Add a collection of egl_fb_*() helper functions to manage and use opengl
framebuffers, which is a common pattern in UI code with opengl support.
Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
include/ui/egl-helpers.h | 15 ++++++++++
ui/egl-helpers.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 91 insertions(+)
diff --git a/include/ui/egl-helpers.h b/include/ui/egl-helpers.h
index c785d60e91..be8908737c 100644
--- a/include/ui/egl-helpers.h
+++ b/include/ui/egl-helpers.h
@@ -8,6 +8,21 @@
extern EGLDisplay *qemu_egl_display;
extern EGLConfig qemu_egl_config;
+typedef struct egl_fb {
+ int width;
+ int height;
+ GLuint texture;
+ GLuint framebuffer;
+ bool delete_texture;
+} egl_fb;
+
+void egl_fb_destroy(egl_fb *fb);
+void egl_fb_setup_default(egl_fb *fb, int width, int height);
+void egl_fb_create_for_tex(egl_fb *fb, int width, int height, GLuint texture);
+void egl_fb_create_new_tex(egl_fb *fb, int width, int height);
+void egl_fb_blit(egl_fb *dst, egl_fb *src, bool flip);
+void egl_fb_read(void *dst, egl_fb *src);
+
#ifdef CONFIG_OPENGL_DMABUF
extern int qemu_egl_rn_fd;
diff --git a/ui/egl-helpers.c b/ui/egl-helpers.c
index 4a4d3370ee..bb19a5eeca 100644
--- a/ui/egl-helpers.c
+++ b/ui/egl-helpers.c
@@ -24,6 +24,82 @@
EGLDisplay *qemu_egl_display;
EGLConfig qemu_egl_config;
+/* ------------------------------------------------------------------ */
+
+void egl_fb_destroy(egl_fb *fb)
+{
+ if (!fb->framebuffer) {
+ return;
+ }
+
+ if (fb->delete_texture) {
+ glDeleteTextures(1, &fb->texture);
+ fb->delete_texture = false;
+ }
+ glDeleteFramebuffers(1, &fb->framebuffer);
+
+ fb->width = 0;
+ fb->height = 0;
+ fb->texture = 0;
+ fb->framebuffer = 0;
+}
+
+void egl_fb_setup_default(egl_fb *fb, int width, int height)
+{
+ fb->width = width;
+ fb->height = height;
+ fb->framebuffer = 0; /* default framebuffer */
+}
+
+void egl_fb_create_for_tex(egl_fb *fb, int width, int height, GLuint texture)
+{
+ fb->width = width;
+ fb->height = height;
+ fb->texture = texture;
+ if (!fb->framebuffer) {
+ glGenFramebuffers(1, &fb->framebuffer);
+ }
+
+ glBindFramebuffer(GL_FRAMEBUFFER_EXT, fb->framebuffer);
+ glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+ GL_TEXTURE_2D, fb->texture, 0);
+}
+
+void egl_fb_create_new_tex(egl_fb *fb, int width, int height)
+{
+ GLuint texture;
+
+ glGenTextures(1, &texture);
+ glBindTexture(GL_TEXTURE_2D, texture);
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height,
+ 0, GL_BGRA, GL_UNSIGNED_BYTE, 0);
+
+ egl_fb_create_for_tex(fb, width, height, texture);
+ fb->delete_texture = true;
+}
+
+void egl_fb_blit(egl_fb *dst, egl_fb *src, bool flip)
+{
+ GLuint y1, y2;
+
+ glBindFramebuffer(GL_READ_FRAMEBUFFER, src->framebuffer);
+ glBindFramebuffer(GL_DRAW_FRAMEBUFFER, dst->framebuffer);
+ glViewport(0, 0, dst->width, dst->height);
+ y1 = flip ? src->height : 0;
+ y2 = flip ? 0 : src->height;
+ glBlitFramebuffer(0, y1, src->width, y2,
+ 0, 0, dst->width, dst->height,
+ GL_COLOR_BUFFER_BIT, GL_LINEAR);
+}
+
+void egl_fb_read(void *dst, egl_fb *src)
+{
+ glBindFramebuffer(GL_READ_FRAMEBUFFER, src->framebuffer);
+ glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
+ glReadPixels(0, 0, src->width, src->height,
+ GL_BGRA, GL_UNSIGNED_BYTE, dst);
+}
+
/* ---------------------------------------------------------------------- */
#ifdef CONFIG_OPENGL_DMABUF
--
2.9.3
