Three.js shader内置矩阵注入

common matrices （公共矩阵）
three.js 在WebGLRender中setProgram函数注入

p_uniforms.setValue( _gl, 'modelViewMatrix', object.modelViewMatrix );
p_uniforms.setValue( _gl, 'normalMatrix', object.normalMatrix );
p_uniforms.setValue( _gl, 'modelMatrix', object.matrixWorld );

// = object.matrixWorld
uniform mat4 modelMatrix;

// = camera.matrixWorldInverse * object.matrixWorld
uniform mat4 modelViewMatrix;

// = camera.projectionMatrix
uniform mat4 projectionMatrix;

// = camera.matrixWorldInverse
uniform mat4 viewMatrix;

// = inverse transpose of modelViewMatrix
uniform mat3 normalMatrix;

// = camera position in world space
uniform vec3 cameraPosition;

// default vertex attributes provided by BufferGeometry
attribute vec3 position;
attribute vec3 normal;
attribute vec2 uv;

gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4( position, 1.0 );

#ifdef USE_TANGENT
	attribute vec4 tangent;
#endif
#if defined( USE_COLOR_ALPHA )
	// vertex color attribute with alpha
	attribute vec4 color;
#elif defined( USE_COLOR )
	// vertex color attribute
	attribute vec3 color;
#endif

#ifdef USE_MORPHTARGETS

	attribute vec3 morphTarget0;
	attribute vec3 morphTarget1;
	attribute vec3 morphTarget2;
	attribute vec3 morphTarget3;

	#ifdef USE_MORPHNORMALS

		attribute vec3 morphNormal0;
		attribute vec3 morphNormal1;
		attribute vec3 morphNormal2;
		attribute vec3 morphNormal3;

	#else

		attribute vec3 morphTarget4;
		attribute vec3 morphTarget5;
		attribute vec3 morphTarget6;
		attribute vec3 morphTarget7;

	#endif
#endif

#ifdef USE_SKINNING
	attribute vec4 skinIndex;
	attribute vec4 skinWeight;
#endif

#ifdef USE_INSTANCING
	// Note that modelViewMatrix is not set when rendering an instanced model,
	// but can be calculated from viewMatrix * modelMatrix.
	//
	// Basic Usage:
	//   gl_Position = projectionMatrix * viewMatrix * modelMatrix * instanceMatrix * vec4(position, 1.0);
	attribute mat4 instanceMatrix;
#endif

uniform mat4 viewMatrix;
uniform vec3 cameraPosition;