add 'fill_image' script function, rename 'offset' combine mode to 'lightmap'

doc/function/fill_image.txt

@@ -0,0 +1,14 @@
+Function: fill_image
+
+DOC_MSE_VERSION: since 2.6.0
+
+--Usage--
+> fill_image(input: image, color: color)
+
+Fill an image with a single color, but keep the alpha channel unchanged.
+
+
+--Parameters--
+! Parameter	Type			Description
+| @input@	[[type:image]]		Image to fill.
+| @color@	[[type:color]]		Color to fill with.

doc/function/index.txt

@@ -86,6 +86,7 @@ These functions are built into the program, other [[type:function]]s can be defi
 | [[fun:set_mask]]		Set the transparancy mask of an image.
 | [[fun:set_alpha]]		Change the transparency of an image.
 | [[fun:set_combine]]		Change how the image should be combined with the background.
+| [[fun:fill_image]]		Fill an image with a single color.
 | [[fun:saturate_image]]		Saturate/desaturate an image.
 | [[fun:brighten_image]]		Brighten/darken an image.
 | [[fun:invert_image]]		Invert the colors of an image.

src/gfx/combine_image.cpp

@@ -42,7 +42,8 @@ String combine_to_string(const ImageCombine& combine) {
     case COMBINE_OR:                  return "or";
     case COMBINE_XOR:                 return "xor";
     case COMBINE_SHADOW:              return "shadow";
-    case COMBINE_OFFSET:              return "offset";
+    case COMBINE_LIGHTMAP_ABSOLUTE:   return "lightmap absolute";
+    case COMBINE_LIGHTMAP_RELATIVE:   return "lightmap relative";
     case COMBINE_SYMMETRIC_OVERLAY:   return "symmetric overlay";
     case COMBINE_BRIGHTNESS_TO_ALPHA: return "brightness to alpha";
     case COMBINE_DARKNESS_TO_ALPHA:   return "darkness to alpha";
@@ -175,7 +176,8 @@ IMPLEMENT_REFLECTION_ENUM(ImageCombine) {
   VALUE_N("or",                  COMBINE_OR);
   VALUE_N("xor",                 COMBINE_XOR);
   VALUE_N("shadow",              COMBINE_SHADOW);
-  VALUE_N("offset",              COMBINE_OFFSET);
+  VALUE_N("lightmap absolute",   COMBINE_LIGHTMAP_ABSOLUTE);
+  VALUE_N("lightmap relative",   COMBINE_LIGHTMAP_RELATIVE);
   VALUE_N("symmetric overlay",   COMBINE_SYMMETRIC_OVERLAY);
   VALUE_N("brightness to alpha", COMBINE_BRIGHTNESS_TO_ALPHA);
   VALUE_N("darkness to alpha",   COMBINE_DARKNESS_TO_ALPHA);
@@ -308,12 +310,12 @@ COMBINE_FUN(COMBINE_LIGHTEN,     max(a, b))
 COMBINE_FUN(COMBINE_COLOR_DODGE,         b == 255 ? 255 : top(a * 255 / (255 - b)))
 COMBINE_FUN(COMBINE_COLOR_BURN,          b == 0   ? 0   : bot(255 - (255-a) * 255 / b))
 COMBINE_FUN(COMBINE_SCREEN,              255 - (((255 - a) * (255 - b)) / 255))
-COMBINE_FUN(COMBINE_OVERLAY,  a < 128
+COMBINE_FUN(COMBINE_OVERLAY,             a < 128 ?
-                  ? (a * b) >> 7
+                                         (a * b) >> 7 :
-                  : 255 - (((255 - a) * (255 - b)) >> 7))
+                                         255 - (((255 - a) * (255 - b)) >> 7))
-COMBINE_FUN(COMBINE_HARD_LIGHT,  b < 128
+COMBINE_FUN(COMBINE_HARD_LIGHT,          b < 128 ?
-                  ? (a * b) >> 7
+                                         (a * b) >> 7 :
-                  : 255 - (((255 - a) * (255 - b)) >> 7))
+                                         255 - (((255 - a) * (255 - b)) >> 7))
 COMBINE_FUN(COMBINE_SOFT_LIGHT,          b)
 COMBINE_FUN(COMBINE_REFLECT,             b == 255 ? 255 : top(a * a / (255 - b)))
 COMBINE_FUN(COMBINE_GLOW,                a == 255 ? 255 : top(b * b / (255 - a)))
@@ -323,7 +325,10 @@ COMBINE_FUN(COMBINE_AND,         a & b)
 COMBINE_FUN(COMBINE_OR,                  a | b)
 COMBINE_FUN(COMBINE_XOR,                 a ^ b)
 COMBINE_FUN(COMBINE_SHADOW,              (b * a * a) / (255 * 255))
-COMBINE_FUN(COMBINE_OFFSET,      col(a + b - 128))
+COMBINE_FUN(COMBINE_LIGHTMAP_ABSOLUTE,   col(a + b - 128))
+COMBINE_FUN(COMBINE_LIGHTMAP_RELATIVE,   b < 128 ?
+                                         a * b / 128 :
+                                         a + (255 - a) * (b - 128) / 128)
 COMBINE_FUN(COMBINE_SYMMETRIC_OVERLAY,   (Combine<COMBINE_OVERLAY>::f(a, b) + Combine<COMBINE_OVERLAY>::f(b, a)) / 2)
 COMBINE_FUN(COMBINE_BRIGHTNESS_TO_ALPHA, ((255 - a) * a + a * b) / 255)
 COMBINE_FUN(COMBINE_DARKNESS_TO_ALPHA,   (255 * a + (255 - a) * b) / 255)
@@ -480,7 +485,8 @@ void combine_image(Image& a, const Image& b, ImageCombine combine) {
     DISPATCH(COMBINE_OR);
     DISPATCH(COMBINE_XOR);
     DISPATCH(COMBINE_SHADOW);
-    DISPATCH(COMBINE_OFFSET);
+    DISPATCH(COMBINE_LIGHTMAP_ABSOLUTE);
+    DISPATCH(COMBINE_LIGHTMAP_RELATIVE);
     DISPATCH(COMBINE_SYMMETRIC_OVERLAY);
     DISPATCH(COMBINE_BRIGHTNESS_TO_ALPHA);
     DISPATCH(COMBINE_DARKNESS_TO_ALPHA);

src/gfx/generated_image.cpp

@@ -188,6 +188,19 @@ bool SetCombineImage::operator == (const GeneratedImage& that) const {
     && image_combine == that2->image_combine;
 }
 
+// ----------------------------------------------------------------------------- : FillImage
+
+Image FillImage::generate(const Options& opt) {
+  Image img = image->generate(opt);
+  fill_image(img, color);
+  return img;
+}
+bool FillImage::operator == (const GeneratedImage& that) const {
+  const FillImage* that2 = dynamic_cast<const FillImage*>(&that);
+  return that2 && *image == *that2->image
+    && color == that2->color;
+}
+
 // ----------------------------------------------------------------------------- : SaturateImage
 
 Image SaturateImage::generate(const Options& opt) {

src/gfx/generated_image.hpp

@@ -189,6 +189,20 @@ private:
   ImageCombine image_combine;
 };
 
+// ----------------------------------------------------------------------------- : FillImage
+
+/// Fill an image with a given color, without touching the alpha channel
+class FillImage : public SimpleFilterImage {
+public:
+  inline FillImage(const GeneratedImageP& image, Color color)
+    : SimpleFilterImage(image), color(color)
+  {}
+  Image generate(const Options& opt) override;
+  bool operator == (const GeneratedImage& that) const override;
+private:
+  Color color;
+};
+
 // ----------------------------------------------------------------------------- : SaturateImage
 
 /// Saturate/desaturate an image

src/gfx/gfx.hpp

@@ -144,7 +144,8 @@ enum ImageCombine
 ,  COMBINE_OR
 ,  COMBINE_XOR
 ,  COMBINE_SHADOW
-,  COMBINE_OFFSET
+,  COMBINE_LIGHTMAP_ABSOLUTE
+,  COMBINE_LIGHTMAP_RELATIVE
 ,  COMBINE_SYMMETRIC_OVERLAY
 ,  COMBINE_BRIGHTNESS_TO_ALPHA
 ,  COMBINE_DARKNESS_TO_ALPHA

src/script/functions/image.cpp

@@ -162,6 +162,12 @@ SCRIPT_FUNCTION(set_combine) {
   return make_intrusive<SetCombineImage>(input, image_combine);
 }
 
+SCRIPT_FUNCTION(fill_image) {
+  SCRIPT_PARAM_C(GeneratedImageP, input);
+  SCRIPT_PARAM(Color, color);
+  return make_intrusive<FillImage>(input,color);
+}
+
 SCRIPT_FUNCTION(saturate) {
   SCRIPT_PARAM_C(GeneratedImageP, input);
   SCRIPT_PARAM(double, amount);
@@ -349,6 +355,7 @@ void init_script_image_functions(Context& ctx) {
   ctx.setVariable(_("set_mask"),         script_set_mask);
   ctx.setVariable(_("set_alpha"),        script_set_alpha);
   ctx.setVariable(_("set_combine"),      script_set_combine);
+  ctx.setVariable(_("fill_image"),       script_fill_image);
   ctx.setVariable(_("saturate"),         script_saturate);
   ctx.setVariable(_("saturate_image"),   script_saturate);
   ctx.setVariable(_("brighten_image"),   script_brighten_image);