From 115630b520668304af1ccd3eb0b13c06e17ecccc Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sun, 24 Oct 2021 04:52:30 +0200
Subject: Add function to load image from memory, initialize window from an
 existing window, allow creating text without font/string

---
 include/mgl/graphics/image.h  |  1 +
 include/mgl/graphics/sprite.h |  2 +-
 include/mgl/graphics/text.h   | 13 +++++++++----
 include/mgl/window/window.h   |  1 +
 src/graphics/image.c          | 19 +++++++++++++++++++
 src/graphics/text.c           |  9 +++++++--
 src/window/window.c           | 41 ++++++++++++++++++++++++++++++-----------
 7 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/include/mgl/graphics/image.h b/include/mgl/graphics/image.h
index b10a028..40625bb 100644
--- a/include/mgl/graphics/image.h
+++ b/include/mgl/graphics/image.h
@@ -21,6 +21,7 @@ struct mgl_image {
 };
 
 int mgl_image_load_from_file(mgl_image *self, const char *filepath);
+int mgl_image_load_from_memory(mgl_image *self, const unsigned char *data, size_t size);
 void mgl_image_unload(mgl_image *self);
 
 size_t mgl_image_get_size(mgl_image *self);
diff --git a/include/mgl/graphics/sprite.h b/include/mgl/graphics/sprite.h
index 8c84153..03f81ab 100644
--- a/include/mgl/graphics/sprite.h
+++ b/include/mgl/graphics/sprite.h
@@ -8,7 +8,7 @@ typedef struct mgl_context mgl_context;
 typedef struct mgl_texture mgl_texture;
 
 typedef struct {
-    mgl_texture *texture;
+    mgl_texture *texture; /* nullable */
     mgl_color color;
     mgl_vec2f position;
     mgl_vec2f scale;
diff --git a/include/mgl/graphics/text.h b/include/mgl/graphics/text.h
index 33c75d0..2c2eeaf 100644
--- a/include/mgl/graphics/text.h
+++ b/include/mgl/graphics/text.h
@@ -8,18 +8,23 @@ typedef struct mgl_font mgl_font;
 typedef struct mgl_context mgl_context;
 
 typedef struct {
-    mgl_font *font;
-    const char *text;
+    mgl_font *font; /* nullable */
+    const char *text; /* nullable */
     mgl_color color;
     mgl_vec2f position;
 } mgl_text;
 
-/* Note: keeps a reference to |text|. |text| needs to be valid as long as |self| is used. */
+/*
+    Note: keeps a reference to |text|. |text| needs to be valid as long as |self| is used.
+    |font| and |text| may be NULL.
+*/
 int mgl_text_init(mgl_text *self, mgl_font *font, const char *text, float x, float y);
 void mgl_text_deinit(mgl_text *self);
 
-/* Note: keeps a reference to |text|. |text| needs to be valid as long as |self| is used. */
+/* Note: keeps a reference to |text|. |text| needs to be valid as long as |self| is used. |text| may be NULL. */
 void mgl_text_set_string(mgl_text *self, const char *str);
+/* |font| may be NULL */
+void mgl_text_set_font(mgl_text *self, mgl_font *font);
 void mgl_text_set_position(mgl_text *self, mgl_vec2f position);
 void mgl_text_set_color(mgl_text *self, mgl_color color);
 void mgl_text_draw(mgl_context *context, mgl_text *text);
diff --git a/include/mgl/window/window.h b/include/mgl/window/window.h
index c1517da..c1542b4 100644
--- a/include/mgl/window/window.h
+++ b/include/mgl/window/window.h
@@ -20,6 +20,7 @@ struct mgl_window {
 int mgl_window_create(mgl_window *self, const char *title, int width, int height);
 /* if |parent_window| is 0 then the root window is used */
 int mgl_window_create_with_params(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window);
+int mgl_window_init_from_existing_window(mgl_window *self, mgl_window_handle existing_window);
 void mgl_window_deinit(mgl_window *self);
 
 void mgl_window_clear(mgl_window *self, mgl_color color);
diff --git a/src/graphics/image.c b/src/graphics/image.c
index 430f03a..593a3d2 100644
--- a/src/graphics/image.c
+++ b/src/graphics/image.c
@@ -52,6 +52,25 @@ int mgl_image_load_from_file(mgl_image *self, const char *filepath) {
     return 0;
 }
 
+/* TODO: Ensure texture is power of 2 if the hardware doesn't support non power of two textures */
+/* TODO: Verify if source format should always be 4 components (RGBA) because apparently if its another format then opengl will internally convert it to RGBA */
+int mgl_image_load_from_memory(mgl_image *self, const unsigned char *data, size_t size) {
+    self->data = NULL;
+    self->width = 0;
+    self->height = 0;
+    
+    int format;
+    self->data = stbi_load_from_memory(data, size, &self->width, &self->height, &format, 0);
+    if(!self->data) {
+        fprintf(stderr, "Error: failed to load image from memory, error: %s\n", stbi_failure_reason());
+        mgl_image_unload(self);
+        return -1;
+    }
+    self->format = stbi_format_to_mgl_image_format(format);
+
+    return 0;
+}
+
 void mgl_image_unload(mgl_image *self) {
     if(self->data) {
         stbi_image_free(self->data);
diff --git a/src/graphics/text.c b/src/graphics/text.c
index e7b31a0..76fd852 100644
--- a/src/graphics/text.c
+++ b/src/graphics/text.c
@@ -18,6 +18,10 @@ void mgl_text_set_string(mgl_text *self, const char *str) {
     self->text = str;
 }
 
+void mgl_text_set_font(mgl_text *self, mgl_font *font) {
+    self->font = font;
+}
+
 void mgl_text_set_position(mgl_text *self, mgl_vec2f position) {
     self->position = position;
 }
@@ -43,10 +47,11 @@ static void mgl_text_draw_glyph(mgl_context *context, mgl_font_glyph *glyph, mgl
 /* TODO: Use opengl buffer object instead */
 /* TODO: Cache texture bind to not bind texture if its already bound and do not bind texture 0 */
 void mgl_text_draw(mgl_context *context, mgl_text *text) {
-    const char *str = text->text;
-    if(!str)
+    if(!text->text || !text->font)
         return;
 
+    const char *str = text->text;
+
     mgl_font_glyph glyph;
     mgl_vec2f position = text->position;
     position.y += text->font->character_size;
diff --git a/src/window/window.c b/src/window/window.c
index 691a647..2e9a1ba 100644
--- a/src/window/window.c
+++ b/src/window/window.c
@@ -41,7 +41,7 @@ int mgl_window_create(mgl_window *self, const char *title, int width, int height
     return mgl_window_create_with_params(self, title, width, height, 0);
 }
 
-int mgl_window_create_with_params(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window) {
+static int mgl_window_init(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window, Window existing_window) {
     self->window = 0;
 
     mgl_context *context = mgl_get_context();
@@ -64,18 +64,29 @@ int mgl_window_create_with_params(mgl_window *self, const char *title, int width
         StructureNotifyMask;
     window_attr.bit_gravity = NorthWestGravity;
 
-    self->window = XCreateWindow(context->connection, parent_window, 0, 0, width, height, 0,
-        ((XVisualInfo*)context->visual_info)->depth, InputOutput, ((XVisualInfo*)context->visual_info)->visual,
-        CWColormap | CWEventMask | CWBitGravity, &window_attr);
-    XFreeColormap(context->connection, color_map);
-    if(!self->window) {
-        fprintf(stderr, "XCreateWindow failed\n");
-        mgl_window_deinit(self);
-        return -1;
+    if(existing_window) {
+        if(!XChangeWindowAttributes(context->connection, existing_window, CWColormap | CWEventMask | CWBitGravity, &window_attr)) {
+            fprintf(stderr, "XChangeWindowAttributes failed\n");
+            XFreeColormap(context->connection, color_map);
+            return -1;
+        }
+        XFreeColormap(context->connection, color_map);
+        self->window = existing_window;
+    } else {
+        self->window = XCreateWindow(context->connection, parent_window, 0, 0, width, height, 0,
+            ((XVisualInfo*)context->visual_info)->depth, InputOutput, ((XVisualInfo*)context->visual_info)->visual,
+            CWColormap | CWEventMask | CWBitGravity, &window_attr);
+        XFreeColormap(context->connection, color_map);
+        if(!self->window) {
+            fprintf(stderr, "XCreateWindow failed\n");
+            mgl_window_deinit(self);
+            return -1;
+        }
+
+        XStoreName(context->connection, self->window, title);
+        XMapWindow(context->connection, self->window);
     }
 
-    XStoreName(context->connection, self->window, title);
-    XMapWindow(context->connection, self->window);
     XFlush(context->connection);
 
     /* TODO: Switch current when rendering to another window, and set current to NULL when destroying the currently selected context */
@@ -102,6 +113,14 @@ int mgl_window_create_with_params(mgl_window *self, const char *title, int width
     return 0;
 }
 
+int mgl_window_create_with_params(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window) {
+    return mgl_window_init(self, title, width, height, parent_window, None);
+}
+
+int mgl_window_init_from_existing_window(mgl_window *self, mgl_window_handle existing_window) {
+    return mgl_window_init(self, "", 0, 0, 0, existing_window);
+}
+
 void mgl_window_deinit(mgl_window *self) {
     mgl_context *context = mgl_get_context();
     if(self->window) {
-- 
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