[PATCH v2 3/3] compositor: Adds the ability to invert colors with Alt + I.

[John Kåre Alsaker]

---
 src/compositor.h     |  3 +++
 src/gles2-renderer.c | 18 ++++++++++++++++--
 src/shell.c          | 11 +++++++++++
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/compositor.h b/src/compositor.h
index 284c0ac..8305058 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -296,6 +296,7 @@ struct weston_compositor {
 	struct weston_shader texture_shader_y_uv;
 	struct weston_shader texture_shader_y_u_v;
 	struct weston_shader texture_shader_y_xuxv;
+	struct weston_shader invert_color_shader;
 	struct weston_shader solid_shader;
 	struct weston_shader *current_shader;
 	struct wl_display *wl_display;
@@ -340,6 +341,8 @@ struct weston_compositor {
 	struct weston_plane primary_plane;
 	int fan_debug;
 
+	int invert_color;
+
 	uint32_t focus;
 
 	struct weston_renderer *renderer;
diff --git a/src/gles2-renderer.c b/src/gles2-renderer.c
index 6505344..167ada3 100644
--- a/src/gles2-renderer.c
+++ b/src/gles2-renderer.c
@@ -571,7 +571,7 @@ weston_compositor_use_shader(struct weston_compositor *compositor,
 static void
 repaint_surfaces_start(struct weston_output *output, pixman_region32_t *damage)
 {
-	output->indirect_drawing = 0 && !output->indirect_disable;
+	output->indirect_drawing = output->compositor->invert_color && !output->indirect_disable;
 
 	if(output->indirect_drawing) {
 		if(!output->indirect_fbo)
@@ -613,7 +613,7 @@ repaint_surfaces_finish(struct weston_output *output, pixman_region32_t *damage)
 	if(output->indirect_drawing) {
 		glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
-		struct weston_shader *shader = &ec->texture_shader_rgba;
+		struct weston_shader *shader = &ec->invert_color_shader;
 
 		weston_compositor_use_shader(ec, shader);
 
@@ -1073,6 +1073,17 @@ static const char texture_fragment_shader_y_xuxv[] =
 	FRAGMENT_CONVERT_YUV
 	"}\n";
 
+static const char invert_color_fragment_shader[] =
+	"precision mediump float;\n"
+	"varying vec2 v_texcoord;\n"
+	"uniform sampler2D tex;\n"
+	"uniform float alpha;\n"
+	"void main()\n"
+	"{\n"
+	"   gl_FragColor = texture2D(tex, v_texcoord);\n;"
+	"   gl_FragColor.rgb = vec3(1.0) - gl_FragColor.rgb;\n;"
+	"}\n";
+
 static const char solid_fragment_shader[] =
 	"precision mediump float;\n"
 	"uniform vec4 color;\n"
@@ -1316,6 +1327,9 @@ gles2_renderer_init(struct weston_compositor *ec)
 	if (weston_shader_init(&ec->texture_shader_y_xuxv,
 			       vertex_shader, texture_fragment_shader_y_xuxv) < 0)
 		return -1;
+	if (weston_shader_init(&ec->invert_color_shader,
+			       vertex_shader, invert_color_fragment_shader) < 0)
+		return -1;
 	if (weston_shader_init(&ec->solid_shader,
 			     vertex_shader, solid_fragment_shader) < 0)
 		return -1;
diff --git a/src/shell.c b/src/shell.c
index 06d8684..b40a738 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -3488,6 +3488,15 @@ debug_repaint_binding(struct wl_seat *seat, uint32_t time, uint32_t key,
 	}
 }
 
+static void
+invert_color_binding(struct wl_seat *seat, uint32_t time, uint32_t key,
+			  void *data)
+{
+	struct desktop_shell *shell = data;
+	struct weston_compositor *compositor = shell->compositor;
+	compositor->invert_color = !compositor->invert_color;
+	weston_compositor_damage_all(compositor);
+}
 
 static void
 fan_debug_repaint_binding(struct wl_seat *seat, uint32_t time, uint32_t key,
@@ -3664,6 +3673,8 @@ shell_add_bindings(struct weston_compositor *ec, struct desktop_shell *shell)
 				          backlight_binding, ec);
 	weston_compositor_add_key_binding(ec, KEY_SPACE, mod | MODIFIER_SHIFT,
 				          debug_repaint_binding, shell);
+	weston_compositor_add_key_binding(ec, KEY_I, mod | MODIFIER_ALT,
+					  invert_color_binding, shell);
 	weston_compositor_add_key_binding(ec, KEY_SPACE, mod | MODIFIER_ALT,
 				          fan_debug_repaint_binding, shell);
 	weston_compositor_add_key_binding(ec, KEY_K, mod,
-- 
1.7.12