From 44fb887737a1b742b6349fb63716677993073b84 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 28 Feb 2023 23:34:55 -0800
Subject: [PATCH] SDL: Border rendering

---
 src/platform/sdl/gl-common.c | 77 ++++++++++++++++++++++++++++++++++++
 src/platform/sdl/gl-common.h |  1 +
 src/platform/video-backend.c | 19 ++++-----
 src/platform/video-backend.h |  1 +
 4 files changed, 89 insertions(+), 9 deletions(-)

diff --git a/src/platform/sdl/gl-common.c b/src/platform/sdl/gl-common.c
index 47988497d..53219a7bb 100644
--- a/src/platform/sdl/gl-common.c
+++ b/src/platform/sdl/gl-common.c
@@ -9,6 +9,11 @@
 #include <mgba/core/thread.h>
 #include <mgba/core/version.h>
 
+#ifdef USE_PNG
+#include <mgba-util/png-io.h>
+#include <mgba-util/vfs.h>
+#endif
+
 void mSDLGLDoViewport(int w, int h, struct VideoBackend* v) {
 	v->contextResized(v, w, h);
 	v->clear(v);
@@ -26,6 +31,60 @@ void mSDLGLCommonSwap(struct VideoBackend* context) {
 #endif
 }
 
+bool mSDLGLCommonLoadBackground(struct VideoBackend* context) {
+#ifdef USE_PNG
+	struct mSDLRenderer* renderer = context->user;
+	const char* bgImage = mCoreConfigGetValue(&renderer->core->config, "backgroundImage");
+	if (!bgImage) {
+		return false;
+	}
+	struct VFile* vf = VFileOpen(bgImage, O_RDONLY);
+	if (!vf) {
+		return false;
+	}
+
+	bool ok = false;
+	png_structp png = PNGReadOpen(vf, 0);
+	png_infop info = png_create_info_struct(png);
+	png_infop end = png_create_info_struct(png);
+	if (!png || !info || !end) {
+		goto done;
+	}
+
+	if (!PNGReadHeader(png, info)) {
+		goto done;
+	}
+	unsigned width = png_get_image_width(png, info);
+	unsigned height = png_get_image_height(png, info);
+	uint32_t* pixels = malloc(width * height * 4);
+	if (!pixels) {
+		goto done;
+	}
+
+	if (!PNGReadPixels(png, info, pixels, width, height, width) || !PNGReadFooter(png, end)) {
+		free(pixels);
+		goto done;
+	}
+
+	struct Rectangle dims = {
+		.width = width,
+		.height = height
+	};
+	context->setLayerDimensions(context, VIDEO_LAYER_BACKGROUND, &dims);
+	context->setImage(context, VIDEO_LAYER_BACKGROUND, pixels);
+	free(pixels);
+	ok = true;
+
+done:
+	PNGReadClose(png, info, end);
+	vf->close(vf);
+	return ok;
+#else
+	UNUSED(context);
+	return false;
+#endif
+}
+
 bool mSDLGLCommonInit(struct mSDLRenderer* renderer) {
 #ifndef COLOR_16_BIT
 	SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
@@ -74,6 +133,24 @@ void mSDLGLCommonRunloop(struct mSDLRenderer* renderer, void* user) {
 	SDL_Event event;
 	struct VideoBackend* v = renderer->backend;
 
+	if (mSDLGLCommonLoadBackground(v)) {
+		renderer->player.windowUpdated = true;
+
+		struct Rectangle frame;
+		VideoBackendGetFrame(v, &frame);
+		int i;
+		for (i = 0; i <= VIDEO_LAYER_IMAGE; ++i) {
+			struct Rectangle dims;
+			v->layerDimensions(v, i, &dims);
+			RectangleCenter(&frame, &dims);
+			v->setLayerDimensions(v, i, &dims);
+		}
+
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+		SDL_SetWindowSize(renderer->window, frame.width * renderer->ratio, frame.height * renderer->ratio);
+#endif
+	}
+
 	while (mCoreThreadIsActive(context)) {
 		while (SDL_PollEvent(&event)) {
 			mSDLHandleEvent(context, &renderer->player, &event);
diff --git a/src/platform/sdl/gl-common.h b/src/platform/sdl/gl-common.h
index 5658abee4..f52cfd633 100644
--- a/src/platform/sdl/gl-common.h
+++ b/src/platform/sdl/gl-common.h
@@ -16,6 +16,7 @@ void mSDLGLDoViewport(int w, int h, struct VideoBackend* v);
 void mSDLGLCommonSwap(struct VideoBackend* context);
 bool mSDLGLCommonInit(struct mSDLRenderer* renderer);
 void mSDLGLCommonRunloop(struct mSDLRenderer* renderer, void* user);
+bool mSDLGLCommonLoadBackground(struct VideoBackend* context);
 
 CXX_GUARD_END
 
diff --git a/src/platform/video-backend.c b/src/platform/video-backend.c
index 3447fcdd8..998764d0d 100644
--- a/src/platform/video-backend.c
+++ b/src/platform/video-backend.c
@@ -5,18 +5,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "video-backend.h"
 
-void VideoBackendGetFrameSize(const struct VideoBackend* v, unsigned* width, unsigned* height) {
-	*width = 0;
-	*height = 0;
+void VideoBackendGetFrame(const struct VideoBackend* v, struct Rectangle* frame) {
+	memset(frame, 0, sizeof(*frame));
 	int i;
 	for (i = 0; i < VIDEO_LAYER_MAX; ++i) {
 		struct Rectangle dims;
 		v->layerDimensions(v, i, &dims);
-		if (dims.x + dims.width > *width) {
-			*width = dims.x + dims.width;
-		}
-		if (dims.y + dims.height > *height) {
-			*height = dims.y + dims.height;
-		}
+		RectangleUnion(frame, &dims);
 	}
 }
+
+void VideoBackendGetFrameSize(const struct VideoBackend* v, unsigned* width, unsigned* height) {
+	struct Rectangle frame;
+	VideoBackendGetFrame(v, &frame);
+	*width = frame.width;
+	*height = frame.height;
+}
diff --git a/src/platform/video-backend.h b/src/platform/video-backend.h
index 3bb1c0a69..5a3319721 100644
--- a/src/platform/video-backend.h
+++ b/src/platform/video-backend.h
@@ -56,6 +56,7 @@ struct VideoShader {
 	size_t nPasses;
 };
 
+void VideoBackendGetFrame(const struct VideoBackend*, struct Rectangle* frame);
 void VideoBackendGetFrameSize(const struct VideoBackend*, unsigned* width, unsigned* height);
 
 CXX_GUARD_END