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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
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src/modules/graphics/opengl/wrap_Graphics.lua
+66 -3
View File
@@ -66,9 +66,66 @@ uniform LOVE_UNIFORM_PRECISION mat3 NormalMatrix;
#endif
uniform mediump vec4 love_ScreenSize;]]
GLSL.FUNCTIONS = [[
float gammaToLinearPrecise(float c) {
return c <= 0.04045 ? c * 0.077399380804954 : pow((c + 0.055) * 0.9478672985782, 2.4);
}
vec3 gammaToLinearPrecise(vec3 c) {
bvec3 leq = lessThanEqual(c, vec3(0.04045));
c.r = leq.r ? c.r * 0.077399380804954 : pow((c.r + 0.055) * 0.9478672985782, 2.4);
c.g = leq.g ? c.g * 0.077399380804954 : pow((c.g + 0.055) * 0.9478672985782, 2.4);
c.b = leq.b ? c.b * 0.077399380804954 : pow((c.b + 0.055) * 0.9478672985782, 2.4);
return c;
}
vec4 gammaToLinearPrecise(vec4 c) { return vec4(gammaToLinearPrecise(c.rgb), c.a); }
float linearToGammaPrecise(float c) {
return c < 0.0031308 ? c * 12.92 : 1.055 * pow(c, 1.0 / 2.4) - 0.055;
}
vec3 linearToGammaPrecise(vec3 c) {
bvec3 lt = lessThan(c, vec3(0.0031308));
c.r = lt.r ? c.r * 12.92 : 1.055 * pow(c.r, 1.0 / 2.4) - 0.055;
c.g = lt.g ? c.g * 12.92 : 1.055 * pow(c.g, 1.0 / 2.4) - 0.055;
c.b = lt.b ? c.b * 12.92 : 1.055 * pow(c.b, 1.0 / 2.4) - 0.055;
return c;
}
vec4 linearToGammaPrecise(vec4 c) { return vec4(linearToGammaPrecise(c.rgb), c.a); }
// pow(x, 2.2) isn't an amazing approximation, but at least it's efficient...
mediump float gammaToLinearFast(mediump float c) { return pow(max(c, 0.0), 2.2); }
mediump vec3 gammaToLinearFast(mediump vec3 c) { return pow(max(c, vec3(0.0)), vec3(2.2)); }
mediump vec4 gammaToLinearFast(mediump vec4 c) { return vec4(gammaToLinearFast(c.rgb), c.a); }
mediump float linearToGammaFast(mediump float c) { return pow(max(c, 0.0), 1.0 / 2.2); }
mediump vec3 linearToGammaFast(mediump vec3 c) { return pow(max(c, vec3(0.0)), vec3(1.0 / 2.2)); }
mediump vec4 linearToGammaFast(mediump vec4 c) { return vec4(linearToGammaFast(c.rgb), c.a); }
#ifdef LOVE_PRECISE_GAMMA
#define gammaToLinear gammaToLinearPrecise
#define linearToGamma linearToGammaPrecise
#else
#define gammaToLinear gammaToLinearFast
#define linearToGamma linearToGammaFast
#endif
#ifdef LOVE_GAMMA_CORRECT
#define gammaCorrectColor gammaToLinear
#define unGammaCorrectColor linearToGamma
#define gammaCorrectColorPrecise gammaToLinearPrecise
#define unGammaCorrectColorPrecise linearToGammaPrecise
#define gammaCorrectColorFast gammaToLinearFast
#define unGammaCorrectColorFast linearToGammaFast
#else
#define gammaCorrectColor
#define unGammaCorrectColor
#define gammaCorrectColorPrecise
#define unGammaCorrectColorPrecise
#define gammaCorrectColorFast
#define unGammaCorrectColorFast
#endif]]
GLSL.VERTEX = {
HEADER = [[
#define VERTEX
#define LOVE_PRECISE_GAMMA
attribute vec4 VertexPosition;
attribute vec4 VertexTexCoord;
@@ -85,7 +142,7 @@ uniform mediump float love_PointSize;
FOOTER = [[
void main() {
VaryingTexCoord = VertexTexCoord;
VaryingColor = VertexColor * ConstantColor;
VaryingColor = gammaCorrectColor(VertexColor) * ConstantColor;
#ifdef GL_ES
gl_PointSize = love_PointSize;
#endif
@@ -134,7 +191,10 @@ void main() {
local function createVertexCode(vertexcode, lang)
local vertexcodes = {
lang == "glsles" and GLSL.VERSION_ES or GLSL.VERSION,
GLSL.SYNTAX, GLSL.VERTEX.HEADER, GLSL.UNIFORMS,
GLSL.SYNTAX,
love.graphics.isGammaCorrect() and "#define LOVE_GAMMA_CORRECT 1" or "",
GLSL.VERTEX.HEADER, GLSL.UNIFORMS,
GLSL.FUNCTIONS,
lang == "glsles" and "#line 1" or "#line 0",
vertexcode,
GLSL.VERTEX.FOOTER,
@@ -145,7 +205,10 @@ end
local function createPixelCode(pixelcode, is_multicanvas, lang)
local pixelcodes = {
lang == "glsles" and GLSL.VERSION_ES or GLSL.VERSION,
GLSL.SYNTAX, GLSL.PIXEL.HEADER, GLSL.UNIFORMS,
GLSL.SYNTAX,
love.graphics.isGammaCorrect() and "#define LOVE_GAMMA_CORRECT 1" or "",
GLSL.PIXEL.HEADER, GLSL.UNIFORMS,
GLSL.FUNCTIONS,
lang == "glsles" and "#line 1" or "#line 0",
pixelcode,
is_multicanvas and GLSL.PIXEL.FOOTER_MULTI_CANVAS or GLSL.PIXEL.FOOTER,