1/*******************************************************************************************
2*
3* raylib [shaders] example - Sieve of Eratosthenes
4*
5* Sieve of Eratosthenes, the earliest known (ancient Greek) prime number sieve.
6*
7* "Sift the twos and sift the threes,
8* The Sieve of Eratosthenes.
9* When the multiples sublime,
10* the numbers that are left are prime."
11*
12* NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
13* OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version.
14*
15* NOTE: Shaders used in this example are #version 330 (OpenGL 3.3).
16*
17* This example has been created using raylib 2.5 (www.raylib.com)
18* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
19*
20* Example contributed by ProfJski and reviewed by Ramon Santamaria (@raysan5)
21*
22* Copyright (c) 2019 ProfJski and Ramon Santamaria (@raysan5)
23*
24********************************************************************************************/
25
26#include "raylib.h"
27
28#if defined(PLATFORM_DESKTOP)
29 #define GLSL_VERSION 330
30#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
31 #define GLSL_VERSION 100
32#endif
33
34int main(void)
35{
36 // Initialization
37 //--------------------------------------------------------------------------------------
38 const int screenWidth = 800;
39 const int screenHeight = 450;
40
41 InitWindow(screenWidth, screenHeight, "raylib [shaders] example - Sieve of Eratosthenes");
42
43 RenderTexture2D target = LoadRenderTexture(screenWidth, screenHeight);
44
45 // Load Eratosthenes shader
46 // NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
47 Shader shader = LoadShader(0, FormatText("resources/shaders/glsl%i/eratosthenes.fs", GLSL_VERSION));
48
49 SetTargetFPS(60); // Set our game to run at 60 frames-per-second
50 //--------------------------------------------------------------------------------------
51
52 // Main game loop
53 while (!WindowShouldClose()) // Detect window close button or ESC key
54 {
55 // Update
56 //----------------------------------------------------------------------------------
57 // Nothing to do here, everything is happening in the shader
58 //----------------------------------------------------------------------------------
59
60 // Draw
61 //----------------------------------------------------------------------------------
62 BeginDrawing();
63
64 ClearBackground(RAYWHITE);
65
66 BeginTextureMode(target); // Enable drawing to texture
67 ClearBackground(BLACK); // Clear the render texture
68
69 // Draw a rectangle in shader mode to be used as shader canvas
70 // NOTE: Rectangle uses font white character texture coordinates,
71 // so shader can not be applied here directly because input vertexTexCoord
72 // do not represent full screen coordinates (space where want to apply shader)
73 DrawRectangle(0, 0, GetScreenWidth(), GetScreenHeight(), BLACK);
74 EndTextureMode(); // End drawing to texture (now we have a blank texture available for the shader)
75
76 BeginShaderMode(shader);
77 // NOTE: Render texture must be y-flipped due to default OpenGL coordinates (left-bottom)
78 DrawTextureRec(target.texture, (Rectangle){ 0, 0, target.texture.width, -target.texture.height }, (Vector2){ 0.0f, 0.0f }, WHITE);
79 EndShaderMode();
80
81 EndDrawing();
82 //----------------------------------------------------------------------------------
83 }
84
85 // De-Initialization
86 //--------------------------------------------------------------------------------------
87 UnloadShader(shader); // Unload shader
88 UnloadRenderTexture(target); // Unload texture
89
90 CloseWindow(); // Close window and OpenGL context
91 //--------------------------------------------------------------------------------------
92
93 return 0;
94}
95