InfiniSim/gif-h/gif-h-demo.cpp
Reinhold Gschweicher a594446ef0 Add gif-h helper to create screen capture
Press key `I` (shift+`i`) to start a screen capture creating a gif with
the captured screen. Hit `I` again to stop the screen recording.

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Add gif-h helper header only library

Copied from https://github.com/charlietangora/gif-h

3d2657b9ad
2022-06-19 22:31:25 +02:00

81 lines
2.0 KiB
C++

//
// gif-h-demo.cpp
// by Charlie Tangora
// Public domain.
// Email me : ctangora -at- gmail -dot- com
//
// Shows an example usage of gif.h
//
#include "gif.h"
#include <math.h>
const int width = 256;
const int height = 256;
uint8_t image[ width * height * 4 ];
void SetPixel( int xx, int yy, uint8_t red, uint8_t grn, uint8_t blu )
{
uint8_t* pixel = &image[(yy*width+xx)*4];
pixel[0] = red;
pixel[1] = blu;
pixel[2] = grn;
pixel[3] = 255; // no alpha for this demo
}
void SetPixelFloat( int xx, int yy, float fred, float fgrn, float fblu )
{
// convert float to unorm
uint8_t red = (uint8_t)roundf( 255.0f * fred );
uint8_t grn = (uint8_t)roundf( 255.0f * fgrn );
uint8_t blu = (uint8_t)roundf( 255.0f * fblu );
SetPixel( xx, yy, red, grn, blu );
}
int main(int argc, const char * argv[])
{
const char* filename = "./MyGif.gif";
if( argc > 1 )
{
filename = argv[1];
}
// Create a gif
GifWriter writer = {};
GifBegin( &writer, filename, width, height, 2, 8, true );
for( int frame=0; frame<256; ++frame )
{
// Make an image, somehow
// this is the default shadertoy - credit to shadertoy.com
float tt = frame * 3.14159f * 2 / 255.0f;
for( int yy=0; yy<height; ++yy )
{
for( int xx=0; xx<width; ++xx )
{
float fx = xx / (float)width;
float fy = yy / (float)height;
float red = 0.5f + 0.5f * cosf(tt+fx);
float grn = 0.5f + 0.5f * cosf(tt+fy+2.f);
float blu = 0.5f + 0.5f * cosf(tt+fx+4.f);
SetPixelFloat( xx, yy, red, grn, blu );
}
}
// Write the frame to the gif
printf( "Writing frame %d...\n", frame );
GifWriteFrame( &writer, image, width, height, 2, 8, true );
}
// Write EOF
GifEnd( &writer );
return 0;
}