gl_common: implement image_op

Implement image processing in gl_compose using a frag shader.
gl_image_op is used to set flags corresponds to what processing is
needed for a texture.

Also implement proper reference counting for textures.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/backend/gl/gl_common.c

@@ -39,6 +39,8 @@
 	}                                                                                \
 	while (0)
 
+#define GLSL(version, ...) "#version " #version "\n" #__VA_ARGS__
+
 GLuint gl_create_shader(GLenum shader_type, const char *shader_str) {
 	log_trace("===\n%s\n===", shader_str);
 
@@ -366,22 +368,6 @@ bool gl_dim_reg(session_t *ps, int dx, int dy, int width, int height, float z,
 	return true;
 }
 
-static inline int gl_gen_texture(GLenum tex_tgt, int width, int height, GLuint *tex) {
-	glGenTextures(1, tex);
-	if (!*tex)
-		return -1;
-	glEnable(tex_tgt);
-	glBindTexture(tex_tgt, *tex);
-	glTexParameteri(tex_tgt, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-	glTexParameteri(tex_tgt, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-	glTexParameteri(tex_tgt, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-	glTexParameteri(tex_tgt, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-	glTexImage2D(tex_tgt, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
-	glBindTexture(tex_tgt, 0);
-
-	return 0;
-}
-
 #if 0
 /**
  * Blur contents in a particular region.
@@ -606,8 +592,8 @@ GLuint glGetUniformLocationChecked(GLuint p, const char *name) {
 /**
  * Load a GLSL main program from shader strings.
  */
-int gl_win_shader_from_string(session_t *ps, const char *vshader_str,
+static int gl_win_shader_from_string(const char *vshader_str, const char *fshader_str,
-                              const char *fshader_str, gl_win_shader_t *ret) {
+                                     gl_win_shader_t *ret) {
 	// Build program
 	ret->prog = gl_create_program_from_str(vshader_str, fshader_str);
 	if (!ret->prog) {
@@ -798,6 +784,22 @@ err:
 }
 #endif
 
+// clang-format off
+const char *win_shader_glsl = GLSL(110,
+	uniform float opacity;
+	uniform bool invert_color;
+	uniform sampler2D tex;
+
+	void main() {
+		vec4 c = texture2D(tex, gl_TexCoord[0].xy);
+		if (invert_color)
+			c = vec4(c.aaa - c.rgb, c.a);
+		c *= opacity;
+		gl_FragColor = c;
+	}
+);
+// clang-format on
+
 bool gl_init(struct gl_data *gd, session_t *ps) {
 	// Initialize GLX data structure
 	for (int i = 0; i < MAX_BLUR_PASS; ++i) {
@@ -846,6 +848,7 @@ bool gl_init(struct gl_data *gd, session_t *ps) {
 
 	// Initialize blur filters
 	// gl_create_blur_filters(ps, gd->blur_shader, &gd->cap);
+	gl_win_shader_from_string(NULL, win_shader_glsl, &gd->win_shader);
 
 	return true;
 }
@@ -881,6 +884,7 @@ GLuint gl_new_texture(GLenum target) {
 		return 0;
 	}
 
+	glEnable(target);
 	glBindTexture(target, texture);
 	glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 	glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
@@ -894,16 +898,18 @@ GLuint gl_new_texture(GLenum target) {
 /// stub for backend_operations::image_op
 bool gl_image_op(backend_t *base, enum image_operations op, void *image_data,
                  const region_t *reg_op, const region_t *reg_visible, void *arg) {
+	struct gl_texture *tex = image_data;
+	switch (op) {
+	case IMAGE_OP_INVERT_COLOR_ALL: tex->color_inverted = true; break;
+	case IMAGE_OP_DIM_ALL: log_warn("IMAGE_OP_DIM_ALL not implemented yet"); break;
+	case IMAGE_OP_APPLY_ALPHA_ALL: tex->opacity *= *(double *)arg; break;
+	case IMAGE_OP_APPLY_ALPHA:
+		log_warn("IMAGE_OP_APPLY_ALPHA not implemented yet");
+		break;
+	}
 	return true;
 }
 
-/// stub for backend_operations::copy
-void *gl_copy(backend_t *base, const void *image_data, const region_t *reg_visible) {
-	struct gl_texture *t = (void *)image_data;
-	t->refcount++;
-	return (void *)image_data;
-}
-
 bool gl_is_image_transparent(backend_t *base, void *image_data) {
 	gl_texture_t *img = image_data;
 	return img->has_alpha;

src/backend/gl/gl_common.h

@@ -43,7 +43,7 @@ typedef struct {
 /// @brief Wrapper of a binded GLX texture.
 typedef struct gl_texture {
 	double opacity;
-	int refcount;
+	int *refcount;
 	GLuint texture;
 	GLenum target;
 	unsigned width;
@@ -89,12 +89,7 @@ GLuint gl_create_program_from_str(const char *vert_shader_str, const char *frag_
 void gl_compose(backend_t *, void *ptex, int dst_x, int dst_y, const region_t *reg_tgt,
                 const region_t *reg_visible);
 
-bool gl_load_prog_main(session_t *ps, const char *vshader_str, const char *fshader_str,
-                       gl_win_shader_t *pprogram);
-
-unsigned char *gl_take_screenshot(session_t *ps, int *out_length);
 void gl_resize(struct gl_data *, int width, int height);
-//bool gl_create_blur_filters(session_t *ps, gl_blur_shader_t *passes, const gl_cap_t *cap);
 
 GLuint glGetUniformLocationChecked(GLuint p, const char *name);
 
@@ -106,8 +101,6 @@ GLuint gl_new_texture(GLenum target);
 bool gl_image_op(backend_t *base, enum image_operations op, void *image_data,
                  const region_t *reg_op, const region_t *reg_visible, void *arg);
 
-void *gl_copy(backend_t *base, const void *image_data, const region_t *reg_visible);
-
 bool gl_blur(backend_t *base, double opacity, const region_t *reg_blur,
              const region_t *reg_visible);
 

src/backend/gl/glx.c

@@ -161,8 +161,8 @@ struct glx_fbconfig_info *glx_find_fbconfig(Display *dpy, int screen, struct xvi
 void glx_release_image(backend_t *base, void *image_data) {
 	struct _glx_image_data *wd = image_data;
 	struct _glx_data *gd = (void *)base;
-	wd->texture.refcount--;
+	(*wd->texture.refcount)--;
-	if (wd->texture.refcount != 0) {
+	if (*wd->texture.refcount != 0) {
 		return;
 	}
 	// Release binding
@@ -300,8 +300,8 @@ end:
 	return &gd->gl.base;
 }
 
-static void *glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap,
+static void *
-                             struct xvisual_info fmt, bool owned) {
+glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap, struct xvisual_info fmt, bool owned) {
 	struct _glx_data *gd = (void *)base;
 	// Retrieve pixmap parameters, if they aren't provided
 	if (fmt.visual_depth > OPENGL_MAX_DEPTH) {
@@ -370,7 +370,8 @@ static void *glx_bind_pixmap(backend_t *base, xcb_pixmap_t pixmap,
 	wd->texture.depth = fmt.visual_depth;
 	wd->texture.color_inverted = false;
 	wd->texture.has_alpha = fmt.alpha_size != 0;
-	wd->texture.refcount = 1;
+	wd->texture.refcount = ccalloc(1, int);
+	*wd->texture.refcount = 1;
 	glBindTexture(wd->texture.target, wd->texture.texture);
 	glXBindTexImageEXT(gd->display, wd->glpixmap, GLX_FRONT_LEFT_EXT, NULL);
 	glBindTexture(wd->texture.target, 0);
@@ -404,6 +405,14 @@ static int glx_buffer_age(backend_t *base) {
 	return (int)val ?: -1;
 }
 
+static void *glx_copy(backend_t *base, const void *image_data, const region_t *reg_visible) {
+	const struct _glx_image_data *img = image_data;
+	auto new_img = ccalloc(1, struct _glx_image_data);
+	*new_img = *img;
+	(*new_img->texture.refcount)++;
+	return new_img;
+}
+
 struct backend_operations glx_ops = {
     .init = glx_init,
     .deinit = glx_deinit,
@@ -411,7 +420,7 @@ struct backend_operations glx_ops = {
     .release_image = glx_release_image,
     .compose = gl_compose,
     .image_op = gl_image_op,
-    .copy = gl_copy,
+    .copy = glx_copy,
     .blur = gl_blur,
     .is_image_transparent = gl_is_image_transparent,
     .present = glx_present,