Add mgl_texture_init_reference_existing_gl_texture to easily create a texture and then a sprite from an existing opengl texture

2 files changed, 39 insertions, 0 deletions

diff --git a/src/gl.c b/src/gl.c
index 7c9a6bc..bb2e90b 100644
--- a/src/gl.c
+++ b/src/gl.c
@@ -29,6 +29,7 @@ static int mgl_gl_load_gl(mgl_gl *self) {
         { (void**)&self->glBlendFunc, "glBlendFunc" },
         { (void**)&self->glGenTextures, "glGenTextures" },
         { (void**)&self->glDeleteTextures, "glDeleteTextures" },
+        { (void**)&self->glGetTexLevelParameteriv, "glGetTexLevelParameteriv" },
         { (void**)&self->glTexImage2D, "glTexImage2D" },
         { (void**)&self->glTexSubImage2D, "glTexSubImage2D" },
         { (void**)&self->glBindTexture, "glBindTexture" },
diff --git a/src/graphics/texture.c b/src/graphics/texture.c
index 5de3d2b..9a13314 100644
--- a/src/graphics/texture.c
+++ b/src/graphics/texture.c
@@ -51,6 +51,17 @@ static mgl_texture_format mgl_image_format_to_mgl_texture_format(mgl_image_forma
     return 0;
 }
 
+static void gl_get_texture_size(unsigned int texture_id, int *width, int *height) {
+    *width = 0;
+    *height = 0;
+
+    mgl_context *context = mgl_get_context();
+    context->gl.glBindTexture(GL_TEXTURE_2D, texture_id);
+    context->gl.glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, width);
+    context->gl.glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, height);
+    context->gl.glBindTexture(GL_TEXTURE_2D, 0);
+}
+
 int mgl_texture_init(mgl_texture *self) {
     self->id = 0;
     self->width = 0;
@@ -59,6 +70,8 @@ int mgl_texture_init(mgl_texture *self) {
     self->max_width = 0;
     self->max_height = 0;
     self->pixel_coordinates = false;
+    self->mipmap = false;
+    self->owned = true;
 
     mgl_context *context = mgl_get_context();
     context->gl.glGenTextures(1, &self->id);
@@ -75,6 +88,28 @@ int mgl_texture_init(mgl_texture *self) {
     return 0;
 }
 
+int mgl_texture_init_reference_existing_gl_texture(mgl_texture *self, unsigned int texture_id, mgl_texture_format format, const mgl_texture_reference_options *reference_options) {
+    self->id = texture_id;
+    self->width = 0;
+    self->height = 0;
+    self->format = format;
+    self->max_width = 0;
+    self->max_height = 0;
+    self->pixel_coordinates = reference_options && reference_options->pixel_coordinates;
+    self->mipmap = false;
+    self->owned = false;
+
+    gl_get_texture_size(self->id, &self->width, &self->height);
+
+    int max_texture_size = 0;
+    mgl_context *context = mgl_get_context();
+    context->gl.glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
+    self->max_width = max_texture_size;
+    self->max_height = max_texture_size;
+
+    return 0;
+}
+
 int mgl_texture_load_from_file(mgl_texture *self, const char *filepath, const mgl_texture_load_options *load_options) {
     mgl_image image;
     if(mgl_image_load_from_file(&image, filepath) != 0)
@@ -199,6 +234,9 @@ const mgl_texture* mgl_texture_current_texture(void) {
 
 void mgl_texture_unload(mgl_texture *self) {
     mgl_context *context = mgl_get_context();
+    if(!self->owned)
+        return;
+
     if(self->id) {
         context->gl.glDeleteTextures(1, &self->id);
         self->id = 0;