81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
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package render
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import (
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"edgaru089.ml/go/gl01/internal/util/itype"
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"github.com/go-gl/mathgl/mgl32"
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)
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// View represents a viewport in the 3-d world.
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// It is essentialy a projection and a view matrix.
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type View struct {
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EyePos itype.Vec3f // position of the eye
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rotY, rotZ, fovY itype.Angle
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aspect float32
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near, far float32
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clipSet bool
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}
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// View returns the View matrix from parameters set with LookAt().
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func (r *View) View() mgl32.Mat4 {
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delta := mgl32.Rotate3DY(r.rotY.Radians()).Mul3(mgl32.Rotate3DZ(r.rotZ.Radians())).Mul3x1(mgl32.Vec3{1, 0, 0})
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return mgl32.LookAt(
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r.EyePos[0], r.EyePos[1], r.EyePos[2],
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r.EyePos[0]+delta[0],
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r.EyePos[1]+delta[1],
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r.EyePos[2]+delta[2],
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0, 1, 0,
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)
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}
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// Perspective returns the Perspective matrix with parameters set with Aspect(), FovY() and Clip().
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func (r *View) Perspective() mgl32.Mat4 {
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if r.clipSet {
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return mgl32.Perspective(r.fovY.Radians(), r.aspect, r.near, r.far)
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} else {
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return mgl32.Perspective(r.fovY.Radians(), r.aspect, 0.1, 200)
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}
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}
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// LookAt resets the View matrix with a camera looking from Eye.
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// The camera points to +RotY from X+ axis rotating around Y axis (right-handed);
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// +/-RotZ form X+ axis rotating up/down around Z axis.
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// ( RotZ should be in the (-90,90) degrees range )
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//
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// It also returns itself so that operations can be chained.
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func (r *View) LookAt(eye itype.Vec3f, rotY, rotZ itype.Angle) *View {
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r.EyePos = eye
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r.rotY = rotY
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r.rotZ = rotZ
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return r
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}
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// Aspect sets the aspect (width / height) of the viewport.
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//
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// It also returns itself so that operations can be chained.
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func (r *View) Aspect(aspectRatio float32) *View {
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r.aspect = aspectRatio
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return r
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}
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// FovY sets the Field of View (an angle) on the Y axis.
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// FovX = FovY * aspect.
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//
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// With FovX, call SetFovY(FovX / aspect).
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//
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// It also returns itself so that operations can be chained.
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func (r *View) FovY(fovy itype.Angle) *View {
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r.fovY = fovy
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return r
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}
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// Clip sets the near/far clipping distance of the Perspective.
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// It defaults to 0.1 / 200.
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//
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// It also returns itself so that operations can be chained.
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func (r *View) Clip(near, far float32) *View {
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r.near, r.far = near, far
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r.clipSet = true
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return r
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}
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