Add a split screen example showing render texture use and multiple cameras. (#1806)

Co-authored-by: Jeffery Myers <JefMyers@blizzard.com>

examples/core/core_split_screen.c

@@ -0,0 +1,161 @@
+/*******************************************************************************************
+*
+*   raylib [core] example - split screen
+*
+*   Welcome to raylib!
+*
+*   To test examples, just press F6 and execute raylib_compile_execute script
+*   Note that compiled executable is placed in the same folder as .c file
+*
+*   You can find all basic examples on C:\raylib\raylib\examples folder or
+*   raylib official webpage: www.raylib.com
+*
+*   Enjoy using raylib. :)
+*
+*   This example has been created using raylib 3.7 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Copyright (c) 2013-2016 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+Texture2D GridTexture;
+Camera Player1Camera = { 0 };
+Camera Player2Camera = { 0 };
+
+void DrawScene()
+{
+    // grid of cube trees on a plane to make a "world"
+    DrawPlane((Vector3){ 0, 0, 0 }, (Vector2){ 50, 50 }, BEIGE); // simple world plane
+    float spacing = 4;
+    int count = 5;
+
+    for (float x = -count * spacing; x <= count * spacing; x += spacing)
+    {
+        for (float z = -count * spacing; z <= count * spacing; z += spacing)
+        {
+            Vector3 pos = { x, 0.5f, z };
+
+            Vector3 min = { x - 0.5f,0,z - 0.5f };
+            Vector3 max = { x + 0.5f,1,z + 0.5f };
+ 
+            DrawCubeTexture(GridTexture, (Vector3) { x, 1.5f, z }, 1, 1, 1, GREEN);
+            DrawCubeTexture(GridTexture, (Vector3) { x, 0.5f, z }, 0.25f, 1, 0.25f, BROWN);
+        }
+    }
+
+    // draw a cube at each player's position
+    DrawCube(Player1Camera.position, 1, 1, 1, RED);
+    DrawCube(Player2Camera.position, 1, 1, 1, BLUE);
+}
+
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [core] example - split screen");
+    SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
+
+    // generate a simple texture to use for trees
+    Image img = GenImageChecked(256, 256, 32, 32, DARKGRAY, WHITE);
+    GridTexture = LoadTextureFromImage(img);
+    UnloadImage(img);
+    SetTextureFilter(GridTexture, TEXTURE_FILTER_ANISOTROPIC_16X);
+    SetTextureWrap(GridTexture, TEXTURE_WRAP_CLAMP);
+
+
+    // setup player 1 camera and screen
+    Player1Camera.fovy = 45;
+    Player1Camera.up.y = 1;
+    Player1Camera.target.y = 1;
+    Player1Camera.position.z = -3;
+    Player1Camera.position.y = 1;
+
+    RenderTexture player1Screen = LoadRenderTexture(screenWidth / 2, screenHeight);
+
+    // setup player two camera and screen
+    Player2Camera.fovy = 45;
+    Player2Camera.up.y = 1;
+    Player2Camera.target.y =3;
+    Player2Camera.position.x = -3;
+    Player2Camera.position.y = 3;
+
+    RenderTexture player2Screen = LoadRenderTexture(screenWidth / 2, screenHeight);
+   
+    // build a flipped rectangle the size of the split view to use for drawing later
+    Rectangle splitScreenRect = { 0,0, (float)player1Screen.texture.width, (float)-player1Screen.texture.height };
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // if anyone moves this frame, how far will they move based on the time since the last frame
+        // this moves thigns at 10 world units per second, regardless of the actual FPS
+        float offsetThisFrame = 10 * GetFrameTime();
+
+
+        // move player 1 forward and backwards (no turning)
+        if (IsKeyDown(KEY_W))
+        {
+            Player1Camera.position.z += offsetThisFrame;
+            Player1Camera.target.z += offsetThisFrame;
+        }
+        else if (IsKeyDown(KEY_S))
+        {
+            Player1Camera.position.z -= offsetThisFrame;
+            Player1Camera.target.z -= offsetThisFrame;
+        }
+
+        // move player 2 forward and backwards (no turning)
+        if (IsKeyDown(KEY_UP))
+        {
+            Player2Camera.position.x += offsetThisFrame;
+            Player2Camera.target.x += offsetThisFrame;
+        }
+        else if (IsKeyDown(KEY_DOWN))
+        {
+            Player2Camera.position.x -= offsetThisFrame;
+            Player2Camera.target.x -= offsetThisFrame;
+        }
+
+        // draw player 1's view to the render texture
+        BeginTextureMode(player1Screen);
+        ClearBackground(SKYBLUE);
+        BeginMode3D(Player1Camera);
+        DrawScene();
+        EndMode3D();
+        DrawText("PLAYER1 W/S to move", 0, 0, 20, RED);
+        EndTextureMode();
+
+        // draw player 2's view to the render texture
+        BeginTextureMode(player2Screen);
+        ClearBackground(SKYBLUE);
+        BeginMode3D(Player2Camera);
+        DrawScene();
+        EndMode3D();
+        DrawText("PLAYER2 UP/DOWN to move", 0, 0, 20, BLUE);
+        EndTextureMode();
+
+        // draw both view render textures to the screen side by side
+        BeginDrawing();
+        ClearBackground(BLACK);
+        DrawTextureRec(player1Screen.texture, splitScreenRect, (Vector2) { 0, 0 }, WHITE);
+        DrawTextureRec(player2Screen.texture, splitScreenRect, (Vector2) { screenWidth/2.0f, 0 }, WHITE);
+        EndDrawing();
+    }
+
+    UnloadRenderTexture(player1Screen);
+    UnloadRenderTexture(player2Screen);
+    UnloadTexture(GridTexture);
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}