From 1856e677a3bf45cebcebec201ed127804db3e569 Mon Sep 17 00:00:00 2001
From: Amaryllis Kulla <ancurio@mapleshrine.eu>
Date: Fri, 5 Nov 2021 18:18:43 +0100
Subject: [PATCH] Bitmap: Add ::writeToPng()

---
 binding-mri/bitmap-binding.cpp | 14 ++++++++++++++
 src/bitmap.cpp                 | 33 +++++++++++++++++++++------------
 src/bitmap.h                   |  3 +++
 3 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/binding-mri/bitmap-binding.cpp b/binding-mri/bitmap-binding.cpp
index 49e0093..11a0697 100644
--- a/binding-mri/bitmap-binding.cpp
+++ b/binding-mri/bitmap-binding.cpp
@@ -433,6 +433,18 @@ RB_METHOD(bitmapInitializeCopy)
 	return self;
 }
 
+RB_METHOD(bitmapWriteToPng)
+{
+	Bitmap *b = getPrivateData<Bitmap>(self);
+	const char *filename;
+
+	rb_get_args(argc, argv, "z", &filename RB_ARG_END);
+
+	b->writeToPng(filename);
+
+	return self;
+}
+
 
 void
 bitmapBindingInit()
@@ -466,5 +478,7 @@ bitmapBindingInit()
 	_rb_define_method(klass, "radial_blur",        bitmapRadialBlur);
 	}
 
+	_rb_define_method(klass, "write_to_png", bitmapWriteToPng);
+
 	INIT_PROP_BIND(Bitmap, Font, "font");
 }
diff --git a/src/bitmap.cpp b/src/bitmap.cpp
index a2f27be..cec61bb 100644
--- a/src/bitmap.cpp
+++ b/src/bitmap.cpp
@@ -245,6 +245,20 @@ struct BitmapPrivate
 
 		self->modified();
 	}
+
+	void downloadToSurface()
+	{
+		if (!surface)
+			allocSurface();
+
+		FBO::bind(gl.fbo);
+
+		glState.viewport.pushSet(IntRect(0, 0, gl.width, gl.height));
+
+		::gl.ReadPixels(0, 0, gl.width, gl.height, GL_RGBA, GL_UNSIGNED_BYTE, surface->pixels);
+
+		glState.viewport.pop();
+	}
 };
 
 struct BitmapOpenHandler : FileSystem::OpenHandler
@@ -900,18 +914,7 @@ Color Bitmap::getPixel(int x, int y) const
 	if (x < 0 || y < 0 || x >= width() || y >= height())
 		return Vec4();
 
-	if (!p->surface)
-	{
-		p->allocSurface();
-
-		FBO::bind(p->gl.fbo);
-
-		glState.viewport.pushSet(IntRect(0, 0, width(), height()));
-
-		gl.ReadPixels(0, 0, width(), height(), GL_RGBA, GL_UNSIGNED_BYTE, p->surface->pixels);
-
-		glState.viewport.pop();
-	}
+	p->downloadToSurface();
 
 	uint32_t pixel = getPixelAt(p->surface, p->format, x, y);
 
@@ -1400,6 +1403,12 @@ void Bitmap::setInitFont(Font *value)
 	p->font = value;
 }
 
+void Bitmap::writeToPng(const char *filename)
+{
+	p->downloadToSurface();
+	IMG_SavePNG(p->surface, filename);
+}
+
 TEXFBO &Bitmap::getGLTypes()
 {
 	return p->gl;
diff --git a/src/bitmap.h b/src/bitmap.h
index b744911..68bb7f9 100644
--- a/src/bitmap.h
+++ b/src/bitmap.h
@@ -105,6 +105,9 @@ public:
 	 * use at construction */
 	void setInitFont(Font *value);
 
+	/* extensions */
+	void writeToPng(const char *filename);
+
 	/* <internal> */
 	TEXFBO &getGLTypes();
 	SDL_Surface *megaSurface() const;