Gamma-correct blending and shader math can be enabled globally via the new 't.gammacorrect' boolean flag in love.conf.
The new function love.graphics.isGammaCorrect will return true if it was requested in love.conf and is supported on the system.
When gamma correct rendering is enabled, colors (including the colors of pixels from images) are automatically converted from sRGB to linear RGB before use. When drawing to the main screen or to a canvas with the 'normal' or 'srgb' format, the final output colors of pixel shaders are automatically converted from linear RGB to sRGB after blending and before the color is stored in the pixel.
This lets the rendering pipeline do math using linear RGB values for colors rather than sRGB values, so the math is correct, without making users of the APIs manually linearize their colors with the love.math.gammaToLinear function (which still exists). The final output of the screen is encoded as sRGB, which is what systems expect. Canvases (except when otherwise requested) store their contents with sRGB encoding for increased precision with darker colors.
the 'srgb' window setting flag has been removed, as well as the 'srgb' image flag. A new image flag 'linear' has been added, which when set to true will cause the colors of the image to always be treated as linear RGB rather than sRGB, when gamma-correct rendering is enabled.
A new function 'Shader:sendColor' has been added, which has the same argument structure as 'Shader:send' but expects colors in the range of [0, 255]. When gamma-correct rendering is enabled it automatically gamma-corrects the given colors (by applying gammaToLinear to them.)
New shader code functions have been added: gammaToLinear, linearToGamma, gammaCorrectColor, and unGammaCorrectColor. When gamma-correct rendering is enabled, the LOVE_GAMMA_CORRECT #define is set and gammaCorrectColor and unGammaCorrectColor are aliases for gammaToLinear and linearToGamma respectively, otherwise the functions do nothing.
The new shader functions have 'precise' and 'fast' variants. If the LOVE_PRECISE_GAMMA define is set, then the normal functions default to the precise variants, otherwise they default to the fast variants. Currently the define is set in vertex shaders and not set in pixel shaders.
The default per-vertex color is automatically gamma-corrected by LÖVE when gamma correct rendering is enabled, but any custom named per-vertex attribute specified with the new custom attribute Mesh functionality won't be, unless 'gammaCorrectColor' or similar functions are explicitly used (preferably inside the vertex shader code that has the custom attribute.)
Previously, calling e.g. love.graphics.getFont() 10,000 times would retain the object 10,000 times (and release it 10,000 times when the Font object was garbage-collected in the Lua state.) Now it will only retain it once and release it once.
It has two variants: showMessageBox(type, title, message [, attachtowindow=true]), and showMessageBox(type, title, message, buttons [, attachtowindow=true]). The former shows a simple message box with a single OK button, and the latter displays several buttons. The buttons argument is an array of button names.
The second variant returns the index of the pressed button, or 0 if the message box was closed some other way. showMessageBox will block until the message box is closed (and it can't be called on a separate thread.)
love.window.getWidth/getHeight were originally added to help deal with high-dpi mode, but the API ended up going in a different direction (love.window.getPixelScale).
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branch : minor
love.graphics.newImage(path, “srgb”) creates a new Image whose texels are treated as being in the sRGB color space, so they are linearized when drawing/sampling from the image.
love.graphics.newCanvas(w, h, “srgb”) creates a new Canvas whose texels are treated as being in the sRGB color space, so drawing to the Canvas does a linear->sRGB conversion (but blends linearly), and sampling from it (drawing it or using it in a shader) converts from sRGB to linear space.
The "srgb" window flag does the same as Canvases for the main screen.
Added a ‘highdpi’ boolean flag to t.window/love.window.setMode (defaults to false.)
When the window is actually in high-dpi mode on a supported display, the graphics width and height and the mouse position are in pixels, rather than ‘window coordinates’.
Added love.window.getPixelScale. Returns the scale factor of the window from user-space points to pixels (e.g. it will be 1 normally, and 2 on a retina display in OS X with high-dpi mode enabled.)
Alex Szpakowski
Bart van Strien