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GRAPHICS: Add an in-place Surface PixelFormat conversion.

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This commit is contained in:
Johannes Schickel 2012-07-14 06:03:04 +02:00
parent e8cf0adf95
commit eeb3959259
2 changed files with 81 additions and 0 deletions
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67
graphics/surface.cpp
View File

@ -26,6 +26,7 @@
#include "common/textconsole.h"
#include "graphics/primitives.h"
#include "graphics/surface.h"
#include "graphics/conversion.h"
namespace Graphics {
@ -271,6 +272,72 @@ void Surface::move(int dx, int dy, int height) {
}
}
void Surface::convertToInPlace(const PixelFormat &dstFormat, const byte *palette) {
// Do not convert to the same format and ignore empty surfaces.
if (format == dstFormat || pixels == 0) {
return;
}
if (format.bytesPerPixel == 0 || format.bytesPerPixel > 4)
error("Surface::convertToInPlace(): Can only convert from 1Bpp, 2Bpp, 3Bpp, and 4Bpp");
if (dstFormat.bytesPerPixel != 2 && dstFormat.bytesPerPixel != 4)
error("Surface::convertToInPlace(): Can only convert to 2Bpp and 4Bpp");
// In case the surface data needs more space allocate it.
if (dstFormat.bytesPerPixel > format.bytesPerPixel) {
void *const newPixels = realloc(pixels, w * h * dstFormat.bytesPerPixel);
if (!newPixels) {
error("Surface::convertToInPlace(): Out of memory");
}
pixels = newPixels;
}
// We take advantage of the fact that pitch is always w * format.bytesPerPixel.
// This is assured by the logic of Surface::create.
// We need to handle 1 Bpp surfaces special here.
if (format.bytesPerPixel == 1) {
assert(palette);
for (int y = h; y > 0; --y) {
const byte *srcRow = (const byte *)pixels + y * pitch - 1;
byte *dstRow = (byte *)pixels + y * w * dstFormat.bytesPerPixel - dstFormat.bytesPerPixel;
for (int x = 0; x < w; x++) {
byte index = *srcRow--;
byte r = palette[index * 3];
byte g = palette[index * 3 + 1];
byte b = palette[index * 3 + 2];
uint32 color = dstFormat.RGBToColor(r, g, b);
if (dstFormat.bytesPerPixel == 2)
*((uint16 *)dstRow) = color;
else
*((uint32 *)dstRow) = color;
dstRow -= dstFormat.bytesPerPixel;
}
}
} else {
crossBlit((byte *)pixels, (const byte *)pixels, w * dstFormat.bytesPerPixel, pitch, w, h, dstFormat, format);
}
// In case the surface data got smaller, free up some memory.
if (dstFormat.bytesPerPixel < format.bytesPerPixel) {
void *const newPixels = realloc(pixels, w * h * dstFormat.bytesPerPixel);
if (!newPixels) {
error("Surface::convertToInPlace(): Freeing memory failed");
}
pixels = newPixels;
}
// Update the surface specific data.
format = dstFormat;
pitch = w * dstFormat.bytesPerPixel;
}
Graphics::Surface *Surface::convertTo(const PixelFormat &dstFormat, const byte *palette) const {
assert(pixels);

14
graphics/surface.h
View File

@ -134,6 +134,20 @@ struct Surface {
*/
void copyFrom(const Surface &surf);
/**
* Convert the data to another pixel format.
*
* This works in-place. This means it will not create an additional buffer
* for the conversion process. The value of pixels might change though.
*
* Note that you should only use this, when you created the Surface data via
* create! Otherwise this function has undefined behavior.
*
* @param dstFormat The desired format
* @param palette The palette (in RGB888), if the source format has a Bpp of 1
*/
void convertToInPlace(const PixelFormat &dstFormat, const byte *palette = 0);
/**
* Convert the data to another pixel format.
*