Improve gltf support (#1647)

* Implement a load values from accessor function.
Added some more value types for the different GLTF attributes.
Fixed crash when loading animated triangle.

* Split GLTF model loading into separate functions for readability.

* Fixed the already working models that I broke when introducing GLTFReadValue.
Improved the example for gltf models to be able to switch between a few models.

* Removed license from screen. It is pu inside a license file anyway.

* Small improvements on the naming of functions
Removed (*model). and replaced it with model->

examples/models/models_gltf_model.c

@@ -39,7 +39,18 @@ int main(void)
     camera.fovy = 45.0f;                                // Camera field-of-view Y
     camera.type = CAMERA_PERSPECTIVE;                   // Camera mode type
 
-    Model model = LoadModel("resources/gltf/Avocado.glb");               // Load the animated model mesh and
+    Model model[7];
+    
+    model[0] = LoadModel("resources/gltf/raylib_32x32.glb");
+    model[1] = LoadModel("resources/gltf/rigged_figure.glb");
+    model[2] = LoadModel("resources/gltf/Avocado.glb");
+    model[3] = LoadModel("resources/gltf/GearboxAssy.glb");
+    model[4] = LoadModel("resources/gltf/BoxAnimated.glb");
+    model[5] = LoadModel("resources/gltf/AnimatedTriangle.gltf");
+    model[6] = LoadModel("resources/gltf/AnimatedMorphCube.glb");
+    
+    int currentModel = 0;
+    int modelCount = 7;
 
     Vector3 position = { 0.0f, 0.0f, 0.0f };            // Set model position
 
@@ -54,23 +65,39 @@ int main(void)
         // Update
         //----------------------------------------------------------------------------------
         UpdateCamera(&camera);
+        
+        if(IsKeyReleased(KEY_RIGHT))
+        {
+            currentModel++;
+            if(currentModel == modelCount)
+            {
+                currentModel = 0;
+            }
+        }
+    
+        if(IsKeyReleased(KEY_LEFT))
+        {
+            currentModel--;
+            if(currentModel < 0)
+            {
+                currentModel = modelCount - 1;
+            }
+        }
 
         // Draw
         //----------------------------------------------------------------------------------
         BeginDrawing();
 
-             ClearBackground(RAYWHITE);
+            ClearBackground(SKYBLUE);
 
             BeginMode3D(camera);
 
-                DrawModelEx(model, position, (Vector3){ 0.0f, 1.0f, 0.0f }, 180.0f, (Vector3){ 15.0f, 15.0f, 15.0f }, WHITE);
+                DrawModelEx(model[currentModel], position, (Vector3){ 0.0f, 1.0f, 0.0f }, 180.0f, (Vector3){ 2.0f, 2.0f, 2.0f }, WHITE);
 
                 DrawGrid(10, 1.0f);         // Draw a grid
 
             EndMode3D();
 
-            DrawText("(cc0) Avocado by @Microsoft", screenWidth - 200, screenHeight - 20, 10, GRAY);
-
         EndDrawing();
         //----------------------------------------------------------------------------------
     }
@@ -78,7 +105,10 @@ int main(void)
     // De-Initialization
     //--------------------------------------------------------------------------------------
 
-    UnloadModel(model);         // Unload model
+    for(int i = 0; i < modelCount; i++)
+    {
+        UnloadModel(model[i]);         // Unload model
+    }
 
     CloseWindow();              // Close window and OpenGL context
     //--------------------------------------------------------------------------------------