[examples] Added: textures_screen_buffer (#5357)

* Example textures_screen_buffer

* remove resource preload for web makefile

* update description

* code formatting

examples/Makefile

@@ -619,6 +619,7 @@ TEXTURES = \
     textures/textures_sprite_button \
     textures/textures_sprite_explosion \
     textures/textures_srcrec_dstrec \
+    textures/textures_screen_buffer \
     textures/textures_textured_curve \
     textures/textures_tiled_drawing \
     textures/textures_to_image

examples/Makefile.Web

@@ -607,6 +607,7 @@ TEXTURES = \
     textures/textures_sprite_button \
     textures/textures_sprite_explosion \
     textures/textures_srcrec_dstrec \
+    textures/textures_screen_buffer \
     textures/textures_textured_curve \
     textures/textures_tiled_drawing \
     textures/textures_to_image
@@ -1058,6 +1059,9 @@ textures/textures_srcrec_dstrec: textures/textures_srcrec_dstrec.c
 	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDE_PATHS) $(LDFLAGS) $(LDLIBS) -D$(PLATFORM) \
     --preload-file textures/resources/scarfy.png@resources/scarfy.png
 
+textures/textures_screen_buffer: textures/textures_screen_buffer.c
+	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDE_PATHS) $(LDFLAGS) $(LDLIBS) -D$(PLATFORM)
+
 textures/textures_textured_curve: textures/textures_textured_curve.c
 	$(CC) -o $@$(EXT) $< $(CFLAGS) $(INCLUDE_PATHS) $(LDFLAGS) $(LDLIBS) -D$(PLATFORM) \
     --preload-file textures/resources/road.png@resources/road.png

examples/README.md

@@ -17,7 +17,7 @@ You may find it easier to use than other toolchains, especially when it comes to
 - `zig build [module]` to compile all examples for a module (e.g. `zig build core`)
 - `zig build [example]` to compile _and run_ a particular example (e.g. `zig build core_basic_window`)
 
-## EXAMPLES COLLECTION [TOTAL: 194]
+## EXAMPLES COLLECTION [TOTAL: 195]
 
 ### category: core [47]
 
@@ -114,7 +114,7 @@ Examples using raylib shapes drawing functionality, provided by raylib [shapes](
 | [shapes_lines_drawing](shapes/shapes_lines_drawing.c) | <img src="shapes/shapes_lines_drawing.png" alt="shapes_lines_drawing" width="80"> | ⭐☆☆☆ | 5.6-dev | 5.6 | [Robin](https://github.com/RobinsAviary) |
 | [shapes_math_angle_rotation](shapes/shapes_math_angle_rotation.c) | <img src="shapes/shapes_math_angle_rotation.png" alt="shapes_math_angle_rotation" width="80"> | ⭐☆☆☆ | 5.6-dev | 5.6 | [Kris](https://github.com/krispy-snacc) |
 
-### category: textures [26]
+### category: textures [27]
 
 Examples using raylib textures functionality, including image/textures loading/generation and drawing, provided by raylib [textures](../src/rtextures.c) module.
 
@@ -145,6 +145,7 @@ Examples using raylib textures functionality, including image/textures loading/g
 | [textures_image_kernel](textures/textures_image_kernel.c) | <img src="textures/textures_image_kernel.png" alt="textures_image_kernel" width="80"> | ⭐⭐⭐⭐️ | 1.3 | 1.3 | [Karim Salem](https://github.com/kimo-s) |
 | [textures_image_channel](textures/textures_image_channel.c) | <img src="textures/textures_image_channel.png" alt="textures_image_channel" width="80"> | ⭐⭐☆☆ | 5.5 | 5.5 | [Bruno Cabral](https://github.com/brccabral) |
 | [textures_image_rotate](textures/textures_image_rotate.c) | <img src="textures/textures_image_rotate.png" alt="textures_image_rotate" width="80"> | ⭐⭐☆☆ | 1.0 | 1.0 | [Ramon Santamaria](https://github.com/raysan5) |
+| [textures_screen_buffer](textures/textures_screen_buffer.c) | <img src="textures/textures_screen_buffer.png" alt="textures_screen_buffer" width="80"> | ⭐⭐☆☆ | 5.5 | 5.5 | [Agnis Aldins](https://github.com/nezvers) |
 | [textures_textured_curve](textures/textures_textured_curve.c) | <img src="textures/textures_textured_curve.png" alt="textures_textured_curve" width="80"> | ⭐⭐⭐☆ | 4.5 | 4.5 | [Jeffery Myers](https://github.com/JeffM2501) |
 
 ### category: text [15]

examples/examples_list.txt

@@ -113,6 +113,7 @@ textures;textures_gif_player;★★★☆;4.2;4.2;2021;2025;"Ramon Santamaria";@
 textures;textures_image_kernel;★★★★;1.3;1.3;2015;2025;"Karim Salem";@kimo-s
 textures;textures_image_channel;★★☆☆;5.5;5.5;2024;2025;"Bruno Cabral";@brccabral
 textures;textures_image_rotate;★★☆☆;1.0;1.0;2014;2025;"Ramon Santamaria";@raysan5
+textures;textures_screen_buffer;★★☆☆;5.5;5.5;2014;2025;"Agnis Aldins";@nezvers
 textures;textures_textured_curve;★★★☆;4.5;4.5;2022;2025;"Jeffery Myers";@JeffM2501
 text;text_sprite_fonts;★☆☆☆;1.7;3.7;2017;2025;"Ramon Santamaria";@raysan5
 text;text_font_spritefont;★☆☆☆;1.0;1.0;2014;2025;"Ramon Santamaria";@raysan5

examples/textures/textures_screen_buffer.c

@@ -0,0 +1,161 @@
+/*******************************************************************************************
+*
+*   raylib [textures] example - screen buffer / update Image as screen buffer and display with texture
+*
+*   Example complexity rating: [★★☆☆] 2/4
+*
+*   Example originally created with raylib 5.5, last time updated with raylib 5.6
+*
+*   Example contributed by Agnis Aldiņš (@nezvers) 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) 2025 Agnis Aldiņš (@nezvers)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+#define MAX_COLORS 256
+#define SCREEN_WIDTH 800
+#define SCREEN_HEIGHT 450
+#define SCALE_FACTOR 2
+// buffer size at least for screenImage pixel count
+#define INDEX_BUFFER_SIZE ((SCREEN_WIDTH * SCREEN_HEIGHT) / SCALE_FACTOR)
+#define FLAME_WIDTH (SCREEN_WIDTH / SCALE_FACTOR)
+
+static void GeneretePalette(Color *palette);
+static void ClearIndexBuffer(unsigned char *buffer, int count);
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = SCREEN_WIDTH;
+    const int screenHeight = SCREEN_HEIGHT;
+    const int pixelScale = SCALE_FACTOR;
+    const int imageWidth = screenWidth / pixelScale;
+    const int imageHeight = screenHeight / pixelScale;
+    InitWindow(screenWidth, screenHeight, "raylib [<module>] example - <name>");
+
+    Color palette[MAX_COLORS] = {0};
+    unsigned char indexBuffer[INDEX_BUFFER_SIZE] = {0};
+    unsigned char flameRootBuffer[FLAME_WIDTH] = {0};
+    
+    Image screenImage = GenImageColor(imageWidth, imageHeight, BLACK);
+    Texture screenTexture = LoadTextureFromImage(screenImage);
+    GeneretePalette(palette);
+    ClearIndexBuffer(indexBuffer, INDEX_BUFFER_SIZE);
+    ClearIndexBuffer(flameRootBuffer, FLAME_WIDTH);
+
+    SetTargetFPS(60);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Grow flameRoot
+        for (int x = 2; x < FLAME_WIDTH; ++x)
+        {
+            unsigned short flame = flameRootBuffer[x];
+            if (flame == 255) continue;
+            flame += GetRandomValue(0, 2);
+            if (flame > 255) flame = 255;
+            flameRootBuffer[x] = flame;
+        }
+
+        // transfer flameRoot to indexBuffer
+        for (int x = 0; x < FLAME_WIDTH; ++x)
+        {
+            int i = x + (imageHeight - 1) * imageWidth;
+            indexBuffer[i] = flameRootBuffer[x];
+        }
+        
+        // Clear top row, because it can't move any higher
+        for (int x = 0; x < imageWidth; ++x)
+        {
+            if (indexBuffer[x] == 0) continue;
+            indexBuffer[x] = 0;
+        }
+
+        // Skip top row, it is already cleared
+        for (int y = 1; y < imageHeight; ++y)
+        {
+            for (int x = 0; x < imageWidth; ++x)
+            {
+                unsigned i = x + y * imageWidth;
+                unsigned char colorIndex = indexBuffer[i];
+                if (colorIndex == 0) continue;
+                
+                // Move pixel a row above
+                indexBuffer[i] = 0;
+                int moveX = GetRandomValue(0, 2) - 1;
+                int newX = x + moveX;
+                if (newX < 0 || newX >= imageWidth) continue;
+
+                unsigned i_above = i - imageWidth + moveX;
+                int decay = GetRandomValue(0, 3);
+                colorIndex -= (decay < colorIndex) ? decay : colorIndex;
+                indexBuffer[i_above] = colorIndex;
+            }
+        }
+
+        // Update screenImage with palette colors
+        for (int y = 1; y < imageHeight; ++y)
+        {
+            for (int x = 0; x < imageWidth; ++x)
+            {
+                unsigned i = x + y * imageWidth;
+                unsigned char colorIndex = indexBuffer[i];
+                Color col = palette[colorIndex];
+                ImageDrawPixel(&screenImage, x, y, col);
+            }
+        }
+        
+        UpdateTexture(screenTexture, screenImage.data);
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+            const Vector2 origin = (Vector2){0, 0};
+            const float rotation = 0.f;
+            DrawTextureEx(screenTexture, origin, rotation, pixelScale, WHITE);
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+
+    UnloadTexture(screenTexture);
+    UnloadImage(screenImage);
+
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
+
+static void GeneretePalette(Color *palette)
+{
+    for (int i = 0; i < MAX_COLORS; ++i)
+    {
+        float t = (float)i/(float)(MAX_COLORS - 1);
+        float hue = t * t;
+        float saturation = t;
+        float value = t;
+        palette[i] = ColorFromHSV(250.f + 150.f * hue, saturation, value);
+    }
+}
+
+static void ClearIndexBuffer(unsigned char *buffer, int count)
+{
+    // Use memset to set to ZERO, but for demonstration a plain for loop is used
+    for (int i = 0; i < count; ++i)
+    {
+        buffer[i] = 0;
+    }
+}