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Reworked sRGB / gamma-correct APIs:

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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.)
This commit is contained in:
Alex Szpakowski
2015-08-09 21:46:21 -03:00
parent b13ba42ec4
commit d215d8a91e
32 changed files with 512 additions and 282 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/modules/window/sdl/Window.cpp
+31 -15
View File
@@ -58,9 +58,14 @@ Window::Window()
, context(nullptr)
, displayedWindowError(false)
, displayedContextError(false)
, hasSDL203orEarlier(false)
{
if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0)
throw love::Exception("Could not initialize SDL video subsystem (%s)", SDL_GetError());
SDL_version version = {};
SDL_GetVersion(&version);
hasSDL203orEarlier = (version.major == 2 && version.minor == 0 && version.patch <= 3);
}
Window::~Window()
@@ -84,12 +89,17 @@ void Window::setGLFramebufferAttributes(int msaa, bool sRGB)
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, (msaa > 0) ? 1 : 0);
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, (msaa > 0) ? msaa : 0);
// SDL or GLX may have bugs with this: https://bugzilla.libsdl.org/show_bug.cgi?id=2897
// It's fine to leave the attribute disabled on desktops though, because in
// practice the framebuffer will be sRGB-capable even if it's not requested.
#if !defined(LOVE_LINUX)
SDL_GL_SetAttribute(SDL_GL_FRAMEBUFFER_SRGB_CAPABLE, sRGB ? 1 : 0);
#endif
const char *driver = SDL_GetCurrentVideoDriver();
if (driver && strstr(driver, "x11") == driver)
{
// Always disable the sRGB flag when GLX is used with older SDL versions,
// because of this bug: https://bugzilla.libsdl.org/show_bug.cgi?id=2897
// In practice GLX will always give an sRGB-capable framebuffer anyway.
if (hasSDL203orEarlier)
SDL_GL_SetAttribute(SDL_GL_FRAMEBUFFER_SRGB_CAPABLE, 0);
}
#if defined(LOVE_WINDOWS)
// Avoid the Microsoft OpenGL 1.1 software renderer on Windows. Apparently
@@ -154,7 +164,7 @@ bool Window::checkGLVersion(const ContextAttribs &attribs)
return true;
}
bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowflags, int msaa, bool sRGB)
bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowflags, int msaa)
{
bool preferGLES = false;
@@ -171,6 +181,14 @@ bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowfla
if (curdriver && strstr(curdriver, glesdriver) == curdriver)
{
preferGLES = true;
// Prior to SDL 2.0.4, backends that use OpenGL ES didn't properly
// ask for a sRGB framebuffer when requested by SDL_GL_SetAttribute.
// FIXME: This doesn't account for windowing backends that sometimes
// use EGL, e.g. the X11 and windows SDL backends.
if (hasSDL203orEarlier)
graphics::setGammaCorrect(false);
break;
}
}
@@ -192,11 +210,8 @@ bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowfla
{2, 0, true, debug}, // OpenGL ES 2.
};
SDL_version sdlversion = {};
SDL_GetVersion(&sdlversion);
// OpenGL ES 3+ contexts are only properly supported in SDL 2.0.4+.
if (sdlversion.major == 2 && sdlversion.minor == 0 && sdlversion.patch <= 3)
if (hasSDL203orEarlier)
attribslist.erase(attribslist.begin() + 1);
// Move OpenGL ES to the front of the list if we should prefer GLES.
@@ -225,7 +240,7 @@ bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowfla
}
int curMSAA = msaa;
bool curSRGB = sRGB;
bool curSRGB = love::graphics::isGammaCorrect();
setGLFramebufferAttributes(curMSAA, curSRGB);
setGLContextAttributes(attribs);
@@ -308,7 +323,10 @@ bool Window::createWindowAndContext(int x, int y, int w, int h, Uint32 windowfla
}
if (context)
{
love::graphics::setGammaCorrect(curSRGB);
break;
}
}
if (!context || !window)
@@ -428,7 +446,7 @@ bool Window::setWindow(int width, int height, WindowSettings *settings)
close();
if (!createWindowAndContext(x, y, width, height, sdlflags, f.msaa, f.sRGB))
if (!createWindowAndContext(x, y, width, height, sdlflags, f.msaa))
return false;
// Make sure the window keeps any previously set icon.
@@ -451,7 +469,7 @@ bool Window::setWindow(int width, int height, WindowSettings *settings)
auto gfx = Module::getInstance<graphics::Graphics>(Module::M_GRAPHICS);
if (gfx != nullptr)
gfx->setMode(curMode.pixelwidth, curMode.pixelheight, curMode.settings.sRGB);
gfx->setMode(curMode.pixelwidth, curMode.pixelheight);
return true;
}
@@ -521,8 +539,6 @@ void Window::updateSettings(const WindowSettings &newsettings)
else
SDL_SetHint(SDL_HINT_VIDEO_MINIMIZE_ON_FOCUS_LOSS, "0");
curMode.settings.sRGB = newsettings.sRGB;
// Verify MSAA setting.
int buffers = 0;
int samples = 0;
src/modules/window/sdl/Window.h
+3 -1
View File
@@ -119,7 +119,7 @@ private:
void setGLFramebufferAttributes(int msaa, bool sRGB);
void setGLContextAttributes(const ContextAttribs &attribs);
bool checkGLVersion(const ContextAttribs &attribs);
bool createWindowAndContext(int x, int y, int w, int h, Uint32 windowflags, int msaa, bool sRGB);
bool createWindowAndContext(int x, int y, int w, int h, Uint32 windowflags, int msaa);
// Update the saved window settings based on the window's actual state.
void updateSettings(const WindowSettings &newsettings);
@@ -149,6 +149,8 @@ private:
bool displayedWindowError;
bool displayedContextError;
bool hasSDL203orEarlier;
}; // Window
} // sdl