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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "common/std/memory.h"
#include "ags/shared/core/platform.h"
#include "ags/engine/gfx/gfx_util.h"
#include "ags/engine/gfx/blender.h"
namespace AGS3 {
namespace AGS {
namespace Engine {
using namespace Shared;
namespace GfxUtil {
Bitmap *ConvertBitmap(Bitmap *src, int dst_color_depth) {
int src_col_depth = src->GetColorDepth();
if (src_col_depth != dst_color_depth) {
int old_conv = get_color_conversion();
// TODO: find out what is this, and why do we need to call this every time (do we?)
set_color_conversion(COLORCONV_KEEP_TRANS | COLORCONV_TOTAL);
Bitmap *dst = BitmapHelper::CreateBitmapCopy(src, dst_color_depth);
set_color_conversion(old_conv);
return dst;
}
return src;
}
struct BlendModeSetter {
// Blender setter for destination with and without alpha channel;
// assign kRgbToRgbBlender if not supported
BlenderMode AllAlpha; // src w alpha -> dst w alpha
BlenderMode AlphaToOpaque; // src w alpha -> dst w/o alpha
BlenderMode OpaqueToAlpha; // src w/o alpha -> dst w alpha
BlenderMode OpaqueToAlphaNoTrans; // src w/o alpha -> dst w alpha (opt-ed for no transparency)
BlenderMode AllOpaque; // src w/o alpha -> dst w/o alpha
};
// Array of blender descriptions
// NOTE: set kRgbToRgbBlender to fallback to common image blitting
static const BlendModeSetter BlendModeSets[kNumBlendModes] = {
{ kRgbToRgbBlender, kRgbToRgbBlender, kRgbToRgbBlender, kRgbToRgbBlender, kRgbToRgbBlender }, // kBlendMode_NoAlpha
{ kArgbToArgbBlender, kArgbToRgbBlender, kRgbToArgbBlender, kOpaqueBlenderMode, kRgbToRgbBlender }, // kBlendMode_Alpha
// NOTE: add new modes here
};
bool SetBlender(BlendMode blend_mode, bool dst_has_alpha, bool src_has_alpha, int blend_alpha) {
if (blend_mode < 0 || blend_mode >= kNumBlendModes)
return false;
const BlendModeSetter &set = BlendModeSets[blend_mode];
BlenderMode blender;
if (dst_has_alpha)
blender = src_has_alpha ? set.AllAlpha :
(blend_alpha == 0xFF ? set.OpaqueToAlphaNoTrans : set.OpaqueToAlpha);
else
blender = src_has_alpha ? set.AlphaToOpaque : set.AllOpaque;
set_blender_mode(blender, 0, 0, 0, blend_alpha);
return true;
}
void DrawSpriteBlend(Bitmap *ds, const Point &ds_at, Bitmap *sprite,
BlendMode blend_mode, bool dst_has_alpha, bool src_has_alpha, int blend_alpha) {
if (blend_alpha <= 0)
return; // do not draw 100% transparent image
if (// support only 32-bit blending at the moment
ds->GetColorDepth() == 32 && sprite->GetColorDepth() == 32 &&
// set blenders if applicable and tell if succeeded
SetBlender(blend_mode, dst_has_alpha, src_has_alpha, blend_alpha)) {
ds->TransBlendBlt(sprite, ds_at.X, ds_at.Y);
} else {
GfxUtil::DrawSpriteWithTransparency(ds, sprite, ds_at.X, ds_at.Y, blend_alpha);
}
}
void DrawSpriteWithTransparency(Bitmap *ds, Bitmap *sprite, int x, int y, int alpha) {
if (alpha <= 0) {
// fully transparent, don't draw it at all
return;
}
const int surface_depth = ds->GetColorDepth();
const int sprite_depth = sprite->GetColorDepth();
// Allegro does not support masked blit or blend between different formats
// *except* when drawing 8-bit sprites onto a higher dest.
std::unique_ptr<Bitmap> conv_bm;
if ((surface_depth != sprite_depth) && (sprite_depth > 8)) {
// use ConvertBitmap in order to keep mask pixels
conv_bm.reset(ConvertBitmap(sprite, surface_depth));
sprite = conv_bm.get();
}
if ((alpha < 0xFF) && (surface_depth > 8) && (sprite_depth > 8)) {
set_trans_blender(0, 0, 0, alpha);
ds->TransBlendBlt(sprite, x, y);
} else {
ds->Blit(sprite, x, y, kBitmap_Transparency);
}
}
} // namespace GfxUtil
} // namespace Engine
} // namespace AGS
} // namespace AGS3
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