DrawTriangles() for mojo

Monkey Forums/Monkey Code/DrawTriangles() for mojo

Difference

(Posted 2014) [#1]

Updated code to fix small error in GLFW

Difference

(Posted 2014) [#2]

In order to draw convex polygons, we need to have a DrawTriangles() function

See my Tesselate code here http://www.monkey-x.com/Community/posts.php?topic=8035

and the SVG Project topic here: http://www.monkey-x.com/Community/posts.php?topic=7898 for intended use.

These are the steps to patch mojo to Add DrawTriangles.
There are versions for HTML5, GLFW and fallback for all other platforms.
You can use the GLFW version for IOS too.

In graphics.monkey add this at the end:

' Function for drawing indexed triangles
' fallback for unsupported platforms included in the code
' indexes 
Function DrawTriangles:Void(points:Float[],indexes:Int[])
#If CONFIG="debug"
	DebugRenderDevice
#End

#If TARGET="html5" Or TARGET="glfw" 'Or TARGET="ios"
		context.Validate
		renderDevice.DrawTriangles(points,indexes )
#Else

	Local tri:Float[6]
	For Local n:Int=0 Until  indexes.Length() Step 3
	 
 		Local tri:Float[6]
 		
		tri[0] = points[indexes[n]]
		tri[1] = points[indexes[n]+1]
		tri[2] = points[indexes[n+1]]
		tri[3] = points[indexes[n+1]+1]				
		tri[4] = points[indexes[n+2]]
		tri[5] = points[indexes[n+2]+1]

		DrawPoly tri
	Next
#End
End Function

In graphicsdevice.moneky add this after Method Readpixels.....

	Method DrawTriangles( verts#[],indexes[] )

In mojo.html5.js add this , just above "// ***** gxtkSurface class ***** "

gxtkGraphics.prototype.DrawTriangles=function( verts ,indexes){
	if( verts.length<6 ) return;
	if( indexes.length<3 ) return;
	
	if( this.tformed ) this.gc.setTransform( this.ix,this.iy,this.jx,this.jy,this.tx,this.ty );
	
	this.gc.beginPath();

	for( var i=0;i<indexes.length;i+=3 ){
    
        this.gc.moveTo(verts[indexes[i]],verts[indexes[i]+1]); 
 	  	this.gc.lineTo(verts[indexes[i+1]],verts[indexes[i+1]+1]);
		this.gc.lineTo(verts[indexes[i+2]],verts[indexes[i+2]+1]);
               
	}
	this.gc.fill();
	this.gc.closePath();
	return;

}

In mojo.glfw.cpp:

just below virtual int WritePixels2......

virtual int DrawTriangles( Array<float> verts,Array<int> indexes );

just before "//***** gxtkSurface *****"

int gxtkGraphics::DrawTriangles( Array<float> verts , Array<int> indexes){
    
    int n=verts.Length()/2;
	
    int indexcount = indexes.Length();
    if( n<3 || n>MAX_VERTS ) return 0;
	
    Flush();
    
    float *vp=vertices;

    unsigned short triangleIndices[indexcount];
    unsigned short *ip=triangleIndices;
	
    for( int i=0;i<indexcount;++i ){
        ip[0]=(short)indexes[i]/2;
        ip+=1;
    }
	
    for( int i=0;i<n;++i ){
		
        float px=verts[i*2];
        float py=verts[i*2+1];
		
        if( tformed ){
            float ppx=px;
            px=ppx * ix + py * jx + tx;
            py=ppx * iy + py * jy + ty;
            
		}
        
        vp[0]=px;vp[1]=py;(int&)vp[4]=colorARGB;
        vp+=5;
    }
	
    glDrawElements( GL_TRIANGLES,indexcount ,GL_UNSIGNED_SHORT,triangleIndices );
    
	return 0;
}

Difference

(Posted 2014) [#3]

.deleted