TTriangle

Croquet-Teapot

Comment: 

TTriangle is a TPrimitive used to render triangles.

This creates and renders your simple OpenGL triangle. Usually used for testing, but you have to start somewhere...

Hierarchy:

ProtoObject
Object
TObject
TFrame
TPrimitive
TTriangle

Summary:

instance variables:

normal v1 v2 v3

methods:

instance class
accessing initialize render no messages

Detail:

instance variables:

normal
v1
v2
v3

instance methods:

accessing
v1: vv1 v2: vv2 v3: vv3 


	v1 _ vv1.
	v2 _ vv2.
	v3 _ vv3.
	normal _ nil.
	self boundsChanged.

initialize
initBounds 


	| d1 d2 d3 c1 c2 c3 c radius center|

" Graphics Gems 1 - page 22"

	d1 _ (v2-v1) dot: (v2-v1).
	d2 _ (v3-v2) dot: (v1- v2).
	d3 _ (v1-v3) dot: (v2-v3).
	c1 _ d2*d3.
	c2 _ d3*d1.
	c3 _ d1*d2.
	c _ c1+c2+c3.

	radius _ ((d1+d2)*(d2+d3)*(d3+d1)/c)sqrt * 0.5.
	center _ (((c2+c3)*v1) + ((c3+c1)*v2) + ((c1+c2)*v3))/(2*c).
	boundSphere _ TBoundSphere localPosition: center radius: radius.
	boundSphere frame: self.
initialize 


	| c h |
	super initialize.
	h _ (1-(0.5*0.5))sqrt.
	c _ ((0.5*0.5)/h )negated.

	v1 _ B3DVector3 x: 0.0 y:h+c z: 0.0.
	v2 _ B3DVector3 x: -0.5 y:c z: 0.0.
	v3 _ B3DVector3 x: 0.5 y:c z:0.0.
	self initBounds.
	normal _ (v1 cross: v2) normalized.
	^self

render
pick: pointer 


	^ pointer pickTriangle: normal tri: v1 tri: v2 tri: v3.
renderPrimitive: ogl 


	normal ifNil: [ normal _ (v1 cross: v2) normalized.].

	ogl
		glBegin: GLTriangles;
			glNormal3fv: normal;
			glTexCoord2f:0.5 with: 0.0;	glVertex3fv: v1;
			glTexCoord2f:1.0 with:1.0;	glVertex3fv: v3;
			glTexCoord2f:0.0 with:1.0;	glVertex3fv: v2;
		glEnd.

class methods:

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- made by Dandelion -