3D Graphics with OpenGL ES and M3G- P41:Mobile phones are the new vehicle for bringing interactive graphics technologies to consumers. Graphics that in the 1980s was only seen in industrial flight simulators and at the turn of the millennium in desktop PCs and game consoles is now in the hands of billions of people. This book is about the technology underpinnings of mobile threedimensional graphics, the newest and most rapidly advancing area of computer graphics. | 384 ANIMATION IN M3G CHAPTER 16 form tors o 100 6 2 Vertices 6 7 form tors o 100 12 2 12 13 form tors o 100 18 2 18 19 form tors o 100 20 2 20 and 21 neck 30 4 4 Vertices 4 5 6 and 7 head 100 0 6 etc. rightForeArm 100 8 4 rightUpperArm 100 10 4 Our mesh is now ready for animation. Any further transformations to the bones will deform the mesh accordingly so let us make our character raise his right hand to say hello API review Constructing a SkinnedMesh is again similar to creating a regular Mesh except for the extra skeleton parameter SkinnedMesh VertexBuffer vertices IndexBuffer submeshes Appearance appearances Group skeleton The set of bones for your skinning animation are contained by the skeleton group. It is actually a completely generic scene graph branch that can contain any objects even other SkinnedMesh nodes are permitted. Each node to be used as a bone is defined by calling addTransform Node bone int weight int firstVertex int numVertices . This specifies that transformations of the skeleton node bone will influence the numVertices vertices starting at firstVertex with a given weight. The weights for skinning are normalized during vertex transformation by dividing the bone weights with the sum of all weights contributing to each vertex. After adding all bone influences animating the transformations of the bone nodes will automatically deform the SkinnedMesh. Note that the transformations Bi for the rest pose Section are not explicitly given to the API. These are inferred from the bone node transformations at the time of the addTransform function call. So before using addTransform be sure to set your bones to their initial positions. Skinning in OpenGL and graphics hardware
