diff --git a/examples/textures/textures_frame_buffer_rendering.png b/examples/textures/textures_frame_buffer_rendering.png new file mode 100644 index 000000000..e6829f0bd Binary files /dev/null and b/examples/textures/textures_frame_buffer_rendering.png differ diff --git a/examples/textures/textures_framebuffer_rendering.c b/examples/textures/textures_framebuffer_rendering.c new file mode 100644 index 000000000..a8b466187 --- /dev/null +++ b/examples/textures/textures_framebuffer_rendering.c @@ -0,0 +1,208 @@ +/******************************************************************************************* +* +* raylib [textures] example - framebuffer rendering +* +* Example complexity rating: [★★☆☆] 2/4 +* +* Example originally created with raylib 5.6, last time updated with raylib 5.6 +* +* Example contributed by Jack Boakes (@jackboakes) and reviewed by Ramon Santamaria (@raysan5) +* +* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified, +* BSD-like license that allows static linking with closed source software +* +* Copyright (c) 2026-2026 Jack Boakes (@jackboakes) +* +********************************************************************************************/ + +#include "raylib.h" +#include "raymath.h" + +//------------------------------------------------------------------------------------ +// Module Functions Declaration +//------------------------------------------------------------------------------------ +static void DrawCameraPrism(Camera3D camera, float aspect, Color color); + +//------------------------------------------------------------------------------------ +// Program main entry point +//------------------------------------------------------------------------------------ +int main(void) +{ + // Initialization + //-------------------------------------------------------------------------------------- + const int screenWidth = 800; + const int screenHeight = 450; + const int splitWidth = screenWidth/2; + + InitWindow(screenWidth, screenHeight, "raylib [textures] example - framebuffer rendering"); + + // Camera to look at the 3D world + Camera3D subjectCamera = { 0 }; + subjectCamera.position = (Vector3){ 5.0f, 5.0f, 5.0f }; + subjectCamera.target = (Vector3){ 0.0f, 0.0f, 0.0f }; + subjectCamera.up = (Vector3){ 0.0f, 1.0f, 0.0f }; + subjectCamera.fovy = 45.0f; + subjectCamera.projection = CAMERA_PERSPECTIVE; + + // Camera to observe the subject camera and 3D world + Camera3D observerCamera = { 0 }; + observerCamera.position = (Vector3){ 10.0f, 10.0f, 10.0f }; + observerCamera.target = (Vector3){ 0.0f, 0.0f, 0.0f }; + observerCamera.up = (Vector3){ 0.0f, 1.0f, 0.0f }; + observerCamera.fovy = 45.0f; + observerCamera.projection = CAMERA_PERSPECTIVE; + + // Set up render textures + RenderTexture2D observerTarget = LoadRenderTexture(splitWidth, screenHeight); + Rectangle observerSource = { 0.0f, 0.0f, (float)observerTarget.texture.width, -(float)observerTarget.texture.height }; + Rectangle observerDest = { 0.0f, 0.0f, (float)splitWidth, (float)screenHeight }; + + RenderTexture2D subjectTarget = LoadRenderTexture(splitWidth, screenHeight); + Rectangle subjectSource = { 0.0f, 0.0f, (float)subjectTarget.texture.width, -(float)subjectTarget.texture.height }; + Rectangle subjectDest = { (float)splitWidth, 0.0f, (float)splitWidth, (float)screenHeight }; + const float textureAspectRatio = (float)subjectTarget.texture.width/(float)subjectTarget.texture.height; + + // Rectangles for cropping render texture + const float captureSize = 128.0f; + Rectangle cropSource = { (subjectTarget.texture.width - captureSize)/2.0f, (subjectTarget.texture.height - captureSize)/2.0f, captureSize, -captureSize }; + Rectangle cropDest = { splitWidth + 20, 20, captureSize, captureSize}; + + SetTargetFPS(60); + DisableCursor(); + //-------------------------------------------------------------------------------------- + + // Main game loop + while (!WindowShouldClose()) // Detect window close button or ESC key + { + // Update + //---------------------------------------------------------------------------------- + UpdateCamera(&observerCamera, CAMERA_FREE); + UpdateCamera(&subjectCamera, CAMERA_ORBITAL); + + if (IsKeyPressed(KEY_R)) observerCamera.target = (Vector3){ 0.0f, 0.0f, 0.0f }; + + // Build LHS observer view texture + BeginTextureMode(observerTarget); + + ClearBackground(RAYWHITE); + + BeginMode3D(observerCamera); + + DrawGrid(10, 1.0f); + DrawCube((Vector3){ 0.0f, 0.0f, 0.0f }, 2.0f, 2.0f, 2.0f, GOLD); + DrawCubeWires((Vector3){ 0.0f, 0.0f, 0.0f }, 2.0f, 2.0f, 2.0f, PINK); + DrawCameraPrism(subjectCamera, textureAspectRatio, GREEN); + + EndMode3D(); + + DrawText("Observer View", 10, observerTarget.texture.height - 30, 20, BLACK); + DrawText("WASD + Mouse to Move", 10, 10, 20, DARKGRAY); + DrawText("Scroll to Zoom", 10, 30, 20, DARKGRAY); + DrawText("R to Reset Observer Target", 10, 50, 20, DARKGRAY); + + EndTextureMode(); + + // Build RHS subject view texture + BeginTextureMode(subjectTarget); + + ClearBackground(RAYWHITE); + + BeginMode3D(subjectCamera); + + DrawCube((Vector3){ 0.0f, 0.0f, 0.0f }, 2.0f, 2.0f, 2.0f, GOLD); + DrawCubeWires((Vector3){ 0.0f, 0.0f, 0.0f }, 2.0f, 2.0f, 2.0f, PINK); + DrawGrid(10, 1.0f); + + EndMode3D(); + + DrawRectangleLines((subjectTarget.texture.width - captureSize)/2, (subjectTarget.texture.height - captureSize)/2, captureSize, captureSize, GREEN); + DrawText("Subject View", 10, subjectTarget.texture.height - 30, 20, BLACK); + + EndTextureMode(); + //---------------------------------------------------------------------------------- + + // Draw + //---------------------------------------------------------------------------------- + BeginDrawing(); + + ClearBackground(BLACK); + + // Draw observer texture LHS + DrawTexturePro(observerTarget.texture, observerSource, observerDest, (Vector2){0.0f, 0.0f }, 0.0f, WHITE); + + // Draw subject texture RHS + DrawTexturePro(subjectTarget.texture, subjectSource, subjectDest, (Vector2){ 0.0f, 0.0f }, 0.0f, WHITE); + + // Draw the small crop overlay on top + DrawTexturePro(subjectTarget.texture, cropSource, cropDest, (Vector2){ 0.0f, 0.0f }, 0.0f, WHITE); + DrawRectangleLinesEx(cropDest, 2, BLACK); + + // Draw split screen divider line + DrawLine(splitWidth, 0, splitWidth, screenHeight, BLACK); + + EndDrawing(); + //---------------------------------------------------------------------------------- + } + + // De-Initialization + //-------------------------------------------------------------------------------------- + UnloadRenderTexture(observerTarget); + UnloadRenderTexture(subjectTarget); + CloseWindow(); // Close window and OpenGL context + //-------------------------------------------------------------------------------------- + + return 0; +} + +//---------------------------------------------------------------------------------- +// Module Functions Definition +//---------------------------------------------------------------------------------- +static void DrawCameraPrism(Camera3D camera, float aspect, Color color) +{ + float length = Vector3Distance(camera.position, camera.target); + // Define the 4 corners of the camera's prism plane sliced at the target in Normalized Device Coordinates + Vector3 planeNDC[4] = { + { -1.0f, -1.0f, 1.0f }, // Bottom Left + { 1.0f, -1.0f, 1.0f }, // Bottom Right + { 1.0f, 1.0f, 1.0f }, // Top Right + { -1.0f, 1.0f, 1.0f } // Top Left + }; + + // Build the matrices + Matrix view = GetCameraMatrix(camera); + Matrix proj = MatrixPerspective(camera.fovy * DEG2RAD, aspect, 0.05f, length); + // Combine view and projection so we can reverse the full camera transform + Matrix viewProj = MatrixMultiply(view, proj); + // Invert the view-projection matrix to unproject points from NDC space back into world space + Matrix inverseViewProj = MatrixInvert(viewProj); + + // Transform the 4 plane corners from NDC into world space + Vector3 corners[4]; + for (int i = 0; i < 4; i++) + { + float x = planeNDC[i].x; + float y = planeNDC[i].y; + float z = planeNDC[i].z; + + // Multiply NDC position by the inverse view-projection matrix + // This produces a homogeneous (x, y, z, w) position in world space + float vx = inverseViewProj.m0*x + inverseViewProj.m4*y + inverseViewProj.m8*z + inverseViewProj.m12; + float vy = inverseViewProj.m1*x + inverseViewProj.m5*y + inverseViewProj.m9*z + inverseViewProj.m13; + float vz = inverseViewProj.m2*x + inverseViewProj.m6*y + inverseViewProj.m10*z + inverseViewProj.m14; + float vw = inverseViewProj.m3*x + inverseViewProj.m7*y + inverseViewProj.m11*z + inverseViewProj.m15; + + corners[i] = (Vector3){ vx/vw, vy/vw, vz/vw }; + } + + // Draw the far plane sliced at the target + DrawLine3D(corners[0], corners[1], color); + DrawLine3D(corners[1], corners[2], color); + DrawLine3D(corners[2], corners[3], color); + DrawLine3D(corners[3], corners[0], color); + + // Draw the prism lines from the far plane to the camera position + for (int i = 0; i < 4; i++) + { + DrawLine3D(camera.position, corners[i], color); + } +} \ No newline at end of file