OpenGL 2D Graphics

Version: 4.2.1.5

OpenGL 2D Graphics

Jay McCarthy <jay at plt-scheme dot org>

This package provides convenience routines for 2D graphics with OpenGL.

(require (planet jaymccarthy/gl2d))

(gl-init width height mw mh vw vh cx cy) → void
  width : integer?
  height : integer?
  mw : real?
  mh : real?
  vw : real?
  vh : real?
  cx : real?
  cy : real?

Initializes the GL canvas to be width wide and height tall (in pixels) with a vw by vh viewport centered around (cx,cy) where the maximum area in the scene is mw by mh. All real values are not necessarily pixels.

(gl-draw-point x y) → void

x : real?

y : real?

(gl-draw-line x1 y1 x2 y2) → void

x1 : real?

y1 : real?

x2 : real?

y2 : real?

The obvious operations.

mode/c : contract?

Equivalent to (symbols 'solid 'outline)

(gl-draw-circle mode) → void
mode : mode/c

Draws an approximation of the unit circle. Use call-with-scale for a different radius and call-with-translate for a different center.

(gl-draw-rectangle mode w h) → void
  mode : mode/c
  w : real?
  h : real?

Draws a rectangle. Use call-with-translate for a different corner.

(call-with-rotation degrees thnk) → void

degrees : real?

thnk : (-> void)

(call-with-mirror figure-width thnk) → void

figure-width : real?

thnk : (-> void)

(call-with-scale x y thnk) → void

x : real?

y : real?

thnk : (-> void)

(call-with-translate x y thnk) → void

x : real?

y : real?

thnk : (-> void)

Render with a transformation matrix.

(with-rotation degrees e ...)

(with-mirror figure-width e ...)

(with-scale x y e ...)

(with-translate x y e ...)

Syntax versions of the above.

1 Textures

(gl-texture? v) → boolean?
v : any/c

Tests texture-ness.

(valid-gl-texture? v) → boolean?
v : any/c

Only true if texture has not been freed.

(gl-texture-width tex) → exact-nonnegative-integer?

tex : gl-texture?

(gl-texture-height tex) → exact-nonnegative-integer?

tex : gl-texture?

Accessors

(gl-load-texture pth) → valid-gl-texture?
pth : path-string?

Loads a PNG with an alpha mask as a texture.

(gl-bind-texture tex) → void
tex : valid-gl-texture?

Binds a texture for subsequent rendering.

(gl-draw-rectangle/texture w h) → void
w : real?
h : real?

Renders the currently bound texture on a rectangle.

(gl-draw-rectangle/texture-part tx
ty
tw
th
w
h) → void
  tx : (real-in 0 1)
  ty : (real-in 0 1)
  tw : (real-in 0 1)
  th : (real-in 0 1)
  w : real?
  h : real?

Renders part of the currently bound texture on a rectangle. (The texture is normalized to a 1x1 square.)

(gl-free-texture tex) → void
tex : valid-gl-texture?

Frees a texture. It is no longer a valid-gl-texture?.