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/*******************************************************************************************
*
* 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_WEB)
#include <emscripten/emscripten.h>
#endif
#if defined(PLATFORM_DESKTOP)
#define GLSL_VERSION 330
#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
#define GLSL_VERSION 100
#endif
//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
int screenWidth = 800;
int screenHeight = 450;
// NOTE: Textures MUST be loaded after Window initialization (OpenGL context is required)
RenderTexture2D target = { 0 };
Shader shader = { 0 };
//----------------------------------------------------------------------------------
// Module Functions Declaration
//----------------------------------------------------------------------------------
void UpdateDrawFrame(void); // Update and Draw one frame
//----------------------------------------------------------------------------------
// Main Enry Point
//----------------------------------------------------------------------------------
int main()
{
// Initialization
//--------------------------------------------------------------------------------------
InitWindow(screenWidth, screenHeight, "raylib [shaders] example - Sieve of Eratosthenes");
// Load Eratosthenes shader
// NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
shader = LoadShader(0, FormatText("resources/shaders/glsl%i/eratosthenes.fs", GLSL_VERSION));
// Create render texture to render to
target = LoadRenderTexture(screenWidth, screenHeight);
#if defined(PLATFORM_WEB)
emscripten_set_main_loop(UpdateDrawFrame, 0, 1);
#else
SetTargetFPS(60); // Set our game to run at 60 frames-per-second
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
UpdateDrawFrame();
}
#endif
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadShader(shader); // Unload shader
UnloadRenderTexture(target); // Unload texture
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------
void UpdateDrawFrame(void)
{
// 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();
//----------------------------------------------------------------------------------
}
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