Scripting: Export new image masking function

include/mgba-util/image.h

@@ -138,6 +138,7 @@ void mPainterInit(struct mPainter*, struct mImage* backing);
 void mPainterDrawRectangle(struct mPainter*, int x, int y, int width, int height);
 void mPainterDrawLine(struct mPainter*, int x1, int y1, int x2, int y2);
 void mPainterDrawCircle(struct mPainter*, int x, int y, int diameter);
+void mPainterDrawMask(struct mPainter*, const struct mImage* mask, int x, int y);
 
 uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat to);
 uint32_t mImageColorConvert(uint32_t color, const struct mImage* from, enum mColorFormat to);

res/scripts/color-mask.lua

@@ -0,0 +1,34 @@
+local state = {}
+state.wheel = image.load(script.dir .. "/wheel.png")
+state.overlay = canvas:newLayer(state.wheel.width, state.wheel.height)
+state.painter = image.newPainter(state.overlay.image)
+state.phase = 0
+state.speed = 0.01
+state.painter:setFill(true)
+state.painter:setStrokeWidth(0)
+
+function state.update()
+	local r = math.fmod(state.phase * 3, math.pi * 2)
+	local g = math.fmod(state.phase * 5, math.pi * 2)
+	local b = math.fmod(state.phase * 7, math.pi * 2)
+	local color = 0xFF000000
+	color = color | math.floor((math.sin(r) + 1) * 127.5) << 16
+	color = color | math.floor((math.sin(g) + 1) * 127.5) << 8
+	color = color | math.floor((math.sin(b) + 1) * 127.5)
+
+	-- Clear image
+	state.painter:setBlend(false)
+	state.painter:setFillColor(0)
+	state.painter:drawRectangle(0, 0, state.wheel.width, state.wheel.height)
+	-- Draw mask
+	state.painter:setBlend(true)
+	state.painter:setFillColor(color | 0xFF000000)
+	state.painter:drawMask(state.wheel, 0, 0)
+
+	state.overlay:update()
+	state.phase = math.fmod(state.phase + state.speed, math.pi * 2 * 3 * 5 * 7)
+end
+
+callbacks:add("frame", state.update)
+
+

res/scripts/logo-bounce.lua

@@ -1,44 +1,61 @@
 math.randomseed(os.time())
 local state = {}
-state.logo = image.load(script.dir .. "/logo.png")
+state.logo_fg = image.load(script.dir .. "/logo-fg.png")
-state.overlay = canvas:newLayer(state.logo.width, state.logo.height)
+state.logo_bg = image.load(script.dir .. "/logo-bg.png")
-state.overlay.image:drawImageOpaque(state.logo, 0, 0)
+state.overlay = canvas:newLayer(state.logo_fg.width, state.logo_fg.height)
-state.x = math.random() * (canvas:screenWidth() - state.logo.width)
+state.x = math.random() * (canvas:screenWidth() - state.logo_fg.width)
-state.y = math.random() * (canvas:screenHeight() - state.logo.height)
+state.y = math.random() * (canvas:screenHeight() - state.logo_fg.height)
+state.overlay:setPosition(math.floor(state.x), math.floor(state.y))
 state.direction = math.floor(math.random() * 3)
 state.speed = 0.5
 
-state.overlay:setPosition(math.floor(state.x), math.floor(state.y))
+function state.recolor()
-state.overlay:update()
+	local r = math.floor(math.random() * 255)
+	local g = math.floor(math.random() * 255)
+	local b = math.floor(math.random() * 255)
+	local color = 0xFF000000 | (r << 16) | (g << 8) | b
+	state.overlay.image:drawImageOpaque(state.logo_bg, 0, 0)
+	local painter = image.newPainter(state.overlay.image)
+	painter:setFill(true)
+	painter:setFillColor(color)
+	painter:setBlend(true)
+	painter:drawMask(state.logo_fg, 0, 0)
+	state.overlay:update()
+end
 
 function state.update()
 	if state.direction & 1 == 1 then
 		state.x = state.x + 1
-		if state.x > canvas:screenWidth() - state.logo.width then
+		if state.x > canvas:screenWidth() - state.logo_fg.width then
-			state.x = (canvas:screenWidth() - state.logo.width) * 2 - state.x
+			state.x = (canvas:screenWidth() - state.logo_fg.width) * 2 - state.x
 			state.direction = state.direction ~ 1
+			state.recolor()
 		end
 	else
 		state.x = state.x - 1
 		if state.x < 0 then
 			state.x = -state.x
 			state.direction = state.direction ~ 1
+			state.recolor()
 		end
 	end
 	if state.direction & 2 == 2 then
 		state.y = state.y + 1
-		if state.y > canvas:screenHeight() - state.logo.height then
+		if state.y > canvas:screenHeight() - state.logo_fg.height then
-			state.y = (canvas:screenHeight() - state.logo.height) * 2 - state.y
+			state.y = (canvas:screenHeight() - state.logo_fg.height) * 2 - state.y
 			state.direction = state.direction ~ 2
+			state.recolor()
 		end
 	else
 		state.y = state.y - 1
 		if state.y < 0 then
 			state.y = -state.y
 			state.direction = state.direction ~ 2
+			state.recolor()
 		end
 	end
 	state.overlay:setPosition(math.floor(state.x), math.floor(state.y))
 end
 
+state.recolor()
 callbacks:add("frame", state.update)

src/script/image.c

@@ -141,6 +141,7 @@ mSCRIPT_DECLARE_STRUCT_VOID_METHOD(mPainter, setStrokeColor, _mPainterSetStrokeC
 mSCRIPT_DECLARE_STRUCT_VOID_METHOD(mPainter, drawRectangle, mPainterDrawRectangle, 4, S32, x, S32, y, S32, width, S32, height);
 mSCRIPT_DECLARE_STRUCT_VOID_METHOD(mPainter, drawLine, mPainterDrawLine, 4, S32, x1, S32, y1, S32, x2, S32, y2);
 mSCRIPT_DECLARE_STRUCT_VOID_METHOD(mPainter, drawCircle, mPainterDrawCircle, 3, S32, x, S32, y, S32, diameter);
+mSCRIPT_DECLARE_STRUCT_VOID_METHOD(mPainter, drawMask, mPainterDrawMask, 3, CS(mImage), mask, S32, x, S32, y);
 
 mSCRIPT_DEFINE_STRUCT(mPainter)
 	mSCRIPT_DEFINE_CLASS_DOCSTRING(
@@ -162,6 +163,13 @@ mSCRIPT_DEFINE_STRUCT(mPainter)
 	mSCRIPT_DEFINE_STRUCT_METHOD(mPainter, drawLine)
 	mSCRIPT_DEFINE_DOCSTRING("Draw a circle with the specified diameter with the given origin at the top-left corner of the bounding box")
 	mSCRIPT_DEFINE_STRUCT_METHOD(mPainter, drawCircle)
+	mSCRIPT_DEFINE_DOCSTRING(
+		"Draw a mask image with each color channel multiplied by the current fill color. This can "
+		"be useful for displaying graphics with dynamic colors. By making a grayscale template "
+		"image on a transparent background in advance, a script can set the fill color to a desired "
+		"target color and use this function to draw it into a destination image."
+	)
+	mSCRIPT_DEFINE_STRUCT_METHOD(mPainter, drawMask)
 mSCRIPT_DEFINE_END;
 
 mSCRIPT_DECLARE_STRUCT_METHOD(mScriptPainter, W(mPainter), _get, _mScriptPainterGet, 1, CHARP, name);

src/util/image.c

@@ -42,6 +42,53 @@
 	memcpy((void*) (DST), &_color, (DEPTH)); \
 } while (0);
 
+static uint32_t _mColorMultiply(uint32_t colorA, uint32_t colorB) {
+	uint32_t color = 0;
+
+	uint32_t a, b;
+	a = colorA & 0xFF;
+	b = colorB & 0xFF;
+	b = a * b;
+	b /= 0xFF;
+	if (b > 0xFF) {
+		color |= 0xFF;
+	} else {
+		color |= b;
+	}
+
+	a = (colorA >> 8) & 0xFF;
+	b = (colorB >> 8) & 0xFF;
+	b = a * b;
+	b /= 0xFF;
+	if (b > 0xFF) {
+		color |= 0xFF00;
+	} else {
+		color |= b << 8;
+	}
+
+	a = (colorA >> 16) & 0xFF;
+	b = (colorB >> 16) & 0xFF;
+	b = a * b;
+	b /= 0xFF;
+	if (b > 0xFF) {
+		color |= 0xFF0000;
+	} else {
+		color |= b << 16;
+	}
+
+	a = (colorA >> 24) & 0xFF;
+	b = (colorB >> 24) & 0xFF;
+	b = a * b;
+	b /= 0xFF;
+	if (b > 0xFF) {
+		color |= 0xFF000000;
+	} else {
+		color |= b << 24;
+	}
+
+	return color;
+}
+
 struct mImage* mImageCreate(unsigned width, unsigned height, enum mColorFormat format) {
 	return mImageCreateWithStride(width, height, width, format);
 }
@@ -395,18 +442,18 @@ void mImageSetPaletteEntry(struct mImage* image, unsigned index, uint32_t color)
 	image->palette[index] = color;
 }
 
-#define COMPOSITE_BOUNDS_INIT \
+#define COMPOSITE_BOUNDS_INIT(SOURCE, DEST) \
 	struct mRectangle dstRect = { \
 		.x = 0, \
 		.y = 0, \
-		.width = image->width, \
+		.width = (DEST)->width, \
-		.height = image->height \
+		.height = (DEST)->height \
 	}; \
 	struct mRectangle srcRect = { \
 		.x = x, \
 		.y = y, \
-		.width = source->width, \
+		.width = (SOURCE)->width, \
-		.height = source->height \
+		.height = (SOURCE)->height \
 	}; \
 	if (!mRectangleIntersection(&srcRect, &dstRect)) { \
 		return; \
@@ -436,7 +483,7 @@ void mImageBlit(struct mImage* image, const struct mImage* source, int x, int y)
 		return;
 	}
 
-	COMPOSITE_BOUNDS_INIT;
+	COMPOSITE_BOUNDS_INIT(source, image);
 
 	for (y = 0; y < srcRect.height; ++y) {
 		uintptr_t srcPixel = (uintptr_t) PIXEL(source, srcStartX, srcStartY + y);
@@ -461,7 +508,7 @@ void mImageComposite(struct mImage* image, const struct mImage* source, int x, i
 		return;
 	}
 
-	COMPOSITE_BOUNDS_INIT;
+	COMPOSITE_BOUNDS_INIT(source, image);
 
 	for (y = 0; y < srcRect.height; ++y) {
 		uintptr_t srcPixel = (uintptr_t) PIXEL(source, srcStartX, srcStartY + y);
@@ -498,7 +545,7 @@ void mImageCompositeWithAlpha(struct mImage* image, const struct mImage* source,
 		alpha = 256;
 	}
 
-	COMPOSITE_BOUNDS_INIT;
+	COMPOSITE_BOUNDS_INIT(source, image);
 
 	int fixedAlpha = alpha * 0x200;
 
@@ -821,6 +868,33 @@ void mPainterDrawCircle(struct mPainter* painter, int x, int y, int diameter) {
 	}
 }
 
+void mPainterDrawMask(struct mPainter* painter, const struct mImage* mask, int x, int y) {
+	if (!painter->fill) {
+		return;
+	}
+
+	COMPOSITE_BOUNDS_INIT(mask, painter->backing);
+
+	for (y = 0; y < srcRect.height; ++y) {
+		uintptr_t dstPixel = (uintptr_t) PIXEL(painter->backing, dstStartX, dstStartY + y);
+		uintptr_t maskPixel = (uintptr_t) PIXEL(mask, srcStartX, srcStartY + y);
+		for (x = 0; x < srcRect.width; ++x, dstPixel += painter->backing->depth, maskPixel += mask->depth) {
+			uint32_t color;
+			GET_PIXEL(color, maskPixel, mask->depth);
+			color = mColorConvert(color, mask->format, mCOLOR_ARGB8);
+			color = _mColorMultiply(painter->fillColor, color);
+			if (painter->blend || painter->fillColor < 0xFF000000) {
+				uint32_t current;
+				GET_PIXEL(current, dstPixel, painter->backing->depth);
+				current = mColorConvert(current, painter->backing->format, mCOLOR_ARGB8);
+				color = mColorMixARGB8(color, current);
+			}
+			color = mColorConvert(color, mCOLOR_ARGB8, painter->backing->format);
+			PUT_PIXEL(color, dstPixel, painter->backing->depth);
+		}
+	}
+}
+
 uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat to) {
 	if (from == to) {
 		return color;

src/util/test/image.c

@@ -2038,6 +2038,97 @@ M_TEST_DEFINE(painterDrawCircleInvalid) {
 	mImageDestroy(image);
 }
 
+M_TEST_DEFINE(painterDrawMask) {
+	struct mImage* image;
+	struct mImage* mask;
+	struct mPainter painter;
+
+	image = mImageCreate(4, 4, mCOLOR_XRGB8);
+	mPainterInit(&painter, image);
+	painter.blend = false;
+	painter.fill = true;
+
+	mask = mImageCreate(2, 2, mCOLOR_XRGB8);
+	mImageSetPixel(mask, 0, 0, 0xFFFFFFFF);
+	mImageSetPixel(mask, 1, 0, 0xFFFF0000);
+	mImageSetPixel(mask, 0, 1, 0xFF00FF00);
+	mImageSetPixel(mask, 1, 1, 0xFF0000FF);
+
+	painter.fillColor = 0xFFFFFFFF;
+	mPainterDrawMask(&painter, mask, 0, 0);
+	painter.fillColor = 0xFFFF0000;
+	mPainterDrawMask(&painter, mask, 2, 0);
+	painter.fillColor = 0xFF00FF00;
+	mPainterDrawMask(&painter, mask, 0, 2);
+	painter.fillColor = 0xFF0000FF;
+	mPainterDrawMask(&painter, mask, 2, 2);
+
+	COMPARE4X(0xFFFFFF, 0xFF0000, 0xFF0000, 0xFF0000,
+			  0x00FF00, 0x0000FF, 0x000000, 0x000000,
+			  0x00FF00, 0x000000, 0x0000FF, 0x000000,
+			  0x00FF00, 0x000000, 0x000000, 0x0000FF);
+
+	painter.fillColor = 0xFF808080;
+	mPainterDrawMask(&painter, mask, 0, 0);
+	painter.fillColor = 0xFFFFFF00;
+	mPainterDrawMask(&painter, mask, 2, 0);
+	painter.fillColor = 0xFF00FFFF;
+	mPainterDrawMask(&painter, mask, 0, 2);
+	painter.fillColor = 0xFFFF00FF;
+	mPainterDrawMask(&painter, mask, 2, 2);
+
+	COMPARE4X(0x808080, 0x800000, 0xFFFF00, 0xFF0000,
+			  0x008000, 0x000080, 0x00FF00, 0x000000,
+			  0x00FFFF, 0x000000, 0xFF00FF, 0xFF0000,
+			  0x00FF00, 0x0000FF, 0x000000, 0x0000FF);
+
+	painter.fillColor = 0xFFFFFFFF;
+	mPainterDrawMask(&painter, mask, -1, -1);
+	mPainterDrawMask(&painter, mask, 3, 3);
+	assert_int_equal(0xFF0000FF, mImageGetPixel(image, 0, 0));
+	assert_int_equal(0xFFFFFFFF, mImageGetPixel(image, 3, 3));
+
+	mImageDestroy(image);
+	mImageDestroy(mask);
+}
+
+M_TEST_DEFINE(painterDrawMaskBlend) {
+	struct mImage* image;
+	struct mImage* mask;
+	struct mPainter painter;
+	const uint8_t lut[4] = { 0x00, 0x55, 0xAA, 0xFF };
+	int x, y;
+
+	image = mImageCreate(4, 4, mCOLOR_XRGB8);
+	mPainterInit(&painter, image);
+	painter.blend = true;
+	painter.fill = true;
+	painter.fillColor = 0xFFFF8000;
+
+	for (y = 0; y < 4; ++y) {
+		for (x = 0; x < 4; ++x) {
+			mImageSetPixel(image, x, y, 0xFF808080);
+		}
+	}
+
+	mask = mImageCreate(4, 4, mCOLOR_ARGB8);
+	for (y = 0; y < 4; ++y) {
+		for (x = 0; x < 4; ++x) {
+			mImageSetPixel(mask, x, y, (lut[x] << 24) | (lut[y] * 0x010101));
+		}
+	}
+
+	mPainterDrawMask(&painter, mask, 0, 0);
+
+	COMPARE4X(0x808080, 0x555555, 0x2A2A2A, 0x000000,
+			  0x808080, 0x716355, 0x63462A, 0x552A00,
+			  0x808080, 0x8E7155, 0x9C632A, 0xAA5500,
+			  0x808080, 0xAA8055, 0xD4802A, 0xFF8000);
+
+	mImageDestroy(image);
+	mImageDestroy(mask);
+}
+
 #undef COMPARE3X
 #undef COMPARE3
 #undef COMPARE4X
@@ -2083,4 +2174,6 @@ M_TEST_SUITE_DEFINE(Image,
 	cmocka_unit_test(painterDrawCircleOffset),
 	cmocka_unit_test(painterDrawCircleBlend),
 	cmocka_unit_test(painterDrawCircleInvalid),
+	cmocka_unit_test(painterDrawMask),
+	cmocka_unit_test(painterDrawMaskBlend),
 )