ttri - nesbox/TIC-80 GitHub Wiki

ttri(x1, y1, x2, y2, x3, y3, u1, v1, u2, v2, u3, v3, [texsrc=0], [chromakey=-1], [z1=0], [z2=0], [z3=0])

Parameters

• x1, y1 : the screen coordinates of the first corner
• x2, y2 : the screen coordinates of the second corner
• x3, y3 : the screen coordinates of the third corner
• u1, v1 : the UV coordinates of the first corner
• u2, v2 : the UV coordinates of the second corner
• u3, v3 : the UV coordinates of the third corner
• texsrc : if 0 (default), the triangle's texture is read from SPRITES RAM. If 1, the texture comes from the MAP RAM.If 2, the texture comes from the screen RAM in the next VBANK (the one following the VBANK on which the ttri() is set to be displayed) (e.g., a ttri() on vbank(0) with the texsrc=2 will use vbank(1) as its texture at the time of its execution and vice versa).
• chromakey : index (or array of indexes 0.80) of the color(s) that will be used as transparent
• z1, z2, z3 : depth parameters for perspective correction and depth buffer

A note on UV Coordinates

The letters "U" and "V" denote the axes of the 2D texture because "X", "Y" are already used. These can be thought of as the window inside SPRITES or MAP RAM. Note that the sprite sheet or map in this case is treated as a single large image, with U and V addressing its pixels directly, rather than by sprite ID. So for example the top left corner of sprite #2 would be located at u=16 (horizontal), v=0 (vertical).

Description

This function draws a triangle filled with texture from either SPRITES or MAP RAM or VBANK.

Depth Buffer

A depth buffer is implemented in ttri when z1, z2, z3 arguments are set. The depth buffer can be cleared using the cls() function.

Examples

-- title:  triangle demo
-- author: MonstersGoBoom
-- desc:   wiki demo for ttri
-- script: lua
-- input:  gamepad

usize = 32
vsize = 32
function TIC()
  cls(1)
  if btn(0) then usize=usize-1 end
  if btn(1) then usize=usize+1 end
  if btn(2) then vsize=vsize-1 end
  if btn(3) then vsize=vsize+1 end

-- draw a scaling view into the map ram

  ttri(0,0,
         64,0,
         0,64,
         0,0,
         usize,0,
         0,vsize,
         true,
         14)
  ttri(64,0,
         0,64,
         64,64,
         usize,0,
         0,vsize,
         usize,vsize,
         true,
         14)
end

UV show

• Sprite x,y,z rotation with ttri here