390 lines
16 KiB
C#
390 lines
16 KiB
C#
/*******************************************************************************************
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*
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* raylib [models] example - animation blend custom
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*
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* Example complexity rating: [★★★★] 4/4
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*
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* Example originally created with raylib 5.5, last time updated with raylib 6.0
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*
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* Example contributed by dmitrii-brand (@dmitrii-brand) and reviewed by Ramon Santamaria (@raysan5)
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*
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* DETAILS: Example demonstrates per-bone animation blending, allowing smooth transitions
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* between two animations by interpolating bone transforms. This is useful for:
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* - Blending movement animations (walk/run) with action animations (jump/attack)
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* - Creating smooth animation transitions
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* - Layering animations (e.g., upper body attack while lower body walks)
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*
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* WARNING: GPU skinning must be enabled in raylib with a compilation flag,
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* if not enabled, CPU skinning will be used instead
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2026 dmitrii-brand (@dmitrii-brand)
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*
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********************************************************************************************/
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using System;
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using System.Numerics;
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using static Raylib_cs.Raylib;
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using static Raylib_cs.Raymath;
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namespace Examples.Models;
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public partial class AnimationBlendCustom : IExample
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{
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private const int screenWidth = 800;
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private const int screenHeight = 450;
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#if BROWSER
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private const int GlslVersion = 100; // WebGL1 needs GLSL ES 100
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#else
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private const int GlslVersion = 330;
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#endif
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public string Name => "Models / Animation Blend Custom";
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public string Title => "raylib [models] example - animation blend custom";
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private Camera3D camera;
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private Model model;
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private Vector3 position;
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private Shader skinningShader;
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private unsafe ModelAnimation* anims;
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private int animCount;
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private int animIndex0;
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private int animIndex1;
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private int animCurrentFrame0;
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private int animCurrentFrame1;
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private bool upperBodyBlend;
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public unsafe void Init()
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{
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// Define the camera to look into our 3d world
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camera = new();
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camera.Position = new Vector3(4.0f, 4.0f, 4.0f); // Camera position
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camera.Target = new Vector3(0.0f, 1.0f, 0.0f); // Camera looking at point
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camera.Up = new Vector3(0.0f, 1.0f, 0.0f); // Camera up vector (rotation towards target)
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camera.FovY = 45.0f; // Camera field-of-view Y
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camera.Projection = CameraProjection.Perspective; // Camera projection type
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// Load gltf model
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model = LoadModel("resources/models/gltf/greenman.glb");
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position = new Vector3(0.0f, 0.0f, 0.0f); // Set model position
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// Load skinning shader
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// WARNING: GPU skinning must be enabled in raylib with a compilation flag,
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// if not enabled, CPU skinning will be used instead
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skinningShader = LoadShader(
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$"resources/shaders/glsl{GlslVersion}/skinning.vs",
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$"resources/shaders/glsl{GlslVersion}/skinning.fs"
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);
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model.Materials[1].Shader = skinningShader;
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// Load gltf model animations
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animCount = 0;
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anims = LoadModelAnimations("resources/models/gltf/greenman.glb", ref animCount);
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// Use specific animation indices: 2-walk/move, 3-attack
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animIndex0 = 2; // Walk/Move animation (index 2)
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animIndex1 = 3; // Attack animation (index 3)
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animCurrentFrame0 = 0;
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animCurrentFrame1 = 0;
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// Validate indices
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if (animIndex0 >= animCount)
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{
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animIndex0 = 0;
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}
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if (animIndex1 >= animCount)
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{
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animIndex1 = (animCount > 1) ? 1 : 0;
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}
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upperBodyBlend = true; // Toggle: true = upper/lower body blending, false = uniform blending (50/50)
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}
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public unsafe void Update()
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{
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// Update
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//----------------------------------------------------------------------------------
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UpdateCamera(ref camera, CameraMode.Orbital);
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// Toggle upper/lower body blending mode (SPACE key)
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if (IsKeyPressed(KeyboardKey.Space))
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{
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upperBodyBlend = !upperBodyBlend;
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}
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// Update animation frames
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var anim0 = anims[animIndex0];
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var anim1 = anims[animIndex1];
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animCurrentFrame0 = (animCurrentFrame0 + 1) % anim0.KeyFrameCount;
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animCurrentFrame1 = (animCurrentFrame1 + 1) % anim1.KeyFrameCount;
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// Blend the two animations
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// When upperBodyBlend is ON: upper body = attack (1.0), lower body = walk (0.0)
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// When upperBodyBlend is OFF: uniform blend at 0.5 (50% walk, 50% attack)
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var blendFactor = upperBodyBlend ? 1.0f : 0.5f;
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UpdateModelAnimationBones(anim0, animCurrentFrame0, anim1, animCurrentFrame1, blendFactor, upperBodyBlend);
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// raylib provided animation blending function
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//UpdateModelAnimationEx(model, anim0, (float)animCurrentFrame0,
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// anim1, (float)animCurrentFrame1, blendFactor);
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(Color.RayWhite);
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BeginMode3D(camera);
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DrawModel(model, position, 1.0f, Color.White);
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DrawGrid(10, 1.0f);
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EndMode3D();
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// Draw UI
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DrawText($"ANIM 0: {anim0.NameToString()}", 10, 10, 20, Color.Gray);
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DrawText($"ANIM 1: {anim1.NameToString()}", 10, 40, 20, Color.Gray);
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DrawText($"[SPACE] Toggle blending mode: {(upperBodyBlend ? "Upper/Lower Body Blending" : "Uniform Blending")}",
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10, GetScreenHeight() - 30, 20, Color.DarkGray);
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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public unsafe void Unload()
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{
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UnloadModelAnimations(anims, animCount); // Unload model animation
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UnloadModel(model); // Unload model and meshes/material
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UnloadShader(skinningShader); // Unload GPU skinning shader
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}
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// Check if a bone is part of upper body (for selective blending)
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private static bool IsUpperBodyBone(string boneName)
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{
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// Common upper body bone names (adjust based on your model)
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if (boneName is "spine" or "spine1" or "spine2" or
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"chest" or "upperChest" or
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"neck" or "head" or
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"shoulder" or "shoulder_L" or "shoulder_R" or
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"upperArm" or "upperArm_L" or "upperArm_R" or
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"lowerArm" or "lowerArm_L" or "lowerArm_R" or
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"hand" or "hand_L" or "hand_R" or
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"clavicle" or "clavicle_L" or "clavicle_R")
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{
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return true;
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}
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// Check if bone name contains upper body keywords
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if (boneName.Contains("spine") || boneName.Contains("chest") ||
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boneName.Contains("neck") || boneName.Contains("head") ||
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boneName.Contains("shoulder") || boneName.Contains("arm") ||
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boneName.Contains("hand") || boneName.Contains("clavicle"))
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{
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return true;
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}
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return false;
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}
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// Blend two animations per-bone with selective upper/lower body blending
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private unsafe void UpdateModelAnimationBones(ModelAnimation anim0, int frame0,
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ModelAnimation anim1, int frame1, float blend, bool upperBodyBlend)
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{
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// Validate inputs
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if ((anim0.BoneCount != 0) && (anim0.KeyframePoses != null) &&
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(anim1.BoneCount != 0) && (anim1.KeyframePoses != null) &&
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(model.Skeleton.BoneCount != 0) && (model.Skeleton.BindPose != null))
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{
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// Clamp blend factor to [0, 1]
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blend = MathF.Min(1.0f, MathF.Max(0.0f, blend));
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// Ensure frame indices are valid
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if (frame0 >= anim0.KeyFrameCount)
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{
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frame0 = anim0.KeyFrameCount - 1;
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}
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if (frame1 >= anim1.KeyFrameCount)
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{
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frame1 = anim1.KeyFrameCount - 1;
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}
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if (frame0 < 0)
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{
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frame0 = 0;
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}
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if (frame1 < 0)
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{
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frame1 = 0;
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}
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// Get bone count (use minimum of all to be safe)
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var boneCount = model.Skeleton.BoneCount;
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if (anim0.BoneCount < boneCount)
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{
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boneCount = anim0.BoneCount;
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}
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if (anim1.BoneCount < boneCount)
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{
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boneCount = anim1.BoneCount;
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}
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// Blend each bone
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for (var boneIndex = 0; boneIndex < boneCount; boneIndex++)
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{
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// Determine blend factor for this bone
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var boneBlendFactor = blend;
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// If upper body blending is enabled, use different blend factors for upper vs lower body
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if (upperBodyBlend)
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{
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var boneName = model.Skeleton.Bones[boneIndex].NameToString();
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var isUpperBody = IsUpperBodyBone(boneName);
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// Upper body: use anim1 (attack), Lower body: use anim0 (walk)
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// blend = 0.0 means full anim0 (walk), 1.0 means full anim1 (attack)
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if (isUpperBody)
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{
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boneBlendFactor = blend; // Upper body: blend towards anim1 (attack)
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}
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else
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{
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boneBlendFactor = 1.0f - blend; // Lower body: blend towards anim0 (walk) - invert the blend
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}
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}
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// Get transforms from both animations
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var bindTransform = model.Skeleton.BindPose[boneIndex];
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var animTransform0 = anim0.KeyframePoses[frame0][boneIndex];
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var animTransform1 = anim1.KeyframePoses[frame1][boneIndex];
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// Blend the transforms
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Transform blended = new();
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blended.Translation = Vector3Lerp(animTransform0.Translation, animTransform1.Translation, boneBlendFactor);
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blended.Rotation = QuaternionSlerp(animTransform0.Rotation, animTransform1.Rotation, boneBlendFactor);
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blended.Scale = Vector3Lerp(animTransform0.Scale, animTransform1.Scale, boneBlendFactor);
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// Convert bind pose to matrix
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var bindMatrix = MatrixMultiply(MatrixMultiply(
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MatrixScale(bindTransform.Scale.X, bindTransform.Scale.Y, bindTransform.Scale.Z),
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QuaternionToMatrix(bindTransform.Rotation)),
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MatrixTranslate(bindTransform.Translation.X, bindTransform.Translation.Y, bindTransform.Translation.Z));
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// Convert blended transform to matrix
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var blendedMatrix = MatrixMultiply(MatrixMultiply(
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MatrixScale(blended.Scale.X, blended.Scale.Y, blended.Scale.Z),
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QuaternionToMatrix(blended.Rotation)),
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MatrixTranslate(blended.Translation.X, blended.Translation.Y, blended.Translation.Z));
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// Calculate final bone matrix (similar to UpdateModelAnimationBones)
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model.BoneMatrices[boneIndex] = MatrixMultiply(MatrixInvert(bindMatrix), blendedMatrix);
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}
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// CPU skinning, updates CPU buffers and uploads them to GPU (if available)
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// NOTE: Fallback in case GPU skinning is not supported or enabled
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for (var m = 0; m < model.MeshCount; m++)
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{
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var mesh = model.Meshes[m];
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Vector3 animVertex;
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Vector3 animNormal;
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var vertexValuesCount = mesh.VertexCount * 3;
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var boneCounter = 0;
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var bufferUpdateRequired = false; // Flag to check when anim vertex information is updated
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// Skip if missing bone data or missing anim buffers initialization
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if ((mesh.BoneWeights == null) || (mesh.BoneIndices == null) ||
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(mesh.AnimVertices == null) || (mesh.AnimNormals == null))
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{
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continue;
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}
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for (var vCounter = 0; vCounter < vertexValuesCount; vCounter += 3)
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{
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mesh.AnimVertices[vCounter] = 0;
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mesh.AnimVertices[vCounter + 1] = 0;
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mesh.AnimVertices[vCounter + 2] = 0;
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if (mesh.AnimNormals != null)
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{
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mesh.AnimNormals[vCounter] = 0;
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mesh.AnimNormals[vCounter + 1] = 0;
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mesh.AnimNormals[vCounter + 2] = 0;
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}
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// Iterates over 4 bones per vertex
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for (var j = 0; j < 4; j++, boneCounter++)
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{
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var boneWeight = mesh.BoneWeights[boneCounter];
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var boneIndex = mesh.BoneIndices[boneCounter];
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// Early stop when no transformation will be applied
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if (boneWeight == 0.0f)
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{
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continue;
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}
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animVertex = new Vector3(mesh.Vertices[vCounter], mesh.Vertices[vCounter + 1], mesh.Vertices[vCounter + 2]);
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animVertex = Vector3Transform(animVertex, model.BoneMatrices[boneIndex]);
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mesh.AnimVertices[vCounter] += animVertex.X * boneWeight;
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mesh.AnimVertices[vCounter + 1] += animVertex.Y * boneWeight;
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mesh.AnimVertices[vCounter + 2] += animVertex.Z * boneWeight;
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bufferUpdateRequired = true;
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// Normals processing
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// NOTE: We use meshes.baseNormals (default normal) to calculate meshes.normals (animated normals)
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if ((mesh.Normals != null) && (mesh.AnimNormals != null))
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{
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animNormal = new Vector3(mesh.Normals[vCounter], mesh.Normals[vCounter + 1], mesh.Normals[vCounter + 2]);
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animNormal = Vector3Transform(animNormal, MatrixTranspose(MatrixInvert(model.BoneMatrices[boneIndex])));
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mesh.AnimNormals[vCounter] += animNormal.X * boneWeight;
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mesh.AnimNormals[vCounter + 1] += animNormal.Y * boneWeight;
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mesh.AnimNormals[vCounter + 2] += animNormal.Z * boneWeight;
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}
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}
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}
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if (bufferUpdateRequired)
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{
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// Update GPU vertex buffers with updated data (position + normals)
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Rlgl.UpdateVertexBuffer(mesh.VboId[(int)ShaderLocationIndex.VertexPosition], mesh.AnimVertices, mesh.VertexCount * 3 * sizeof(float), 0);
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if (mesh.Normals != null)
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{
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Rlgl.UpdateVertexBuffer(mesh.VboId[(int)ShaderLocationIndex.VertexNormal], mesh.AnimNormals, mesh.VertexCount * 3 * sizeof(float), 0);
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}
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}
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}
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}
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}
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public static int Main()
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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InitWindow(screenWidth, screenHeight, "raylib [models] example - animation blend custom");
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SetTargetFPS(60); // Set our game to run at 60 frames-per-second
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//--------------------------------------------------------------------------------------
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var game = new AnimationBlendCustom();
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game.Init();
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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game.Update();
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}
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game.Unload();
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// De-Initialization
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//--------------------------------------------------------------------------------------
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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}
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}
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