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Align colors in SDL package to Go specification #581

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merged 6 commits into from
Nov 25, 2023
+427 −282
Merged

Align colors in SDL package to Go specification #581

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795e462
sdl/surface: handle colors correctly in Surface.Set method
mokiat Nov 20, 2023
4cbca37
sdl/pixels: fix color models
mokiat Nov 20, 2023
46502a4
sdl/surface: handle RGBA correctly in Surface.At method
mokiat Nov 20, 2023
51ef282
sdl/pixels: make sdl.Color be of type color.NRGBA
mokiat Nov 20, 2023
7a62974
sdl/struct_test: fix compilation issue in sdl package
mokiat Nov 20, 2023
38619c1
sdl/pixels: improve binary upscale/downscale precision
mokiat Nov 21, 2023
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sdl/surface: handle colors correctly in Surface.Set method
@mokiat
mokiat committed Nov 21, 2023
commit 795e4620139b69428a616cfcc6d140fce686baf1
173 changes: 79 additions & 94 deletions sdl/surface.go
View file
Original file line number Diff line number Diff line change
@@ -653,165 +653,150 @@ func (surface *Surface) At(x, y int) color.Color {
return color.RGBA{r, g, b, a}
}

// Set the color of the pixel at (x, y) using this surface's color model to
// convert c to the appropriate color. This method is required for the
// Set the color of the pixel at (x, y) using this surface's color format to
// convert c to the appropriate byte sequence. This method is required for the
// draw.Image interface. The surface may require locking before calling Set.
func (surface *Surface) Set(x, y int, c color.Color) {
// All sdl2 colors are a subset of NRGBA so it is safe precision-wise to
// convert to NRGBA and use the color components from there.
nrgbaColor := color.NRGBAModel.Convert(c).(color.NRGBA)
colR, colG, colB, colA := nrgbaColor.R, nrgbaColor.G, nrgbaColor.B, nrgbaColor.A

pix := surface.Pixels()
i := int32(y)*surface.Pitch + int32(x)*int32(surface.Format.BytesPerPixel)
switch surface.Format.Format {
case PIXELFORMAT_ARGB8888:
col := surface.ColorModel().Convert(c).(ARGB8888)
pix[i+3] = col.A
pix[i+2] = col.R
pix[i+1] = col.G
pix[i+0] = col.B
pix[i+3] = colA
pix[i+2] = colR
pix[i+1] = colG
pix[i+0] = colB
case PIXELFORMAT_ABGR8888:
col := surface.ColorModel().Convert(c).(ABGR8888)
pix[i+3] = col.A
pix[i+2] = col.B
pix[i+1] = col.G
pix[i+0] = col.R
pix[i+3] = colA
pix[i+2] = colB
pix[i+1] = colG
pix[i+0] = colR
case PIXELFORMAT_RGB24, PIXELFORMAT_RGB888:
col := surface.ColorModel().Convert(c).(RGB888)
pix[i+2] = col.R
pix[i+1] = col.G
pix[i+0] = col.B
pix[i+2] = colR
pix[i+1] = colG
pix[i+0] = colB
case PIXELFORMAT_BGR24, PIXELFORMAT_BGR888:
col := surface.ColorModel().Convert(c).(BGR888)
pix[i+2] = col.B
pix[i+1] = col.G
pix[i+0] = col.R
pix[i+2] = colB
pix[i+1] = colG
pix[i+0] = colR
case PIXELFORMAT_RGB444:
col := surface.ColorModel().Convert(c).(RGB444)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 4 & 0x0F
g := uint32(col.G) >> 4 & 0x0F
b := uint32(col.B) >> 4 & 0x0F
r := uint32(colR) >> 4 & 0x0F
g := uint32(colG) >> 4 & 0x0F
b := uint32(colB) >> 4 & 0x0F
*buf = r<<8 | g<<4 | b
case PIXELFORMAT_RGB332:
col := surface.ColorModel().Convert(c).(RGB332)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 5 & 0x0F
g := uint32(col.G) >> 5 & 0x0F
b := uint32(col.B) >> 6 & 0x0F
r := uint32(colR) >> 5 & 0x0F
g := uint32(colG) >> 5 & 0x0F
b := uint32(colB) >> 6 & 0x0F
*buf = r<<5 | g<<2 | b
case PIXELFORMAT_RGB565:
col := surface.ColorModel().Convert(c).(RGB565)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 2 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 2 & 0xFF
b := uint32(colB) >> 3 & 0xFF
*buf = r<<11 | g<<5 | b
case PIXELFORMAT_RGB555:
col := surface.ColorModel().Convert(c).(RGB555)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
*buf = r<<10 | g<<5 | b
case PIXELFORMAT_BGR565:
col := surface.ColorModel().Convert(c).(BGR565)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 2 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 2 & 0xFF
b := uint32(colB) >> 3 & 0xFF
*buf = b<<11 | g<<5 | r
case PIXELFORMAT_BGR555:
col := surface.ColorModel().Convert(c).(BGR555)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
*buf = b<<10 | g<<5 | r
case PIXELFORMAT_ARGB4444:
col := surface.ColorModel().Convert(c).(ARGB4444)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
a := uint32(col.A) >> 4 & 0x0F
r := uint32(col.R) >> 4 & 0x0F
g := uint32(col.G) >> 4 & 0x0F
b := uint32(col.B) >> 4 & 0x0F
a := uint32(colA) >> 4 & 0x0F
r := uint32(colR) >> 4 & 0x0F
g := uint32(colG) >> 4 & 0x0F
b := uint32(colB) >> 4 & 0x0F
*buf = a<<12 | r<<8 | g<<4 | b
case PIXELFORMAT_ABGR4444:
col := surface.ColorModel().Convert(c).(ABGR4444)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
a := uint32(col.A) >> 4 & 0x0F
r := uint32(col.R) >> 4 & 0x0F
g := uint32(col.G) >> 4 & 0x0F
b := uint32(col.B) >> 4 & 0x0F
a := uint32(colA) >> 4 & 0x0F
r := uint32(colR) >> 4 & 0x0F
g := uint32(colG) >> 4 & 0x0F
b := uint32(colB) >> 4 & 0x0F
*buf = a<<12 | b<<8 | g<<4 | r
case PIXELFORMAT_RGBA4444:
col := surface.ColorModel().Convert(c).(RGBA4444)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 4 & 0x0F
g := uint32(col.G) >> 4 & 0x0F
b := uint32(col.B) >> 4 & 0x0F
a := uint32(col.A) >> 4 & 0x0F
r := uint32(colR) >> 4 & 0x0F
g := uint32(colG) >> 4 & 0x0F
b := uint32(colB) >> 4 & 0x0F
a := uint32(colA) >> 4 & 0x0F
*buf = r<<12 | g<<8 | b<<4 | a
case PIXELFORMAT_BGRA4444:
col := surface.ColorModel().Convert(c).(BGRA4444)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 4 & 0x0F
g := uint32(col.G) >> 4 & 0x0F
b := uint32(col.B) >> 4 & 0x0F
a := uint32(col.A) >> 4 & 0x0F
r := uint32(colR) >> 4 & 0x0F
g := uint32(colG) >> 4 & 0x0F
b := uint32(colB) >> 4 & 0x0F
a := uint32(colA) >> 4 & 0x0F
*buf = b<<12 | g<<8 | r<<4 | a
case PIXELFORMAT_ARGB1555:
col := surface.ColorModel().Convert(c).(ARGB1555)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
a := uint32(0)
if col.A > 0 {
if colA > 0 {
a = 1
}
*buf = a<<15 | r<<10 | g<<5 | b
case PIXELFORMAT_RGBA5551:
col := surface.ColorModel().Convert(c).(RGBA5551)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
a := uint32(0)
if col.A > 0 {
if colA > 0 {
a = 1
}
*buf = r<<11 | g<<6 | b<<1 | a
case PIXELFORMAT_ABGR1555:
col := surface.ColorModel().Convert(c).(ABGR1555)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
a := uint32(0)
if col.A > 0 {
if colA > 0 {
a = 1
}
*buf = a<<15 | b<<10 | g<<5 | r
case PIXELFORMAT_BGRA5551:
col := surface.ColorModel().Convert(c).(BGRA5551)
buf := (*uint32)(unsafe.Pointer(&pix[i]))
r := uint32(col.R) >> 3 & 0xFF
g := uint32(col.G) >> 3 & 0xFF
b := uint32(col.B) >> 3 & 0xFF
r := uint32(colR) >> 3 & 0xFF
g := uint32(colG) >> 3 & 0xFF
b := uint32(colB) >> 3 & 0xFF
a := uint32(0)
if col.A > 0 {
if colA > 0 {
a = 1
}
*buf = b<<11 | g<<6 | r<<1 | a
case PIXELFORMAT_RGBA8888:
col := surface.ColorModel().Convert(c).(RGBA8888)
pix[i+3] = col.R
pix[i+2] = col.G
pix[i+1] = col.B
pix[i+0] = col.A
pix[i+3] = colR
pix[i+2] = colG
pix[i+1] = colB
pix[i+0] = colA
case PIXELFORMAT_BGRA8888:
col := surface.ColorModel().Convert(c).(BGRA8888)
pix[i+3] = col.B
pix[i+2] = col.G
pix[i+1] = col.R
pix[i+0] = col.A
pix[i+3] = colB
pix[i+2] = colG
pix[i+1] = colR
pix[i+0] = colA
default:
panic("Unknown pixel format!")
}