uniform mat4 u_mvpMatrix;

uniform vec3 texSize;

uniform vec2 edgePosScale;

attribute vec4 a_position;

attribute vec3 a_texCoord;

varying vec2 mid;

varying vec2 leftTop;

varying vec2 edgePos;

varying vec2 weightPos;

varying vec2 texStep2; // could be uniform

varying vec2 videoCoord;

void main()

{

	gl_Position = u_mvpMatrix * a_position;

	vec2 texStep = 1.0 / texSize.xy;

	mid     = a_texCoord.xy;

	leftTop = a_texCoord.xy - texStep;

	edgePos = a_texCoord.xy * edgePosScale;

	weightPos = a_texCoord.xy * texSize.xy;

	texStep2 = 2.0 * texStep;

#if SUPERIMPOSE

	videoCoord = a_texCoord.xz;

#endif

}