package renderapi

import (
	"zworld/engine/renderapi/color"
	"zworld/plugins/math/mat4"
	"zworld/plugins/math/transform"
	"zworld/plugins/math/vec2"
	"zworld/plugins/math/vec3"
)

// Args holds the arguments used to perform a draw pass.
// Includes the various transformation matrices and position of the camera.
type Args struct {
	Frame      int
	Time       float32
	Delta      float32
	VP         mat4.T
	VPInv      mat4.T
	MVP        mat4.T
	Projection mat4.T
	View       mat4.T
	ViewInv    mat4.T
	Transform  mat4.T
	Position   vec3.T
	Forward    vec3.T
	Fov        float32
	Near       float32
	Far        float32
	Viewport   Screen
	Clear      color.T
}

type Screen struct {
	Width  int
	Height int
	Scale  float32
}

func (s Screen) Size() vec2.T {
	return vec2.NewI(s.Width, s.Height)
}

func (s Screen) NormalizeCursor(cursor vec2.T) vec2.T {
	return cursor.Div(s.Size()).Sub(vec2.New(0.5, 0.5)).Scaled(2)
}

// Apply the effects of a transform
func (d Args) Apply(t mat4.T) Args {
	d.Transform = d.Transform.Mul(&t)
	d.MVP = d.VP.Mul(&d.Transform)
	return d
}

func (d Args) Set(t transform.T) Args {
	d.Transform = t.Matrix()
	d.MVP = d.VP.Mul(&d.Transform)
	return d
}