From 2d0db169422b74e5ef7c07965c376273c7bb2961 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <agx@sigxcpu.org>
Date: Wed, 7 Mar 2018 15:41:12 +0100
Subject: [PATCH] render: Flip textures in case of inverted_y

---
 include/wlr/render.h    | 1 +
 render/gles2/renderer.c | 3 ++-
 render/gles2/shaders.c  | 7 ++++++-
 render/gles2/texture.c  | 1 +
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/wlr/render.h b/include/wlr/render.h
index 747603da..77449556 100644
--- a/include/wlr/render.h
+++ b/include/wlr/render.h
@@ -85,6 +85,7 @@ struct wlr_texture {
 	bool valid;
 	uint32_t format;
 	int width, height;
+	bool inverted_y;
 	struct wl_signal destroy_signal;
 	struct wl_resource *resource;
 };
diff --git a/render/gles2/renderer.c b/render/gles2/renderer.c
index ad739cf8..ba03f599 100644
--- a/render/gles2/renderer.c
+++ b/render/gles2/renderer.c
@@ -179,7 +179,8 @@ static bool wlr_gles2_render_texture(struct wlr_renderer *wlr_renderer,
 
 	wlr_texture_bind(texture);
 	GL_CALL(glUniformMatrix4fv(0, 1, GL_FALSE, *matrix));
-	GL_CALL(glUniform1f(2, alpha));
+	GL_CALL(glUniform1i(1, texture->inverted_y));
+	GL_CALL(glUniform1f(3, alpha));
 	draw_quad();
 	return true;
 }
diff --git a/render/gles2/shaders.c b/render/gles2/shaders.c
index 46a10248..38c61f9c 100644
--- a/render/gles2/shaders.c
+++ b/render/gles2/shaders.c
@@ -50,6 +50,7 @@ const GLchar ellipse_fragment_src[] =
 // Textured quads
 const GLchar vertex_src[] =
 "uniform mat4 proj;"
+"uniform bool invert_y;"
 "attribute vec2 pos;"
 "attribute vec2 texcoord;"
 "varying vec2 v_texcoord;"
@@ -69,7 +70,11 @@ const GLchar vertex_src[] =
 "}"
 "void main() {"
 "	gl_Position = transpose(proj) * vec4(pos, 0.0, 1.0);"
-"	v_texcoord = texcoord;"
+"  if (invert_y) {"
+"    v_texcoord = vec2(texcoord.s, 1.0 - texcoord.t);"
+"  } else {"
+"    v_texcoord = texcoord;"
+"  }"
 "}";
 
 const GLchar fragment_src_rgba[] =
diff --git a/render/gles2/texture.c b/render/gles2/texture.c
index 241b94a8..d25d1809 100644
--- a/render/gles2/texture.c
+++ b/render/gles2/texture.c
@@ -164,6 +164,7 @@ static bool gles2_texture_upload_drm(struct wlr_texture *_tex,
 
 	EGLint inverted_y;
 	wlr_egl_query_buffer(tex->egl, buf, EGL_WAYLAND_Y_INVERTED_WL, &inverted_y);
+	tex->wlr_texture.inverted_y = !!inverted_y;
 
 	GLenum target;
 	const struct pixel_format *pf;