mame/src/emu/rendutil.cpp
2017-09-03 12:51:21 +10:00

831 lines
25 KiB
C++

// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
rendutil.c
Core rendering utilities.
***************************************************************************/
#include "emu.h"
#include "render.h"
#include "rendutil.h"
#include "png.h"
#include "jpeglib.h"
/***************************************************************************
FUNCTION PROTOTYPES
***************************************************************************/
/* utilities */
static void resample_argb_bitmap_average(u32 *dest, u32 drowpixels, u32 dwidth, u32 dheight, const u32 *source, u32 srowpixels, u32 swidth, u32 sheight, const render_color &color, u32 dx, u32 dy);
static void resample_argb_bitmap_bilinear(u32 *dest, u32 drowpixels, u32 dwidth, u32 dheight, const u32 *source, u32 srowpixels, u32 swidth, u32 sheight, const render_color &color, u32 dx, u32 dy);
static bool copy_png_alpha_to_bitmap(bitmap_argb32 &bitmap, const png_info &png);
/***************************************************************************
RENDER UTILITIES
***************************************************************************/
/*-------------------------------------------------
render_resample_argb_bitmap_hq - perform a high
quality resampling of a texture
-------------------------------------------------*/
void render_resample_argb_bitmap_hq(bitmap_argb32 &dest, bitmap_argb32 &source, const render_color &color, bool force)
{
if (dest.width() == 0 || dest.height() == 0)
return;
/* adjust the source base */
const u32 *sbase = &source.pix32(0);
/* determine the steppings */
u32 swidth = source.width();
u32 sheight = source.height();
u32 dwidth = dest.width();
u32 dheight = dest.height();
u32 dx = (swidth << 12) / dwidth;
u32 dy = (sheight << 12) / dheight;
/* if the source is higher res than the target, use full averaging */
if (dx > 0x1000 || dy > 0x1000 || force)
resample_argb_bitmap_average(&dest.pix(0), dest.rowpixels(), dwidth, dheight, sbase, source.rowpixels(), swidth, sheight, color, dx, dy);
else
resample_argb_bitmap_bilinear(&dest.pix(0), dest.rowpixels(), dwidth, dheight, sbase, source.rowpixels(), swidth, sheight, color, dx, dy);
}
/*-------------------------------------------------
resample_argb_bitmap_average - resample a texture
by performing a true weighted average over
all contributing pixels
-------------------------------------------------*/
static void resample_argb_bitmap_average(u32 *dest, u32 drowpixels, u32 dwidth, u32 dheight, const u32 *source, u32 srowpixels, u32 swidth, u32 sheight, const render_color &color, u32 dx, u32 dy)
{
u64 sumscale = u64(dx) * u64(dy);
u32 r, g, b, a;
u32 x, y;
/* precompute premultiplied R/G/B/A factors */
r = color.r * color.a * 256.0f;
g = color.g * color.a * 256.0f;
b = color.b * color.a * 256.0f;
a = color.a * 256.0f;
/* loop over the target vertically */
for (y = 0; y < dheight; y++)
{
u32 starty = y * dy;
/* loop over the target horizontally */
for (x = 0; x < dwidth; x++)
{
u64 sumr = 0, sumg = 0, sumb = 0, suma = 0;
u32 startx = x * dx;
u32 xchunk, ychunk;
u32 curx, cury;
u32 yremaining = dy;
/* accumulate all source pixels that contribute to this pixel */
for (cury = starty; yremaining; cury += ychunk)
{
u32 xremaining = dx;
/* determine the Y contribution, clamping to the amount remaining */
ychunk = 0x1000 - (cury & 0xfff);
if (ychunk > yremaining)
ychunk = yremaining;
yremaining -= ychunk;
/* loop over all source pixels in the X direction */
for (curx = startx; xremaining; curx += xchunk)
{
u32 factor;
/* determine the X contribution, clamping to the amount remaining */
xchunk = 0x1000 - (curx & 0xfff);
if (xchunk > xremaining)
xchunk = xremaining;
xremaining -= xchunk;
/* total contribution = x * y */
factor = xchunk * ychunk;
/* fetch the source pixel */
rgb_t pix = source[(cury >> 12) * srowpixels + (curx >> 12)];
/* accumulate the RGBA values */
sumr += factor * pix.r();
sumg += factor * pix.g();
sumb += factor * pix.b();
suma += factor * pix.a();
}
}
/* apply scaling */
suma = (suma / sumscale) * a / 256;
sumr = (sumr / sumscale) * r / 256;
sumg = (sumg / sumscale) * g / 256;
sumb = (sumb / sumscale) * b / 256;
/* if we're translucent, add in the destination pixel contribution */
if (a < 256)
{
rgb_t dpix = dest[y * drowpixels + x];
suma += dpix.a() * (256 - a);
sumr += dpix.r() * (256 - a);
sumg += dpix.g() * (256 - a);
sumb += dpix.b() * (256 - a);
}
/* store the target pixel, dividing the RGBA values by the overall scale factor */
dest[y * drowpixels + x] = rgb_t(suma, sumr, sumg, sumb);
}
}
}
/*-------------------------------------------------
resample_argb_bitmap_bilinear - perform texture
sampling via a bilinear filter
-------------------------------------------------*/
static void resample_argb_bitmap_bilinear(u32 *dest, u32 drowpixels, u32 dwidth, u32 dheight, const u32 *source, u32 srowpixels, u32 swidth, u32 sheight, const render_color &color, u32 dx, u32 dy)
{
u32 maxx = swidth << 12, maxy = sheight << 12;
u32 r, g, b, a;
u32 x, y;
/* precompute premultiplied R/G/B/A factors */
r = color.r * color.a * 256.0f;
g = color.g * color.a * 256.0f;
b = color.b * color.a * 256.0f;
a = color.a * 256.0f;
/* loop over the target vertically */
for (y = 0; y < dheight; y++)
{
u32 starty = y * dy;
/* loop over the target horizontally */
for (x = 0; x < dwidth; x++)
{
u32 startx = x * dx;
rgb_t pix0, pix1, pix2, pix3;
u32 sumr, sumg, sumb, suma;
u32 nextx, nexty;
u32 curx, cury;
u32 factor;
/* adjust start to the center; note that this math will tend to produce */
/* negative results on the first pixel, which is why we clamp below */
curx = startx + dx / 2 - 0x800;
cury = starty + dy / 2 - 0x800;
/* compute the neighboring pixel */
nextx = curx + 0x1000;
nexty = cury + 0x1000;
/* fetch the four relevant pixels */
pix0 = pix1 = pix2 = pix3 = 0;
if (s32(cury) >= 0 && cury < maxy && s32(curx) >= 0 && curx < maxx)
pix0 = source[(cury >> 12) * srowpixels + (curx >> 12)];
if (s32(cury) >= 0 && cury < maxy && s32(nextx) >= 0 && nextx < maxx)
pix1 = source[(cury >> 12) * srowpixels + (nextx >> 12)];
if (s32(nexty) >= 0 && nexty < maxy && s32(curx) >= 0 && curx < maxx)
pix2 = source[(nexty >> 12) * srowpixels + (curx >> 12)];
if (s32(nexty) >= 0 && nexty < maxy && s32(nextx) >= 0 && nextx < maxx)
pix3 = source[(nexty >> 12) * srowpixels + (nextx >> 12)];
/* compute the x/y scaling factors */
curx &= 0xfff;
cury &= 0xfff;
/* contributions from pixel 0 (top,left) */
factor = (0x1000 - curx) * (0x1000 - cury);
sumr = factor * pix0.r();
sumg = factor * pix0.g();
sumb = factor * pix0.b();
suma = factor * pix0.a();
/* contributions from pixel 1 (top,right) */
factor = curx * (0x1000 - cury);
sumr += factor * pix1.r();
sumg += factor * pix1.g();
sumb += factor * pix1.b();
suma += factor * pix1.a();
/* contributions from pixel 2 (bottom,left) */
factor = (0x1000 - curx) * cury;
sumr += factor * pix2.r();
sumg += factor * pix2.g();
sumb += factor * pix2.b();
suma += factor * pix2.a();
/* contributions from pixel 3 (bottom,right) */
factor = curx * cury;
sumr += factor * pix3.r();
sumg += factor * pix3.g();
sumb += factor * pix3.b();
suma += factor * pix3.a();
/* apply scaling */
suma = (suma >> 24) * a / 256;
sumr = (sumr >> 24) * r / 256;
sumg = (sumg >> 24) * g / 256;
sumb = (sumb >> 24) * b / 256;
/* if we're translucent, add in the destination pixel contribution */
if (a < 256)
{
rgb_t dpix = dest[y * drowpixels + x];
suma += dpix.a() * (256 - a);
sumr += dpix.r() * (256 - a);
sumg += dpix.g() * (256 - a);
sumb += dpix.b() * (256 - a);
}
/* store the target pixel, dividing the RGBA values by the overall scale factor */
dest[y * drowpixels + x] = rgb_t(suma, sumr, sumg, sumb);
}
}
}
/*-------------------------------------------------
render_clip_line - clip a line to a rectangle
-------------------------------------------------*/
bool render_clip_line(render_bounds *bounds, const render_bounds *clip)
{
/* loop until we get a final result */
while (1)
{
u8 code0 = 0, code1 = 0;
u8 thiscode;
float x, y;
/* compute Cohen Sutherland bits for first coordinate */
if (bounds->y0 > clip->y1)
code0 |= 1;
if (bounds->y0 < clip->y0)
code0 |= 2;
if (bounds->x0 > clip->x1)
code0 |= 4;
if (bounds->x0 < clip->x0)
code0 |= 8;
/* compute Cohen Sutherland bits for second coordinate */
if (bounds->y1 > clip->y1)
code1 |= 1;
if (bounds->y1 < clip->y0)
code1 |= 2;
if (bounds->x1 > clip->x1)
code1 |= 4;
if (bounds->x1 < clip->x0)
code1 |= 8;
/* trivial accept: just return false */
if ((code0 | code1) == 0)
return false;
/* trivial reject: just return true */
if ((code0 & code1) != 0)
return true;
/* fix one of the OOB cases */
thiscode = code0 ? code0 : code1;
/* off the bottom */
if (thiscode & 1)
{
x = bounds->x0 + (bounds->x1 - bounds->x0) * (clip->y1 - bounds->y0) / (bounds->y1 - bounds->y0);
y = clip->y1;
}
/* off the top */
else if (thiscode & 2)
{
x = bounds->x0 + (bounds->x1 - bounds->x0) * (clip->y0 - bounds->y0) / (bounds->y1 - bounds->y0);
y = clip->y0;
}
/* off the right */
else if (thiscode & 4)
{
y = bounds->y0 + (bounds->y1 - bounds->y0) * (clip->x1 - bounds->x0) / (bounds->x1 - bounds->x0);
x = clip->x1;
}
/* off the left */
else
{
y = bounds->y0 + (bounds->y1 - bounds->y0) * (clip->x0 - bounds->x0) / (bounds->x1 - bounds->x0);
x = clip->x0;
}
/* fix the appropriate coordinate */
if (thiscode == code0)
{
bounds->x0 = x;
bounds->y0 = y;
}
else
{
bounds->x1 = x;
bounds->y1 = y;
}
}
}
/*-------------------------------------------------
render_clip_quad - clip a quad to a rectangle
-------------------------------------------------*/
bool render_clip_quad(render_bounds *bounds, const render_bounds *clip, render_quad_texuv *texcoords)
{
/* ensure our assumptions about the bounds are correct */
assert(bounds->x0 <= bounds->x1);
assert(bounds->y0 <= bounds->y1);
/* trivial reject */
if (bounds->y1 < clip->y0)
return true;
if (bounds->y0 > clip->y1)
return true;
if (bounds->x1 < clip->x0)
return true;
if (bounds->x0 > clip->x1)
return true;
/* clip top (x0,y0)-(x1,y1) */
if (bounds->y0 < clip->y0)
{
float frac = (clip->y0 - bounds->y0) / (bounds->y1 - bounds->y0);
bounds->y0 = clip->y0;
if (texcoords != nullptr)
{
texcoords->tl.u += (texcoords->bl.u - texcoords->tl.u) * frac;
texcoords->tl.v += (texcoords->bl.v - texcoords->tl.v) * frac;
texcoords->tr.u += (texcoords->br.u - texcoords->tr.u) * frac;
texcoords->tr.v += (texcoords->br.v - texcoords->tr.v) * frac;
}
}
/* clip bottom (x3,y3)-(x2,y2) */
if (bounds->y1 > clip->y1)
{
float frac = (bounds->y1 - clip->y1) / (bounds->y1 - bounds->y0);
bounds->y1 = clip->y1;
if (texcoords != nullptr)
{
texcoords->bl.u -= (texcoords->bl.u - texcoords->tl.u) * frac;
texcoords->bl.v -= (texcoords->bl.v - texcoords->tl.v) * frac;
texcoords->br.u -= (texcoords->br.u - texcoords->tr.u) * frac;
texcoords->br.v -= (texcoords->br.v - texcoords->tr.v) * frac;
}
}
/* clip left (x0,y0)-(x3,y3) */
if (bounds->x0 < clip->x0)
{
float frac = (clip->x0 - bounds->x0) / (bounds->x1 - bounds->x0);
bounds->x0 = clip->x0;
if (texcoords != nullptr)
{
texcoords->tl.u += (texcoords->tr.u - texcoords->tl.u) * frac;
texcoords->tl.v += (texcoords->tr.v - texcoords->tl.v) * frac;
texcoords->bl.u += (texcoords->br.u - texcoords->bl.u) * frac;
texcoords->bl.v += (texcoords->br.v - texcoords->bl.v) * frac;
}
}
/* clip right (x1,y1)-(x2,y2) */
if (bounds->x1 > clip->x1)
{
float frac = (bounds->x1 - clip->x1) / (bounds->x1 - bounds->x0);
bounds->x1 = clip->x1;
if (texcoords != nullptr)
{
texcoords->tr.u -= (texcoords->tr.u - texcoords->tl.u) * frac;
texcoords->tr.v -= (texcoords->tr.v - texcoords->tl.v) * frac;
texcoords->br.u -= (texcoords->br.u - texcoords->bl.u) * frac;
texcoords->br.v -= (texcoords->br.v - texcoords->bl.v) * frac;
}
}
return false;
}
/*-------------------------------------------------
render_line_to_quad - convert a line and a
width to four points
-------------------------------------------------*/
void render_line_to_quad(const render_bounds *bounds, float width, float length_extension, render_bounds *bounds0, render_bounds *bounds1)
{
render_bounds modbounds = *bounds;
/*
High-level logic -- due to math optimizations, this info is lost below.
Imagine a thick line of width (w), drawn from (p0) to (p1), with a unit
vector (u) indicating the direction from (p0) to (p1).
B C
+---------------- ... ------------------+
| ^ |
| | |
| | |
* (p0) ------------> (w)| * (p1)
| (u) | |
| | |
| v |
+---------------- ... ------------------+
A D
To convert this into a quad, we need to compute the four points A, B, C
and D.
Starting with point A. We first multiply the unit vector by 0.5w and then
rotate the result 90 degrees. Thus, we have:
A.x = p0.x + 0.5 * w * u.x * cos(90) - 0.5 * w * u.y * sin(90)
A.y = p0.y + 0.5 * w * u.x * sin(90) + 0.5 * w * u.y * cos(90)
Conveniently, sin(90) = 1, and cos(90) = 0, so this simplifies to:
A.x = p0.x - 0.5 * w * u.y
A.y = p0.y + 0.5 * w * u.x
Working clockwise around the polygon, the same fallout happens all around as
we rotate the unit vector by -90 (B), -90 (C), and 90 (D) degrees:
B.x = p0.x + 0.5 * w * u.y
B.y = p0.y - 0.5 * w * u.x
C.x = p1.x - 0.5 * w * u.y
C.y = p1.y + 0.5 * w * u.x
D.x = p1.x + 0.5 * w * u.y
D.y = p1.y - 0.5 * w * u.x
*/
/* we only care about the half-width */
float half_width = width * 0.5f;
/* compute a vector from point 0 to point 1 */
float unitx = modbounds.x1 - modbounds.x0;
float unity = modbounds.y1 - modbounds.y0;
/* points just use a +1/+1 unit vector; this gives a nice diamond pattern */
if (unitx == 0 && unity == 0)
{
/* length of a unit vector (1,1) */
float unit_length = 0.70710678f;
unitx = unity = unit_length * half_width;
modbounds.x0 -= unitx;
modbounds.y0 -= unity;
modbounds.x1 += unitx;
modbounds.y1 += unity;
}
/* lines need to be divided by their length */
else
{
float length = sqrtf(unitx * unitx + unity * unity);
/* extend line length */
if (length_extension > 0.0f)
{
float half_length_extension = length_extension *0.5f;
float directionx = unitx / length;
float directiony = unity / length;
modbounds.x0 -= directionx * half_length_extension;
modbounds.y0 -= directiony * half_length_extension;
modbounds.x1 += directionx * half_length_extension;
modbounds.y1 += directiony * half_length_extension;
}
/* prescale unitx and unity by the half-width */
float invlength = half_width / length;
unitx *= invlength;
unity *= invlength;
}
/* rotate the unit vector by 90 degrees and add to point 0 */
bounds0->x0 = modbounds.x0 - unity;
bounds0->y0 = modbounds.y0 + unitx;
/* rotate the unit vector by -90 degrees and add to point 0 */
bounds0->x1 = modbounds.x0 + unity;
bounds0->y1 = modbounds.y0 - unitx;
/* rotate the unit vector by 90 degrees and add to point 1 */
bounds1->x0 = modbounds.x1 - unity;
bounds1->y0 = modbounds.y1 + unitx;
/* rotate the unit vector by -90 degrees and add to point 1 */
bounds1->x1 = modbounds.x1 + unity;
bounds1->y1 = modbounds.y1 - unitx;
}
/*-------------------------------------------------
render_load_jpeg - load a JPG file into a
bitmap
-------------------------------------------------*/
void render_load_jpeg(bitmap_argb32 &bitmap, emu_file &file, const char *dirname, const char *filename)
{
// deallocate previous bitmap
bitmap.reset();
// define file's full name
std::string fname;
if (dirname == nullptr)
fname = filename;
else
fname.assign(dirname).append(PATH_SEPARATOR).append(filename);
if (file.open(fname.c_str()) != osd_file::error::NONE)
return;
// define standard JPEG structures
jpeg_decompress_struct cinfo;
jpeg_error_mgr jerr;
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_decompress(&cinfo);
// allocates a buffer for the image
u32 jpg_size = file.size();
std::unique_ptr<unsigned char[]> jpg_buffer = std::make_unique<unsigned char[]>(jpg_size);
// read data from the file and set them in the buffer
file.read(jpg_buffer.get(), jpg_size);
jpeg_mem_src(&cinfo, jpg_buffer.get(), jpg_size);
// read JPEG header and start decompression
jpeg_read_header(&cinfo, true);
jpeg_start_decompress(&cinfo);
// allocates the destination bitmap
int w = cinfo.output_width;
int h = cinfo.output_height;
int s = cinfo.output_components;
bitmap.allocate(w, h);
// allocates a buffer to receive the information and copy them into the bitmap
int row_stride = cinfo.output_width * cinfo.output_components;
JSAMPARRAY buffer = (JSAMPARRAY)malloc(sizeof(JSAMPROW));
buffer[0] = (JSAMPROW)malloc(sizeof(JSAMPLE) * row_stride);
while ( cinfo.output_scanline < cinfo.output_height )
{
int j = cinfo.output_scanline;
jpeg_read_scanlines(&cinfo, buffer, 1);
if (s == 1)
for (int i = 0; i < w; ++i)
bitmap.pix32(j, i) = rgb_t(0xFF, buffer[0][i], buffer[0][i], buffer[0][i]);
else if (s == 3)
for (int i = 0; i < w; ++i)
bitmap.pix32(j, i) = rgb_t(0xFF, buffer[0][i * s], buffer[0][i * s + 1], buffer[0][i * s + 2]);
else
{
osd_printf_error("Cannot read JPEG data from %s file.\n", fname.c_str());
bitmap.reset();
break;
}
}
// finish decompression and frees the memory
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
file.close();
free(buffer[0]);
free(buffer);
}
/*-------------------------------------------------
render_load_png - load a PNG file into a
bitmap
-------------------------------------------------*/
bool render_load_png(bitmap_argb32 &bitmap, emu_file &file, const char *dirname, const char *filename, bool load_as_alpha_to_existing)
{
// deallocate if we're not overlaying alpha
if (!load_as_alpha_to_existing)
bitmap.reset();
// open the file
std::string fname;
if (dirname)
fname.assign(dirname).append(PATH_SEPARATOR).append(filename);
else
fname.assign(filename);
osd_file::error const filerr = file.open(fname.c_str());
if (filerr != osd_file::error::NONE)
return false;
// read the PNG data
png_info png;
png_error const result = png.read_file(file);
file.close();
if (result != PNGERR_NONE)
{
osd_printf_error("%s: Error reading PNG file\n", filename);
return false;
}
// if less than 8 bits, upsample
if (PNGERR_NONE != png.expand_buffer_8bit())
{
osd_printf_error("%s: Error upsampling PNG bitmap\n", filename);
return false;
}
bool hasalpha = false;
if (!load_as_alpha_to_existing)
{
// non-alpha case
if (PNGERR_NONE != png.copy_to_bitmap(bitmap, hasalpha))
{
osd_printf_error("%s: Error copying PNG bitmap to MAME bitmap\n", filename);
return false;
}
}
else if (png.width == bitmap.width() && png.height == bitmap.height())
{
// verify we can handle this PNG
if (png.bit_depth > 8)
{
osd_printf_error("%s: Unsupported bit depth %d (8 bit max)\n", filename, png.bit_depth);
return false;
}
// alpha case
hasalpha = copy_png_alpha_to_bitmap(bitmap, png);
}
// free PNG data
return hasalpha;
}
/*-------------------------------------------------
copy_png_alpha_to_bitmap - copy the PNG data
to the alpha channel of a bitmap
-------------------------------------------------*/
static bool copy_png_alpha_to_bitmap(bitmap_argb32 &bitmap, const png_info &png)
{
// FIXME: this function is basically copy/pasted from the PNG code in util, and should be unified with it
u8 accumalpha = 0xff;
// colour format table
static constexpr unsigned samples[] = { 1, 0, 3, 1, 2, 0, 4 };
// adam7 interlace tables
static constexpr unsigned x_bias[7] = { 7, 3, 3, 1, 1, 0, 0 };
static constexpr unsigned y_bias[7] = { 7, 7, 3, 3, 1, 1, 0 };
static constexpr unsigned x_shift[7] = { 3, 3, 2, 2, 1, 1, 0 };
static constexpr unsigned y_shift[7] = { 3, 3, 3, 2, 2, 1, 1 };
unsigned const pass_count(png.interlace_method ? 7 : 1);
u32 pass_offset[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
for (unsigned pass = 0; pass_count > pass; ++pass)
{
// calculate offset for next interlace pass
u32 const width(png.interlace_method ? ((png.width + x_bias[pass]) >> x_shift[pass]) : png.width);
u32 const height(png.interlace_method ? ((png.height + y_bias[pass]) >> y_shift[pass]) : png.height);
u32 const rowbytes(((width * samples[png.color_type] * png.bit_depth) + 7) >> 3);
pass_offset[pass + 1] = pass_offset[pass] + (height * (rowbytes + 1));
u8 const *src(&png.image[pass_offset[pass]]);
auto const x_trans = [offs = (1 << x_shift[pass]) - x_bias[pass] - 1, shift = x_shift[pass]] (u32 x) { return (x << shift) + offs; };
auto const y_trans = [offs = (1 << y_shift[pass]) - y_bias[pass] - 1, shift = y_shift[pass]] (u32 y) { return (y << shift) + offs; };
if (png.color_type == 3)
{
// handle 8bpp palettized case
for (u32 y = 0; height > y; ++y)
{
for (u32 x = 0; width > x; ++x, ++src)
{
bitmap_argb32::pixel_t &dest(png.interlace_method ? bitmap.pix32(y_trans(y), x_trans(x)) : bitmap.pix32(y, x));
rgb_t const pixel(dest);
u8 const alpha(rgb_t(png.palette[*src * 3], png.palette[*src * 3 + 1], png.palette[*src * 3 + 2]).brightness());
accumalpha &= alpha;
dest = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b());
}
}
}
else if (png.color_type == 0)
{
// handle 8bpp grayscale non-alpha case
for (u32 y = 0; height > y; ++y)
{
for (u32 x = 0; width > x; ++x, ++src)
{
bitmap_argb32::pixel_t &dest(png.interlace_method ? bitmap.pix32(y_trans(y), x_trans(x)) : bitmap.pix32(y, x));
rgb_t const pixel(dest);
accumalpha &= *src;
dest = rgb_t(*src, pixel.r(), pixel.g(), pixel.b());
}
}
}
else if (png.color_type == 4)
{
// handle 8bpp grayscale alpha case
for (u32 y = 0; height > y; ++y)
{
for (u32 x = 0; width > x; ++x, src += 2)
{
bitmap_argb32::pixel_t &dest(png.interlace_method ? bitmap.pix32(y_trans(y), x_trans(x)) : bitmap.pix32(y, x));
rgb_t const pixel(dest);
accumalpha &= *src;
dest = rgb_t(*src, pixel.r(), pixel.g(), pixel.b());
}
}
}
else if (png.color_type == 2)
{
// handle 32bpp non-alpha case
for (u32 y = 0; height > y; ++y)
{
for (u32 x = 0; width > x; ++x, src += 3)
{
bitmap_argb32::pixel_t &dest(png.interlace_method ? bitmap.pix32(y_trans(y), x_trans(x)) : bitmap.pix32(y, x));
rgb_t const pixel(dest);
u8 const alpha(rgb_t(src[0], src[1], src[2]).brightness());
accumalpha &= alpha;
dest = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b());
}
}
}
else
{
// handle 32bpp alpha case
for (u32 y = 0; height > y; ++y)
{
for (u32 x = 0; width > x; ++x, src += 4)
{
bitmap_argb32::pixel_t &dest(png.interlace_method ? bitmap.pix32(y_trans(y), x_trans(x)) : bitmap.pix32(y, x));
rgb_t const pixel(dest);
u8 const alpha(rgb_t(src[0], src[1], src[2]).brightness());
accumalpha &= alpha;
dest = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b());
}
}
}
}
// set the hasalpha flag
return (accumalpha != 0xff);
}
/*-------------------------------------------------
render_detect_image - detect image format
-------------------------------------------------*/
ru_imgformat render_detect_image(emu_file &file, const char *dirname, const char *filename)
{
// open the file
std::string fname;
if (dirname)
fname.assign(dirname).append(PATH_SEPARATOR).append(filename);
else
fname.assign(filename);
osd_file::error const filerr = file.open(fname.c_str());
if (filerr != osd_file::error::NONE)
return RENDUTIL_IMGFORMAT_ERROR;
// PNG: check for valid header
png_error const result = png_info::verify_header(file);
if (result == PNGERR_NONE)
{
file.close();
return RENDUTIL_IMGFORMAT_PNG;
}
file.seek(0, SEEK_SET);
// TODO: add more when needed
file.close();
return RENDUTIL_IMGFORMAT_UNKNOWN;
}