new example: shaders_eratosthenes

Contributed by ProfJski
This commit is contained in:
Ray 2019-05-16 17:23:31 +02:00
parent 9fd410b8a8
commit ce87d2ced4
5 changed files with 212 additions and 0 deletions

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@ -451,6 +451,7 @@ EXAMPLES = \
shaders/shaders_texture_drawing \
shaders/shaders_texture_waves \
shaders/shaders_julia_set \
shaders/shaders_eratosthenes \
audio/audio_module_playing \
audio/audio_music_stream \
audio/audio_raw_stream \

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@ -0,0 +1,58 @@
#version 100
precision mediump float;
/*************************************************************************************
The Sieve of Eratosthenes -- a simple shader by ProfJski
An early prime number sieve: https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
The screen is divided into a square grid of boxes, each representing an integer value.
Each integer is tested to see if it is a prime number. Primes are colored white.
Non-primes are colored with a color that indicates the smallest factor which evenly divdes our integer.
You can change the scale variable to make a larger or smaller grid.
Total number of integers displayed = scale squared, so scale = 100 tests the first 10,000 integers.
WARNING: If you make scale too large, your GPU may bog down!
***************************************************************************************/
// Input vertex attributes (from vertex shader)
varying vec2 fragTexCoord;
varying vec4 fragColor;
// Make a nice spectrum of colors based on counter and maxSize
vec4 Colorizer(float counter, float maxSize)
{
float red = 0.0, green = 0.0, blue = 0.0;
float normsize = counter/maxSize;
red = smoothstep(0.3, 0.7, normsize);
green = sin(3.14159*normsize);
blue = 1.0 - smoothstep(0.0, 0.4, normsize);
return vec4(0.8*red, 0.8*green, 0.8*blue, 1.0);
}
void main()
{
vec4 color = vec4(1.0);
float scale = 1000.0; // Makes 100x100 square grid. Change this variable to make a smaller or larger grid.
int value = int(scale*floor(fragTexCoord.y*scale) + floor(fragTexCoord.x*scale)); // Group pixels into boxes representing integer values
if ((value == 0) || (value == 1) || (value == 2)) gl_FragColor = vec4(1.0);
else
{
for (int i = 2; (i < max(2, sqrt(value) + 1)); i++)
{
if ((value - i*floor(value/i)) == 0)
{
color = Colorizer(float(i), scale);
//break; // Uncomment to color by the largest factor instead
}
}
gl_FragColor = color;
}
}

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#version 330
/*************************************************************************************
The Sieve of Eratosthenes -- a simple shader by ProfJski
An early prime number sieve: https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
The screen is divided into a square grid of boxes, each representing an integer value.
Each integer is tested to see if it is a prime number. Primes are colored white.
Non-primes are colored with a color that indicates the smallest factor which evenly divdes our integer.
You can change the scale variable to make a larger or smaller grid.
Total number of integers displayed = scale squared, so scale = 100 tests the first 10,000 integers.
WARNING: If you make scale too large, your GPU may bog down!
***************************************************************************************/
// Input vertex attributes (from vertex shader)
in vec2 fragTexCoord;
in vec4 fragColor;
// Output fragment color
out vec4 finalColor;
// Make a nice spectrum of colors based on counter and maxSize
vec4 Colorizer(float counter, float maxSize)
{
float red = 0.0, green = 0.0, blue = 0.0;
float normsize = counter/maxSize;
red = smoothstep(0.3, 0.7, normsize);
green = sin(3.14159*normsize);
blue = 1.0 - smoothstep(0.0, 0.4, normsize);
return vec4(0.8*red, 0.8*green, 0.8*blue, 1.0);
}
void main()
{
vec4 color = vec4(1.0);
float scale = 1000.0; // Makes 100x100 square grid. Change this variable to make a smaller or larger grid.
int value = int(scale*floor(fragTexCoord.y*scale)+floor(fragTexCoord.x*scale)); // Group pixels into boxes representing integer values
if ((value == 0) || (value == 1) || (value == 2)) finalColor = vec4(1.0);
else
{
for (int i = 2; (i < max(2, sqrt(value) + 1)); i++)
{
if ((value - i*floor(value/i)) == 0)
{
color = Colorizer(float(i), scale);
//break; // Uncomment to color by the largest factor instead
}
}
finalColor = color;
}
}

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@ -0,0 +1,94 @@
/*******************************************************************************************
*
* raylib [shaders] example - Sieve of Eratosthenes
*
* Sieve of Eratosthenes, the earliest known (ancient Greek) prime number sieve.
*
* "Sift the twos and sift the threes,
* The Sieve of Eratosthenes.
* When the multiples sublime,
* the numbers that are left are prime."
*
* NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
* OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version.
*
* NOTE: Shaders used in this example are #version 330 (OpenGL 3.3).
*
* This example has been created using raylib 2.5 (www.raylib.com)
* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
* Example contributed by ProfJski and reviewed by Ramon Santamaria (@raysan5)
*
* Copyright (c) 2019 ProfJski and Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#if defined(PLATFORM_DESKTOP)
#define GLSL_VERSION 330
#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
#define GLSL_VERSION 100
#endif
int main()
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [shaders] example - Sieve of Eratosthenes");
RenderTexture2D target = LoadRenderTexture(screenWidth, screenHeight);
// Load Eratosthenes shader
// NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
Shader shader = LoadShader(0, FormatText("resources/shaders/glsl%i/eratosthenes.fs", GLSL_VERSION));
SetTargetFPS(60);
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Update
//----------------------------------------------------------------------------------
// Nothing to do here, everything is happening in the shader
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
BeginTextureMode(target); // Enable drawing to texture
ClearBackground(BLACK); // Clear the render texture
// Draw a rectangle in shader mode to be used as shader canvas
// NOTE: Rectangle uses font white character texture coordinates,
// so shader can not be applied here directly because input vertexTexCoord
// do not represent full screen coordinates (space where want to apply shader)
DrawRectangle(0, 0, GetScreenWidth(), GetScreenHeight(), BLACK);
EndTextureMode(); // End drawing to texture (now we have a blank texture available for the shader)
BeginShaderMode(shader);
// NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
DrawTextureRec(target.texture, (Rectangle){ 0, 0, target.texture.width, -target.texture.height }, (Vector2){ 0.0f, 0.0f }, WHITE);
EndShaderMode();
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadShader(shader); // Unload shader
UnloadRenderTexture(target); // Unload texture
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}

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