Table of Contents

• Table line

  • line methods

    • line new

    • line add

    • line set

    • line setColor

    • line size

    • line drawBounding

    • line setPhysics

    • line setPhysics

  • line shader

    • line fragment shader

    • line vertex shader

7. Table line

A table line inherit from renderizable and implement all methods as usual. Also line has a default animation with a particular shader table which can be accessed by getShader method as usual.

This table allow to create lines dynamically. Each table line might have one or more lines.

7.1. line methods

7.1.1. line new

new(string * world, number * x, number * y, number * z)

Create a new instance of a line passing the world desired (detail) and position.

Parameters

• string – world can be 2ds, 2dw or 3d.

• number – x position (optional).

• number – y position (optional).

• number – z position (optional).

Returns

line table.

Example:

tLine = line:new('2dw')

7.1.2. line add

add(table[x,y,*z])

Add new line. Optionally the table might have z coordinate. Each x,y,*z is a point in the line.

Parameters

table – points to line.

Returns

number - index from current line (1 based).

Example:

tLine = line:new('2dw')
local tPoints = {0,0,  100,100} --minimum two points to be a line
local index = tLine:add(tPoints)
print('Line added index:',index)

Figure 7.1 Draw a simple line at 2d world.

Figure 7.2 Output.

Note the difference to 2D screen. more detail

tLine = line:new('2ds')-- 2d screen
local tPoints = {0,0,  100,100} --minimum two points to be a line
local index = tLine:add(tPoints)

7.1.3. line set

set(table[x,y,*z], number index)

Update the line passing the table and index (1 based).

Parameters

• table – points to line.

• number – index to line.

Example:

tLine = line:new('2ds')
local t = {0,0,  0,500, 500,500, 500, 0, 0,0 }
local index = tLine:add(t)

local tNewLine = {0,0,  0,250, 250,250, 250, 0, 0,0 }
tLine:set(tNewLine,index)

7.1.4. line setColor

setColor(number r, number g, number b, number * a)

Update the color from line passing the color RGB and optionally alpha.

Parameters

• number – r red color (0 to 1).

• number – g green color (0 to 1).

• number – b blue color (0 to 1).

• number – a alpha color (0 to 1) (optional).

Example:

mbm.setColor(0,0,0) --set background color to black

tLine = line:new('2dw')
local tXY = {-50,-50,  -50,50,  50,50,  50,-50,  -50,-50 }
local index = tLine:add(tXY)
tLine:setColor(1,1,1) --white color

Figure 7.3 Set line color to white

Note

This method is directly dependent from current (default) shader used on line.

This method look for a variable named color.

The shader for line is available here.

7.1.5. line size

size

Retrieve the size of lines added.

Returns

number - size of lines added.

Example:

tLine = line:new('2ds')
local t = {0,0,  0,500, 500,500, 500, 0, 0,0 }
local index = tLine:add(t)
local size = tLine:size() -- 1

7.1.6. line drawBounding

drawBounding(table renderizable, boolean * useAABB)

Draw a bounding from a renderizable. The flag useAABB consider the rotation from a object.

Parameters

• renderizable – render to set values from physics.

• boolean – useAABB is a flag enable AABB (default true).

Example:

mbm.setColor(0,0,0) --set background color to black

tTexture = texture:new('2dw') -- new texture
tTexture:load('#ffffffff') -- load white color
tTexture:setSize(150,50)

tLine = line:new('2dw')
tLine:drawBounding(tTexture)

Figure 7.4 Draw a simple bounding line. Get the bound from texture.

Disabled AABB:

mbm.setColor(0,0,0) --set background color to black

tTexture = texture:new('2dw') -- new texture
tTexture:load('#ffffffff') -- load white color
tTexture:setSize(150,50)

tLine = line:new('2dw')
tLine:drawBounding(tTexture)

Figure 7.5 Draw a simple bounding line. Get the size from texture not considering AABB.

Enabled AABB:

mbm.setColor(0,0,0) --set background color to black

tTexture = texture:new('2dw') -- new texture
tTexture:load('#ffffffff') -- load white color
tTexture:setSize(150,50)

tLine = line:new('2dw')
tLine:drawBounding(tTexture,true)

Figure 7.6 Draw a simple bounding line. Get the size from texture considering AABB.

7.1.7. line setPhysics

setPhysics(table renderizable, boolean * bDrawLines)

Set physic from a renderizable (copy the values to itself). The flag bDrawLines instruct to draw the physics line. It is used in general for debugging proposal.

Parameters

• renderizable – render to set values from physics.

• boolean – bDrawLines instruct to draw the line.

Example:

tShape = shape:new('2dw')
tShape:create('rectangle',100,50)

local bDrawLines = true
tLine = line:new('2dw')
tLine:setPhysics(tShape,bDrawLines)

Figure 7.7 Setting the physics and drawing it.

7.1.8. line setPhysics

setPhysics(table tPhysics, boolean * bDrawLines)

Apply physics from a table. The flag bDrawLines instruct to draw the physics line.

It is very useful in general for debugging proposal.

Parameters

• table – info to set values to physics.

• boolean – bDrawLines instruct to draw the line (default is false).

The following table describe the table available for the primitives 2d types:

type / name	position x,y information ?	width, height information ?	points information ?	ray information ?
rect	yes	yes	no	no
circle	yes	yes	no	yes
ellipse	yes	yes	no	yes
triangle	yes	no	yes	no
polygon	yes	no	yes	no

Example:

 1 function onInitScene()
 2 
 3    mbm.setColor(0,0,0) --set background color to black
 4 
 5    local bDrawLines = true --instruct to draw the lines
 6    local tRect      = {type = 'rect',   width=100,  height=100,  x=0,  y=0}
 7    local tCircle    = {type = 'circle', ray = 50,  x=0,  y=0}
 8    local tEllipse   = {type = 'ellipse', width=100,  height=70,  x=0,  y=0}
 9    local tTriangle  = {type = 'triangle',  x=0,  y=0,  points={[1]={x=-50,y=-50},--must have 3 points
10                                                                [2]={x=0,y=50},
11                                                                [3]={x=50,y=-50}}}
12    local tPolygon   = {type = 'polygon',  x=0,  y=0,  points={ --each 3 points
13                                                                [1]={x=-50,y=-50},
14                                                                [2]={x=0,y=0},
15                                                                [3]={x=40,y=-40},
16                                                                [4]={x=50,y=50},
17                                                                [5]={x=0,y=0},
18                                                                [6]={x=-50,y=50},
19                                                                [7]={x=-250,y=250},--this point will be ignored
20                                                             }}
21 
22    
23    tLineRect = line:new('2dw')
24    tLineRect:setPhysics(tRect,bDrawLines)
25    tLineRect.x = -200
26 
27    tLineCircle = line:new('2dw')
28    tLineCircle:setPhysics(tCircle,bDrawLines)
29    tLineCircle.x = -100
30 
31    tLineEllipse = line:new('2dw')
32    tLineEllipse:setPhysics(tEllipse,bDrawLines)
33    tLineEllipse.x = 0
34 
35    tLineTriangle = line:new('2dw')
36    tLineTriangle:setPhysics(tTriangle,bDrawLines)
37    tLineTriangle.x = 100
38 
39    tLinePolygon = line:new('2dw')
40    tLinePolygon:setPhysics(tPolygon,bDrawLines)
41    tLinePolygon.x = 200
42 
43    tAllObjs = {}
44    table.insert(tAllObjs,tLineRect)
45    table.insert(tAllObjs,tLineCircle)
46    table.insert(tAllObjs,tLineEllipse)
47    table.insert(tAllObjs,tLineTriangle)
48    table.insert(tAllObjs,tLinePolygon)
49 
50 end
51 
52 
53 function loop(delta)
54    for i=1, #tAllObjs do
55       local tObj = tAllObjs[i]
56       tObj:rotate('z',math.rad(90))
57    end
58 end

download.

Figure 7.8 Example creating physics from lua table.

7.2. line shader

The table line has its own shader and can be accessed by the shortcut setColor.

The equivalent using table shader is:

mbm.setColor(0,0,0)

--common
local r,g,b,a = 1,1,1,1
local tXY = {-50,-50,  -50,50,  50,50,  50,-50,  -50,-50 }

--using setColor to modify the line color
tLine_1 = line:new('2dw')
local index = tLine_1:add(tXY)
tLine_1:setColor(r,g,b,a) --set the variable color in the shader to white

--using shader to modify the line color
tLine_2 = line:new('2dw',200)--200 to right (x)
index = tLine_2:add(tXY)
local tShader = tLine_2:getShader()
tShader:setPSall('color',r,g,b,a)--set the variable color in the shader to white

Figure 7.9 changing color using setcolor and shader directly.

7.2.1. line fragment shader

The fragment shader (pixel shader) used for the line is:

precision mediump float;
uniform vec4 color;
void main()
{
    gl_FragColor =  color;
}

7.2.2. line vertex shader

The vertex shader used for the line is:

attribute vec4 aPosition;
uniform mat4 mvpMatrix;
void main()
{
    gl_Position = mvpMatrix * aPosition;
}