I need help with a morphing program.

I am a first year student and i need some help with a program, i need to make a program that morphs 2D shapes and i do not know what to do further from this point. My code keeps giving me errors and for some reason to some other computers it doesn't open at all or just count frames(that is odd and idk why this happen)

>> % Def parameters

numShapes = 9;

numFrames = 100;

colors = rand(numShapes, 3); % random colours for each shape

% Create a figure

figure;

for frame = 1:numFrames

clf; % Clear figure

for shapeIndex = 1:numShapes

t = frame / numFrames; % interpolate shapes

% Interpoleaza intre diferite forme

currentShape = shape(shapeIndex, 1);

nextShape = shape(mod(shapeIndex, numShapes) + 1, 1);

x = (1 - t) * currentShape(:, 1) + t * nextShape(:, 1);

y = (1 - t) * currentShape(:, 2) + t * nextShape(:, 2);

% schimba culoare in functie de forma

color = (1 - t) * colors(shapeIndex, :) + t * colors(mod(shapeIndex, numShapes) + 1, :);

% Plot forma

fill(x, y, color);

hold on;

end

axis([-5, 5, -5, 5]); % for a better visuailsation

axis equal;

axis off;

title(['Frame: ' num2str(frame)]);

pause(0.1); % pause between frames

switch index

case 1 % triangle

theta = linspace(0, 2 * pi, 3);

case 2 % square

theta = linspace(0, 2 * pi, 4);

case 3 % pentagon

theta = linspace(0, 2 * pi, 5);

case 4 % hexagon

theta = linspace(0, 2 * pi, 6);

case 5 % heptagon

theta = linspace(0, 2 * pi, 7);

case 6 % octogon

theta = linspace(0, 2 * pi, 8);

case 7 % Nonagon

theta = linspace(0, 2 * pi, 9);

case 8 % Decagon

theta = linspace(0, 2 * pi, 10);

case 9 % Circle

theta = linspace(0, 2 * pi, 100);

end

radius = shapeSize / 2;

shapeData = [radius * cos(theta), radius * sin(theta)];

end

I do not want some one to solve it, rather i want to explain it for some one whom just started learning matlab. i really wana learn even if i do this for one semestre.

thx yall

Answer 1

[Steven Lord]

My code keeps giving me errors

The full and exact text of those messages (all the text displayed in orange and/or red in the Command Window) may be useful in determining what's going on and how to avoid the warning and/or error.

When I try running the code, I receive the error "Unrecognized function or variable 'shape'." Indeed, I see you use shape() to try to define currentShape and nextShape in your inner for loop but nowhere in the code you've posted do you define that function or variable.

Also, a couple potential enhancements for your code:

It wouldn't give exactly the same plot, but you might be interested in the nsidedpoly function for creating regular N-sided polygons. You could plot, rotate, scale, translate, etc. the object returned by nsidedpoly so their "first" points lie on the X axis.

Alternately you could use linspace to generate numbers between 0 and 2 (rather than 0 and 2*pi) and then use cospi and sinpi to compute the cosine or sine of pi times that vector of angles (without actually multiplying by pi.) Since pi does not return the full transcendental value of π but the double-precision value closest to it, as an example sin(pi) is not exactly 0 but sinpi(1) is exactly 0.

sin(pi)

ans = 1.2246e-16

sinpi(1)

ans = 0

Answer 2

[Hassaan]

function morphShapes
    numShapes = 9;
    numFrames = 100;
    colors = rand(numShapes, 3); % random colours for each shape
    shapeSize = 4; % Define a size for the shapes

    figure;

    for frame = 1:numFrames
        clf; % Clear figure
        for shapeIndex = 1:numShapes
            t = frame / numFrames; % interpolate shapes
            currentShape = getShape(shapeIndex, shapeSize);
            nextShape = getShape(mod(shapeIndex, numShapes) + 1, shapeSize);
            x = (1 - t) * currentShape(:, 1) + t * nextShape(:, 1);
            y = (1 - t) * currentShape(:, 2) + t * nextShape(:, 2);
            color = (1 - t) * colors(shapeIndex, :) + t * colors(mod(shapeIndex, numShapes) + 1, :);
            fill(x, y, color);
            hold on;
        end
        axis([-5, 5, -5, 5]); % for a better visualization
        axis equal;
        axis off;
        title(['Frame: ' num2str(frame)]);
        pause(0.1); % pause between frames
    end
end

% Placeholder for getShape function. Implement the shape logic here.
function shapeData = getShape(index, shapeSize)
    switch index
        case 1 % triangle
            theta = linspace(0, 2 * pi, 4);
        case 2 % square
            theta = linspace(0, 2 * pi, 5);
        % Add cases for other shapes...
        case 9 % Circle
            theta = linspace(0, 2 * pi, 100);
        otherwise
            theta = linspace(0, 2 * pi, 100); % Default circle
    end
    theta(end) = []; % Remove duplicate point at the end
    radius = shapeSize / 2;
    shapeData = [radius * cos(theta)', radius * sin(theta)'];
end

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