diff options
Diffstat (limited to 'plugins/gme/Game_Music_Emu-0.5.2/player/Audio_Scope.cpp')
| -rw-r--r-- | plugins/gme/Game_Music_Emu-0.5.2/player/Audio_Scope.cpp | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/plugins/gme/Game_Music_Emu-0.5.2/player/Audio_Scope.cpp b/plugins/gme/Game_Music_Emu-0.5.2/player/Audio_Scope.cpp new file mode 100644 index 00000000..74cb2c32 --- /dev/null +++ b/plugins/gme/Game_Music_Emu-0.5.2/player/Audio_Scope.cpp @@ -0,0 +1,198 @@ +// Game_Music_Emu 0.5.2. http://www.slack.net/~ant/ + +#include "Audio_Scope.h" + +#include <assert.h> +#include <stdlib.h> + +/* Copyright (C) 2005-2006 by Shay Green. Permission is hereby granted, free of +charge, to any person obtaining a copy of this software module and associated +documentation files (the "Software"), to deal in the Software without +restriction, including without limitation the rights to use, copy, modify, +merge, publish, distribute, sublicense, and/or sell copies of the Software, and +to permit persons to whom the Software is furnished to do so, subject to the +following conditions: The above copyright notice and this permission notice +shall be included in all copies or substantial portions of the Software. THE +SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, +INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A +PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR +COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER +IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ + +int const step_bits = 8; +int const step_unit = 1 << step_bits; +int const erase_color = 1; +int const draw_color = 2; + +Audio_Scope::Audio_Scope() +{ + surface = 0; + buf = 0; +} + +Audio_Scope::~Audio_Scope() +{ + free( buf ); + + if ( surface ) + SDL_FreeSurface( surface ); +} + +const char* Audio_Scope::init( int width, int height ) +{ + assert( height <= 256 ); + assert( !buf ); // can only call init() once + + buf = (byte*) calloc( width * sizeof *buf, 1 ); + if ( !buf ) + return "Out of memory"; + + low_y = 0; + high_y = height; + buf_size = width; + + for ( sample_shift = 6; sample_shift < 14; ) + if ( ((0x7FFFL * 2) >> sample_shift++) < height ) + break; + + v_offset = height / 2 - (0x10000 >> sample_shift); + + screen = SDL_SetVideoMode( width, height, 0, 0 ); + if ( !screen ) + return "Couldn't set video mode"; + + surface = SDL_CreateRGBSurface( SDL_SWSURFACE, width, height, 8, 0, 0, 0, 0 ); + if ( !screen ) + return "Couldn't create surface"; + + static SDL_Color palette [2] = { {0, 0, 0}, {0, 255, 0} }; + SDL_SetColors( surface, palette, 1, 2 ); + + return 0; // success +} + +const char* Audio_Scope::draw( const short* in, long count, double step ) +{ + int low = low_y; + int high = high_y; + + if ( count >= buf_size ) + { + count = buf_size; + low_y = 0x7FFF; + high_y = 0; + } + + if ( SDL_LockSurface( surface ) < 0 ) + return "Couldn't lock surface"; + render( in, count, (long) (step * step_unit) ); + SDL_UnlockSurface( surface ); + + if ( low > low_y ) + low = low_y; + + if ( high < high_y ) + high = high_y; + + SDL_Rect r; + r.x = 0; + r.w = buf_size; + r.y = low + v_offset; + r.h = high - low + 1; + + if ( SDL_BlitSurface( surface, &r, screen, &r ) < 0 ) + return "Blit to screen failed"; + + if ( SDL_Flip( screen ) < 0 ) + return "Couldn't flip screen"; + + return 0; // success +} + +void Audio_Scope::render( short const* in, long count, long step ) +{ + byte* old_pos = buf; + long surface_pitch = surface->pitch; + byte* out = (byte*) surface->pixels + v_offset * surface_pitch; + int old_erase = *old_pos; + int old_draw = 0; + long in_pos = 0; + + int low_y = this->low_y; + int high_y = this->high_y; + int half_step = (step + step_unit / 2) >> (step_bits + 1); + + while ( count-- ) + { + // Line drawing/erasing starts at previous sample and ends one short of + // current sample, except when previous and current are the same. + + // Extra read on the last iteration of line loops will always be at the + // height of the next sample, and thus within the gworld bounds. + + // Erase old line + { + int delta = *old_pos - old_erase; + int offset = old_erase * surface_pitch; + old_erase += delta; + + int next_line = surface_pitch; + if ( delta < 0 ) + { + delta = -delta; + next_line = -surface_pitch; + } + + do + { + out [offset] = erase_color; + offset += next_line; + } + while ( delta-- > 1 ); + } + + // Draw new line and put in old_buf + { + + int in_whole = in_pos >> step_bits; + int sample = (0x7FFF * 2 - in [in_whole] - in [in_whole + half_step]) >> sample_shift; + if ( !in_pos ) + old_draw = sample; + in_pos += step; + + int delta = sample - old_draw; + int offset = old_draw * surface_pitch; + old_draw += delta; + + int next_line = surface_pitch; + if ( delta < 0 ) + { + delta = -delta; + next_line = -surface_pitch; + } + + *old_pos++ = sample; + + // min/max updating can be interleved anywhere + + if ( low_y > sample ) + low_y = sample; + + do + { + out [offset] = draw_color; + offset += next_line; + } + while ( delta-- > 1 ); + + if ( high_y < sample ) + high_y = sample; + } + + out++; + } + + this->low_y = low_y; + this->high_y = high_y; +} |