[rmodels] Added implementation of UpdateModelAnimationBonesWithBlending() function (#4578)

* [rmodels] Added implementation of `UpdateModelAnimationBonesWithBlending()` function

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* [rmodels] Added example for animation blending and fixed wrap issue for blend factor

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* [rmodels] Updated build information for animation blending example

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* [rmodels] Fixed typos in anmation blending example

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* [rmodels] Updated blend function signature and added function to update verts from bones

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* [rmodels] Updated documentation

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>

* rlparser: update raylib_api.* by CI

* rlparser: update raylib_api.* by CI

---------

Signed-off-by: Kirandeep-Singh-Khehra <kirandeepsinghkhehra@gmail.com>
Co-authored-by: Ray <raysan5@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

examples/models/models_animation_blending.c

@@ -0,0 +1,152 @@
+/*******************************************************************************************
+*
+*   raylib [core] example - Model animation blending
+* 
+*   Example originally created with raylib 5.5
+*
+*   Example contributed by Kirandeep (@Kirandeep-Singh-Khehra)
+*
+*   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) 2024 Kirandeep (@Kirandeep-Singh-Khehra)
+* 
+*   Note: Due to limitations in the Apple OpenGL driver, this feature does not work on MacOS
+*   Note: This example uses CPU for updating meshes.
+*           For GPU skinning see comments with 'INFO:'.
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+#define clamp(x,a,b) ((x < a)? a : (x > b)? b : x)
+
+#if defined(PLATFORM_DESKTOP)
+    #define GLSL_VERSION            330
+#else   // PLATFORM_ANDROID, PLATFORM_WEB
+    #define GLSL_VERSION            100
+#endif
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [models] example - Model Animation Blending");
+
+    // Define the camera to look into our 3d world
+    Camera camera = { 0 };
+    camera.position = (Vector3){ 8.0f, 8.0f, 8.0f }; // Camera position
+    camera.target = (Vector3){ 0.0f, 2.0f, 0.0f };  // Camera looking at point
+    camera.up = (Vector3){ 0.0f, 1.0f, 0.0f };      // Camera up vector (rotation towards target)
+    camera.fovy = 45.0f;                            // Camera field-of-view Y
+    camera.projection = CAMERA_PERSPECTIVE;         // Camera projection type
+
+    // Load gltf model
+    Model characterModel = LoadModel("resources/models/gltf/robot.glb"); // Load character model
+    
+/* INFO: Uncomment this to use GPU skinning
+    // Load skinning shader
+    Shader skinningShader = LoadShader(TextFormat("resources/shaders/glsl%i/skinning.vs", GLSL_VERSION),
+                                       TextFormat("resources/shaders/glsl%i/skinning.fs", GLSL_VERSION));
+
+    for (int i = 0; i < characterModel.materialCount; i++)
+    {
+        characterModel.materials[i].shader = skinningShader;
+    }
+*/
+
+    // Load gltf model animations
+    int animsCount = 0;
+    unsigned int animIndex0 = 0;
+    unsigned int animIndex1 = 0;
+    unsigned int animCurrentFrame = 0;
+    ModelAnimation *modelAnimations = LoadModelAnimations("resources/models/gltf/robot.glb", &animsCount);
+
+    float blendFactor = 0.5f;
+
+    DisableCursor();                    // Limit cursor to relative movement inside the window
+
+    SetTargetFPS(60);                   // Set our game to run at 60 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())        // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        UpdateCamera(&camera, CAMERA_THIRD_PERSON);
+        
+        // Select current animation
+        if (IsKeyPressed(KEY_T)) animIndex0 = (animIndex0 + 1)%animsCount;
+        else if (IsKeyPressed(KEY_G)) animIndex0 = (animIndex0 + animsCount - 1)%animsCount;
+        if (IsKeyPressed(KEY_Y)) animIndex1 = (animIndex1 + 1)%animsCount;
+        else if (IsKeyPressed(KEY_H)) animIndex1 = (animIndex1 + animsCount - 1)%animsCount;
+        
+        // Select blend factor
+        if (IsKeyPressed(KEY_U)) blendFactor = clamp(blendFactor - 0.1, 0.0f, 1.0f);
+        else if (IsKeyPressed(KEY_J)) blendFactor = clamp(blendFactor + 0.1, 0.0f, 1.0f);
+
+        // Update animation
+        animCurrentFrame++;
+
+        // Update bones
+        // Note: Same animation frame index is used below. By default it loops both animations
+        UpdateModelAnimationBonesLerp(characterModel, modelAnimations[animIndex0], animCurrentFrame, modelAnimations[animIndex1], animCurrentFrame, blendFactor);
+
+// INFO: Comment the following line to use GPU skinning
+        UpdateModelVertsToCurrentBones(characterModel);
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            BeginMode3D(camera);
+
+/* INFO: Uncomment this to use GPU skinning
+                // Draw character mesh, pose calculation is done in shader (GPU skinning)
+                for (int i = 0; i < characterModel.meshCount; i++)
+                {
+                    DrawMesh(characterModel.meshes[i], characterModel.materials[characterModel.meshMaterial[i]], characterModel.transform);
+                }
+*/
+
+// INFO: Comment the following line to use GPU skinning
+                DrawModel(characterModel, (Vector3){0.0f, 0.0f, 0.0f}, 1.0f, WHITE);
+
+
+                DrawGrid(10, 1.0f);
+                
+            EndMode3D();
+
+            DrawText("Use the U/J to adjust blend factor", 10, 10, 20, GRAY);
+            DrawText("Use the T/G to switch first animation", 10, 30, 20, GRAY);
+            DrawText("Use the Y/H to switch second animation", 10, 50, 20, GRAY);
+            DrawText(TextFormat("Animations: %s, %s", modelAnimations[animIndex0].name, modelAnimations[animIndex1].name), 10, 70, 20, BLACK);
+            DrawText(TextFormat("Blend Factor: %f", blendFactor), 10, 86, 20, BLACK);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    UnloadModelAnimations(modelAnimations, animsCount); // Unload model animation
+    UnloadModel(characterModel);    // Unload model and meshes/material
+
+// INFO: Uncomment the following line to use GPU skinning
+    // UnloadShader(skinningShader);   // Unload GPU skinning shader
+    
+    CloseWindow();                  // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}