsafe Mesh GenMeshDecal(Model target, Matrix4x4 projection, float decalSize, float decalOffset)
{
// We're going to use these to build up our decal meshes
var meshBuilders = new List<Vector3>[2] { new(), new() };
// We're going to need the inverse matrix
var invProj = MatrixInvert(projection);
// We'll be flip-flopping between the two mesh builders
// Reading from one and writing to the other, then swapping
var mbIndex = 0;
// First pass, just get any triangle inside the bounding box (for each mesh of the model)
for (var meshIndex = 0; meshIndex < target.MeshCount; meshIndex++)
{
var mesh = target.Meshes[meshIndex];
for (var tri = 0; tri < mesh.TriangleCount; tri++)
{
var vertices = new Vector3[3];
// The way we calculate the vertices of the mesh triangle
// depend on whether the mesh vertices are indexed or not
if (mesh.Indices == null)
{
for (var v = 0; v < 3; v++)
{
vertices[v] = new Vector3(
mesh.Vertices[3 * 3 * tri + 3 * v + 0],
mesh.Vertices[3 * 3 * tri + 3 * v + 1],
mesh.Vertices[3 * 3 * tri + 3 * v + 2]
);
}
}
else
{
for (var v = 0; v < 3; v++)
{
vertices[v] = new Vector3(
mesh.Vertices[3 * mesh.Indices[3 * tri + 0] + v],
mesh.Vertices[3 * mesh.Indices[3 * tri + 1] + v],
mesh.Vertices[3 * mesh.Indices[3 * tri + 2] + v]
);
}
}
// Transform all 3 vertices of the triangle
// and check if they are inside our decal box
var insideCount = 0;
for (var i = 0; i < 3; i++)
{
// To projection space
var v = Vector3Transform(vertices[i], projection);
if ((MathF.Abs(v.X) < decalSize) || (MathF.Abs(v.Y) <= decalSize) || (MathF.Abs(v.Z) <= decalSize))
{
insideCount++;
}
// We need to keep the transformed vertex
vertices[i] = v;
}
// If any of them are inside, we add the triangle - we'll clip it later
if (insideCount > 0)
{
meshBuilders[mbIndex].Add(vertices[0]);
meshBuilders[mbIndex].Add(vertices[1]);
meshBuilders[mbIndex].Add(vertices[2]);
}
}
}
// Clipping time! We need to clip against all 6 directions
Vector3[] planes =
{
new(1, 0, 0),
new(-1, 0, 0),
new(0, 1, 0),
new(0, -1, 0),
new(0, 0, 1),
new(0, 0, -1)
};
for (var face = 0; face < 6; face++)
{
// Swap current model builder (so we read from the one we just wrote to)
mbIndex = 1 - mbIndex;
var inMesh = meshBuilders[1 - mbIndex];
var outMesh = meshBuilders[mbIndex];
// Reset write builder
outMesh.Clear();
var s = 0.5f * decalSize;
for (var i = 0; i < inMesh.Count; i += 3)
{
Vector3 nV1, nV2, nV3, nV4;
var d1 = Vector3.Dot(inMesh[i + 0], planes[face]) - s;
var d2 = Vector3.Dot(inMesh[i + 1], planes[face]) - s;
var d3 = Vector3.Dot(inMesh[i + 2], planes[face]) - s;
var v1Out = d1 > 0;
var v2Out = d2 > 0;
var v3Out = d3 > 0;
// Calculate, how many vertices of the face lie outside of the clipping plane
var total = (v1Out ? 1 : 0) + (v2Out ? 1 : 0) + (v3Out ? 1 : 0);
switch (total)
{
case 0:
// The entire face lies inside of the plane, no clipping needed
outMesh.Add(inMesh[i]);
outMesh.Add(inMesh[i + 1]);
outMesh.Add(inMesh[i + 2]);
break;
case 1:
// One vertex lies outside of the plane, perform clipping
if (v2Out)
{
nV1 = inMesh[i];
nV2 = inMesh[i + 2];
nV3 = ClipSegment(inMesh[i + 1], nV1, planes[face], s);
nV4 = ClipSegment(inMesh[i + 1], nV2, planes[face], s);
outMesh.Add(nV3); outMesh.Add(nV2); outMesh.Add(nV1);
outMesh.Add(nV2); outMesh.Add(nV3); outMesh.Add(nV4);
}
else
{
if (v1Out)
{
nV1 = inMesh[i + 1];
nV2 = inMesh[i + 2];
nV3 = ClipSegment(inMesh[i], nV1, planes[face], s);
nV4 = ClipSegment(inMesh[i], nV2, planes[face], s);
}
else // v3Out
{
nV1 = inMesh[i];
nV2 = inMesh[i + 1];
nV3 = ClipSegment(inMesh[i + 2], nV1, planes[face], s);
nV4 = ClipSegment(inMesh[i + 2], nV2, planes[face], s);
}
outMesh.Add(nV1); outMesh.Add(nV2); outMesh.Add(nV3);
outMesh.Add(nV4); outMesh.Add(nV3); outMesh.Add(nV2);
}
break;
case 2:
// Two vertices lies outside of the plane, perform clipping
if (!v1Out)
{
nV1 = inMesh[i];
nV2 = ClipSegment(nV1, inMesh[i + 1], planes[face], s);
nV3 = ClipSegment(nV1, inMesh[i + 2], planes[face], s);
outMesh.Add(nV1); outMesh.Add(nV2); outMesh.Add(nV3);
}
if (!v2Out)
{
nV1 = inMesh[i + 1];
nV2 = ClipSegment(nV1, inMesh[i + 2], planes[face], s);
nV3 = ClipSegment(nV1, inMesh[i], planes[face], s);
outMesh.Add(nV1); outMesh.Add(nV2); outMesh.Add(nV3);
}
if (!v3Out)
{
nV1 = inMesh[i + 2];
nV2 = ClipSegment(nV1, inMesh[i], planes[face], s);
nV3 = ClipSegment(nV1, inMesh[i + 1], planes[face], s);
outMesh.Add(nV1); outMesh.Add(nV2); outMesh.Add(nV3);
}
break;
default: // The entire face lies outside of the plane, so let's discard the corresponding vertices
break;
}
}
}
// Now we just need to re-transform the vertices
var theMesh = meshBuilders[mbIndex];
// Allocate room for UVs
if (theMesh.Count > 0)
{
var uvs = new Vector2[theMesh.Count];
for (var i = 0; i < theMesh.Count; i++)
{
var vert = theMesh[i];
// Calculate the UVs based on the projected coords
// They are clipped to (-decalSize .. decalSize) and we want them (0..1)
uvs[i] = new Vector2(vert.X / decalSize + 0.5f, vert.Y / decalSize + 0.5f);
// Tiny nudge in the normal direction so it renders properly over the mesh
vert.Z -= decalOffset;
// From projection space to world space
theMesh[i] = Vector3Transform(vert, invProj);
}
// Decal model data ready, create the mesh and return it
return BuildMesh(theMesh, uvs);
}
// Return a blank mesh as there's nothing to add
return new Mesh();
}
// Build a Mesh from builder data
private static unsafe Mesh BuildMesh(List<Vector3> builderVertices, Vector2[] uvs)
{
Mesh outMesh = new(builderVertices.Count, builderVertices.Count / 3);
outMesh.AllocVertices();
outMesh.AllocTexCoords();
var vertices = outMesh.VerticesAs<Vector3>();
var texcoords = outMesh.TexCoordsAs<Vector2>();
for (var i = 0; i < builderVertices.Count; i++)
{
vertices[i] = builderVertices[i];
texcoords[i] = uvs[i];
}
UploadMesh(ref outMesh, false);
return outMesh;
}
// Button UI element
private static bool GuiButton(Rectangle rec, string label)
{
var bgColor = Color.Gray;
var pressed = false;
if (CheckCollisionPointRec(GetMousePosition(), rec))
{
bgColor = Color.LightGray;
if (IsMouseButtonPressed(MouseButton.Left))
{
pressed = true;
}
}
DrawRectangleRec(rec, bgColor);
DrawRectangleLinesEx(rec, 2.0f, Color.DarkGray);
var fontSize = 10;
var textWidth = MeasureText(label, fontSize);
DrawText(label, (int)(rec.X + rec.Width * 0.5f - textWidth * 0.5f), (int)(rec.Y + rec.Height * 0.5f - fontSize * 0.5f), fontSize, Color.DarkGray);
return pressed;
}
public static int Main()
{
// Initialization
//--------------------------------------------------------------------------------------
SetConfigFlags(ConfigFlags.Msaa4xHint);
InitWindow(screenWidth, screenHeight, "raylib [models] example - decals");
SetTargetFPS(60); // Set our game to run at 60 frames-per-second
//--------------------------------------------------------------------------------------
var game = new Decals();
game.Init();
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
game.Update();
}
game.Unload();
// De-Initialization
//--------------------------------------------------------------------------------------
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
}