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REVIEWED: example: shaders_julia_set

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Ray 2025-01-12 20:29:46 +01:00
parent 1cdf3bb791
commit af163ba22a
1 changed files with 10 additions and 13 deletions
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23
examples/shaders/resources/shaders/glsl100/julia_set.fs
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@ -13,23 +13,20 @@ uniform float zoom; // Zoom of the scale.
// NOTE: Maximum number of shader for-loop iterations depend on GPU,
// for example, on RasperryPi for this examply only supports up to 60
const int maxIterations = 48; // Max iterations to do.
const float colorCycles = 1.0f; // Number of times the color palette repeats.
const float colorCycles = 1.0; // Number of times the color palette repeats.
// Square a complex number
vec2 ComplexSquare(vec2 z)
{
return vec2(
z.x*z.x - z.y*z.y,
z.x*z.y*2.0f
);
return vec2(z.x*z.x - z.y*z.y, z.x*z.y*2.0);
}
// Convert Hue Saturation Value (HSV) color into RGB
vec3 Hsv2rgb(vec3 c)
{
vec4 K = vec4(1.0f, 2.0f/3.0f, 1.0f/3.0f, 3.0f);
vec3 p = abs(fract(c.xxx + K.xyz)*6.0f - K.www);
return c.z*mix(K.xxx, clamp(p - K.xxx, 0.0f, 1.0f), c.y);
vec4 K = vec4(1.0, 2.0/3.0, 1.0/3.0, 3.0);
vec3 p = abs(fract(c.xxx + K.xyz)*6.0 - K.www);
return c.z*mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}
void main()
@ -55,7 +52,7 @@ void main()
// The pixel coordinates are scaled so they are on the mandelbrot scale
// NOTE: fragTexCoord already comes as normalized screen coordinates but offset must be normalized before scaling and zoom
vec2 z = vec2((fragTexCoord.x - 0.5f)*2.5f, (fragTexCoord.y - 0.5f)*1.5f)/zoom;
vec2 z = vec2((fragTexCoord.x - 0.5)*2.5, (fragTexCoord.y - 0.5)*1.5)/zoom;
z.x += offset.x;
z.y += offset.y;
@ -63,7 +60,7 @@ void main()
for (int iterations = 0; iterations < 60; iterations++)
{
z = ComplexSquare(z) + c; // Iterate function
if (dot(z, z) > 4.0f) break;
if (dot(z, z) > 4.0) break;
iter = iterations;
}
@ -74,12 +71,12 @@ void main()
z = ComplexSquare(z) + c;
// This last part smooths the color (again see link above).
float smoothVal = float(iter) + 1.0f - (log(log(length(z)))/log(2.0f));
float smoothVal = float(iter) + 1.0 - (log(log(length(z)))/log(2.0));
// Normalize the value so it is between 0 and 1.
float norm = smoothVal/float(maxIterations);
// If in set, color black. 0.999 allows for some float accuracy error.
if (norm > 0.999f) gl_FragColor = vec4(0.0f, 0.0f, 0.0f, 1.0f);
else gl_FragColor = vec4(Hsv2rgb(vec3(norm*colorCycles, 1.0f, 1.0f)), 1.0f);
if (norm > 0.999) gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
else gl_FragColor = vec4(Hsv2rgb(vec3(norm*colorCycles, 1.0, 1.0)), 1.0);
}