Added love.graphics.setColorMask(r, g, b, a) and love.graphics.getColorMask()

setColorMask enables or disables specific color components when rendering and clearing the screen.
For example, setColorMask(true, false, true, true) will prevent the green component of the color of all rendered objects from being written to the current frame buffer.
setColorMask is a wrapper for http://www.opengl.org/sdk/docs/man2/xhtml/glColorMask.xml

--HG--
branch : love.graphics.setColorMask

src/modules/graphics/opengl/Graphics.cpp

@@ -86,6 +86,9 @@ DisplayState Graphics::saveState()
 	if (s.scissor)
 		glGetIntegerv(GL_SCISSOR_BOX, s.scissorBox);
 
+	for (int i = 0; i < 4; i++)
+		s.colorMask[i] = colorMask[i];
+
 	return s;
 }
 
@@ -101,6 +104,7 @@ void Graphics::restoreState(const DisplayState &s)
 		setScissor(s.scissorBox[0], s.scissorBox[1], s.scissorBox[2], s.scissorBox[3]);
 	else
 		setScissor();
+	setColorMask(s.colorMask[0], s.colorMask[1], s.colorMask[2], s.colorMask[3]);
 }
 
 bool Graphics::setMode(int width, int height, bool fullscreen, bool vsync, int fsaa)
@@ -136,6 +140,9 @@ bool Graphics::setMode(int width, int height, bool fullscreen, bool vsync, int f
 	// "Normal" blending
 	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
+	// Enable all color component writes.
+	setColorMask(true, true, true, true);
+
 	// Enable line/point smoothing.
 	setLineStyle(LINE_SMOOTH);
 	glEnable(GL_POINT_SMOOTH);
@@ -331,12 +338,12 @@ void Graphics::useStencil(bool invert)
 {
 	glStencilFunc(GL_EQUAL, (int)(!invert), 1); // invert ? 0 : 1
 	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
-	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+	setColorMask(colorMask[0], colorMask[1], colorMask[2], colorMask[3]);
 }
 
 void Graphics::discardStencil()
 {
-	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+	setColorMask(colorMask[0], colorMask[1], colorMask[2], colorMask[3]);
 	glDisable(GL_STENCIL_TEST);
 }
 
@@ -500,6 +507,21 @@ Font *Graphics::getFont() const
 	return currentFont;
 }
 
+void Graphics::setColorMask(bool r, bool g, bool b, bool a)
+{
+	colorMask[0] = r;
+	colorMask[1] = g;
+	colorMask[2] = b;
+	colorMask[3] = a;
+
+	glColorMask((GLboolean) r, (GLboolean) g, (GLboolean) b, (GLboolean) a);
+}
+
+const bool *Graphics::getColorMask() const
+{
+	return colorMask;
+}
+
 void Graphics::setBlendMode(Graphics::BlendMode mode)
 {
 	if (GLEE_VERSION_1_4 || GLEE_ARB_imaging)

src/modules/graphics/opengl/Graphics.h

@@ -76,6 +76,9 @@ struct DisplayState
 	bool scissor;
 	GLint scissorBox[4];
 
+	// Color mask.
+	bool colorMask[4];
+
 	// Window info.
 	std::string caption;
 	bool mouseVisible;
@@ -94,6 +97,7 @@ struct DisplayState
 		pointSize = 1.0f;
 		pointStyle = Graphics::POINT_SMOOTH;
 		scissor = false;
+		colorMask[0] = colorMask[1] = colorMask[2] = colorMask[3] = true;
 		caption = "";
 		mouseVisible = true;
 	}
@@ -303,6 +307,17 @@ public:
 	 **/
 	Font *getFont() const;
 
+	/**
+	 * Sets the enabled color components when rendering.
+	 **/
+	void setColorMask(bool r, bool g, bool b, bool a);
+
+	/**
+	 * Gets the current color mask.
+	 * Returns an array of 4 booleans representing the mask.
+	 **/
+	const bool *getColorMask() const;
+
 	/**
 	 * Sets the current blend mode.
 	 **/
@@ -521,6 +536,7 @@ private:
 	float lineWidth;
 	GLint matrixLimit;
 	GLint userMatrices;
+	bool colorMask[4];
 
 	int getRenderHeight() const;
 }; // Graphics

src/modules/graphics/opengl/wrap_Graphics.cpp

@@ -589,6 +589,28 @@ int w_getFont(lua_State *L)
 	return 1;
 }
 
+int w_setColorMask(lua_State *L)
+{
+	bool mask[4];
+	for (int i = 0; i < 4; i++)
+		mask[i] = luax_toboolean(L, i + 1);
+
+	// r, g, b, a
+	instance->setColorMask(mask[0], mask[1], mask[2], mask[3]);
+
+	return 0;
+}
+
+int w_getColorMask(lua_State *L)
+{
+	const bool *mask = instance->getColorMask();
+
+	for (int i = 0; i < 4; i++)
+		luax_pushboolean(L, mask[i]);
+
+	return 4;
+}
+
 int w_setBlendMode(lua_State *L)
 {
 	Graphics::BlendMode mode;
@@ -1285,6 +1307,8 @@ static const luaL_Reg functions[] =
 	{ "setFont", w_setFont },
 	{ "getFont", w_getFont },
 
+	{ "setColorMask", w_setColorMask },
+	{ "getColorMask", w_getColorMask },
 	{ "setBlendMode", w_setBlendMode },
 	{ "setColorMode", w_setColorMode },
 	{ "setDefaultImageFilter", w_setDefaultImageFilter },

src/modules/graphics/opengl/wrap_Graphics.h

@@ -70,6 +70,8 @@ int w_setBackgroundColor(lua_State *L);
 int w_getBackgroundColor(lua_State *L);
 int w_setFont(lua_State *L);
 int w_getFont(lua_State *L);
+int w_setColorMask(lua_State *L);
+int w_getColorMask(lua_State *L);
 int w_setBlendMode(lua_State *L);
 int w_setColorMode(lua_State *L);
 int w_setDefaultImageFilter(lua_State *L);