Windows: Factor out GL backend

1 files changed, 302 insertions, 0 deletions

diff --git a/pugl/pugl_win_gl.c b/pugl/pugl_win_gl.c
new file mode 100644
index 0000000..d86a78b
--- /dev/null
+++ b/pugl/pugl_win_gl.c
@@ -0,0 +1,302 @@
+/*
+  Copyright 2012-2019 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "pugl/pugl_gl_backend.h"
+#include "pugl/pugl_internal_types.h"
+#include "pugl/pugl_win.h"
+
+#include <windows.h>
+
+#include <GL/gl.h>
+
+#include <stdbool.h>
+#include <stdlib.h>
+
+#define WGL_DRAW_TO_WINDOW_ARB    0x2001
+#define WGL_ACCELERATION_ARB      0x2003
+#define WGL_SUPPORT_OPENGL_ARB    0x2010
+#define WGL_DOUBLE_BUFFER_ARB     0x2011
+#define WGL_PIXEL_TYPE_ARB        0x2013
+#define WGL_COLOR_BITS_ARB        0x2014
+#define WGL_RED_BITS_ARB          0x2015
+#define WGL_GREEN_BITS_ARB        0x2017
+#define WGL_BLUE_BITS_ARB         0x2019
+#define WGL_ALPHA_BITS_ARB        0x201b
+#define WGL_DEPTH_BITS_ARB        0x2022
+#define WGL_STENCIL_BITS_ARB      0x2023
+#define WGL_FULL_ACCELERATION_ARB 0x2027
+#define WGL_TYPE_RGBA_ARB         0x202b
+#define WGL_SAMPLE_BUFFERS_ARB    0x2041
+#define WGL_SAMPLES_ARB           0x2042
+
+#define WGL_CONTEXT_MAJOR_VERSION_ARB 0x2091
+#define WGL_CONTEXT_MINOR_VERSION_ARB 0x2092
+#define WGL_CONTEXT_LAYER_PLANE_ARB   0x2093
+#define WGL_CONTEXT_FLAGS_ARB         0x2094
+#define WGL_CONTEXT_PROFILE_MASK_ARB  0x9126
+
+#define WGL_CONTEXT_CORE_PROFILE_BIT_ARB          0x00000001
+#define WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB 0x00000002
+
+typedef HGLRC (*WglCreateContextAttribs)(HDC, HGLRC, const int*);
+typedef BOOL (*WglSwapInterval)(int);
+typedef BOOL (*WglChoosePixelFormat)(
+	HDC, const int*, const FLOAT*, UINT, int*, UINT*);
+
+typedef struct {
+	WglChoosePixelFormat    wglChoosePixelFormat;
+	WglCreateContextAttribs wglCreateContextAttribs;
+	WglSwapInterval         wglSwapInterval;
+} PuglWinGlProcs;
+
+typedef struct {
+	PuglWinGlProcs procs;
+	HGLRC          hglrc;
+} PuglWinGlSurface;
+
+// Struct to manage the fake window used during configuration
+typedef struct {
+	HWND hwnd;
+	HDC  hdc;
+} PuglFakeWindow;
+
+static int
+puglWinError(PuglFakeWindow* fakeWin, const int status)
+{
+	if (fakeWin->hwnd) {
+		ReleaseDC(fakeWin->hwnd, fakeWin->hdc);
+		DestroyWindow(fakeWin->hwnd);
+	}
+
+	return status;
+}
+
+static PuglWinGlProcs puglWinGlGetProcs(void)
+{
+	const PuglWinGlProcs procs = {
+		(WglChoosePixelFormat)(
+			wglGetProcAddress("wglChoosePixelFormatARB")),
+		(WglCreateContextAttribs)(
+			wglGetProcAddress("wglCreateContextAttribsARB")),
+		(WglSwapInterval)(
+			wglGetProcAddress("wglSwapIntervalEXT"))
+	};
+
+	return procs;
+}
+
+static int
+puglWinGlConfigure(PuglView* view)
+{
+	PuglInternals* impl = view->impl;
+
+	const int pixelAttrs[] = {
+		WGL_DRAW_TO_WINDOW_ARB, GL_TRUE,
+		WGL_ACCELERATION_ARB,   WGL_FULL_ACCELERATION_ARB,
+		WGL_SUPPORT_OPENGL_ARB, GL_TRUE,
+		WGL_DOUBLE_BUFFER_ARB,  view->hints.double_buffer,
+		WGL_PIXEL_TYPE_ARB,     WGL_TYPE_RGBA_ARB,
+		WGL_SAMPLE_BUFFERS_ARB, view->hints.samples ? 1 : 0,
+		WGL_SAMPLES_ARB,        view->hints.samples,
+		WGL_RED_BITS_ARB,       view->hints.red_bits,
+		WGL_GREEN_BITS_ARB,     view->hints.green_bits,
+		WGL_BLUE_BITS_ARB,      view->hints.blue_bits,
+		WGL_ALPHA_BITS_ARB,     view->hints.alpha_bits,
+		WGL_DEPTH_BITS_ARB,     view->hints.depth_bits,
+		WGL_STENCIL_BITS_ARB,   view->hints.stencil_bits,
+		0,
+	};
+
+	PuglWinGlSurface* const surface =
+		(PuglWinGlSurface*)calloc(1, sizeof(PuglWinGlSurface));
+	impl->surface = surface;
+
+	// Create fake window for getting at GL context
+	PuglStatus     st      = PUGL_SUCCESS;
+	PuglFakeWindow fakeWin = { 0, 0 };
+	if ((st = puglWinCreateWindow(view, "Pugl Configuration",
+	                              &fakeWin.hwnd, &fakeWin.hdc))) {
+		return puglWinError(&fakeWin, st);
+	}
+
+	// Set pixel format for fake window
+	const PuglWinPFD fakePfd  = puglWinGetPixelFormatDescriptor(&view->hints);
+	const int        fakePfId = ChoosePixelFormat(fakeWin.hdc, &fakePfd);
+	if (!fakePfId) {
+		return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+	} else if (!SetPixelFormat(fakeWin.hdc, fakePfId, &fakePfd)) {
+		return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+	}
+
+	// Create fake GL context to get at the functions we need
+	HGLRC fakeRc = wglCreateContext(fakeWin.hdc);
+	if (!fakeRc) {
+		return puglWinError(&fakeWin, PUGL_ERR_CREATE_CONTEXT);
+	}
+
+	// Enter fake context and get extension functions
+	wglMakeCurrent(fakeWin.hdc, fakeRc);
+	surface->procs = puglWinGlGetProcs();
+
+	if (surface->procs.wglChoosePixelFormat) {
+		// Choose pixel format based on attributes
+		UINT numFormats = 0;
+		if (!surface->procs.wglChoosePixelFormat(
+			    fakeWin.hdc, pixelAttrs, NULL, 1u, &impl->pfId, &numFormats)) {
+			return puglWinError(&fakeWin, PUGL_ERR_SET_FORMAT);
+		}
+
+		DescribePixelFormat(
+			impl->hdc, impl->pfId, sizeof(impl->pfd), &impl->pfd);
+	} else {
+		// Modern extensions not available, use basic pixel format
+		impl->pfd  = fakePfd;
+		impl->pfId = fakePfId;
+	}
+
+	// Dispose of fake window and context
+	wglMakeCurrent(NULL, NULL);
+	wglDeleteContext(fakeRc);
+	ReleaseDC(fakeWin.hwnd, fakeWin.hdc);
+	DestroyWindow(fakeWin.hwnd);
+
+	return 0;
+}
+
+static int
+puglWinGlCreate(PuglView* view)
+{
+	PuglInternals* const    impl    = view->impl;
+	PuglWinGlSurface* const surface = (PuglWinGlSurface*)impl->surface;
+	PuglStatus              st      = PUGL_SUCCESS;
+
+	const int contextAttribs[] = {
+		WGL_CONTEXT_MAJOR_VERSION_ARB, view->hints.context_version_major,
+		WGL_CONTEXT_MINOR_VERSION_ARB, view->hints.context_version_minor,
+		WGL_CONTEXT_PROFILE_MASK_ARB,
+		(view->hints.use_compat_profile
+		 ? WGL_CONTEXT_CORE_PROFILE_BIT_ARB
+		 : WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB),
+		0
+	};
+
+	// Create real window with desired pixel format
+	if ((st = puglWinCreateWindow(view, "Pugl", &impl->hwnd, &impl->hdc))) {
+		return st;
+	} else if (!SetPixelFormat(impl->hdc, impl->pfId, &impl->pfd)) {
+		ReleaseDC(impl->hwnd, impl->hdc);
+		DestroyWindow(impl->hwnd);
+		impl->hwnd = NULL;
+		impl->hdc  = NULL;
+		return PUGL_ERR_SET_FORMAT;
+	}
+
+	// Create GL context
+	if (surface->procs.wglCreateContextAttribs &&
+	    !(surface->hglrc = surface->procs.wglCreateContextAttribs(
+		      impl->hdc, 0, contextAttribs))) {
+		return PUGL_ERR_CREATE_CONTEXT;
+	} else if (!(surface->hglrc = wglCreateContext(impl->hdc))) {
+		return PUGL_ERR_CREATE_CONTEXT;
+	}
+
+	// Enter context and set swap interval
+	wglMakeCurrent(impl->hdc, surface->hglrc);
+	if (surface->procs.wglSwapInterval) {
+		surface->procs.wglSwapInterval(1);
+	}
+
+	return 0;
+}
+
+static int
+puglWinGlDestroy(PuglView* view)
+{
+	PuglWinGlSurface* surface = (PuglWinGlSurface*)view->impl->surface;
+	if (surface) {
+		wglMakeCurrent(NULL, NULL);
+		wglDeleteContext(surface->hglrc);
+		free(surface);
+		view->impl->surface = NULL;
+	}
+
+	return 0;
+}
+
+static int
+puglWinGlEnter(PuglView* view, bool drawing)
+{
+	PuglWinGlSurface* surface = (PuglWinGlSurface*)view->impl->surface;
+
+	wglMakeCurrent(view->impl->hdc, surface->hglrc);
+
+	if (drawing) {
+		PAINTSTRUCT ps;
+		BeginPaint(view->impl->hwnd, &ps);
+	}
+
+	return 0;
+}
+
+static int
+puglWinGlLeave(PuglView* view, bool drawing)
+{
+	if (drawing) {
+		PAINTSTRUCT ps;
+		EndPaint(view->impl->hwnd, &ps);
+		SwapBuffers(view->impl->hdc);
+	}
+
+	wglMakeCurrent(NULL, NULL);
+
+	return 0;
+}
+
+static int
+puglWinGlResize(PuglView* PUGL_UNUSED(view),
+                int       PUGL_UNUSED(width),
+                int       PUGL_UNUSED(height))
+{
+	return 0;
+}
+
+static void*
+puglWinGlGetContext(PuglView* PUGL_UNUSED(view))
+{
+	return NULL;
+}
+
+PuglGlFunc
+puglGetProcAddress(const char* name)
+{
+	return (PuglGlFunc)wglGetProcAddress(name);
+}
+
+const PuglBackend*
+puglGlBackend()
+{
+	static const PuglBackend backend = {
+		puglWinGlConfigure,
+		puglWinGlCreate,
+		puglWinGlDestroy,
+		puglWinGlEnter,
+		puglWinGlLeave,
+		puglWinGlResize,
+		puglWinGlGetContext
+	};
+
+	return &backend;
+}