BlitzNG/bmx-site @ 3fb229494ec1a950bfa97cd7ee412c2c715f8dfe

id: brl.graphics title: BRL.Graphics

sidebar_label: BRL.Graphics

The graphics module provides the ability to create and 'flip' graphics objects.

A graphics object represents a rectangular area you can render to. However, the graphics module does not provide any commands for actual rendering - this is left to other modules such as max2D to implement.

The graphics module maintains 2 'current' objects - the current graphics driver and the currect graphics object. To change the current graphics driver, use SetGraphicsDriver. To change the current graphics object, use SetGraphics.

To create a graphics object, use either Graphics or CreateGraphics. The kind of graphics object created will depend upon the current graphics driver. For example, the following code:

SetGraphicsDriver GLGraphicsDriver()
Local g:TGraphics=CreateGraphics( 640,480,32,60,GRAPHICS_BACKBUFFER )
````

Will create an OpenGL graphics object.

You can 'select' this object for rendering using:

SetGraphics g 'we can now execute OpenGL code glClearColor .5,0,1,1 'tada! glClear 'yes! Flip 'must do this as the graphics is double buffered ````

One you have finished with a graphics object, use CloseGraphics to close it.

Graphics and CreateGraphics both accept the following parameters: width, height, depth, hertz and flags.

The width and height parameters specify the dimensions of the graphics, in pixels.

The depth parameter selects a pixel bit depth. This value can be 0, 16, 24 or 32 depending on the graphics modes available. A depth of 0 can be used to select 'windowed mode' graphics, while non-0 depths select 'fullscreen' graphics.

The hertz parameter selects a refresh rate, which refers to the number of times the screen refreshes per second. The refresh rates available depend on the graphics modes available, which differ from graphics card to graphics card. Note that creating graphics with an unsupported refresh rate will not fail - instead, a default refresh rate will be used.

The Graphics command can be used to achieve a fixed refresh rate. When using Flip to present such graphics, BlitzMax will guarantee the desired refresh rate is honored regardless of the available hardware's capabilities. This is achieved by using software timing techniques when necessary.

The flags parameter can be any combination of the following:

Flags can be combined with the | (or) operator. For example, GRAPHICS_BACKBUFFER|GRAPHICS_DEPTHBUFFER can be used to create graphics which has both a back buffer and a depth buffer.

Graphics created with the GRAPHICS_BACKBUFFER flag must be 'flipped' after you have finished rendering using Flip.

Functions

`Function SetGraphicsDriver( driver:TGraphicsDriver,defaultFlags=GRAPHICS_BACKBUFFER )`

Set current graphics driver

The current graphics driver determines what kind of graphics are created when you use the CreateGraphics or Graphics functions, as well as the graphics modes available.

The GLGraphicsDriver, GLMax2DDriver, D3D7Max2DDriver and D3D9Max2DDriver functions can all be used to obtain a graphics driver.

The defaultFlags parameter allows you to specify graphics flags that will be applied to any graphics created with CreateGraphics or Graphics.

Example

SetGraphicsDriver GLMax2DDriver()

Graphics 640,480
DrawText "OpenGL Max2D Graphics! Hit any key (next to the whatever key)...",0,0
Flip
WaitKey
EndGraphics

SetGraphicsDriver GLGraphicsDriver()

Graphics 640,480
glClear GL_COLOR_BUFFER_BIT
GLDrawText "'Raw' OpenGL Graphics! Hit any key...",0,0
Flip
WaitKey

`Function GetGraphicsDriver:TGraphicsDriver()`

Get current graphics driver

Returns the current graphics driver as selected by SetGraphicsDriver

`Function DefaultGraphicsFlags()`

Get current default graphics flags

`Function GraphicsModes:TGraphicsMode[]()`

Get graphics modes available under the current graphics driver

A TGraphicsMode object contains the following fields: width, height, depth and hertz

Returns

An array of TGraphicsMode objects

Example

Print "Available graphics modes:"

For mode:TGraphicsMode=EachIn GraphicsModes()

	Print mode.width+","+mode.height+","+mode.depth+","+mode.hertz

Next

`Function CountGraphicsModes()`

Get number of graphics modes available under the current graphics driver

Use GetGraphicsMode To obtain information about an individual Graphics mode

Returns

Number of available Graphics modes

`Function GetGraphicsMode( index,width Var,height Var,depth Var,hertz Var )`

Get information about a graphics mode

GetGraphicsMode returns information about a specific graphics mode. mode should be in the range 0 (inclusive) to the value returned by CountGraphicsModes (exclusive).

`Function GraphicsModeExists( width,height,depth=0,hertz=0 )`

Determine if a graphics mode exists

A value of 0 for any of width, height, depth or hertz will cause that parameter to be ignored.

Returns

True if a matching graphics mode is found

`Function CreateGraphics:TGraphics( width,height,depth,hertz,flags )`

Create a graphics object

CreateGraphics creates a graphics object. To use this object for rendering, you will first have to select it using SetGraphics.

The kind of graphics object returned depends upon the current graphics driver as set by SetGraphicsDriver.

Returns

A graphics object

`Function CloseGraphics( g:TGraphics )`

Close a graphics object

Once closed, a graphics object can no longer be used.

`Function SetGraphics( g:TGraphics )`

Set current graphics object

SetGraphics will also change the current graphics driver if g uses a different driver than the current driver.