REVIEWED: example: Compute shader Game-of-life

examples/others/rlgl_compute_shader.c

@@ -0,0 +1,173 @@
+/*******************************************************************************************
+*
+*   raylib [rlgl] example - compute shader - Conway's Game of Life
+*
+*   NOTE: This example requires raylib OpenGL 4.3 versions for compute shaders support,
+*         shaders used in this example are #version 430 (OpenGL 4.3)
+*
+*   This example has been created using raylib 4.0 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Example contributed by Teddy Astie (@tsnake41) and reviewed by Ramon Santamaria (@raysan5)
+*
+*   Copyright (c) 2021 Teddy Astie (@tsnake41)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+#include "rlgl.h"
+
+#include <stdlib.h>
+
+// IMPORTANT: This must match gol*.glsl GOL_WIDTH constant.
+// This must be a multiple of 16 (check golLogic compute dispatch).
+#define GOL_WIDTH 768
+
+// Maximum amount of queued draw commands (squares draw from mouse down events).
+#define MAX_BUFFERED_TRANSFERTS 48
+
+// Game Of Life Update Command
+typedef struct GolUpdateCmd {
+    unsigned int x;         // x coordinate of the gol command
+    unsigned int y;         // y coordinate of the gol command
+    unsigned int w;         // width of the filled zone
+    unsigned int enabled;   // whether to enable or disable zone
+} GolUpdateCmd;
+
+// Game Of Life Update Commands SSBO
+typedef struct GolUpdateSSBO {
+    unsigned int count;
+    GolUpdateCmd commands[MAX_BUFFERED_TRANSFERTS];
+} GolUpdateSSBO;
+
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    InitWindow(GOL_WIDTH, GOL_WIDTH, "raylib [rlgl] example - compute shader - game of life");
+
+    const Vector2 resolution = { GOL_WIDTH, GOL_WIDTH };
+    unsigned int brushSize = 8;
+
+    // Game of Life logic compute shader
+    char *golLogicCode = LoadFileText("resources/shaders/glsl430/gol.glsl");
+    unsigned int golLogicShader = rlCompileShader(golLogicCode, RL_COMPUTE_SHADER);
+    unsigned int golLogicProgram = rlLoadComputeShaderProgram(golLogicShader);
+    UnloadFileText(golLogicCode);
+
+    // Game of Life logic compute shader
+    Shader golRenderShader = LoadShader(NULL, "resources/shaders/glsl430/gol_render.glsl");
+    int resUniformLoc = GetShaderLocation(golRenderShader, "resolution");
+
+    // Game of Life transfert shader
+    char *golTransfertCode = LoadFileText("resources/shaders/glsl430/gol_transfert.glsl");
+    unsigned int golTransfertShader = rlCompileShader(golTransfertCode, RL_COMPUTE_SHADER);
+    unsigned int golTransfertProgram = rlLoadComputeShaderProgram(golTransfertShader);
+    UnloadFileText(golTransfertCode);
+
+    // SSBOs
+    unsigned int ssboA = rlLoadShaderBuffer(GOL_WIDTH*GOL_WIDTH*sizeof(unsigned int), NULL, RL_DYNAMIC_COPY);
+    unsigned int ssboB = rlLoadShaderBuffer(GOL_WIDTH*GOL_WIDTH*sizeof(unsigned int), NULL, RL_DYNAMIC_COPY);
+
+    struct GolUpdateSSBO transfertBuffer;
+    transfertBuffer.count = 0;
+
+    int transfertSSBO = rlLoadShaderBuffer(sizeof(struct GolUpdateSSBO), NULL, RL_DYNAMIC_COPY);
+
+    // Create a white texture of the size of the window to update 
+    // each pixel of the window using the fragment shader
+    Image whiteImage = GenImageColor(GOL_WIDTH, GOL_WIDTH, WHITE);
+    Texture whiteTex = LoadTextureFromImage(whiteImage);
+    UnloadImage(whiteImage);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        brushSize += (int)GetMouseWheelMove();
+
+        if ((IsMouseButtonDown(MOUSE_BUTTON_LEFT) || IsMouseButtonDown(MOUSE_BUTTON_RIGHT))
+            && (transfertBuffer.count < MAX_BUFFERED_TRANSFERTS))
+        {
+            // Buffer a new command
+            transfertBuffer.commands[transfertBuffer.count].x = GetMouseX() - brushSize/2;
+            transfertBuffer.commands[transfertBuffer.count].y = GetMouseY() - brushSize/2;
+            transfertBuffer.commands[transfertBuffer.count].w = brushSize;
+            transfertBuffer.commands[transfertBuffer.count].enabled = IsMouseButtonDown(MOUSE_BUTTON_LEFT);
+            transfertBuffer.count++;
+        }
+        else if (transfertBuffer.count > 0)
+        {
+            // Process transfert buffer
+
+            // Send SSBO buffer to GPU
+            rlUpdateShaderBufferElements(transfertSSBO, &transfertBuffer, sizeof(struct GolUpdateSSBO), 0);
+            
+            // Process ssbo command
+            rlEnableShader(golTransfertProgram);
+            rlBindShaderBuffer(ssboA, 1);
+            rlBindShaderBuffer(transfertSSBO, 3);
+            rlComputeShaderDispatch(transfertBuffer.count, 1, 1); // each GPU unit will process a command
+            rlDisableShader();
+
+            transfertBuffer.count = 0;
+        }
+        else
+        {
+            // Process game of life logic
+            rlEnableShader(golLogicProgram);
+            rlBindShaderBuffer(ssboA, 1);
+            rlBindShaderBuffer(ssboB, 2);
+            rlComputeShaderDispatch(GOL_WIDTH/16, GOL_WIDTH/16, 1);
+            rlDisableShader();
+
+            // ssboA <-> ssboB
+            int temp = ssboA;
+            ssboA = ssboB;
+            ssboB = temp;
+        }
+
+        rlBindShaderBuffer(ssboA, 1);
+        SetShaderValue(golRenderShader, resUniformLoc, &resolution, SHADER_UNIFORM_VEC2);
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(BLANK);
+
+            BeginShaderMode(golRenderShader);
+                DrawTexture(whiteTex, 0, 0, WHITE);
+            EndShaderMode();
+            
+            DrawRectangleLines(GetMouseX() - brushSize/2, GetMouseY() - brushSize/2, brushSize, brushSize, RED);
+
+            DrawText("Use Mouse wheel to increase/decrease brush size", 10, 10, 20, WHITE);
+            DrawFPS(GetScreenWidth() - 100, 10);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    // Unload shader buffers objects.
+    rlUnloadShaderBuffer(ssboA);
+    rlUnloadShaderBuffer(ssboB);
+    rlUnloadShaderBuffer(transfertSSBO);
+
+    // Unload compute shader programs
+    rlUnloadShaderProgram(golTransfertProgram);
+    rlUnloadShaderProgram(golLogicProgram);
+
+    UnloadTexture(whiteTex);            // Unload white texture
+    UnloadShader(golRenderShader);      // Unload rendering fragment shader
+
+    CloseWindow();                      // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}