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author | 2015-11-08 12:56:12 +0100 | |
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committer | 2015-11-08 12:56:12 +0100 | |
commit | 7c19aac60e12d6f5ea301bdb34d7826a01e0b06f (patch) | |
tree | f310d86aa2c6bfc19d115307dedde4eb0cd52dad /src/emu/rendutil.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/emu/rendutil.cpp')
-rw-r--r-- | src/emu/rendutil.cpp | 731 |
1 files changed, 731 insertions, 0 deletions
diff --git a/src/emu/rendutil.cpp b/src/emu/rendutil.cpp new file mode 100644 index 00000000000..872533583b5 --- /dev/null +++ b/src/emu/rendutil.cpp @@ -0,0 +1,731 @@ +// 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" + + + +/*************************************************************************** + FUNCTION PROTOTYPES +***************************************************************************/ + +/* utilities */ +static void resample_argb_bitmap_average(UINT32 *dest, UINT32 drowpixels, UINT32 dwidth, UINT32 dheight, const UINT32 *source, UINT32 srowpixels, UINT32 swidth, UINT32 sheight, const render_color &color, UINT32 dx, UINT32 dy); +static void resample_argb_bitmap_bilinear(UINT32 *dest, UINT32 drowpixels, UINT32 dwidth, UINT32 dheight, const UINT32 *source, UINT32 srowpixels, UINT32 swidth, UINT32 sheight, const render_color &color, UINT32 dx, UINT32 dy); +static bool copy_png_to_bitmap(bitmap_argb32 &bitmap, const png_info *png); +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) +{ + if (dest.width() == 0 || dest.height() == 0) + return; + + /* adjust the source base */ + const UINT32 *sbase = &source.pix32(0); + + /* determine the steppings */ + UINT32 swidth = source.width(); + UINT32 sheight = source.height(); + UINT32 dwidth = dest.width(); + UINT32 dheight = dest.height(); + UINT32 dx = (swidth << 12) / dwidth; + UINT32 dy = (sheight << 12) / dheight; + + /* if the source is higher res than the target, use full averaging */ + if (dx > 0x1000 || dy > 0x1000) + 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(UINT32 *dest, UINT32 drowpixels, UINT32 dwidth, UINT32 dheight, const UINT32 *source, UINT32 srowpixels, UINT32 swidth, UINT32 sheight, const render_color &color, UINT32 dx, UINT32 dy) +{ + UINT64 sumscale = (UINT64)dx * (UINT64)dy; + UINT32 r, g, b, a; + UINT32 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++) + { + UINT32 starty = y * dy; + + /* loop over the target horizontally */ + for (x = 0; x < dwidth; x++) + { + UINT64 sumr = 0, sumg = 0, sumb = 0, suma = 0; + UINT32 startx = x * dx; + UINT32 xchunk, ychunk; + UINT32 curx, cury; + + UINT32 yremaining = dy; + + /* accumulate all source pixels that contribute to this pixel */ + for (cury = starty; yremaining; cury += ychunk) + { + UINT32 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) + { + UINT32 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(UINT32 *dest, UINT32 drowpixels, UINT32 dwidth, UINT32 dheight, const UINT32 *source, UINT32 srowpixels, UINT32 swidth, UINT32 sheight, const render_color &color, UINT32 dx, UINT32 dy) +{ + UINT32 maxx = swidth << 12, maxy = sheight << 12; + UINT32 r, g, b, a; + UINT32 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++) + { + UINT32 starty = y * dy; + + /* loop over the target horizontally */ + for (x = 0; x < dwidth; x++) + { + UINT32 startx = x * dx; + rgb_t pix0, pix1, pix2, pix3; + UINT32 sumr, sumg, sumb, suma; + UINT32 nextx, nexty; + UINT32 curx, cury; + UINT32 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 ((INT32)cury >= 0 && cury < maxy && (INT32)curx >= 0 && curx < maxx) + pix0 = source[(cury >> 12) * srowpixels + (curx >> 12)]; + if ((INT32)cury >= 0 && cury < maxy && (INT32)nextx >= 0 && nextx < maxx) + pix1 = source[(cury >> 12) * srowpixels + (nextx >> 12)]; + if ((INT32)nexty >= 0 && nexty < maxy && (INT32)curx >= 0 && curx < maxx) + pix2 = source[(nexty >> 12) * srowpixels + (curx >> 12)]; + if ((INT32)nexty >= 0 && nexty < maxy && (INT32)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 +-------------------------------------------------*/ + +int render_clip_line(render_bounds *bounds, const render_bounds *clip) +{ + /* loop until we get a final result */ + while (1) + { + UINT8 code0 = 0, code1 = 0; + UINT8 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 +-------------------------------------------------*/ + +int 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 != NULL) + { + 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 != NULL) + { + 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 != NULL) + { + 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 != NULL) + { + 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, render_bounds *bounds0, render_bounds *bounds1) +{ + render_bounds modbounds = *bounds; + float unitx, unity; + + /* + 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 */ + width *= 0.5f; + + /* compute a vector from point 0 to point 1 */ + unitx = modbounds.x1 - modbounds.x0; + unity = modbounds.y1 - modbounds.y0; + + /* points just use a +1/+1 unit vector; this gives a nice diamond pattern */ + if (unitx == 0 && unity == 0) + { + unitx = unity = 0.70710678f * width; + modbounds.x0 -= 0.5f * unitx; + modbounds.y0 -= 0.5f * unity; + modbounds.x1 += 0.5f * unitx; + modbounds.y1 += 0.5f * unity; + } + + /* lines need to be divided by their length */ + else + { + /* prescale unitx and unity by the half-width */ + float invlength = width / sqrtf(unitx * unitx + unity * unity); + 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 -09 degrees and add to point 1 */ + bounds1->x1 = modbounds.x1 + unity; + bounds1->y1 = modbounds.y1 - unitx; +} + + +/*------------------------------------------------- + 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 == NULL) + fname.assign(filename); + else + fname.assign(dirname).append(PATH_SEPARATOR).append(filename); + file_error filerr = file.open(fname.c_str()); + if (filerr != FILERR_NONE) + return false; + + // read the PNG data + png_info png; + png_error result = png_read_file(file, &png); + file.close(); + if (result != PNGERR_NONE) + return false; + + // 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); + png_free(&png); + return false; + } + if (png.interlace_method != 0) + { + osd_printf_error("%s: Interlace unsupported\n", filename); + png_free(&png); + return false; + } + if (png.color_type != 0 && png.color_type != 3 && png.color_type != 2 && png.color_type != 6) + { + osd_printf_error("%s: Unsupported color type %d\n", filename, png.color_type); + png_free(&png); + return false; + } + + // if less than 8 bits, upsample + png_expand_buffer_8bit(&png); + + // non-alpha case + bool hasalpha = false; + if (!load_as_alpha_to_existing) + { + bitmap.allocate(png.width, png.height); + hasalpha = copy_png_to_bitmap(bitmap, &png); + } + + // alpha case + else if (png.width == bitmap.width() && png.height == bitmap.height()) + hasalpha = copy_png_alpha_to_bitmap(bitmap, &png); + + // free PNG data + png_free(&png); + return hasalpha; +} + + +/*------------------------------------------------- + copy_png_to_bitmap - copy the PNG data to a + bitmap +-------------------------------------------------*/ + +static bool copy_png_to_bitmap(bitmap_argb32 &bitmap, const png_info *png) +{ + UINT8 accumalpha = 0xff; + UINT8 *src; + int x, y; + + /* handle 8bpp palettized case */ + if (png->color_type == 3) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src++) + { + /* determine alpha and expand to 32bpp */ + UINT8 alpha = (*src < png->num_trans) ? png->trans[*src] : 0xff; + accumalpha &= alpha; + bitmap.pix32(y, x) = rgb_t(alpha, png->palette[*src * 3], png->palette[*src * 3 + 1], png->palette[*src * 3 + 2]); + } + } + + /* handle 8bpp grayscale case */ + else if (png->color_type == 0) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src++) + bitmap.pix32(y, x) = rgb_t(0xff, *src, *src, *src); + } + + /* handle 32bpp non-alpha case */ + else if (png->color_type == 2) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src += 3) + bitmap.pix32(y, x) = rgb_t(0xff, src[0], src[1], src[2]); + } + + /* handle 32bpp alpha case */ + else + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src += 4) + { + accumalpha &= src[3]; + bitmap.pix32(y, x) = rgb_t(src[3], src[0], src[1], src[2]); + } + } + + /* set the hasalpha flag */ + return (accumalpha != 0xff); +} + + +/*------------------------------------------------- + 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) +{ + UINT8 accumalpha = 0xff; + UINT8 *src; + int x, y; + + /* handle 8bpp palettized case */ + if (png->color_type == 3) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src++) + { + rgb_t pixel = bitmap.pix32(y, x); + UINT8 alpha = rgb_t(png->palette[*src * 3], png->palette[*src * 3 + 1], png->palette[*src * 3 + 2]).brightness(); + accumalpha &= alpha; + bitmap.pix32(y, x) = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b()); + } + } + + /* handle 8bpp grayscale case */ + else if (png->color_type == 0) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src++) + { + rgb_t pixel = bitmap.pix32(y, x); + accumalpha &= *src; + bitmap.pix32(y, x) = rgb_t(*src, pixel.r(), pixel.g(), pixel.b()); + } + } + + /* handle 32bpp non-alpha case */ + else if (png->color_type == 2) + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src += 3) + { + rgb_t pixel = bitmap.pix32(y, x); + UINT8 alpha = rgb_t(src[0], src[1], src[2]).brightness(); + accumalpha &= alpha; + bitmap.pix32(y, x) = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b()); + } + } + + /* handle 32bpp alpha case */ + else + { + /* loop over width/height */ + src = png->image; + for (y = 0; y < png->height; y++) + for (x = 0; x < png->width; x++, src += 4) + { + rgb_t pixel = bitmap.pix32(y, x); + UINT8 alpha = rgb_t(src[0], src[1], src[2]).brightness(); + accumalpha &= alpha; + bitmap.pix32(y, x) = rgb_t(alpha, pixel.r(), pixel.g(), pixel.b()); + } + } + + /* set the hasalpha flag */ + return (accumalpha != 0xff); +} |