AGS 4: support alpha-blending DrawingSurface operations

Common/CMakeLists.txt

@@ -88,6 +88,8 @@ target_sources(common
     gfx/bitmap.h
     gfx/bitmapdata.cpp
     gfx/bitmapdata.h
+    gfx/blender.cpp
+    gfx/blender.h
     gfx/gfx_def.h
     gfx/image_file.cpp
     gfx/image_file.h

Common/font/ttffontrenderer.cpp

@@ -17,6 +17,7 @@
 #include "core/platform.h"
 #include "core/assetmanager.h"
 #include "font/fonts.h"
+#include "gfx/blender.h"
 #include "util/stream.h"
 
 using namespace AGS::Common;
@@ -63,11 +64,23 @@ void TTFFontRenderer::RenderText(const char *text, int fontNumber, BITMAP *desti
   if (y > destination->cb)  // optimisation
     return;
 
+  // Check if this is a alpha-blending case, and init corresponding draw mode
+  const bool alpha_blend = (bitmap_color_depth(destination) == 32) && (geta32(colour) != 0xFF);
+  if (alpha_blend)
+  {
+    alfont_blend_mode(_argb2argb_blender);
+  }
+
   // Y - 1 because it seems to get drawn down a bit
   if ((ShouldAntiAliasText()) && (bitmap_color_depth(destination) > 8))
     alfont_textout_aa(destination, _fontData[fontNumber].AlFont, text, x, y - 1, colour);
   else
     alfont_textout(destination, _fontData[fontNumber].AlFont, text, x, y - 1, colour);
+
+  if (alpha_blend)
+  {
+    alfont_blend_mode(nullptr);
+  }
 }
 
 bool TTFFontRenderer::LoadFromDisk(int fontNumber, int fontSize)

Common/font/wfnfontrenderer.cpp

@@ -18,6 +18,7 @@
 #include "debug/out.h"
 #include "font/wfnfont.h"
 #include "gfx/bitmap.h"
+#include "gfx/blender.h"
 #include "util/stream.h"
 
 using namespace AGS::Common;
@@ -88,6 +89,14 @@ static int RenderChar(Bitmap *ds, const int at_x, const int at_y, Rect clip,
   const unsigned char *actdata = wfn_char.Data;
   const int bytewid = wfn_char.GetRowByteCount();
 
+  // Check if this is a alpha-blending case, and init corresponding draw mode
+  const bool alpha_blend = (ds->GetColorDepth() == 32) && (geta32(text_color) != 0xFF);
+  if (alpha_blend)
+  {
+    drawing_mode(DRAW_MODE_TRANS, nullptr, 0, 0);
+    set_argb2any_blender();
+  }
+
   int sx = std::max(at_x, clip.Left), ex = clip.Right + 1;
   int sy = std::max(at_y, clip.Top), ey = clip.Bottom + 1;
   int sw = std::max(0, clip.Left - at_x);
@@ -102,13 +111,23 @@ static int RenderChar(Bitmap *ds, const int at_x, const int at_y, Rect clip,
         {
           ds->FillRect(RectWH(x, y, scale, scale), text_color);
         } 
+        else if (alpha_blend)
+        {
+          ds->BlendPixel(x, y, text_color);
+        }
         else
         {
           ds->PutPixel(x, y, text_color);
         }
       }
     }
   }
+
+  if (alpha_blend)
+  {
+    drawing_mode(DRAW_MODE_SOLID, nullptr, 0, 0);
+  }
+
   return width * scale;
 }
 

Common/gfx/allegrobitmap.cpp

@@ -429,11 +429,43 @@ void Bitmap::PutPixel(int x, int y, color_t color)
 		return _putpixel24(_alBitmap, x, y, color);
 	case 32:
 		return _putpixel32(_alBitmap, x, y, color);
+	default: assert(0); // this should not normally happen
 	}
-    assert(0); // this should not normally happen
 	return putpixel(_alBitmap, x, y, color);
 }
 
+// hack into allegro...
+extern "C" {
+    extern BLENDER_FUNC _blender_func15;
+    extern BLENDER_FUNC _blender_func16;
+    extern BLENDER_FUNC _blender_func24;
+    extern BLENDER_FUNC _blender_func32;
+}
+
+void Bitmap::BlendPixel(int x, int y, color_t color)
+{
+    if (x < 0 || x >= _alBitmap->w || y < 0 || y >= _alBitmap->h)
+    {
+        return;
+    }
+
+    switch (bitmap_color_depth(_alBitmap))
+    {
+    case 8:
+        return _putpixel(_alBitmap, x, y, color);
+    case 15:
+        return _putpixel15(_alBitmap, x, y, _blender_func15(color, _getpixel15(_alBitmap, x, y), 0xFF));
+    case 16:
+        return _putpixel16(_alBitmap, x, y, _blender_func16(color, _getpixel16(_alBitmap, x, y), 0xFF));
+    case 24:
+        return _putpixel24(_alBitmap, x, y, _blender_func24(color, _getpixel24(_alBitmap, x, y), 0xFF));
+    case 32:
+        return _putpixel32(_alBitmap, x, y, _blender_func32(color, _getpixel32(_alBitmap, x, y), 0xFF));
+    default: assert(0); // this should not normally happen
+    }
+    return putpixel(_alBitmap, x, y, color);
+}
+
 int Bitmap::GetPixel(int x, int y) const
 {
     if (x < 0 || x >= _alBitmap->w || y < 0 || y >= _alBitmap->h)

Common/gfx/allegrobitmap.h

@@ -237,6 +237,7 @@ class Bitmap
     // blocks of bitmap memory - reading/writing from/to scan lines should be
     // done in such cases.
     void	PutPixel(int x, int y, color_t color);
+    void    BlendPixel(int x, int y, color_t color);
     int		GetPixel(int x, int y) const;
 
     //=========================================================================

Common/libsrc/alfont-2.0.9/alfont.c

@@ -74,6 +74,7 @@ struct ALFONT_FONT {
 BITMAP *default_bmp; //Draw Font on default BITMAP;
 static FT_Library ft_library;
 static int alfont_textmode = 0;
+static BLENDER_FUNC alfont_blend_func = NULL;
 static int alfont_inited = 0;
 
 
@@ -710,6 +711,12 @@ int alfont_text_mode(int mode) {
   return old_mode;
 }
 
+BLENDER_FUNC alfont_blend_mode(BLENDER_FUNC blend_func) {
+  BLENDER_FUNC old_func = alfont_blend_func;
+  alfont_blend_func = blend_func;
+  return old_func;
+}
+
 
 void alfont_destroy_font(ALFONT_FONT *f) {
   if (f == NULL)
@@ -982,7 +989,13 @@ void alfont_textout_aa_ex(BITMAP *bmp, ALFONT_FONT *f, const char *s, int x, int
   }
 
   //build transparency
-  if (f->transparency!=255) {
+  if (alfont_blend_func!=NULL) {
+	  if (bitmap_color_depth(bmp) > 8) {
+		  drawing_mode(DRAW_MODE_TRANS, NULL, 0, 0);
+		  set_blender_mode(NULL, NULL, alfont_blend_func, 0, 0, 0, f->transparency);
+	  }
+  }
+  else if (f->transparency!=255) {
 	  if (bitmap_color_depth(bmp)>8) {
 		drawing_mode(DRAW_MODE_TRANS,NULL,0,0);
 		set_preservedalpha_trans_blender(0,0,0,f->transparency);
@@ -2156,7 +2169,13 @@ void alfont_textout_ex(BITMAP *bmp, ALFONT_FONT *f, const char *s, int x, int y,
   }
 
   //build transparency
-  if (f->transparency!=255) {
+  if (alfont_blend_func!=NULL) {
+	  if (bitmap_color_depth(bmp) > 8) {
+		  drawing_mode(DRAW_MODE_TRANS, NULL, 0, 0);
+		  set_blender_mode(NULL, NULL, alfont_blend_func, 0, 0, 0, f->transparency);
+	  }
+  }
+  else if (f->transparency!=255) {
 	  if (bitmap_color_depth(bmp)>8) {
 		drawing_mode(DRAW_MODE_TRANS,NULL,0,0);
 		set_preservedalpha_trans_blender(0,0,0,f->transparency);

Common/libsrc/alfont-2.0.9/alfont.h

@@ -80,6 +80,7 @@ ALFONT_DLL_DECLSPEC int alfont_get_font_real_height(ALFONT_FONT *f);
 ALFONT_DLL_DECLSPEC void alfont_get_font_real_vextent(ALFONT_FONT *f, int *top, int *bottom);
 
 ALFONT_DLL_DECLSPEC int alfont_text_mode(int mode);
+ALFONT_DLL_DECLSPEC BLENDER_FUNC alfont_blend_mode(BLENDER_FUNC blend_func);
 
 ALFONT_DLL_DECLSPEC void alfont_textout_aa(BITMAP *bmp, ALFONT_FONT *f, const char *s, int x, int y, int color);
 ALFONT_DLL_DECLSPEC void alfont_textout(BITMAP *bmp, ALFONT_FONT *f, const char *s, int x, int y, int color);

Engine/CMakeLists.txt

@@ -285,8 +285,6 @@ target_sources(engine
     gfx/ali3dogl.h
     gfx/ali3dsw.cpp
     gfx/ali3dsw.h
-    gfx/blender.cpp
-    gfx/blender.h
     gfx/ddb.h
     gfx/gfx_util.cpp
     gfx/gfx_util.h

Engine/ac/drawingsurface.cpp

@@ -204,24 +204,12 @@ void DrawingSurface_BlendSurface(ScriptDrawingSurface* target, ScriptDrawingSurf
 
 void DrawingSurface_SetDrawingColor(ScriptDrawingSurface *sds, int newColour) 
 {
-    sds->currentColourScript = newColour;
-    // StartDrawing to set up ds to set the colour at the appropriate
-    // depth for the background
-    Bitmap *ds = sds->StartDrawing();
-    if (newColour == SCR_COLOR_TRANSPARENT)
-    {
-        sds->currentColour = ds->GetMaskColor();
-    }
-    else
-    {
-        sds->currentColour = ds->GetCompatibleColor(newColour);
-    }
-    sds->FinishedDrawingReadOnly();
+    sds->SetDrawingColor(newColour);
 }
 
 int DrawingSurface_GetDrawingColor(ScriptDrawingSurface *sds)
 {
-    return sds->currentColourScript;
+    return sds->GetScriptDrawingColor();
 }
 
 int DrawingSurface_GetHeight(ScriptDrawingSurface *sds) 
@@ -244,7 +232,7 @@ int DrawingSurface_GetColorDepth(ScriptDrawingSurface *sds)
 
 void DrawingSurface_Clear(ScriptDrawingSurface *sds, int colour)
 {
-    Bitmap *ds = sds->StartDrawing();
+    Bitmap *ds = sds->StartDrawing(); // clear is always done in solid mode
     int allegroColor;
     if (colour == SCR_COLOR_TRANSPARENT)
     {
@@ -260,33 +248,29 @@ void DrawingSurface_Clear(ScriptDrawingSurface *sds, int colour)
 
 void DrawingSurface_DrawCircle(ScriptDrawingSurface *sds, int x, int y, int radius)
 {
-    Bitmap *ds = sds->StartDrawing();
-    ds->FillCircle(Circle(x, y, radius), sds->currentColour);
-    sds->FinishedDrawing();
+    Bitmap *ds = sds->StartDrawingWithBrush();
+    ds->FillCircle(Circle(x, y, radius), sds->GetRealDrawingColor());
+    sds->FinishedDrawingWithBrush();
 }
 
 void DrawingSurface_DrawRectangle(ScriptDrawingSurface *sds, int x1, int y1, int x2, int y2)
 {
-    Bitmap *ds = sds->StartDrawing();
-    ds->FillRect(Rect(x1,y1,x2,y2), sds->currentColour);
-    sds->FinishedDrawing();
+    Bitmap *ds = sds->StartDrawingWithBrush();
+    ds->FillRect(Rect(x1,y1,x2,y2), sds->GetRealDrawingColor());
+    sds->FinishedDrawingWithBrush();
 }
 
 void DrawingSurface_DrawTriangle(ScriptDrawingSurface *sds, int x1, int y1, int x2, int y2, int x3, int y3)
 {
-    Bitmap *ds = sds->StartDrawing();
-    ds->DrawTriangle(Triangle(x1,y1,x2,y2,x3,y3), sds->currentColour);
-    sds->FinishedDrawing();
+    Bitmap *ds = sds->StartDrawingWithBrush();
+    ds->DrawTriangle(Triangle(x1,y1,x2,y2,x3,y3), sds->GetRealDrawingColor());
+    sds->FinishedDrawingWithBrush();
 }
 
 void DrawingSurface_DrawString(ScriptDrawingSurface *sds, int xx, int yy, int font, const char* text)
 {
-    Bitmap *ds = sds->StartDrawing();
-    color_t text_color = sds->currentColour;
-    if ((ds->GetColorDepth() <= 8) && (text_color > 255)) {
-        text_color = GUI::GetStandardColorForBitmap(1);
-        debug_script_warn ("DrawingSurface.DrawString: Attempted to use color %d on 256-col surface", text_color);
-    }
+    Bitmap *ds = sds->StartDrawing(); // no need to use "brush", blending is done by font renderer
+    color_t text_color = sds->GetRealDrawingColor();
     String res_str = GUI::ApplyTextDirection(text);
     wouttext_outline(ds, xx, yy, font, text_color, res_str.GetCStr());
     sds->FinishedDrawing();
@@ -299,8 +283,8 @@ void DrawingSurface_DrawStringWrapped(ScriptDrawingSurface *sds, int xx, int yy,
     if (break_up_text_into_lines(draw_text, Lines, wid, font) == 0)
         return;
 
-    Bitmap *ds = sds->StartDrawing();
-    color_t text_color = sds->currentColour;
+    Bitmap *ds = sds->StartDrawing(); // no need to use "brush", blending is done by font renderer
+    color_t text_color = sds->GetRealDrawingColor();
 
     for (size_t i = 0; i < Lines.Count(); i++)
     {
@@ -313,9 +297,9 @@ void DrawingSurface_DrawStringWrapped(ScriptDrawingSurface *sds, int xx, int yy,
 
 void DrawingSurface_DrawLine(ScriptDrawingSurface *sds, int fromx, int fromy, int tox, int toy, int thickness) {
     int ii,jj,xx,yy;
-    Bitmap *ds = sds->StartDrawing();
+    Bitmap *ds = sds->StartDrawingWithBrush();
     // draw several lines to simulate the thickness
-    color_t draw_color = sds->currentColour;
+    color_t draw_color = sds->GetRealDrawingColor();
     for (ii = 0; ii < thickness; ii++) 
     {
         xx = (ii - (thickness / 2));
@@ -325,27 +309,24 @@ void DrawingSurface_DrawLine(ScriptDrawingSurface *sds, int fromx, int fromy, in
             ds->DrawLine (Line(fromx + xx, fromy + yy, tox + xx, toy + yy), draw_color);
         }
     }
-    sds->FinishedDrawing();
+    sds->FinishedDrawingWithBrush();
 }
 
 void DrawingSurface_DrawPixel(ScriptDrawingSurface *sds, int x, int y) {
-    int thickness = 1;
-    int ii,jj;
     Bitmap *ds = sds->StartDrawing();
-    // draw several pixels to simulate the thickness
-    color_t draw_color = sds->currentColour;
-    for (ii = 0; ii < thickness; ii++) 
+    if (sds->IsAlphaBlending())
     {
-        for (jj = 0; jj < thickness; jj++)
-        {
-            ds->PutPixel(x + ii, y + jj, draw_color);
-        }
+        ds->BlendPixel(x, y, sds->GetRealDrawingColor());
+    }
+    else
+    {
+        ds->PutPixel(x, y, sds->GetRealDrawingColor());
     }
     sds->FinishedDrawing();
 }
 
 int DrawingSurface_GetPixel(ScriptDrawingSurface *sds, int x, int y) {
-    Bitmap *ds = sds->StartDrawing();
+    Bitmap *ds = sds->StartDrawingReadOnly();
     int rawPixel = ds->GetPixel(x, y);
     int maskColor = ds->GetMaskColor();
     int colDepth = ds->GetColorDepth();

Engine/ac/dynamicsprite.cpp

@@ -362,7 +362,7 @@ ScriptDynamicSprite* DynamicSprite_CreateFromDrawingSurface(ScriptDrawingSurface
         height = std::max(1, height);
     }
 
-    Bitmap *ds = sds->StartDrawing();
+    Bitmap *ds = sds->StartDrawingReadOnly();
     if ((x < 0) || (y < 0) || (x + width > ds->GetWidth()) || (y + height > ds->GetHeight()))
         quit("!DynamicSprite.CreateFromDrawingSurface: requested area is outside the surface");