func reshape(w, h int) {
gl.Viewport(0, 0, gl.GLsizei(w), gl.GLsizei(h))
gl.MatrixMode(gl.PROJECTION)
gl.LoadIdentity()
gl.Ortho(0, gl.GLdouble(w), 0, gl.GLdouble(h), -1, 1)
gl.Scalef(1, -1, 1)
gl.Translatef(0, gl.GLfloat(-h), 0)
gl.MatrixMode(gl.MODELVIEW)
}
func main() {
sdl.Init(sdl.INIT_VIDEO)
var screen = sdl.SetVideoMode(640, 480, 32, sdl.OPENGL)
if screen == nil {
panic("sdl error")
}
if gl.Init() != 0 {
panic("glew error")
}
pen := Pen{}
gl.MatrixMode(gl.PROJECTION)
gl.Viewport(0, 0, gl.GLsizei(screen.W), gl.GLsizei(screen.H))
gl.LoadIdentity()
gl.Ortho(0, gl.GLdouble(screen.W), gl.GLdouble(screen.H), 0, -1.0, 1.0)
gl.ClearColor(1, 1, 1, 0)
gl.Clear(gl.COLOR_BUFFER_BIT)
var running = true
for running {
e := &sdl.Event{}
for e.Poll() {
switch e.Type {
case sdl.QUIT:
running = false
break
case sdl.KEYDOWN:
running = false
break
case sdl.MOUSEMOTION:
me := e.MouseMotion()
if me.State != 0 {
pen.lineTo(Point{int(me.X), int(me.Y)})
} else {
pen.moveTo(Point{int(me.X), int(me.Y)})
}
break
}
}
sdl.GL_SwapBuffers()
sdl.Delay(25)
}
sdl.Quit()
}
func (f *Font) setupTextRendering(color [3]byte, txt string) (gl.GLuint, *sdl.Surface, *sdl.Surface, *sdl.Surface, int, int) {
//
var texture gl.GLuint
/* Use SDL_TTF to render our text */
var col sdl.Color
col.R = color[0]
col.G = color[1]
col.B = color[2]
// get surface with text
initial := ttf.RenderText_Blended(f.font, txt, col)
/* Convert the rendered text to a known format */
w := next_p2(int(initial.W))
h := next_p2(int(initial.H))
intermediarya := sdl.CreateRGBSurface(0, w, h, 32,
0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000)
var rr *sdl.Rect = nil
intermediarya.Blit(rr, initial, rr)
intermediary := intermediarya.DisplayFormatAlpha()
/* Tell GL about our new texture */
gl.GenTextures(1, &texture)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.TexImage2D(gl.TEXTURE_2D, 0, 4, gl.GLsizei(w), gl.GLsizei(h), 0, gl.BGRA,
gl.UNSIGNED_BYTE, unsafe.Pointer(intermediary.Pixels))
gl.TexEnvi(gl.TEXTURE_ENV, gl.TEXTURE_ENV_MODE, gl.MODULATE)
/* GL_NEAREST looks horrible, if scaled... */
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
/* prepare to render our texture */
gl.Enable(gl.TEXTURE_2D)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.Color4f(1.0, 1.0, 1.0, 1.0)
gl.Enable(gl.BLEND)
// gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
gl.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_COLOR) // TODO : MAke real alpha work!
return texture, initial, intermediarya, intermediary, w, h
}
func reshape(w, h int) {
/* Because Gil specified "screen coordinates" (presumably with an
upper-left origin), this short bit of code sets up the coordinate
system to correspond to actual window coodrinates. This code
wouldn't be required if you chose a (more typical in 3D) abstract
coordinate system. */
gl.Viewport(0, 0, gl.GLsizei(w), gl.GLsizei(h)) /* Establish viewing area to cover entire window. */
gl.MatrixMode(gl.PROJECTION) /* Start modifying the projection matrix. */
gl.LoadIdentity() /* Reset project matrix. */
gl.Ortho(0, gl.GLdouble(w), 0, gl.GLdouble(h), -1, 1) /* Map abstract coords directly to window coords. */
gl.Scalef(1, -1, 1) /* Invert Y axis so increasing Y goes down. */
gl.Translatef(0, gl.GLfloat(-h), 0) /* Shift origin up to upper-left corner. */
}
func uploadTexture_RGBA32(w, h int, data []byte) gl.GLuint {
var id gl.GLuint
gl.GenTextures(1, &id)
gl.BindTexture(gl.TEXTURE_2D, id)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.GLsizei(w), gl.GLsizei(h), 0, gl.RGBA,
gl.UNSIGNED_BYTE, unsafe.Pointer(&data[0]))
if gl.GetError() != gl.NO_ERROR {
gl.DeleteTextures(1, &id)
panic("Failed to load a texture")
return 0
}
return id
}
func ResizeWindow(w int32, h int32) {
// resizeWindow
gl.MatrixMode(gl.PROJECTION)
gl.Viewport(0, 0, gl.GLsizei(w), gl.GLsizei(h))
gl.LoadIdentity()
// glu.Perspective( 45.0, ratio, 0.1, 100.0)
aspect := gl.GLdouble(w) / gl.GLdouble(h)
zNear := gl.GLdouble(0.1)
zFar := gl.GLdouble(100.0)
gl.Frustum(-NearHeight*aspect,
NearHeight*aspect,
-NearHeight,
NearHeight, zNear, zFar)
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
WinW = int(w)
WinH = int(h)
}