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----------------------------------------------------
---- Project: Tutorial 3
---- Description: learn UV coords, load image,
---- create texture, create material,
---- apply texture.
----
---- Created by: Roswell_r, 2008 for ApocalyX Engine
----------------------------------------------------
---- Modules ----
---- This is used for our group of functions starting with callback.
callback = {}
---- ApocalyX uses the axis So we're going to create a square face
---- +y| /+z (0.5, 0.5, 0) 0--------1 (-0.5, 0.5, 0)
---- +x | / |\ _ |
---- ------0------ | \ _ |
---- /| -x | \ |
---- -z/ |-y (0.5, -0.5, 0) 3--------2 (-0.5, -0.5, 0)
----
---- The square face is made up of 2 polygons, you cant see the split line
---- very well as it is hard to be artistic in ascii, but to the point it is
---- made up of 2 triangles.
square = { }
---- Contains our vertex data, specifying each point in space
square.vertices = { 0.5, 0.5, 0,
-0.5, 0.5, 0,
-0.5, -0.5, 0,
0.5, -0.5, 0 }
square.normals = { }
---- This time we will be specifying texture mapping quardinants. UV Texture
---- coords are measured from 0-1. Where U is horizontal and V is vertical.
---- By having a positive Vertical UV it means to go up and therefore the start
---- of UV coordinates 0,0 would start at the bottom left of a texture and end
---- coordinates 1,1 would end at the top right of the texture. We just want to
---- map a whole texture to the 2 faces.
square.mappings = { 0,1, 1,1, 1,0, 0,0 }
---- Again here we specify the faces of the triangles, we're going to create
---- 4 faces this time for the same reason in the last tutorial we want a back
---- face behind this as we're going to rotate it like we did in the last
---- example.
square.faces = { 0, 1, 2,
0, 2, 3,
0, 2, 1,
0, 3, 2 }
function callback.init()
---- We set the title of our render window. We then also set the size
---- of our window. This is part of the WIN object.
setTitle("Tutorial 3: Textured polygons")
setDimension(800, 600)
---- empty() and emptyOverlay() empty the 3D scene objects and 2D
---- scene objects. These methods are part of the WORLD object.
empty()
emptyOverlay()
---- This removes the partial help menu located on the left hand side
---- during rendering. With the following command it will simply
---- display "F1 Show/Hide Help". If you want to disable the help menu
---- completely use the command hideHelp(). These methods are part of
---- the WIN object.
showHelpReduced()
---- This sets the blanking colour of the scene. This is colour
---- fills the screen after each frame. Part of the WORLD object.
setClear(0.0,0.0,1.0)
---- The following loads a image file from hard disk, in this case we
---- are loading a PNG logo of LUA.
squareImage = Image("powered-by-128.png")
---- We now have the image data we're going to now turn it into a
---- texture for skinning a object. Reason we do this is so the engine
---- loads that texture into OpenGL and optimises it for use.
squareTexture = Texture(squareImage)
---- We create a default material like we did for the previous example
---- but this time we're going to set the DiffuseTexture and give it
---- reference to our texture we've just loaded. That means anything
---- that has our squareMaterial applied to it will be textured.
squareMaterial = Material()
squareMaterial:setDiffuseTexture(squareTexture)
---- This creates a new shape based on our array of vertices, normals
---- which are blank, our texture mappings which are also blank and
---- our array of faces.
local squareShape = Shape(square.vertices, square.normals, square.mappings, square.faces)
---- We've only created a shape which is made up of our vertices and
---- faces we now have to add that shape to our mesh. We can use this
---- shape later for another mesh or we can manipulate the vertex data
---- at a later time.
----
---- Here we specify our squareMaterial which contains our texture to
---- be applied to our square face polygons.
squareMesh = Mesh(squareShape, squareMaterial)
---- Here we set the perspective of the camera. Part of WORLD object.
---- The parameters here are degrees of freedom, meaning degress from
---- the camera to render. The second two values are the clipping
---- plane and they specify render objects from 1 to 1000 units of
---- depth in the scene. [TODO: explain this better]
setPerspective(60, 1, 1000)
---- This obtains the default camera for our world. Also WORLD object.
local camera = getCamera()
---- Here we reset the camera's position and rotation. Part of the
---- REFERENCE class.
camera:reset()
---- Because the triangle is positioned at 0,0,0 we need to take a
---- step back before we will actually see anything on the screen. So
---- we move the camera back 3 units so we have a nice view of the
---- mesh. This is part of the REFERENCE class.
camera:moveForward(-3)
---- Add our mesh to our world. This adds the mesh at its current
---- position 0,0,0 and will be rendered in our scene. This is part of
---- the WORLD object.
addObject(squareMesh)
end
function callback.update()
---- Here we could move out objects around and take input
---- Currently we're rotating the Triangle mesh around the Y axis.
squareMesh:rotAround(1 * getTimeStep())
end
function callback.final()
---- empty() and emptyOverlay() empty the 3D scene objects and 2D
---- scene objects. This tutorial has no objects but it is always
---- good practice to clear the scene. These again are part of the
---- WORLD object.
emptyOverlay()
empty()
end
----SCENE SETUP----
---- This is where the engine actually gets initilised. The render loop is
---- controlled by ApocalyX and you gain control back through the CallBack
---- functions.
---- What this means is when ApocalyX Engine starts it runs our function
---- callback.init specified in the first parameter.
---- Before the engine renders its next frame to the screen it also runs our
---- function callback.update specified in the second parameter.
---- When you close the program or end the scene the engine runs our function
---- callback.final specified in the third parameter. This is used to free up
---- any resources or you might want to save some data.
setScene(Scene(callback.init,callback.update,callback.final))
---- Scene is a construct method of Scene object and is used for setScene which
---- is part of the WIN object.
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