MorphOS Developer
Posts: 1516 from 2003/2/24
From: Finland
ScalePixelArray() / ScalePixelArrayAlpha() is accelerated on the most common gfx cards.
Using GL to scale bitmaps requires more work in terms of setting up initial setup but this is what I use in Frodo port for TGL scaling:
Setup:
Quote:
STATIC ULONG mSetupTGL(struct Display_Data *data, ULONG width, ULONG height, ULONG depth)
{
struct Library *TinyGLBase;
TinyGLBase = OpenLibrary("tinygl.library", 0);
if (TinyGLBase)
{
data->TinyGLBase = TinyGLBase;
if ((__tglContext = GLInit()))
{
data->Texture = (GLubyte *)AllocTaskPooled(DISPLAY_X * DISPLAY_Y * 4 * sizeof(GLubyte));
if (data->Texture)
{
if (data->RastPort.BitMap)
data->RastPort.BitMap = AllocBitMap(width, height, depth, BMF_DISPLAYABLE|BMF_MINPLANES, _screen(data->ehn.ehn_Object)->RastPort.BitMap);
if (data->RastPort.BitMap && glAInitializeContextBitMap(data->RastPort.BitMap))
{
glViewport(0 , 0 , width , height);
glClearColor(0.0, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glWindowPos2f(0, 0);
glPixelZoom(1.0f * (float)width/(float)DISPLAY_X, -1.0f * (float)height/(float)DISPLAY_Y);
glColorTable(GL_COLOR_TABLE, GL_RGBA, 256, GL_RGBA, GL_UNSIGNED_BYTE, data->TGLColours);
data->GLRender = TRUE;
return TRUE;
}
}
}
}
mCleanupTGL(data);
return FALSE;
}
Cleanup:
Quote:
STATIC VOID mCleanupTGL(struct Display_Data *data)
{
struct Library *TinyGLBase = data->TinyGLBase;
if (TinyGLBase)
{
if (__tglContext)
{
if (data->Texture)
FreeTaskPooled(data->Texture, DISPLAY_X * DISPLAY_Y * 4 * sizeof(GLubyte));
if (data->RastPort.BitMap)
glADestroyContextBitMap();
GLClose(__tglContext);
}
CloseLibrary(TinyGLBase);
data->Texture = NULL;
data->TinyGLBase = NULL;
data->GLRender = FALSE;
__tglContext = NULL;
}
}
Scaling/drawing:
Quote:
STATIC VOID mUpdateTGL(struct Display_Data *data, struct RastPort *rp, ULONG mleft, ULONG mtop, ULONG mwidth, ULONG mheight, GLubyte *buf)
{
struct Library *TinyGLBase = data->TinyGLBase;
glDrawPixels(DISPLAY_X, DISPLAY_Y, GL_COLOR_INDEX, GL_UNSIGNED_BYTE, buf);
glFinish();
data->GfxBufOk = TRUE;
BltBitMapRastPort(data->RastPort.BitMap, 0, 0, rp, mleft, mtop , mwidth, mheight, 0xc0);
}
It is understandable if you dont want to go this route. It requires relatively lot code to get it done and this example is designed for LUT8 bitmaps.
I think it is better use SW scaling. With altivec optimizations it is very quick.
1 + 1 = 3 with very large values of 1
.
