render/gles: add support for some 16-bpc unsigned shm formats

These formats require EXT_texture_norm16, which in turn needs OpenGL
ES 3.1. The EXT_texture_norm16 extension does not support passing
gl_internalformat = GL_RGBA to glTexImage2D, as can be done for
formats available in OpenGL ES 2.0, so this commit adds a field to
wlr_gles2_pixel_format to provide a more specific internalformat
parameter to glTexImage2D.

include/render/gles2.h

@@ -17,6 +17,8 @@
 
 struct wlr_gles2_pixel_format {
 	uint32_t drm_format;
+	// optional field, if empty then internalformat = format
+	GLint gl_internalformat;
 	GLint gl_format, gl_type;
 	bool has_alpha;
 };
@@ -45,6 +47,7 @@ struct wlr_gles2_renderer {
 		bool OES_egl_image;
 		bool EXT_texture_type_2_10_10_10_REV;
 		bool OES_texture_half_float_linear;
+		bool EXT_texture_norm16;
 	} exts;
 
 	struct {

render/gles2/pixel_format.c

@@ -93,6 +93,20 @@ static const struct wlr_gles2_pixel_format formats[] = {
 		.gl_type = GL_HALF_FLOAT_OES,
 		.has_alpha = true,
 	},
+	{
+		.drm_format = DRM_FORMAT_XBGR16161616,
+		.gl_internalformat = GL_RGBA16_EXT,
+		.gl_format = GL_RGBA,
+		.gl_type = GL_UNSIGNED_SHORT,
+		.has_alpha = false,
+	},
+	{
+		.drm_format = DRM_FORMAT_ABGR16161616,
+		.gl_internalformat = GL_RGBA16_EXT,
+		.gl_format = GL_RGBA,
+		.gl_type = GL_UNSIGNED_SHORT,
+		.has_alpha = true,
+	},
 #endif
 };
 
@@ -112,6 +126,10 @@ bool is_gles2_pixel_format_supported(const struct wlr_gles2_renderer *renderer,
 			&& !renderer->exts.OES_texture_half_float_linear) {
 		return false;
 	}
+	if (format->gl_type == GL_UNSIGNED_SHORT
+			&& !renderer->exts.EXT_texture_norm16) {
+		return false;
+	}
 	/*
 	 * Note that we don't need to check for GL_EXT_texture_format_BGRA8888
 	 * here, since we've already checked if we have it at renderer creation

render/gles2/renderer.c

@@ -765,6 +765,9 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 	renderer->exts.OES_texture_half_float_linear =
 		check_gl_ext(exts_str, "GL_OES_texture_half_float_linear");
 
+	renderer->exts.EXT_texture_norm16 =
+		check_gl_ext(exts_str, "GL_EXT_texture_norm16");
+
 	if (check_gl_ext(exts_str, "GL_KHR_debug")) {
 		renderer->exts.KHR_debug = true;
 		load_gl_proc(&renderer->procs.glDebugMessageCallbackKHR,

render/gles2/texture.c

@@ -210,6 +210,11 @@ static struct wlr_texture *gles2_texture_from_pixels(
 	texture->has_alpha = fmt->has_alpha;
 	texture->drm_format = fmt->drm_format;
 
+	GLint internal_format = fmt->gl_internalformat;
+	if (!internal_format) {
+		internal_format = fmt->gl_format;
+	}
+
 	struct wlr_egl_context prev_ctx;
 	wlr_egl_save_context(&prev_ctx);
 	wlr_egl_make_current(renderer->egl);
@@ -222,7 +227,7 @@ static struct wlr_texture *gles2_texture_from_pixels(
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 	glPixelStorei(GL_UNPACK_ROW_LENGTH_EXT, stride / (drm_fmt->bpp / 8));
-	glTexImage2D(GL_TEXTURE_2D, 0, fmt->gl_format, width, height, 0,
+	glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0,
 		fmt->gl_format, fmt->gl_type, data);
 	glPixelStorei(GL_UNPACK_ROW_LENGTH_EXT, 0);
 

render/pixel_format.c

@@ -128,6 +128,18 @@ static const struct wlr_pixel_format_info pixel_format_info[] = {
 		.bpp = 64,
 		.has_alpha = true,
 	},
+	{
+		.drm_format = DRM_FORMAT_XBGR16161616,
+		.opaque_substitute = DRM_FORMAT_INVALID,
+		.bpp = 64,
+		.has_alpha = false,
+	},
+	{
+		.drm_format = DRM_FORMAT_ABGR16161616,
+		.opaque_substitute = DRM_FORMAT_XBGR16161616,
+		.bpp = 64,
+		.has_alpha = true,
+	},
 };
 
 static const size_t pixel_format_info_size =