diff --git a/examples/core/core_custom_frame_control.c b/examples/core/core_custom_frame_control.c new file mode 100644 index 000000000..c1290abff --- /dev/null +++ b/examples/core/core_custom_frame_control.c @@ -0,0 +1,126 @@ +/******************************************************************************************* +* +* raylib [core] example - custom frame control +* +* WARNING: This is an example for advance users willing to have full control over +* the frame processes. By default, EndDrawing() calls the following processes: +* 1. Draw remaining batch data: rlDrawRenderBatchActive() +* 2. SwapScreenBuffer() +* 3. Frame time control: WaitTime() +* 4. PollInputEvents() +* +* To avoid steps 2, 3 and 4, flag SUPPORT_CUSTOM_FRAME_CONTROL can be enabled in +* config.h (it requires recompiling raylib). This way those steps are up to the user. +* +* Note that enabling this flag invalidates some functions: +* - GetFrameTime() +* - SetTargetFPS() +* - GetFPS() +* +* This example has been created using raylib 3.8 (www.raylib.com) +* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details) +* +* Copyright (c) 2021 Ramon Santamaria (@raysan5) +* +********************************************************************************************/ + +#include "raylib.h" + +int main(void) +{ + // Initialization + //-------------------------------------------------------------------------------------- + const int screenWidth = 800; + const int screenHeight = 450; + + InitWindow(screenWidth, screenHeight, "raylib [core] example - custom frame control"); + + // Custom timming variables + double previousTime = GetTime(); // Previous time measure + double currentTime = 0.0; // Current time measure + double updateDrawTime = 0.0; // Update + Draw time + double waitTime = 0.0; // Wait time (if target fps required) + float deltaTime = 0.0f; // Frame time (Update + Draw + Wait time) + + float timeCounter = 0.0f; // Accumulative time counter (seconds) + float position = 0.0f; // Circle position + bool pause = false; // Pause control flag + + int targetFPS = 60; // Our initial target fps + //-------------------------------------------------------------------------------------- + + // Main game loop + while (!WindowShouldClose()) // Detect window close button or ESC key + { + // Update + //---------------------------------------------------------------------------------- + PollInputEvents(); // Poll input events (SUPPORT_CUSTOM_FRAME_CONTROL) + + if (IsKeyPressed(KEY_SPACE)) pause = !pause; + + if (IsKeyPressed(KEY_UP)) targetFPS += 20; + else if (IsKeyPressed(KEY_DOWN)) targetFPS -= 20; + + if (targetFPS < 0) targetFPS = 0; + + if (!pause) + { + position += 200*deltaTime; // We move at 200 pixels per second + + if (position >= GetScreenWidth()) position = 0; + + timeCounter += deltaTime; // We count time (seconds) + } + //---------------------------------------------------------------------------------- + + // Draw + //---------------------------------------------------------------------------------- + BeginDrawing(); + + ClearBackground(RAYWHITE); + + for (int i = 0; i < GetScreenWidth()/200; i++) DrawRectangle(200*i, 0, 1, GetScreenHeight(), SKYBLUE); + + DrawCircle((int)position, GetScreenHeight()/2 - 25, 50, RED); + + DrawText(FormatText("%03.0f ms", timeCounter*1000.0f), position - 40, GetScreenHeight()/2 - 100, 20, MAROON); + DrawText(FormatText("PosX: %03.0f", position), position - 50, GetScreenHeight()/2 + 40, 20, BLACK); + + DrawText("Circle is moving at a constant 200 pixels/sec,\nindependently of the frame rate.", 10, 10, 20, DARKGRAY); + DrawText("PRESS SPACE to PAUSE MOVEMENT", 10, GetScreenHeight() - 30, 20, GRAY); + DrawText(FormatText("TARGET FPS: %i", targetFPS), GetScreenWidth() - 220, 10, 20, LIME); + DrawText(FormatText("CURRENT FPS: %i", (int)(1.0f/deltaTime)), GetScreenWidth() - 220, 40, 20, GREEN); + + EndDrawing(); + + // NOTE: In case raylib is configured to SUPPORT_CUSTOM_FRAME_CONTROL, + // Events polling, screen buffer swap and frame time control must be managed by the user + + SwapScreenBuffer(); // Flip the back buffer to screen (front buffer) + + currentTime = GetTime(); + updateDrawTime = currentTime - previousTime; + + if (targetFPS > 0) // We want a fixed frame rate + { + waitTime = (1.0f/(float)targetFPS) - updateDrawTime; + if (waitTime > 0.0) + { + WaitTime((float)waitTime*1000.0f); + currentTime = GetTime(); + deltaTime = (float)(currentTime - previousTime); + } + } + else deltaTime = updateDrawTime; // Framerate could be variable + + previousTime = currentTime; + //---------------------------------------------------------------------------------- + } + + // De-Initialization + //-------------------------------------------------------------------------------------- + CloseWindow(); // Close window and OpenGL context + //-------------------------------------------------------------------------------------- + + return 0; +} \ No newline at end of file diff --git a/examples/core/core_custom_frame_control.png b/examples/core/core_custom_frame_control.png new file mode 100644 index 000000000..7d615efe2 Binary files /dev/null and b/examples/core/core_custom_frame_control.png differ