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Merge pull request #51 from achilleasa/fix-vga-text-palette-mapping

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Map EGA color indices to correct DAC entries for VGA HW
This commit is contained in:
Achilleas Anagnostopoulos 2017-08-19 11:07:28 +01:00 committed by GitHub
commit 324022187d
2 changed files with 11 additions and 4 deletions
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9
src/gopheros/device/video/console/vga_text.go
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@ -14,6 +14,13 @@ import (
"unsafe"
)
// egaColorIndexToDACEntry is a LUT that maps an EGA color index to the DAC
// entry used by the VGA hardware when looking up the color.
var egaColorIndexToDACEntry = []uint8{
0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x14, 0x07, 0x38, 0x39, 0x3a, 0x3b,
0x3c, 0x3d, 0x3e, 0x3f,
}
// VgaTextConsole implements an EGA-compatible 80x25 text console using VGA
// mode 0x3. The console supports the default 16 EGA colors which can be
// overridden using the SetPaletteColor method.
@ -183,7 +190,7 @@ func (cons *VgaTextConsole) SetPaletteColor(index uint8, rgba color.RGBA) {
// Load palette entry to the DAC. In this mode, colors are specified
// using 6-bits for each component; the RGB values need to be converted
// to the 0-63 range.
portWriteByteFn(0x3c8, index)
portWriteByteFn(0x3c8, egaColorIndexToDACEntry[index])
portWriteByteFn(0x3c9, rgba.R>>2)
portWriteByteFn(0x3c9, rgba.G>>2)
portWriteByteFn(0x3c9, rgba.B>>2)

6
src/gopheros/device/video/console/vga_text_test.go
View File

@ -286,7 +286,7 @@ func TestVgaTextSetPaletteColor(t *testing.T) {
val uint8
}{
// Values will be normalized in the 0-31 range
{0x3c8, 1},
{0x3c8, 0x3f},
{0x3c9, 63},
{0x3c9, 31},
{0x3c9, 0},
@ -303,9 +303,9 @@ func TestVgaTextSetPaletteColor(t *testing.T) {
}
rgba := color.RGBA{R: 255, G: 127, B: 0}
cons.SetPaletteColor(1, rgba)
cons.SetPaletteColor(15, rgba)
if got := cons.Palette()[1]; got != rgba {
if got := cons.Palette()[15]; got != rgba {
t.Errorf("expected color at index 1 to be:\n%v\ngot:\n%v", rgba, got)
}