248 lines
9.8 KiB
C#
248 lines
9.8 KiB
C#
/*******************************************************************************************
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*
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* raylib [textures] example - framebuffer rendering
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*
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* Example complexity rating: [★★☆☆] 2/4
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*
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* Example originally created with raylib 5.6, last time updated with raylib 5.6
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*
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* Example contributed by Jack Boakes (@jackboakes) 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) 2026 Jack Boakes (@jackboakes)
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*
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********************************************************************************************/
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using System.Numerics;
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using static Raylib_cs.Raylib;
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using static Raylib_cs.Raymath;
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namespace Examples.Textures;
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public partial class FramebufferRendering : IExample
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{
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private const int screenWidth = 800;
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private const int screenHeight = 450;
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private const int splitWidth = screenWidth / 2;
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public string Name => "Textures / Framebuffer Rendering";
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public string Title => "raylib [textures] example - framebuffer rendering";
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public bool CursorDisabled => true;
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private Camera3D subjectCamera;
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private Camera3D observerCamera;
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private RenderTexture2D observerTarget;
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private Rectangle observerSource;
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private Rectangle observerDest;
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private RenderTexture2D subjectTarget;
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private Rectangle subjectSource;
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private Rectangle subjectDest;
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private float textureAspectRatio;
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private const float captureSize = 128.0f;
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private Rectangle cropSource;
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private Rectangle cropDest;
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public void Init()
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{
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// Camera to look at the 3D world
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subjectCamera = new Camera3D();
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subjectCamera.Position = new Vector3(5.0f, 5.0f, 5.0f);
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subjectCamera.Target = new Vector3(0.0f, 0.0f, 0.0f);
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subjectCamera.Up = new Vector3(0.0f, 1.0f, 0.0f);
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subjectCamera.FovY = 45.0f;
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subjectCamera.Projection = CameraProjection.Perspective;
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// Camera to observe the subject camera and 3D world
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observerCamera = new Camera3D();
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observerCamera.Position = new Vector3(10.0f, 10.0f, 10.0f);
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observerCamera.Target = new Vector3(0.0f, 0.0f, 0.0f);
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observerCamera.Up = new Vector3(0.0f, 1.0f, 0.0f);
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observerCamera.FovY = 45.0f;
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observerCamera.Projection = CameraProjection.Perspective;
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// Set up render textures
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observerTarget = LoadRenderTexture(splitWidth, screenHeight);
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observerSource = new Rectangle(0.0f, 0.0f, observerTarget.Texture.Width, -observerTarget.Texture.Height);
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observerDest = new Rectangle(0.0f, 0.0f, splitWidth, screenHeight);
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subjectTarget = LoadRenderTexture(splitWidth, screenHeight);
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subjectSource = new Rectangle(0.0f, 0.0f, subjectTarget.Texture.Width, -subjectTarget.Texture.Height);
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subjectDest = new Rectangle(splitWidth, 0.0f, splitWidth, screenHeight);
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textureAspectRatio = (float)subjectTarget.Texture.Width / subjectTarget.Texture.Height;
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// Rectangles for cropping render texture
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cropSource = new Rectangle((subjectTarget.Texture.Width - captureSize) / 2.0f, (subjectTarget.Texture.Height - captureSize) / 2.0f, captureSize, -captureSize);
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cropDest = new Rectangle(splitWidth + 20.0f, 20.0f, captureSize, captureSize);
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}
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public void Update()
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{
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// Update
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//----------------------------------------------------------------------------------
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UpdateCamera(ref observerCamera, CameraMode.Free);
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UpdateCamera(ref subjectCamera, CameraMode.Orbital);
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if (IsKeyPressed(KeyboardKey.R))
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{
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observerCamera.Target = new Vector3(0.0f, 0.0f, 0.0f);
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}
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// Build LHS observer view texture
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BeginTextureMode(observerTarget);
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ClearBackground(Color.RayWhite);
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BeginMode3D(observerCamera);
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DrawGrid(10, 1.0f);
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DrawCube(new Vector3(0.0f, 0.0f, 0.0f), 2.0f, 2.0f, 2.0f, Color.Gold);
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DrawCubeWires(new Vector3(0.0f, 0.0f, 0.0f), 2.0f, 2.0f, 2.0f, Color.Pink);
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DrawCameraPrism(subjectCamera, textureAspectRatio, Color.Green);
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EndMode3D();
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DrawText("Observer View", 10, observerTarget.Texture.Height - 30, 20, Color.Black);
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DrawText("WASD + Mouse to Move", 10, 10, 20, Color.DarkGray);
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DrawText("Scroll to Zoom", 10, 30, 20, Color.DarkGray);
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DrawText("R to Reset Observer Target", 10, 50, 20, Color.DarkGray);
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EndTextureMode();
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// Build RHS subject view texture
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BeginTextureMode(subjectTarget);
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ClearBackground(Color.RayWhite);
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BeginMode3D(subjectCamera);
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DrawCube(new Vector3(0.0f, 0.0f, 0.0f), 2.0f, 2.0f, 2.0f, Color.Gold);
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DrawCubeWires(new Vector3(0.0f, 0.0f, 0.0f), 2.0f, 2.0f, 2.0f, Color.Pink);
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DrawGrid(10, 1.0f);
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EndMode3D();
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DrawRectangleLines((int)((subjectTarget.Texture.Width - captureSize) / 2.0f), (int)((subjectTarget.Texture.Height - captureSize) / 2.0f), (int)captureSize, (int)captureSize, Color.Green);
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DrawText("Subject View", 10, subjectTarget.Texture.Height - 30, 20, Color.Black);
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EndTextureMode();
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(Color.Black);
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// Draw observer texture LHS
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DrawTexturePro(observerTarget.Texture, observerSource, observerDest, new Vector2(0.0f, 0.0f), 0.0f, Color.White);
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// Draw subject texture RHS
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DrawTexturePro(subjectTarget.Texture, subjectSource, subjectDest, new Vector2(0.0f, 0.0f), 0.0f, Color.White);
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// Draw the small crop overlay on top
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DrawTexturePro(subjectTarget.Texture, cropSource, cropDest, new Vector2(0.0f, 0.0f), 0.0f, Color.White);
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DrawRectangleLinesEx(cropDest, 2, Color.Black);
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// Draw split screen divider line
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DrawLine(splitWidth, 0, splitWidth, screenHeight, Color.Black);
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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public void Unload()
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{
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UnloadRenderTexture(observerTarget);
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UnloadRenderTexture(subjectTarget);
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}
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//----------------------------------------------------------------------------------
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// Module Functions Definition
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//----------------------------------------------------------------------------------
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private static void DrawCameraPrism(Camera3D camera, float aspect, Color color)
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{
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float length = Vector3Distance(camera.Position, camera.Target);
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// Define the 4 corners of the camera's prism plane sliced at the target in Normalized Device Coordinates
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Vector3[] planeNDC =
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{
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new(-1.0f, -1.0f, 1.0f), // Bottom Left
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new( 1.0f, -1.0f, 1.0f), // Bottom Right
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new( 1.0f, 1.0f, 1.0f), // Top Right
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new(-1.0f, 1.0f, 1.0f) // Top Left
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};
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// Build the matrices
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Matrix4x4 view = GetCameraMatrix(camera);
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Matrix4x4 proj = MatrixPerspective(camera.FovY * DEG2RAD, aspect, 0.05f, length);
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// Combine view and projection so we can reverse the full camera transform
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Matrix4x4 viewProj = MatrixMultiply(view, proj);
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// Invert the view-projection matrix to unproject points from NDC space back into world space
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Matrix4x4 inverseViewProj = MatrixInvert(viewProj);
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// Transform the 4 plane corners from NDC into world space
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Vector3[] corners = new Vector3[4];
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for (int i = 0; i < 4; i++)
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{
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float x = planeNDC[i].X;
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float y = planeNDC[i].Y;
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float z = planeNDC[i].Z;
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// Multiply NDC position by the inverse view-projection matrix
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// This produces a homogeneous (x, y, z, w) position in world space
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float vx = inverseViewProj.M11 * x + inverseViewProj.M12 * y + inverseViewProj.M13 * z + inverseViewProj.M14;
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float vy = inverseViewProj.M21 * x + inverseViewProj.M22 * y + inverseViewProj.M23 * z + inverseViewProj.M24;
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float vz = inverseViewProj.M31 * x + inverseViewProj.M32 * y + inverseViewProj.M33 * z + inverseViewProj.M34;
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float vw = inverseViewProj.M41 * x + inverseViewProj.M42 * y + inverseViewProj.M43 * z + inverseViewProj.M44;
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corners[i] = new Vector3(vx / vw, vy / vw, vz / vw);
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}
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// Draw the far plane sliced at the target
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DrawLine3D(corners[0], corners[1], color);
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DrawLine3D(corners[1], corners[2], color);
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DrawLine3D(corners[2], corners[3], color);
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DrawLine3D(corners[3], corners[0], color);
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// Draw the prism lines from the far plane to the camera position
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for (int i = 0; i < 4; i++)
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{
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DrawLine3D(camera.Position, corners[i], color);
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}
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}
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public static int Main()
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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InitWindow(screenWidth, screenHeight, "raylib [textures] example - framebuffer rendering");
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SetTargetFPS(60);
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DisableCursor();
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//--------------------------------------------------------------------------------------
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var game = new FramebufferRendering();
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game.Init();
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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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game.Update();
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}
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game.Unload();
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// De-Initialization
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//--------------------------------------------------------------------------------------
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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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}
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