%% Render Random Scenes
%
% This script will generate numerous random scenes and save the results in
% the Output directory. This is useful to sample a large number of scene.
% Note that each scene will be saved as an image with a date stamp *and*
% the random number generator seed used to generate the seed. Passing this
% number to |rng| before running |example_scene| will result in the scene
% being recreated exactly. This allows a user to examine numerous scenes,
% select a scene of interest, recreate it, explore it, and potentially
% export it for whatever purpose. In other words, the seed number is all
% that's necessary to completely regenerate a scene. For example, if an
% image is named |scene_2012-12-13-18-38-28_seed_59150.png|, then the
% following completely recreates the scene.
%
% >> rng(59150);
% >> example_scene;
%
% Tucker McClure
% Copyright 2012, The MathWorks, Inc.
%% Options
% Number of scenes to create.
n_images = 50;
%% Initialize the Figure
fprintf('Generating %d scenes...\n', n_images);
tic();
% Create or clear a figure for the rendering.
figure(1);
clf();
set(1, 'PaperPositionMode', 'auto', ...
'WindowButtonDownFcn', [], ...
'WindowButtonUpFcn', [], ...
'WindowButtonMotionFcn', [], ...
'WindowScrollWheelFcn', []);
% Choose the next random number generator seed.
rng_seed = mod(floor(1e8*now()), 2^32);
rng(rng_seed);
%%
% Add an Output directory if one doesn't exist.
if ~exist('Output', 'dir')
mkdir('Output');
end
%% Land and Sea
% Create the terrain height map.
[~, ~, ~, hm, xm, ym] = generate_terrain(7, 513, 0, 0.1);
% Generate appropriate colors.
cm = generate_terrain_colors(hm);
% Flatten the oceans.
hmp = max(hm, 0);
% Draw the land and calculate its normal vectors.
h_land = patch(surf2patch(xm, ym, hmp, cm));
[nx, ny, nz] = surfnorm(hmp);
land_normals = [nx(:), ny(:), nz(:)];
% Set it's material properties for interpolated colors and appropriate
% lighting.
set(h_land, 'VertexNormals', land_normals, ...
'DiffuseStrength', 0.8, ... % Reacts to light direction
'SpecularStrength', 0, ... % Not shiny
'AmbientStrength', 0.3, ... % Reacts to ambient light
'BackFaceLighting', 'unlit'); % Don't illuminate reverse
% Add a black backdrop beneath the land. Sometimes a vertex seems to miss
% its position slightly, and sky colors creep through, and that's weird.
patch('Faces', [1 2 3 4], ...
'Vertices', [-1 -1 -0.01; ...
1 -1 -0.01; ...
1 1 -0.01; ...
-1 1 -0.01], ...
'FaceVertexCData', 0.25*ones(4, 3));
%% Sky
% Draw a random time of day between sunrise and sunset. Get the
% corresponding light color. The sky is always the color of the sun at noon
% (and is then affected by the sun color at the current time).
current_time = 0.24 + 0.52 * rand();
sun_color = sun_tones(current_time);
sky_color = sun_tones(0.5);
% Create the sky patch by scaling a sphere. Note that the nothing in the
% scene can be rendered outside of [-100, 100] on any axis due to a
% documented rendering bug. Therefore, the sphere will be scaleld up to
% 99, which is plenty far away since the terrain is limited to [-1, 1].
[xs, ys, zs] = sphere(16);
sky_scale = 99;
sky_patch = surf2patch(sky_scale*xs, sky_scale*ys, sky_scale*zs, ...
repmat(reshape(sky_color, [1 1 3]), [17 17 1]));
h_sky = patch(sky_patch);
% Set appropriate lighting options for the sky.
set(h_sky, 'DiffuseStrength', 0.3, ...
'SpecularStrength', 0, ...
'AmbientStrength', 1, ...
'BackFaceLighting', 'unlit');
% Vertex normals are the opposite of what I expect. Reverse them.
set(h_sky, 'VertexNormals', -get(h_sky, 'VertexNormals'));
%% Sun
% Create a light for the sun.
h_light = lightangle(90, 360*(current_time - 0.25));
% Set the light's color.
set(h_light, 'Color', sun_color);
% Set the ambient color used in the scene.
set(gca(), 'AmbientLightColor', sun_color);
% Use decent lighting.
lighting gouraud;
%% Axes and Global Settings
% Set axes options.
camera_target = [0 0 mean(hmp(:)) + 0.5*std(hmp(:))];
camera_position = camera_target + [1.15 0 0.5];
set(gca, 'DataAspectRatio', [1 1 1], ...
'Visible', 'off', ...
'Projection', 'Perspective', ...
'Position', [0 0 1 1], ...
'CameraTarget', camera_target, ...
'CameraViewAngle', 45, ...
'CameraUpVector', [0 0 1], ...
'CameraPosition', camera_position, ...
'XLim', [-100 100], ...
'YLim', [-100 100], ...
'ZLim', [-100 100]);
camorbit(360*rand(), 0);
% Patches should have no edges and interpolated face colors.
shading interp;
% Force the drawing.
drawnow();
%% Loop, Updating Image Each Time
image_number = 0;
while true
% Increase image count.
image_number = image_number + 1;
% Force a drawing.
drawnow();
% Capture the image.
image_name = sprintf('scene_%s_seed_%d.png', ...
datestr(now(), 'yyyy-mm-dd-HH-MM-SS'), ...
rng_seed);
print('-dpng', ['Output' filesep image_name]);
% If we've generated enough images, stop.
if image_number == n_images
break;
end
% Choose the next random number generator seed.
rng_seed = mod(floor(1e8*now()), 2^32);
rng(rng_seed);
% Generate new terrain.
[~, ~, ~, hm, xm, ym] = generate_terrain(7, 513, 0, 0.1);
cm = generate_terrain_colors(hm);
hmp = max(hm, 0);
current_time = 0.24 + 0.52 * rand();
[nx, ny, nz] = surfnorm(hmp);
land_normals = [nx(:), ny(:), nz(:)];
% Update the patches, lights, and camera.
land_patch = surf2patch(xm, ym, hmp, cm);
set(h_land, 'Vertices', land_patch.vertices, ...
'Faces', land_patch.faces, ...
'FaceVertexCData', land_patch.facevertexcdata, ...
'VertexNormals', land_normals);
lightangle(h_light, 90, 360*(current_time - 0.25));
sun_color = sun_tones(current_time);
set(h_light, 'Color', sun_color);
camera_target = [0 0 mean(hmp(:)) + 0.5*std(hmp(:))];
camera_position = camera_target + [1.15 0 0.5];
set(gca(), 'AmbientLightColor', sun_color, ...
'CameraTarget', camera_target, ...
'CameraPosition', camera_position, ...
'CameraUpVector', [0 0 1]);
camorbit(360*rand(), 0);
end
fprintf('Done.\n');
toc();
