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Merge pull request #120 from jdgleaver/mix-frames-accurate

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Add optional 'accurate' frame mixing mode
This commit is contained in:
hizzlekizzle 2018-12-04 08:56:05 -06:00 committed by GitHub
commit a3073179b8
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1 changed files with 87 additions and 15 deletions
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102
libgambatte/libretro/libretro.cpp
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@ -62,7 +62,7 @@ bool use_official_bootloader = false;
// Colours from previous frame
static gambatte::video_pixel_t prev_colours[160 * NUM_GAMEBOYS * 144] = {0};
static bool blur_motion = false;
static unsigned mix_frames_mode = 0;
bool file_present_in_system(std::string fname)
{
@ -369,7 +369,7 @@ Special 3"
{ "gambatte_dark_filter_level", "Dark Filter Level (percent); 0|5|10|15|20|25|30|35|40|45|50" },
{ "gambatte_gb_hwmode", "Emulated hardware (restart); Auto|GB|GBC|GBA" },
{ "gambatte_gb_bootloader", "Use official bootloader (restart); enabled|disabled" },
{ "gambatte_mix_frames", "Mix frames; disabled|enabled" },
{ "gambatte_mix_frames", "Mix frames; disabled|accurate|fast" },
#ifdef HAVE_NETWORK
{ "gambatte_gb_link_mode", "GameBoy Link Mode; Not Connected|Network Server|Network Client" },
{ "gambatte_gb_link_network_port", "Network Link Port; 56400|56401|56402|56403|56404|56405|56406|56407|56408|56409|56410|56411|56412|56413|56414|56415|56416|56417|56418|56419|56420" },
@ -648,19 +648,20 @@ static void check_variables(void)
else
up_down_allowed = false;
bool prev_blur_motion = blur_motion;
blur_motion = false;
unsigned prev_mix_frames_mode = mix_frames_mode;
mix_frames_mode = 0;
var.key = "gambatte_mix_frames";
var.value = NULL;
if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
{
if (!strcmp(var.value, "enabled")) {
blur_motion = true;
}
if (!strcmp(var.value, "accurate"))
mix_frames_mode = 1;
else if (!strcmp(var.value, "fast"))
mix_frames_mode = 2;
}
// Must reset previous colours when turning 'mix frames'
// on, otherwise first rendered frame may contain garbage
if (!prev_blur_motion && blur_motion) {
if ((prev_mix_frames_mode == 0) && (mix_frames_mode != 0)) {
memset(prev_colours, 0, sizeof(gambatte::video_pixel_t) * 160 * NUM_GAMEBOYS * 144);
}
@ -1052,10 +1053,14 @@ static void render_audio(const int16_t *samples, unsigned frames)
blipper_push_samples(resampler_r, samples + 1, frames, 2);
}
static void mix_frames(void)
static void mix_frames_fast(void)
{
// Simple frame blending: mixes current frame 50:50 with
// previous one
// previous one.
// Uses fast bit twiddling method, suitable for very low
// end devices (NB: rounding errors will cause darkening
// of colours - this is fairly innocuous, but may annoy
// some users)
unsigned offset = 0;
unsigned colour_index = 0;
for (unsigned i = 0; i < 144; i++)
@ -1075,9 +1080,6 @@ static void mix_frames(void)
// Do this in one shot to minimise unnecessary variables...
// > Unpack current/previous frame colours and divide by 2
// > Mix and repack colours for current frame
// Note: This will darken colours, due to rounding errors
// (not much we can do about this without incurring a large
// performance penalty...)
#ifdef VIDEO_RGB565
video_buf[buff_index] = (((rgb >> 11 & 0x1F) >> 1) + ((rgb_prev >> 11 & 0x1F) >> 1)) << 11
| (((rgb >> 6 & 0x1F) >> 1) + ((rgb_prev >> 6 & 0x1F) >> 1)) << 6
@ -1092,6 +1094,66 @@ static void mix_frames(void)
}
}
static void mix_frames_accurate(void)
{
// Simple frame blending: mixes current frame 50:50 with
// previous one.
// Uses slow and accurate floating point conversion
// method. Not suitable for very low end devices, but
// should leave colour levels intact.
// NB: We're repeating some code here, just for performance
// reasons (i.e. putting an 'if' statement inside the inner
// loop to select between fast and accurate methods makes the
// fast method just a tiny bit too slow...)
unsigned offset = 0;
unsigned colour_index = 0;
for (unsigned i = 0; i < 144; i++)
{
for (unsigned j = 0; j < 160 * NUM_GAMEBOYS; j++)
{
// Get colours from current frame + previous frame
unsigned buff_index = offset + j;
gambatte::video_pixel_t rgb = video_buf[buff_index];
gambatte::video_pixel_t rgb_prev = prev_colours[colour_index];
// Store current colours for next frame
prev_colours[colour_index] = rgb;
colour_index++;
// Unpack current/previous frame colours and convert to float
#ifdef VIDEO_RGB565
float r = static_cast<float>(rgb >> 11 & 0x1F);
float g = static_cast<float>(rgb >> 6 & 0x1F);
float b = static_cast<float>(rgb & 0x1F);
float r_prev = static_cast<float>(rgb_prev >> 11 & 0x1F);
float g_prev = static_cast<float>(rgb_prev >> 6 & 0x1F);
float b_prev = static_cast<float>(rgb_prev & 0x1F);
#else
float r = static_cast<float>(rgb >> 16 & 0x1F);
float g = static_cast<float>(rgb >> 8 & 0x1F);
float b = static_cast<float>(rgb & 0x1F);
float r_prev = static_cast<float>(rgb_prev >> 16 & 0x1F);
float g_prev = static_cast<float>(rgb_prev >> 8 & 0x1F);
float b_prev = static_cast<float>(rgb_prev & 0x1F);
#endif
// Mix colours for current frame and convert back to unsigned
unsigned r_mix = static_cast<unsigned>(((r * 0.5) + (r_prev * 0.5)) + 0.5) & 0x1F;
unsigned g_mix = static_cast<unsigned>(((g * 0.5) + (g_prev * 0.5)) + 0.5) & 0x1F;
unsigned b_mix = static_cast<unsigned>(((b * 0.5) + (b_prev * 0.5)) + 0.5) & 0x1F;
// Repack colours for current frame
#ifdef VIDEO_RGB565
video_buf[buff_index] = r_mix << 11 | g_mix << 6 | b_mix;
#else
video_buf[buff_index] = r_mix << 16 | g_mix << 8 | b_mix;
#endif
}
offset += video_pitch;
}
}
void retro_run()
{
static uint64_t samples_count = 0;
@ -1149,8 +1211,18 @@ void retro_run()
render_audio(sound_buf.i16, samples);
#endif
if (blur_motion) {
mix_frames();
switch (mix_frames_mode)
{
case 1:
mix_frames_accurate();
break;
case 2:
mix_frames_fast();
break;
default:
// Do nothing
// (defensive coding - could remove this...)
break;
}
#ifdef VIDEO_RGB565