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implement anti-aliasing for dump image (and dump movie)

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This commit is contained in:
Axel Kohlmeyer
2023-08-16 20:24:57 -04:00
parent 06e2d5d306
commit f91dc3e68a
4 changed files with 89 additions and 13 deletions
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15
doc/src/dump_image.rst
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@ -103,7 +103,7 @@ Syntax
dump_modify dump-ID keyword values ...
* these keywords apply only to the *image* and *movie* styles and are documented on this page
* keyword = *acolor* or *adiam* or *amap* or *gmap* or *backcolor* or *bcolor* or *bdiam* or *bitrate* or *boxcolor* or *color* or *framerate* or *gmap*
* keyword = *acolor* or *adiam* or *amap* or *gmap* or *backcolor* or *bcolor* or *bdiam* or *bitrate* or *boxcolor* or *color* or *framerate* or *fsaa* or *gmap*
* see the :doc:`dump modify <dump_modify>` doc page for more general keywords
.. parsed-literal::
@ -151,6 +151,8 @@ Syntax
R,G,B = red/green/blue numeric values from 0.0 to 1.0
*framerate* arg = fps
fps = frames per second for movie
*fsaa* arg = yes/no
yes/no = do or do not apply anti-aliasing
*gmap* args = identical to *amap* args
Examples
@ -957,6 +959,17 @@ frequently.
----------
.. versionadded:: TBD
The *fsaa* keyword can be used with the dump image command to improve
the image quality by enabling full scene anti-aliasing. Internally the
image is rendered at twice the width and height and then scaled down by
computing the average of each 2x2 block of pixels to produce a single
pixel in the final image at the original size. This produces smoother,
less ragged edges.
----------
The *gmap* keyword can be used with the dump image command, with its
*grid* keyword, to setup a color map. The color map is used to assign
a specific RGB (red/green/blue) color value to an individual grid cell

29
src/dump_image.cpp
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@ -1555,6 +1555,35 @@ int DumpImage::modify_param(int narg, char **arg)
return n;
}
// if antialias state changes, we need to increase the buffer space
// change the (internal) image dimensions and reset the view parameters
if (strcmp(arg[0],"fsaa") == 0) {
if (narg < 2) error->all(FLERR,"Illegal dump_modify command");
int aa = utils::logical(FLERR, arg[1], false, lmp);
if (image->fsaa == NO) {
if (aa == YES) {
image->width = image->width*2;
image->height = image->height*2;
// reallocate buffers to make room
image->buffers();
}
} else {
if (aa == NO) {
image->width = image->width/2;
image->height = image->height/2;
box_bounds();
box_center();
view_params();
}
}
image->fsaa = aa;
// reset size based parameters
box_bounds();
box_center();
view_params();
return 2;
}
if (strcmp(arg[0],"bcolor") == 0) {
if (narg < 3) error->all(FLERR,"Illegal dump_modify command");
if (atom->nbondtypes == 0)

55
src/image.cpp
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@ -55,7 +55,9 @@ enum{NO,YES};
/* ---------------------------------------------------------------------- */
Image::Image(LAMMPS *lmp, int nmap_caller) : Pointers(lmp)
Image::Image(LAMMPS *lmp, int nmap_caller) :
Pointers(lmp), depthBuffer(nullptr), surfaceBuffer(nullptr), imageBuffer(nullptr),
depthcopy(nullptr),surfacecopy(nullptr),rgbcopy(nullptr)
{
MPI_Comm_rank(world,&me);
MPI_Comm_size(world,&nprocs);
@ -69,6 +71,7 @@ Image::Image(LAMMPS *lmp, int nmap_caller) : Pointers(lmp)
persp = 0.0;
shiny = 1.0;
ssao = NO;
fsaa = NO;
up[0] = 0.0;
up[1] = 0.0;
@ -154,6 +157,13 @@ Image::~Image()
void Image::buffers()
{
memory->destroy(depthBuffer);
memory->destroy(surfaceBuffer);
memory->destroy(imageBuffer);
memory->destroy(depthcopy);
memory->destroy(surfacecopy);
memory->destroy(rgbcopy);
npixels = width * height;
memory->create(depthBuffer,npixels,"image:depthBuffer");
memory->create(surfaceBuffer,2*npixels,"image:surfaceBuffer");
@ -380,6 +390,26 @@ void Image::merge()
} else {
writeBuffer = imageBuffer;
}
// scale down image for antialiasing. can be done in place with simple averaging
if (fsaa) {
for (int h=0; h < height; h += 2) {
for (int w=0; w < width; w +=2) {
int idx1 = 3*height*h + 3*w;
int idx2 = 3*height*h + 3*(w+1);
int idx3 = 3*height*(h+1) + 3*w;
int idx4 = 3*height*(h+1) + 3*(w+1);
int out = 3*(height/2)*(h/2) + 3*(w/2);
for (int i=0; i < 3; ++i) {
writeBuffer[out+i] = (unsigned char) (0.25*((int)writeBuffer[idx1+i]
+(int)writeBuffer[idx2+i]
+(int)writeBuffer[idx3+i]
+(int)writeBuffer[idx4+i]));
}
}
}
}
}
/* ----------------------------------------------------------------------
@ -1037,6 +1067,7 @@ void Image::compute_SSAO()
void Image::write_JPG(FILE *fp)
{
#ifdef LAMMPS_JPEG
int aafactor = fsaa ? 2 : 1;
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
JSAMPROW row_pointer;
@ -1044,8 +1075,8 @@ void Image::write_JPG(FILE *fp)
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_compress(&cinfo);
jpeg_stdio_dest(&cinfo,fp);
cinfo.image_width = width;
cinfo.image_height = height;
cinfo.image_width = width/aafactor;
cinfo.image_height = height/aafactor;
cinfo.input_components = 3;
cinfo.in_color_space = JCS_RGB;
@ -1055,7 +1086,7 @@ void Image::write_JPG(FILE *fp)
while (cinfo.next_scanline < cinfo.image_height) {
row_pointer = (JSAMPROW)
&writeBuffer[(cinfo.image_height - 1 - cinfo.next_scanline) * 3 * width];
&writeBuffer[(cinfo.image_height - 1 - cinfo.next_scanline) * 3 * (width/aafactor)];
jpeg_write_scanlines(&cinfo,&row_pointer,1);
}
@ -1071,6 +1102,7 @@ void Image::write_JPG(FILE *fp)
void Image::write_PNG(FILE *fp)
{
#ifdef LAMMPS_PNG
int aafactor = fsaa ? 2 : 1;
png_structp png_ptr;
png_infop info_ptr;
@ -1091,7 +1123,7 @@ void Image::write_PNG(FILE *fp)
png_init_io(png_ptr, fp);
png_set_compression_level(png_ptr,Z_BEST_COMPRESSION);
png_set_IHDR(png_ptr,info_ptr,width,height,8,PNG_COLOR_TYPE_RGB,
png_set_IHDR(png_ptr,info_ptr,width/aafactor,height/aafactor,8,PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE,PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
png_text text_ptr[2];
@ -1111,9 +1143,9 @@ void Image::write_PNG(FILE *fp)
png_set_text(png_ptr,info_ptr,text_ptr,1);
png_write_info(png_ptr,info_ptr);
auto row_pointers = new png_bytep[height];
for (int i=0; i < height; ++i)
row_pointers[i] = (png_bytep) &writeBuffer[(height-i-1)*3*width];
auto row_pointers = new png_bytep[height/aafactor];
for (int i=0; i < height/aafactor; ++i)
row_pointers[i] = (png_bytep) &writeBuffer[((height/aafactor)-i-1)*3*(width/aafactor)];
png_write_image(png_ptr, row_pointers);
png_write_end(png_ptr, info_ptr);
@ -1129,11 +1161,12 @@ void Image::write_PNG(FILE *fp)
void Image::write_PPM(FILE *fp)
{
fprintf(fp,"P6\n%d %d\n255\n",width,height);
int aafactor = fsaa ? 2 : 1;
fprintf(fp,"P6\n%d %d\n255\n",width/aafactor,height/aafactor);
int y;
for (y = height-1; y >= 0; y--)
fwrite(&writeBuffer[y*width*3],3,width,fp);
for (y = (height/aafactor)-1; y >= 0; y--)
fwrite(&writeBuffer[y*(width/aafactor)*3],3,width/aafactor,fp);
}
/* ----------------------------------------------------------------------

3
src/image.h
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@ -28,13 +28,14 @@ class Image : protected Pointers {
double zoom; // zoom factor
double persp; // perspective factor
double shiny; // shininess of objects
int fsaa; // antialiasing on or off
int ssao; // SSAO on or off
int seed; // RN seed for SSAO
double ssaoint; // strength of shading from 0 to 1
double *boxcolor; // color to draw box outline with
int background[3]; // RGB values of background
double ambientColor[3]; // light color settings (adjustable by caller)
double ambientColor[3]; // light color settings (adjustable by caller)
double keyLightColor[3];
double fillLightColor[3];
double backLightColor[3];