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PaletteTexture.go
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PaletteTexture.go
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package graphics
import (
"github.com/inkyblackness/hacked/ss1/content/bitmap"
"github.com/inkyblackness/hacked/ui/opengl"
)
// PaletteTexture contains a palette stored as OpenGL texture.
type PaletteTexture struct {
gl opengl.OpenGL
handle uint32
palette bitmap.Palette
}
// NewPaletteTexture creates a new PaletteTexture instance.
func NewPaletteTexture(gl opengl.OpenGL, palette *bitmap.Palette) *PaletteTexture {
tex := &PaletteTexture{
gl: gl,
handle: gl.GenTextures(1)[0],
}
tex.Update(palette)
return tex
}
// Dispose releases the OpenGL texture.
func (tex *PaletteTexture) Dispose() {
if tex.handle != 0 {
tex.gl.DeleteTextures([]uint32{tex.handle})
tex.handle = 0
}
}
// Palette returns the original palette.
func (tex *PaletteTexture) Palette() bitmap.Palette {
return tex.palette
}
// Handle returns the texture handle.
func (tex *PaletteTexture) Handle() uint32 {
return tex.handle
}
// Update reloads the palette.
func (tex *PaletteTexture) Update(palette *bitmap.Palette) {
gl := tex.gl
const bytesPerRGBA = 4
const colors = 256
var data [colors * bytesPerRGBA]byte
for i := 0; i < colors; i++ {
entry := palette[i]
data[i*bytesPerRGBA+0] = entry.Red
data[i*bytesPerRGBA+1] = entry.Green
data[i*bytesPerRGBA+2] = entry.Blue
data[i*bytesPerRGBA+3] = 0xFF
}
data[3] = 0x00
gl.BindTexture(opengl.TEXTURE_2D, tex.handle)
gl.TexImage2D(opengl.TEXTURE_2D, 0, opengl.RGBA, int32(colors), 1, 0, opengl.RGBA, opengl.UNSIGNED_BYTE, data[:])
gl.TexParameteri(opengl.TEXTURE_2D, opengl.TEXTURE_MAG_FILTER, opengl.NEAREST)
gl.TexParameteri(opengl.TEXTURE_2D, opengl.TEXTURE_MIN_FILTER, opengl.NEAREST)
gl.GenerateMipmap(opengl.TEXTURE_2D)
gl.BindTexture(opengl.TEXTURE_2D, 0)
tex.palette = *palette
}