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100 lines
4.4 KiB
C
100 lines
4.4 KiB
C
/*******************************************************************************************
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*
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* raylib [shaders] example - sieve of Eratosthenes
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*
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* Example complexity rating: [★★★☆] 3/4
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*
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* NOTE: Sieve of Eratosthenes, the earliest known (ancient Greek) prime number sieve
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*
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* "Sift the twos and sift the threes,
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* The Sieve of Eratosthenes.
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* When the multiples sublime,
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* the numbers that are left are prime."
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*
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* NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
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* OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version
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*
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* NOTE: Shaders used in this example are #version 330 (OpenGL 3.3)
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*
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* Example originally created with raylib 2.5, last time updated with raylib 4.0
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*
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* Example contributed by ProfJski (@ProfJski) and reviewed by Ramon Santamaria (@raysan5)
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2019-2025 ProfJski (@ProfJski) and Ramon Santamaria (@raysan5)
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*
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********************************************************************************************/
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#include "raylib.h"
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#if defined(PLATFORM_DESKTOP)
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#define GLSL_VERSION 330
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#else // PLATFORM_ANDROID, PLATFORM_WEB
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#define GLSL_VERSION 100
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#endif
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//------------------------------------------------------------------------------------
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// Program main entry point
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//------------------------------------------------------------------------------------
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int main(void)
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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const int screenWidth = 800;
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const int screenHeight = 450;
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InitWindow(screenWidth, screenHeight, "raylib [shaders] example - sieve of Eratosthenes");
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RenderTexture2D target = LoadRenderTexture(screenWidth, screenHeight);
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// Load Eratosthenes shader
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// NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
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Shader shader = LoadShader(0, TextFormat("resources/shaders/glsl%i/eratosthenes.fs", GLSL_VERSION));
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SetTargetFPS(60); // Set our game to run at 60 frames-per-second
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//--------------------------------------------------------------------------------------
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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// Update
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//----------------------------------------------------------------------------------
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// Nothing to do here, everything is happening in the shader
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginTextureMode(target); // Enable drawing to texture
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ClearBackground(BLACK); // Clear the render texture
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// Draw a rectangle in shader mode to be used as shader canvas
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// NOTE: Rectangle uses font white character texture coordinates,
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// so shader can not be applied here directly because input vertexTexCoord
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// do not represent full screen coordinates (space where want to apply shader)
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DrawRectangle(0, 0, GetScreenWidth(), GetScreenHeight(), BLACK);
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EndTextureMode(); // End drawing to texture (now we have a blank texture available for the shader)
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BeginDrawing();
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ClearBackground(RAYWHITE); // Clear screen background
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BeginShaderMode(shader);
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// NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
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DrawTextureRec(target.texture, (Rectangle){ 0, 0, (float)target.texture.width, (float)-target.texture.height }, (Vector2){ 0.0f, 0.0f }, WHITE);
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EndShaderMode();
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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// De-Initialization
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//--------------------------------------------------------------------------------------
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UnloadShader(shader); // Unload shader
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UnloadRenderTexture(target); // Unload render texture
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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}
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