[debug patch] compositor debug: showrepaint hack

[Pekka Paalanen]

When ever an output is repainted, a random tint color is generated. All
the repainted regions are tinted with this color.
---
 src/compositor.c |   16 ++++++++++++++++
 src/compositor.h |    2 ++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/src/compositor.c b/src/compositor.c
index ab90ded..2082c8f 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -737,6 +737,16 @@ texture_region(struct weston_surface *es, pixman_region32_t *region)
 	return n;
 }
 
+static void
+randomise_tint(GLfloat *c)
+{
+	GLfloat a = 0.5f;
+	c[0] = ((random() % 1000) / 2000.0f + 0.4f) * a;
+	c[1] = ((random() % 1000) / 2000.0f + 0.4f) * a;
+	c[2] = ((random() % 1000) / 2000.0f + 0.4f) * a;
+	c[3] = a;
+}
+
 WL_EXPORT void
 weston_surface_draw(struct weston_surface *es, struct weston_output *output)
 {
@@ -782,6 +792,7 @@ weston_surface_draw(struct weston_surface *es, struct weston_output *output)
 	glUniform1f(es->shader->alpha_uniform, es->alpha / 255.0);
 	glUniform1f(es->shader->texwidth_uniform,
 		    (GLfloat)es->geometry.width / es->pitch);
+	glUniform4fv(es->shader->tint_uniform, 1, ec->tint_color);
 
 	if (es->transform.enabled)
 		filter = GL_LINEAR;
@@ -972,6 +983,8 @@ weston_output_repaint(struct weston_output *output, int msecs)
 		output->border.top + output->border.bottom;
 	glViewport(0, 0, width, height);
 
+	randomise_tint(ec->tint_color);
+
 	pixman_region32_init(&new_damage);
 	pixman_region32_init(&opaque);
 	pixman_region32_init(&overlap);
@@ -1830,6 +1843,7 @@ static const char texture_fragment_shader[] =
 	"uniform sampler2D tex;\n"
 	"uniform float alpha;\n"
 	"uniform float texwidth;\n"
+	"uniform vec4 tint;\n"
 	"void main()\n"
 	"{\n"
 	"   if (v_texcoord.x < 0.0 || v_texcoord.x > texwidth ||\n"
@@ -1837,6 +1851,7 @@ static const char texture_fragment_shader[] =
 	"      discard;\n"
 	"   gl_FragColor = texture2D(tex, v_texcoord)\n;"
 	"   gl_FragColor = alpha * gl_FragColor;\n"
+	"   gl_FragColor.rgb = gl_FragColor.rgb * (1.0 - tint.a) + tint.rgb;\n"
 	"}\n";
 
 static const char solid_fragment_shader[] =
@@ -1899,6 +1914,7 @@ weston_shader_init(struct weston_shader *shader,
 	shader->color_uniform = glGetUniformLocation(shader->program, "color");
 	shader->texwidth_uniform = glGetUniformLocation(shader->program,
 							"texwidth");
+	shader->tint_uniform = glGetUniformLocation(shader->program, "tint");
 
 	return 0;
 }
diff --git a/src/compositor.h b/src/compositor.h
index 966d3f4..975eb53 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -109,6 +109,7 @@ struct weston_shader {
 	GLint alpha_uniform;
 	GLint color_uniform;
 	GLint texwidth_uniform;
+	GLint tint_uniform;
 };
 
 struct weston_animation {
@@ -183,6 +184,7 @@ struct weston_compositor {
 	/* Repaint state. */
 	struct timespec previous_swap;
 	struct wl_array vertices, indices;
+	GLfloat tint_color[4];
 
 	struct weston_surface *overlay;
 	struct weston_switcher *switcher;
-- 
1.7.3.4