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Cleaned up the old gamma table adjustment code a little.

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profi200 2023-10-06 16:11:20 +02:00
parent b554c7c35c
commit 63e4422db1
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1 changed files with 11 additions and 8 deletions
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19
source/arm11/open_agb_firm.c
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@ -158,16 +158,19 @@ static Result loadGbaRom(const char *const path, u32 *const romSizeOut)
static void adjustGammaTableForGba(void)
{
const float gbaGamma = g_oafConfig.gbaGamma;
const float lcdGamma = g_oafConfig.lcdGamma;
const float contrast = g_oafConfig.contrast;
const float brightness = g_oafConfig.brightness;
// Credits for this algo go to Extrems.
const float targetGamma = g_oafConfig.gbaGamma;
const float lcdGamma = 1.f / g_oafConfig.lcdGamma;
const float contrast = g_oafConfig.contrast;
const float brightness = g_oafConfig.brightness / contrast;
const float contrastInTargetGamma = powf(contrast, targetGamma);
for(u32 i = 0; i < 256; i++)
{
// Credits for this algo go to Extrems.
// Originally from Game Boy Interface Standard Edition for the GameCube.
u32 res = powf(powf(contrast, gbaGamma) * powf((float)i / 255.0f + brightness / contrast, gbaGamma),
1.0f / lcdGamma) * 255.0f;
// Adjust i with brightness and convert to target gamma.
const float adjusted = powf((float)i / 255 + brightness, targetGamma);
// Apply contrast, convert to LCD gamma and clamp.
const u32 res = clamp_s32(powf(contrastInTargetGamma * adjusted, lcdGamma) * 255, 0, 255);
// Same adjustment for red/green/blue.
REG_LCD_PDC0_GTBL_FIFO = res<<16 | res<<8 | res;