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Linear scaling using integer math (copied from ts-ddraw)

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This commit is contained in:
FunkyFr3sh 2018-11-17 05:54:22 +01:00
parent ee6266519a
commit e4437a278f
4 changed files with 160 additions and 1 deletions
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1
cnc-ddraw.vcxproj
View File

@ -38,6 +38,7 @@
<ClInclude Include="inc\palette.h" />
<ClInclude Include="inc\openglshader.h" />
<ClInclude Include="inc\d3d9shader.h" />
<ClInclude Include="inc\scale_pattern.h" />
<ClInclude Include="inc\surface.h" />
</ItemGroup>
<ItemGroup>

3
cnc-ddraw.vcxproj.filters
View File

@ -95,6 +95,9 @@
<ClInclude Include="inc\lodepng.h">
<Filter>Header Files</Filter>
</ClInclude>
<ClInclude Include="inc\scale_pattern.h">
<Filter>Header Files</Filter>
</ClInclude>
</ItemGroup>
<ItemGroup>
<ResourceCompile Include="ddraw.rc">

18
inc/scale_pattern.h Normal file
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@ -0,0 +1,18 @@
#ifndef _SCALE_PATTERN_H
#define _SCALE_PATTERN_H
typedef enum {
REPEAT,
SEQUENCE,
ONCE,
END
} SCALE_PATTERN_TYPE;
typedef struct {
SCALE_PATTERN_TYPE type;
int dst_index;
int src_index;
int count;
} scale_pattern;
#endif

139
src/surface.c
View File

@ -19,6 +19,7 @@
#include "main.h"
#include "surface.h"
#include "scale_pattern.h"
void dump_ddbltflags(DWORD dwFlags);
void dump_ddscaps(DWORD dwCaps);
@ -244,7 +245,143 @@ HRESULT __stdcall ddraw_surface_Blt(IDirectDrawSurfaceImpl *This, LPRECT lpDestR
}
}
else
StretchBlt(This->hDC, dst_x, dst_y, dst_w, dst_h, Source->hDC, src_x, src_y, src_w, src_h, SRCCOPY);
{
/* Linear scaling using integer math
* Since the scaling pattern for x will aways be the same, the pattern itself gets pre-calculated
* and stored in an array.
* Y scaling pattern gets calculated during the blit loop
*/
unsigned int x_ratio = (unsigned int)((src_w << 16) / dst_w) + 1;
unsigned int y_ratio = (unsigned int)((src_h << 16) / dst_h) + 1;
unsigned int s_src_x, s_src_y;
unsigned int dest_base, source_base;
scale_pattern *pattern = malloc((dst_w + 1) * (sizeof(scale_pattern)));
int pattern_idx = 0;
unsigned int last_src_x = 0;
if (pattern != NULL)
{
pattern[pattern_idx] = (scale_pattern) { ONCE, 0, 0, 1 };
/* Build the pattern! */
for (int x = 1; x < dst_w; x++) {
s_src_x = (x * x_ratio) >> 16;
if (s_src_x == last_src_x)
{
if (pattern[pattern_idx].type == REPEAT || pattern[pattern_idx].type == ONCE)
{
pattern[pattern_idx].type = REPEAT;
pattern[pattern_idx].count++;
}
else if (pattern[pattern_idx].type == SEQUENCE)
{
pattern_idx++;
pattern[pattern_idx] = (scale_pattern) { REPEAT, x, s_src_x, 1 };
}
}
else if (s_src_x == last_src_x + 1)
{
if (pattern[pattern_idx].type == SEQUENCE || pattern[pattern_idx].type == ONCE)
{
pattern[pattern_idx].type = SEQUENCE;
pattern[pattern_idx].count++;
}
else if (pattern[pattern_idx].type == REPEAT)
{
pattern_idx++;
pattern[pattern_idx] = (scale_pattern) { ONCE, x, s_src_x, 1 };
}
}
else
{
pattern_idx++;
pattern[pattern_idx] = (scale_pattern) { ONCE, x, s_src_x, 1 };
}
last_src_x = s_src_x;
}
pattern[pattern_idx + 1] = (scale_pattern) { END, 0, 0, 0 };
/* Do the actual blitting */
void *d, *s;
int count = 0;
for (int y = 0; y < dst_h; y++) {
dest_base = dst_x + This->width * (y + dst_y);
s_src_y = (y * y_ratio) >> 16;
source_base = src_x + Source->width * (s_src_y + src_y);
pattern_idx = 0;
scale_pattern *current = &pattern[pattern_idx];
do {
switch (current->type)
{
case ONCE:
if (This->bpp == 8)
{
((unsigned char *)This->surface)[dest_base + current->dst_index] =
((unsigned char *)Source->surface)[source_base + current->src_index];
}
else if (This->bpp == 16)
{
((unsigned short *)This->surface)[dest_base + current->dst_index] =
((unsigned short *)Source->surface)[source_base + current->src_index];
}
break;
case REPEAT:
if (This->bpp == 8)
{
d = ((unsigned char *)This->surface + dest_base + current->dst_index);
unsigned char v = ((unsigned char *)Source->surface)[source_base + current->src_index];
count = current->count;
while (count-- > 0)
*((unsigned char *)d)++ = v;
}
else if (This->bpp == 16)
{
d = ((unsigned short *)This->surface + dest_base + current->dst_index);
unsigned short v = ((unsigned short *)Source->surface)[source_base + current->src_index];
count = current->count;
while (count-- > 0)
*((unsigned short *)d)++ = v;
}
break;
case SEQUENCE:
if (This->bpp == 8)
{
d = ((unsigned char *)This->surface) + dest_base + current->dst_index;
s = ((unsigned char *)Source->surface) + source_base + current->src_index;
}
else if (This->bpp == 16)
{
d = ((unsigned short *)This->surface) + dest_base + current->dst_index;
s = ((unsigned short *)Source->surface) + source_base + current->src_index;
}
memcpy(d, s, current->count * This->lXPitch);
break;
case END:
default:
break;
}
current = &pattern[++pattern_idx];
} while (current->type != END);
}
free(pattern);
}
}
}
}