initial commit

2024-06-16 22:35:36 +01:00
commit 5184b36853
6 changed files with 209 additions and 0 deletions
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -0,0 +1,193 @@
+#include <windows.h>
+#include <stdint.h>
+
+#define internal static // for functions
+#define local_persist static // for static variables in a scope
+#define global static // for global variables
+
+struct Win32OffscreenBuffer {
+    BITMAPINFO info;
+    void *memory;
+    int width;
+    int height;
+    int bytesPerPixel;
+};
+
+struct Win32WindowDimensions {
+    int width;
+    int height;
+};
+
+global bool running;
+global Win32OffscreenBuffer globalBackBuffer;
+
+typedef uint8_t uint8;
+typedef uint16_t uint16;
+typedef uint32_t uint32;
+typedef uint64_t uint64;
+typedef int8_t int8;
+typedef int16_t int16;
+typedef int32_t int32;
+typedef int64_t int64;
+
+internal void renderWeirdGradient(Win32OffscreenBuffer buffer, int xOffset, int yOffset) {
+    int bytesPerPixel = 4;
+    int pitch = buffer.width*bytesPerPixel;
+    uint8 *row = (uint8*)buffer.memory;
+    for (int y = 0; y < buffer.height; y++) {
+        uint32 *pixel = (uint32*)row;
+        for (int x = 0; x < buffer.width; x++) {
+            uint8 blue = x + xOffset;
+            uint8 green = y + yOffset;
+            *pixel++ = (green << 8) | blue;
+        }
+        row += pitch;
+    }
+}
+
+internal void resizeDIBSection(Win32OffscreenBuffer *buffer, int width, int height) {
+    if (buffer->memory) {
+        VirtualFree(buffer->memory, NULL, MEM_RELEASE);
+    }
+
+    buffer->width = width;
+    buffer->height = height;
+    buffer->bytesPerPixel = 4;
+
+    buffer->info = {
+        .bmiHeader = {
+            .biSize = sizeof(buffer->info.bmiHeader),
+            .biWidth = buffer->width,
+            .biHeight = -buffer->height,
+            .biPlanes = 1,
+            .biBitCount = 32,
+            .biCompression = BI_RGB,
+        },
+    };
+
+    int bitmapSize = buffer->width*buffer->height*buffer->bytesPerPixel;
+    buffer->memory = VirtualAlloc(NULL, bitmapSize, MEM_COMMIT, PAGE_READWRITE);
+}
+
+Win32WindowDimensions win32GetWindowDimensions(HWND window) {
+    Win32WindowDimensions result;
+    RECT clientRect;
+    GetClientRect(window, &clientRect);
+    result.width = clientRect.right - clientRect.left;
+    result.height = clientRect.bottom - clientRect.top;
+    return result;
+}
+
+void win32DrawBufferInWindow(Win32OffscreenBuffer buffer, HWND window) {
+    Win32WindowDimensions winDims = win32GetWindowDimensions(window);
+    StretchDIBits(
+        GetDC(window),
+        0, 0, winDims.width, winDims.height,
+        0, 0, buffer.width, buffer.height,
+        buffer.memory,
+        &buffer.info, 
+        DIB_RGB_COLORS,
+        SRCCOPY
+    );
+}
+
+LRESULT mainWindowCallback(
+  HWND window,
+  UINT message,
+  WPARAM wParam,
+  LPARAM lParam
+) {
+    LRESULT result = 0;
+    switch (message) {
+        case WM_SIZE: {
+        } break;
+
+        case WM_DESTROY: {
+            //OutputDebugStringA("WM_DESTROY\n");
+        } break;
+
+        case WM_CLOSE: {
+            running = false;
+        } break;
+
+        case WM_PAINT: {
+            PAINTSTRUCT paint = {};
+            HDC deviceContext = BeginPaint(window, &paint);
+            int x = paint.rcPaint.left;
+            int y = paint.rcPaint.top;
+            int width = paint.rcPaint.right - paint.rcPaint.left;
+            int height = paint.rcPaint.bottom - paint.rcPaint.top;
+            win32DrawBufferInWindow(globalBackBuffer, window);
+            EndPaint(window, &paint);
+        } break;
+
+        case WM_ACTIVATEAPP: {
+            running = false;
+        } break;
+
+        default: {
+            result = DefWindowProcA(window, message, wParam, lParam);
+            //OutputDebugStringA("default\n");
+        } break;
+    }
+    return result;
+}
+
+int	APIENTRY WinMain(
+	HINSTANCE instance, 
+	HINSTANCE prevInstance, 
+	PSTR commandLine, 
+	int commandShow
+) {
+    WNDCLASS windowClass = {
+        .style = CS_VREDRAW | CS_HREDRAW,
+        .lpfnWndProc = &mainWindowCallback,
+        .hInstance = instance,
+        .lpszClassName = "HandmadeHeroWindowClass",
+    };
+
+    resizeDIBSection(&globalBackBuffer, 1280, 720);
+
+    if (RegisterClass(&windowClass)) {
+        HWND window = CreateWindowExA(
+            NULL,
+            windowClass.lpszClassName,
+            "Handmade Hero",
+            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            NULL,
+            NULL,
+            instance,
+            NULL
+        );
+        if (window) {
+            MSG message;
+            running = true;
+            int xOffset = 0;
+            int yOffset = 0;
+            while (running) {
+                while(PeekMessageA(&message, NULL, NULL, NULL, PM_REMOVE)) {
+                    if (message.message == WM_QUIT) {
+                        running = false;
+                    }
+                    TranslateMessage(&message);
+                    DispatchMessage(&message);
+                }
+                renderWeirdGradient(globalBackBuffer, xOffset, yOffset);
+                win32DrawBufferInWindow(globalBackBuffer, window);
+                xOffset++;
+                yOffset++;
+            }
+        } else {
+            // failed
+        }
+    } else {
+        // failed
+    }
+    return(0);
+}
+
+