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
}
// load in bitmap as a GL texture
func LoadGLTextures(path string) {
// storage space for the textures
image, format := LoadImage(path)
// Create the textures
gl.GenTextures(textures[:])
genTexture(textures[0], image, format)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
genTexture(textures[1], image, format)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
genTexture(textures[2], image, format)
gl.TexParameteri(gl.TEXTURE_2D, gl.GENERATE_MIPMAP, gl.TRUE)
}
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
}
// load in bitmap as a GL texture
func LoadGLTextures(path string) {
image := sdl.Load(path)
if image == nil { panic(sdl.GetError()) }
// Check that the image's width is a power of 2
if image.W & (image.W - 1) != 0 {
fmt.Println("warning:", path, "has a width that is not a power of 2")
}
// Also check if the height is a power of 2
if image.H & (image.H - 1) != 0 {
fmt.Println("warning:", path, "has an height that is not a power of 2")
}
// get the number of channels in the SDL surface
nOfColors := image.Format.BytesPerPixel
var textureFormat gl.GLenum
if nOfColors == 4 { // contains alpha channel
if image.Format.Rmask == 0x000000ff {
textureFormat = gl.RGBA
} else {
textureFormat = gl.BGRA
}
} else if nOfColors == 3 { // no alpha channel
if image.Format.Rmask == 0x000000ff {
textureFormat = gl.RGB
} else {
textureFormat = gl.BGR
}
} else {
fmt.Println("warning:", path, "is not truecolor, this will probably break")
}
// Create the textures
gl.GenTextures(textures[:])
// First texture
gl.BindTexture(gl.TEXTURE_2D, uint(textures[0]))
gl.TexImage2D(
gl.TEXTURE_2D,
0,
3,
int(image.W),
int(image.H),
0,
textureFormat,
gl.UNSIGNED_BYTE,
image.Pixels,
)
// linear filtering
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
// Second texture
gl.BindTexture(gl.TEXTURE_2D, uint(textures[1]))
gl.TexImage2D(gl.TEXTURE_2D, 0,
3,
int(image.W),
int(image.H),
0, textureFormat, gl.UNSIGNED_BYTE,
image.Pixels,
)
// Mipmapped filtering
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
// Third texture
gl.BindTexture(gl.TEXTURE_2D, uint(textures[2]))
gl.TexImage2D(gl.TEXTURE_2D, 0,
3,
int(image.W),
int(image.H),
0, textureFormat, gl.UNSIGNED_BYTE,
image.Pixels,
)
// Mipmapped filtering
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
glu.Build2DMipmaps(
gl.TEXTURE_2D,
3,
int(image.W),
int(image.H),
textureFormat,
image.Pixels,
)
}