// license:BSD-3-Clause
// copyright-holders:Ryan Holtz
//============================================================
//
//  blit.json: A simple texture-to-target copy.
//
//============================================================
{
	// blend (required): The blend state for this effect.
	"blend": {
		// equation (optional): What equation to perform on the source and destination blend values.
		// values: "add", "sub", "revSub", "min", "max"
		// default: "add"
		//
		// "subtract" and "revSubtract" are provided as aliases for "sub" and "revSub"
		"equation": "add",

		// blend function parameters (optional): What factors to use in the blend function when calculating the final pixel.
		// values: "0", "1", "srccolor", "1-srccolor", "dstcolor", "1-dstcolor", "srcalpha", "1-srcalpha", "dstalpha", "1-dstalpha"
		// defaults (srcColor, srcAlpha): "1"
		// defaults (dstColor, dstAlpha): "0"
		//
		// "zero", "one", "invsrccolor", "invdstcolor", "invsrcalpha", and "invdstalpha" are provided as aliases for "0", "1", "1-srccolor", "1-dstcolor", "1-srcalpha", and "1-dstalpha"
		"srcColor": "srcalpha",
		"dstColor": "1-srcalpha",
		"srcAlpha": "srcalpha",
		"dstAlpha": "1-srcalpha"
	},

	// depth (required): The depth state for this effect.
	"depth": {
		// function (optional): The depth function to use when drawing.
		// values: "never", "less", "equal", "lequal", "greater", "notequal", "gequal", "always"
		// default: "always"
		"function": "always",

		// writeenable (optional): Whether to store Z-buffer data.
		// values: true, false
		// default: false
		"writeenable": false
	},

	// cull (required): The cull mode for this effect.
	"cull": {
		// mode (optional): What winding, if any, to cull.
		// values: "none", "cw", "ccw"
		// default: "ccw"
		//
		// "clockwise" and "counterclockwise" are provided as aliases for "cw" and "ccw"
		"mode": "none"
	},

	// write (required): Write enable for color and alpha channels.
	"write": {
		// rgb (optional): Whether to store color data when drawing.
		// values: true, false
		// default: false
		"rgb": true,

		// alpha (optional): Whether to store alpha data when drawing.
		// values: true, false
		// default: false
		"alpha": true
	},

	// vertex (required): The vertex shader to use when drawing.
	// value: A string containing the path and name of a shader file to use, minus the extension.
	"vertex": "chains/unfiltered/vs_blit",

	// pixel/fragment (required): The pixel or fragment shader to use when drawing.
	// value: A string containing the path and name of a shader file to use, minus the extension.
	"fragment": "chains/unfiltered/fs_blit",

	// uniforms (required): The list of uniforms for this effect. Can be empty, but must exist.
	"uniforms": [
		{
			// name (required): The name of the uniform, as used in either the vertex or pixel/fragment shader.
			// value: A string containing the name of the uniform as described above.
			//
			// NOTE: Some names correspond to special values that will be automatically filled by the BGFX
			//       code if they are used by the shader. These names are:
			//           "u_screen_dims"
			//              The dimensions of the first texture input if present, otherwise the dimensions of the output window.
			//              Valid values: xy
			//           "u_inv_screen_dims"
			//              The reciprocal of u_screen_dims.
			//              Valid values: xy
			//           "u_source_dims"
			//              The size, in pixels, of the screen texture incoming to the chain.
			//              Valid values: xy
			//           "u_rotation_type"
			//              This screen's rotation type. 0 if ROT0, 1 if ROT90, 2 if ROT180, 3 of ROT270.
			//              Valid values: x
			//           "u_swap_xy"
			//              Whether this screen is swapped on the X and Y axes. 1 if true, 0 if false.
			//              Valid values: x
			//           "u_quad_dims"
			//              The dimensions, in pixels, occupied by this one screen primitive itself in the output window.
			//              Valid values: xy
			//           "u_tex_sizeN"
			//              The dimensions, in pixels, of the texture in input pair N. Starts at 0.
			//              valid values: xy
			"name": "s_tex",

			// type (required): The type of the uniform.
			// values: "int", "vec4", "mat3", "mat4"
			//
			// Note: "int" should only be used for samplers.
			"type": "int",

			// values (required): The array of numbers with which to initialize the uniform.
			// value: A JSON array containin the correct amount of numbers to initialize a uniform of the
			//        above-specified type. The following size rules should be followed:
			//            "int": 1 float
			//            "vec4": 4 floats
			//            "mat3": 9 floats
			//            "mat4": 16 floats
			"values": [ 1.0 ]
		}
	]
}
