HOpenGL Libraries (OpenGL package)ContentsIndex
Graphics.Rendering.OpenGL.GL.CoordTrans
Portabilityportable
Stabilityprovisional
Maintainersven.panne@aedion.de
Contents
Controlling the Viewport
Matrices
Normal Transformation
Generating Texture Coordinates
Description
This module corresponds to section 2.11 (Coordinate Transformations) of the OpenGL 1.5 specs.
Synopsis
depthRange :: StateVar (GLclampd, GLclampd)
data Position = Position !GLint !GLint
data Size = Size !GLsizei !GLsizei
viewport :: StateVar (Position, Size)
maxViewportDims :: GettableStateVar Size
data MatrixMode
= Modelview GLsizei
| Projection
| Texture
| Color
| MatrixPalette
matrixMode :: StateVar MatrixMode
data Vector2 a = Vector2 !a !a
data Vector3 a = Vector3 !a !a !a
data MatrixOrder
= ColumnMajor
| RowMajor
class Storable c => MatrixComponent c where
rotate :: c -> Vector3 c -> IO ()
translate :: Vector3 c -> IO ()
scale :: c -> c -> c -> IO ()
class Matrix m where
withNewMatrix :: MatrixComponent c => MatrixOrder -> (Ptr c -> IO ()) -> IO (m c)
withMatrix :: MatrixComponent c => m c -> (MatrixOrder -> Ptr c -> IO a) -> IO a
newMatrix :: MatrixComponent c => MatrixOrder -> [c] -> IO (m c)
getMatrixComponents :: MatrixComponent c => MatrixOrder -> m c -> IO [c]
currentMatrix :: (Matrix m, MatrixComponent c) => StateVar (m c)
matrix :: (Matrix m, MatrixComponent c) => Maybe MatrixMode -> StateVar (m c)
multMatrix :: (Matrix m, MatrixComponent c) => m c -> IO ()
data GLmatrix a
loadIdentity :: IO ()
ortho :: GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> IO ()
frustum :: GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> IO ()
depthClamp :: StateVar Capability
activeTexture :: StateVar TextureUnit
preservingMatrix :: IO a -> IO a
unsafePreservingMatrix :: IO a -> IO a
stackDepth :: Maybe MatrixMode -> GettableStateVar GLsizei
maxStackDepth :: MatrixMode -> GettableStateVar GLsizei
rescaleNormal :: StateVar Capability
normalize :: StateVar Capability
data Plane a = Plane !a !a !a !a
data TextureCoordName
= S
| T
| R
| Q
data TextureGenMode
= EyeLinear (Plane GLdouble)
| ObjectLinear (Plane GLdouble)
| SphereMap
| NormalMap
| ReflectionMap
textureGenMode :: TextureCoordName -> StateVar (Maybe TextureGenMode)
Controlling the Viewport
depthRange :: StateVar (GLclampd, GLclampd)

After clipping and division by w, depth coordinates range from -1 to 1, corresponding to the near and far clipping planes. depthRange specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0 through 1 (like color components). Thus, the values accepted by depthRange are both clamped to this range before they are accepted.

The initial setting of (0, 1) maps the near plane to 0 and the far plane to 1. With this mapping, the depth buffer range is fully utilized.

It is not necessary that the near value be less than the far value. Reverse mappings such as (1, 0) are acceptable.

data Position
A 2-dimensional position, measured in pixels.
Constructors
Position !GLint !GLint
show/hide Instances
data Size
A 2-dimensional size, measured in pixels.
Constructors
Size !GLsizei !GLsizei
show/hide Instances
viewport :: StateVar (Position, Size)

Controls the affine transformation from normalized device coordinates to window coordinates. The viewport state variable consists of the coordinates (x, y) of the lower left corner of the viewport rectangle, (in pixels, initial value (0,0)), and the size (width, height) of the viewport. When a GL context is first attached to a window, width and height are set to the dimensions of that window.

Let (xnd, ynd) be normalized device coordinates. Then the window coordinates (xw, yw) are computed as follows:

xw = (xnd + 1) (width / 2) + x

yw = (ynd + 1) (heigth / 2) + y

Viewport width and height are silently clamped to a range that depends on the implementation, see maxViewportDims.

maxViewportDims :: GettableStateVar Size
The implementation-dependent maximum viewport width and height.
Matrices
data MatrixMode
A matrix stack.
Constructors
Modelview GLsizeiThe modelview matrix stack of the specified vertex unit.
ProjectionThe projection matrix stack.
TextureThe texture matrix stack.
ColorThe color matrix stack.
MatrixPaletteThe matrix palette stack.
show/hide Instances
matrixMode :: StateVar MatrixMode
Controls which matrix stack is the target for subsequent matrix operations. The initial value is (Modelview 0).
data Vector2 a
Constructors
Vector2 !a !a
show/hide Instances
Eq a => Eq (Vector2 a)
Ord a => Ord (Vector2 a)
Show a => Show (Vector2 a)
Storable a => Storable (Vector2 a)
data Vector3 a
Constructors
Vector3 !a !a !a
show/hide Instances
Eq a => Eq (Vector3 a)
Ord a => Ord (Vector3 a)
Show a => Show (Vector3 a)
Storable a => Storable (Vector3 a)
data MatrixOrder
Constructors
ColumnMajor
RowMajor
show/hide Instances
class Storable c => MatrixComponent c where
Methods
rotate :: c -> Vector3 c -> IO ()
translate :: Vector3 c -> IO ()
scale :: c -> c -> c -> IO ()
show/hide Instances
class Matrix m where
Methods
withNewMatrix :: MatrixComponent c => MatrixOrder -> (Ptr c -> IO ()) -> IO (m c)
Create a new matrix of the given order (containing undefined elements) and call the action to fill it with 4x4 elements.
withMatrix :: MatrixComponent c => m c -> (MatrixOrder -> Ptr c -> IO a) -> IO a
Call the action with the given matrix. Note: The action is not allowed to modify the matrix elements!
newMatrix :: MatrixComponent c => MatrixOrder -> [c] -> IO (m c)
getMatrixComponents :: MatrixComponent c => MatrixOrder -> m c -> IO [c]
show/hide Instances
currentMatrix :: (Matrix m, MatrixComponent c) => StateVar (m c)
matrix :: (Matrix m, MatrixComponent c) => Maybe MatrixMode -> StateVar (m c)
multMatrix :: (Matrix m, MatrixComponent c) => m c -> IO ()
data GLmatrix a
show/hide Instances
loadIdentity :: IO ()
ortho :: GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> IO ()
frustum :: GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> GLdouble -> IO ()
depthClamp :: StateVar Capability
activeTexture :: StateVar TextureUnit
preservingMatrix :: IO a -> IO a
Push the current matrix stack down by one, duplicating the current matrix, excute the given action, and pop the current matrix stack, replacing the current matrix with the one below it on the stack (i.e. restoring it to its previous state). The returned value is that of the given action. Note that a round-trip to the server is probably required. For a more efficient version, see unsafePreservingMatrix.
unsafePreservingMatrix :: IO a -> IO a
A more efficient, but potentially dangerous version of preservingMatrix: The given action is not allowed to throw an exception or change the current matrix mode permanently.
stackDepth :: Maybe MatrixMode -> GettableStateVar GLsizei
maxStackDepth :: MatrixMode -> GettableStateVar GLsizei
Normal Transformation
rescaleNormal :: StateVar Capability
If rescaleNormal contains Enabled, normal vectors specified with normal are scaled by a scaling factor derived from the modelview matrix. rescaleNormal requires that the originally specified normals were of unit length, and that the modelview matrix contains only uniform scales for proper results. The initial value of rescaleNormal is Disabled.
normalize :: StateVar Capability
If normalize contains Enabled, normal vectors specified with normal are scaled to unit length after transformation. The initial value of normalize is Disabled.
Generating Texture Coordinates
data Plane a
Constructors
Plane !a !a !a !a
show/hide Instances
Eq a => Eq (Plane a)
Ord a => Ord (Plane a)
Show a => Show (Plane a)
Storable a => Storable (Plane a)
data TextureCoordName
Constructors
S
T
R
Q
show/hide Instances
data TextureGenMode
Constructors
EyeLinear (Plane GLdouble)
ObjectLinear (Plane GLdouble)
SphereMap
NormalMap
ReflectionMap
show/hide Instances
textureGenMode :: TextureCoordName -> StateVar (Maybe TextureGenMode)
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